de HAVILLAND - ROSA P

soon as possible but not later than December 1, 1953, to see that no washers, bushings, etc., D E H A V I L L A N D all threaded terminals at turnbuckles should be inspected at the following locations: Control Number cable Location of turn- circuit buckles Ailerons 1. Base of control column. 2 2. Outboard wing Inspection 4 panels. Elevators 3. Hatch on underside of rear 2 fuselage. Rudder 4. Bear fuselage interior. 2 Damaged or defective cables must be replaced. I f any evidence of defects is found, de Havil- land will supply replacement cables. The F A A concurs in this mandatory action by the Canadian Department of Transport. (de Havilland Technical News Sheet Series B, No. 76 dated June 23, 1954, available from de Havilland Aircraft of Canada, Limited, Postal Station "L," Toronto, Canada, covers this same subject.) 5 5 - 2 0 - 1 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required prior to original cer- tification or by next airworthiness certificate renewal unless already accomplished. Attention of operators of the Dove aircraft is drawn to the manufacturer's recommenda- tion for periodic inspection of the alclad engine mount pickup fittings, P/N 4W1137 and 4W1141. Several cases of fitting failures have been reported. Unless this failure is detected at an early stage, the bottom flange of the front false spar may be subjected to excessive loads and may crack as a result. Accordingly, the de Havilland Aircraft Co., in agreement with the British Registration Board, issued the fol- lowing mandatory modification and informa- tion in which the F A A concurs. 1. To prevent fractures and to give increased strength, Modification No. 524 has been de- vised to change the fittings from aluminum alloy to steel and at the same time to reduce the limits from 0.0009 inch to 0.0003 inch and from 0.0018 inch to 0.0009 inch. 2. Upon incorporation of Modification 524 (and the repair R4W169), the 30-hour periodic inspections specified in TNS C T (104) Num- bers 49 and 50 may be discontinued. (de Havilland Technical News Sheet C T (104) No. 65 dated August 4, 1955, covers this same subject.) 5 5 - 2 5 - 2 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as indicated. Cases have occurred recently where cracks have been found in the left-hand front fin attachment brackets, P/N 4FS.1749 (Pre. Dove Model 7, "Individual fin attachment and rudder control pulley bracket"), and P/N 4FS.6781 (Dove Mod. 7, "To introduce single casting for front fin attachments and control pulley brackets"). The cracks generally ema- nate from the top rivet hole in the left row and pass through the flange. The de Havilland Service strongly recom- mends inspection of thefin attachment brackets at an early date with which the F A A concurs and considers mandatory. Inspect both front fin attachment brackets for cracks, using a magnifying glass after removing the paint, as soon as practical, but not later than the next 25 hours operation unless already accomplished, and thereafter at each check I I (approximately 100-hour pe- riods). Access can be made by entering through bulkhead No. 5. Should any cracks be found, install new front fin attachment and pulley brackets, P/N 4FS.9165 L. H. and 4FS.9166 R. H. (Ref. Dove Modification 903) and secure to bulkhead No. 6 using 2BA bolts and nuts or equivalent in the top six holes. Rivets are used in the other positions. Repetitive inspection may be discontinued when the new front fin attachment and pulley brackets per Modification 903 are installed. (de Havilland Technical News Sheet C T (104) No. 112, Issue 2, dated September 1, 1954, covers this same subject.) 5 5 - 2 5 - 3 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as soon as practical but not later than February 15,1956, unless already accomplished. A case has recently occurred where the presence of corrosion at the main earth connec- tion, situated on the fuselage nose decking in the vicinity of nose frame 4, has reduced the efficiency of this earthing point sufficiently to D E H A V I L L A N D D-3 have been, installed in this fitting and if found they should be removed immediately. I n assembling the wing to fuselage, the front spar must be attached and then the rear wing bolt should be installed. I t is quite normal that the rear spar wing fitting should not touch either inboard side of the fuselage fitting, but in most cases the wing fitting is almost against the forward side. The gaps in the fittings front and rear should not be packed with washers or spacers. The F A A concurs in this mandatory action by the Canadian Department of Transport. (de Havilland Technical News Sheet, Series B , No. 67, dated August 81, 1953, available from de Havilland Aircraft of Canada, L t d . , Toronto, Ontario, Canada, covers this same subject.) 53-23-2 de Havilland Applies to Model D H C - 2 (Beaver) Aircraft, Serial Numbers 164 to 407 Inclusive. Compliance required not later than Decem- ber 15, 1953. When filling the fuel tanks, it is possible for spilled fuel to seep down between the fuel tank filler neck recess box and the aircraft's outer skin. This permits gasoline fumes to accumu- late in the tank bays beneath the floor and can create a fire hazard. The aircraft should be inspected to ascertain if a satisfactory seal exists between the filler neck recess box (C2~ FS-1005ND) and the outer skin ( C 2 - F S - 3829ND). I f seal is unsatisfactory, fill gap with either "Goodyear Plyabond" or "Minne- apolis Mining EC776" metal sealing com- pounds or equivalent. I n the interim, until resealing is accomplished, a "No Smoking" placard should be installed in the cabin. The F A A concurs in this mandatory action by the Canadian Department of Transport. (de Havilland Technical News Sheet No. 68, Series B , dated September 15, 1953, covers this same subject and provides resealing instruc- tions.) 54r-ll-l de Havilland Applies to A l l Model D H C - 2 (Beaver) Aircraft, Serial Numbers 1 to 618 Inclusive, with the Exception of the Agricultural Model. Compliance required as indicated. Special Inspection — Attachment Brackets Tailplane—Fuselage Joint P / N C 2 - F S - 5 4 3 A and C S - F S - 5 4 4 A . Inspect subject brackets for cracks and dis- torted rivets at the location indicated in F i g - ure 3 and replace the tailplane front attach- ment V 4 - i n c h diameter bolts P / N N A S 54AN12 at intervals not exceeding 1,000 flying hours. MODIFICATION TO F U S E L A G E TAILPLANE ATTACHMENT BRACKETS FIGURE 3 I f brackets are defective, replace with new parts. I f existing y8 -inch diameter rivets are distorted, replace with %2 -inch diameter rivets as outlined in Figure 3. I f the aircraft has exceeded 1,000 flying hours, this inspection should be performed at some convenient opportunity not exceeding 200 hours subsequent to the date of this directive. The F A A concurs in this mandatory action by the Canadian Department of Transport. (de Havilland Technical News Sheets, Series B , No. 73 dated March 26, 1954, and Series B , No. 75 dated A p r i l 21, 1954, available from de Havilland Aircraft of Canada, L t d . , Toronto, Ontario, Canada, covers this same subject.) 54-15-1 de Havilland Applies to A l l Model D H C - 2 (Beaver) Aircraft, Serial Numbers 1 to 680 Inclusive. Compliance required by August 30, 1954. Inspect all rudder, elevator and aileron con- trol cable terminals for damaged threads at the turnbuckle. Most reported defects have concerned the right-hand threads on turnbuckle terminals but D E H A V I L L A N D D-7 to be completed by September 30, 1957, with which the F A A concurs. (de Havilland Service Technical News Sheet C T (104) No. 134, Issue 3, dated February 1, 1957, also covers this.) 57-13-2 de Havilland Applies to A l l Model DHC-2 Series Beaver Aircraft. Compliance required as soon as possible but not later than 10 days after the date of this directive and each 50 hours of operation thereafter. The cabin heater assembly must be inspected as follows: 1. For aircraft cabin heating system using Intensifier Tubes; remove the tubes and per- form a close visual inspection on both the intensifier tubes and the exhaust pipe to deter- mine existence of any holes or burned spots that may permit seepage of exhaust gases into the heating system. 2. For aircraft cabin heating system using Heater Jackets; remove jacket and perform close visual inspection on both the heater jacket and the exhaust pipe to determine existence of any holes or burned spots that may permit seepage of exhaust gases into the heating system. 57-20-2 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as indicated. Cases have been reported of cracked pis- tons, P/N AHO.19742, installed in Dunlop pneumatic retraction jacks (cylinders) P/N AH.8463 and AC.11130, fitted to the main and nose landing gear assemblies. These cracks appear on the crown of the piston adjacent to the recessed center section and are due to fatigue. Accordingly, a service life of 10,000 landings on these pistons when installed on Dove aircraft has been specified by de Havil- land in conjunction with Dunlop and the ARB. Pistons having 10,000 or more landings must be replaced as an interim measure pending introduction of a modification being developed by Dunlop. The F A A concurs with this action and con- siders compliance therewith mandatory. (de Havilland Service TNS Series C T (104) No. 141 dated June 24, 1957, covers this subject.) 58- 20-2 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required by January 1,1959. I n an emergency such as a wheels up land- ing, the placing of the ground/flight switch in the "Ground" position to minimize fire risk would isolate the fire extinguisher system. Dove Modification 655 has therefore been introduced which provides an electrical supply to the fire extinguisher circuit from the battery side of the ground/flight switch, even when the switch is in the "Ground" position, thus ensur- ing that the fire extinguisher system is opera- tive at all times. The British Air Registration Board con- siders this mandatory. The F A A concurs with this action and considers compliance therewith mandatory. (de Havilland TNS C T (104) No. 153 covers the same subject.) 59-1-2 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as follows: Aircraft prior to Serial Number 04463—April 1, 1959; Aircraft Serial Numbers 04463 through 04477—September 30, 1959. Cases have occurred where the main under- carriage locking levers P/N 4U 139A (Pre Modification 231) and P/N 4U 461A (Post Modifiication 231) have cracked in service. Dove Modification 868 has therefore been introduced which provides for locking lever assemblies in a material to a revised speci- fication. On aircraft Pre Modification 231 standard, Dove Modification 187—repositioning the un- dercarriage warning lamp and microswitches— and Dove Modification 308—improving the operation of the main undercarriage mechani- cal position indicator—must be embodied at the same time as Modification 868. The British A i r Registration Board con- siders this mandatory. The F A A concurs with this action and considers compliance therewith mandatory. (de Havilland TNS C T (104) No. 155 covers the same subject.) 59-5-2 de Havilland Applies to A l l Model 104 "Dove" Aircraft With Modification PP.173 Embodied. D-8 D E H A V I L L A N D Compliance required as soon as possible but not later than March 30,1959. (1) A case has been reported where faulty readings were obtained from the dipstick used in an oil tank P/N 4LT.475A/1, in which Mod- ification PP.173 was embodied. This would result in low oil content which, on prolonged flights, might give rise to oil starvation with consequent engine seizure. (2) Within the period stated above, dip- sticks must be removed from oil tanks with Modification PP.173 embodied and reworked as follows: (a) Measure along the dipstick a distance of 4.15 inches from the base and file a notch or deep score mark at this point. (This position also falls 0.65-inch above exist- ing one-half mark.) (b) Obliterate the exist- ing one-quarter and one-half marks, (c) Add a stamped arrow pointing to the notch or score mark followed by this marking "6 US gallons minimum accurate reading". (3) The above rework must be accomplished on spare oil tanks prior to fitment to aircraft. The British A i r Registration Board con- siders this mandatory. The F A A concurs with this action and considers compliance therewith mandatory. (de Havilland TNS C T (104) No. 158 Issue 2 covers the same subject.) 59-12-8 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required not later than July 20, 1959. A case has been reported where a powerplant fire extinguisher spray pipe P/N 4M99ND had been installed without having the spray holes drilled in it. (1) Spray pipe P/N 4M99ND must be in- spected to ascertain whether it has the spray holes drilled in it as follows: (a) Open the engine cowlings and inspect the spray pipe running from the distributor unit round the blower casing. (b) I f the pipe has not had the spray holes drilled in it remove the pipe and replace with a serviceable item; or (c) The unserviceable pipe may be ren- dered serviceable by working to the details shown in de Havilland Technical News Sheet C T (104) No. 163. (2) The above inspection, and replacement or rework action where necessary, must be accomplished on all spare powerplants and spares stock before installation in aircraft. The British Air Registration Board con- siders this mandatory. (de Havilland TNS C T (104) No. 163 covers the same subject.) 60-12-2 de Havilland Amdt. 157 Part 507 Federal Register May 24, 1960, revised by Amdt. 157a Federal Register October 5, i960. Applies to Heron Model 114 Aircraft Serial Numbers 14001 Through 14136. Compliance required as indicated. During fatigue tests, cracks caused by cor- rosion and fretting occurred in the wing main lower root joint fitting at an equivalent time in service of 13,000 hours. To preclude the fail- ure of this fitting in service compliance with de Havilland Technical News Sheet C T (114) No. W9 is required by July 15, 1960, for air- craft which have exceeded 12,000 hours time in service. For all other aircraft, compliance required before exceeding 12,000 hours time in service but not later than: December 31, 1960, for Serial Numbers 14001 to i4091 inclusive, that do not have modifications 520 and/or 918 incorporated; December 31, 1961, for Serial Numbers 14001 to 14091, inclusive, that have modifications 520 and/or 918 incorporated, and for Serial Numbers 14092 to 14136, inclusive. Magnetic particle and dye penetrant meth- ods of inspection may be used in lieu of the crack testing methods called for in de Havil- land Technical News Sheet C T (114) No. W9. Other jointing, antifretting and anticorrosive, and sealing compounds, if shown to be equiva- lent to the commercially designated compounds in de Havilland Technical News Sheet C T (114) No. W9 may be used. For aircraft incorporating modifications 520 and/or 918 since date of manufacture, compli- ance time in service begins at the date these modifications were accomplished. 60-12-3 de Havilland Amdt. 168 Part 507 Federal Register June 3, 1960. Applies to A l l Model 104 "Dove" Aircraft Serial Num- bers 04001 Through 04507. Compliance required as indicated. During fatigue tests cracks caused by cor- rosion and fretting occurred in the wing main D-6 DE H A V I L L A N B the earliest opportunity but not later than September 1, 1956, and thereafter at the repeti- tive period indicated. 56-17-2 de Havilland Applies to A l l Model DHC-3 Otter Aircraft. Compliance required as indicated. The Canadian Department of Transport has issued the following directive with which the F A A concurs and considers mandatory. "Any malfunctioning of the flap hydraulic circuit check valve would fail to lock the flaps in any flaps-extended position. When the valve operates properly, the flaps remain, sta- tionary when the flap selector lever is moved to the 'up' position and until the flap pump is operated. However, if the valve sticks open for any reason, selecting 'flaps up' results in a rapid flap retraction without use of the pump. Such retraction at high speeds will produce large stick forces and out-of-trim condition which flight tests have shown to be very dan- gerous when the aeroplane is trimmed for a high flaps-extended speed (full aircraft nose- down trim). "Therefore, until modifications now under development are incorporated, the following restriction is mandatory: "(a) The flap selector must not be placed in the up position until it is desired to retract the flaps, nor at speeds in excess of the following: Flap Setting Landing (35°) Takeoff (30°) Climb (15°) Muwimum Trim, Speed 65 mph I A S 75 mph I A S 85 mph I A S "The previous '15° climb flap limitation' on the use of flaps is canceled and the special 50-hour inspection of the flap controls, etc., may be discontinued." Incorporation of de Havilland Modifications 3/731, 3/744 and 3/745 is required by Novem- ber 1, 1957, as outlined in D. H. Engineering Bulletin Series "O" No. 34, dated January 21, 1957. When these Modifications are incorpo- rated, the operating restrictions in section (a) above will no longer be required. 56-19-1 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as indicated below. A case has occurred in which the mild steel rivet locking the stud, P/N 4CF.607 to the spindle, P/N 4CF.603ND in the aileron differ- ential pulley assembly has sheared, allowing the spindle to unscrew from the stud to such an extent that it, together with the pulley, was on the point of becoming disengaged from the pulley bracket. To prevent a recurrence of this defect, com- pliance with Dove Modification No. 765 (instal- lation of a H.T.S. pin for locking stud on aileron differential pulley spindle) is consid- ered mandatory by the British A i r Registration Board in which the F A A concurs. Accord- ingly, unless already accomplished, Modifica- tion No. 765 should be embodied on all Dove aircraft as soon as possible, but not later than October 15, 1956. (Dove Modification 765 is covered in de Havilland Service Technical News Sheet C T (104) No. 114 dated November 1,1954.) This supersedes AD 55-2-1. 57-5-2 de Havilland Applies to A l l Model 104 "Dove" Aircraft Up to and Including Serial Number 04465 Which Have Not Had Dove Mod. 870 Incorporated. Compliance required as indicated. Tests and inspections of the wing have revealed the possibility of small spanwise cracks existing in the upper spar boom joints at ribs 10 and 11, and in the lower spar boom joint at ribs 8 and 9. The cracks occur in the vertical flange, between 0.1 and 0.2 inch from the horizontal flange. 1. Where suitable equipment is available, it is recommended that X-ray examinations of the spar joints be made by April 30, 1957, fol- lowing the recommendations in Technical News Sheet C T (104) No. 134, Issue 3. Unless the booms are X-rayed, they must be considered as having cracks. 2. When X-rayed and no cracks are found, no further action is necessary unless the air- craft is less than 2 years old, in which case a precautionary X-ray examination should be made approximately one year after the first X-ray and repaired if cracks are found. 3. When X-ray results are positive, incorpo- ration of the repair scheme called for in the Technical News Sheet is classified as manda- tory by the British Air Registration Board and D E H A V I L L A N D D-5 cause overheating of the cockpit lighting cables. The de Havilland Service strongly recom- mends that the following inspection be carried out at the earliest opportunity in order to ascertain the condition of this connection with which the FAA. concurs and considers man- datory. Method. 1. Examine earth post situated in nose floor, and ascertain if it has a protective coating of blue oil base paint D. T. D. 827. ( I f it is pro- tected, do not disturb unless it appears to be in a bad condition.) 2. I f no protection is evident, dismantle ter- minal, clean floor surface locally at the termi- nal with a stiff bristle brush, to ensure removal of any corrosion and to provide good electrical contact between mating faces of terminal assembly. Reassemble terminal, using corro- sion washer D. H. S. 439 G in place of lead plated brass washer 4F.781, A l l other mating surfaces must be clean and free from corrosion. I f steel washer shows signs of deterioration, it must be replaced by another one, cadmium plated. Completed assembly must be painted liberally with blue oil base paint D. T. D. 827 to prevent ingress of moisture. (de Havilland Technical News Sheet C T (104), No. 121, Issue 2, dated July 14, 1955, also covers this same subject.) 56-11-1 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required by May 31,1956. As a result of the two accidents caused by pilots feathering the wrong propeller after engine failure, the British A i r Registration Board has classified the following as an essesn- tial modification. The F A A concurs. The left-hand needle (oil pressure) of the combined oil pressure and temperature gage for the starboard engine could be mistakenly interpreted as applying to the port engine. To minimize the possibility of such confusion either part A or part B of Dove Modification 879 must be incorporated as soon as possible but not later than May 31,1956: Part A, To turn the instruments clockwise through 90° and put temporary markings on the instrument bezel. Part B. To turn the instruments clockwise through 90° and re-mark the dials to give cor- rect presentation or tofit modified instruments with vertical lettering and figures. (Dove Modification 879 is covered in de Havilland Service Technical News Sheet Series C T (104) No. 132 dated April 13, 1956.) 56-15-4 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as indicated. Cases have been reported of cracks appear- ing in the brackets P/N 4FS.401 and 4FS.402 which form part of the main attachment struc- ture of the nose undercarriage leg. The de Havilland Service strongly recommended that these brackets be inspected for cracks. The F A A concurs and considers compliance with de Havilland Service Technical News Sheet C T (104) No. 124, Issue 2, dated Decem- ber 20, 1955, mandatory. Unless already ac- complished, the recommendations in the TNS should be carried out at the earliest oppor- tunity but not later than August 15,1956. 56-15-5 de Havilland Applies to A l l Model 104 "Dove" Aircraft. Compliance required as indicated. Cases have been reported of the discovery in service of cracks appearing in aileron, rudder and elevator hinge links and hinge brackets fitted to Dove aircraft. The de Havilland Service strongly recom- mends that all these components and their associated fittings be carefully inspected for cracks on all aircraft at the earliest oppor- tunity, and thereafter at every 600 hours or 12 months, whichever is sooner, until further notice. The paint should be removed from the components and after inspection they should be reprotected. The de Havilland Service also strongly recommends that concur- rent with the above inspection, the tailplane upper attachment fitting, P/N 4.FS.1935, which is attached to the forward face of bulk- head 7 and through which the tailplane attach- ment eyebolt spars, be inspected for cracks, particularly in the region of the rivets. The F A A concurs and considers compliance with de Havilland Service Technical News Sheet C T (104) No. 123, Issue 3, dated Novem- ber 12, 1956, mandatory. The initial inspec- tion, unless already accomplished, should be at D E H A V I L L A N D D-9 lower root joint fitting at an equivalent time in service of 13,000 hours. To preclude the failure of this fitting in service, compliance with de Havilland Technical News Sheet C T (104) No. 168 Issue No. 2, is required by July 15, 1960, for aircraft which have ex- ceeded 12,000 hours' time in service. For all other aircraft compliance required before the aircraft exceeds 12,000 hours' time in service but not later than: December 31, 1960, for Serial Numbers 04001 through 04463; Decem- ber 31, 1961, for Serial Numbers 04464 through 04507. Magnetic particle and dye penetrant meth- ods of inspection may be used in lieu of the crack testing methods called for in de Havil- land Technical News Sheet C T (104) No. 168 Issue No. 2. Other jointing, antifretting and anticorrosive, and sealing compounds, if shown to be equivalent to the commercially designated compounds in de Havilland Technical News Sheet C T (104) No. 168 Issue No. 2, may be used. 61-11-3 de Havilland Amdt. 289 Part 507 Federal Register May 20, 1961. Applies to A l l Model 104 "Dove" Aircraft. As a result of fatigue tests by the de Havil- land Company, the following modification or replacements must be occomplished: (1) The wing lower spar boom must incorpo- rate Modification 780 or be replaced at or prior to accumulating 5,000 hours' time in service. (2) Wings with Modification 780 must be replaced at 15,000 hours' time in service on aircraft Series 1, 1A, IB, I B A, 2A, 2B, 2BA, 5, 5A, 5B, 5BA, 6, 6A, 6B, 6BA, and at 12,000 hours' time in service on aircraft Series 7, 7A, 8, 8A. (3) The fuselage center section lower spar boom must be replaced at or prior to accumu- lating 2,500 hours' time in service unless Modi- fication 538 is accomplished. (4) Fuselage center section lower spar boom incorporating Modification 538 and Modifica- tion 686 not later than 3,600 hours' time in service after incorporating Modification 538, must be replaced at or prior to accumulating 10,000 hours' time in service. (5) I f the fuselage center section lower spar boom incorporates Modification 779 in lieu of Modification 538, no time limit is imposed. (de Havilland TNS Series C T (104) No. 119, Issue 7 dated December 19, 1960, covers this subject.) This supersedes AD 56-21-3. This directive effective June 20, 1961. 61-11-4 de Havilland Amdt. 290 Part 507 Federal Register May 20, 1961. Applies to A l l "Dove" Model 104 Aircraft Prior to Serial No. 04503. Compliance required as indicated. Due to reports of severe corrosion at the mainplane lower spar booms, the following inspections are required except that any in- spection accomplished in accordance with AD 57-1-1 may be utilized in establishing the less frequent inspection intervals permitted in this directive. (Effective October 13, 1961.) (a) Inspections shall be performed on the upper and lower spar booms from rib No. 1 to the wing tip as follows: (Effective October 13, 1961.) (1) Tank Bay Area, Ribs 1 to 5. Inspec- tion required every six months, the first of such inspections to be made six months after the effective date of this directive or six months after the last inspection with a 10-power glass, whichever date is earlier. I f no signs of cor- rosion are found after two successive inspec- tions, inspect every twelve months thereafter. (2) Wheel Well Area Bibs 5 to 7. In- spection required every month, the first such inspection to be made one month after the effec- tive date of this directive or one month after the last inspection with a 10-power glass, whichever date is earlier. I f no signs of cor- rosion are found after six successive monthly inspections, inspect every six months there- after. This inspection may be discontinued if surface protection is provided in accordance with de Havilland Dove Modification No. 852 and no indication of corrosion is evident after six months. (3) Bib 7 to Wing Tips. Visual inspec- tion required every six months, the first such inspection to be made six months after the effective date of the directive or six months after the last inspection, whichever date is earlier. (Effective October 13, 1961.) I f no corrosion is found after a six-month period, inspect every twelve months thereafter. (b) Any corrosion that is found must be thoroughly cleaned out prior to further flight. D-10 D E H A V I L L A N D I f the depth and width of the pocket are within the limits specified on de Havilland Drawing No. R.4W.349, the surfaces must be reprotected. I f after cleaning out the corrosion pockets the limits of Drawing No. R.4W.349 are exceeded, the spar boom must be replaced prior to fur- ther flight. (de Havilland Technical News Sheet C T (104) No. 125 Issue 5, dated December 19,1960, covers this subject.) This supersedes A D 57-1-1. This directive effective May 20, 1961. 61-18-3 de Havilland Amdt. 329 Part 507 Federal Register September 1,1961. Applies to All "Dove" Model 104 Aircraft Serial Numbers 04000 through 04482. Compliance required as indicated. As a result of recent investigations into wing lower root joint, P / N 4W.271, it has been es- tablished that a number of these parts were fitted to aircraft or supplied as spare items with the bore of the hole for the main wing- to-fuselage attachment bolt chromium plated. Tests have shown that hard chrome plating re- duces the fatigue life of the part. Therefore, the following inspection shall be accomplished: (a) Wing lower root joint fittings, P / N 4W.271, with 9,970 or less hours 'time in serv- ice must be inspected at or prior to accumulat- ing 10,000 hours' time in service. Remove the lower main wing-to-fuselage attachment bolt and inspect the bore of the bolt hole for chro- mium plating in accordance with de Havilland Technical News Sheet C T (104) No. 178 Issue 1. Fittings showing evidence of chrome plating must be replaced prior to accumulating 10,000 hours' time in service. (b) Fittings exceeding 9,970 hours' time in service must be inspected as outlined in para- graph (a) within the next 30 hours' time in service after the effective date of this directive. Fittings showing evidence of chromium plating and having less than 10,000 hours' time in serv- ice must be replaced prior to accumulating 10,000 hours' time in service. Fittings show- ing evidence of chromium plating and having more than 10,000 hours' time in service must be replaced prior to further flight. (de Havilland Technical News Sheet C T (104) No. 178 Issue 1 dated July 10,1961, covers this subject.) This directive effective September 1,1961. 61-23-3 de Havilland Amdt. 358 Part 507 Federal Register November 2, 1961. Applies to All Heron Model 114 Aircraft Without Modification No. 1454. Compliance required as indicated. (a) Cases have occurred of cracking of the wing rear false spar web adjacent to the wing- to-fuselage attachment P / N 14W 253/4. To preclude failure of the spar, an X-ray or visual inspection for cracks must be conducted in ac- cordance with de Havilland Technical News Sheet CT(114) No. W.10 Issue 2, within the next 250 hours' time in service after the effec- tive date of this directive and at each 600 hours' time in service thereafter. I f cracks are found, repair in accordance with de Havil- land Drawing R D 14W 224, Issue 4, or subse- quent, within the time in service given in para- graphs (1), (2), and (3). (1) Cracks less than y2 inch in length must be repaired at the next wing removal and the inspection in (a) must be made every 600 hours' time in service in the interim between the inspection and the wing removal. (2) Cracks of y2 inch to iy2 inches in length must be repaired within 300 hours' time in service after the inspection. (3) Cracks exceeding IV2 inches in length must be repaired within the next 150 hours' time in service after the inspection. (b) The special inspection in (a) is no longer required when the repair per Drawing R D 14W 224, Issue 4, or subsequent, has been incorporated. (de Havilland Technical News Sheet C T (114) No. W.10 Issue 2 dated July 24, 1961, covers this subject.) This directive effective December 4, 1961. 62- 14-1 de Havilland Amdt. 453 Part 507 Federal Register June 20, 1962. Applies to All Model D.H. 114 Heron Aircraft. Compliance required as indicated. As a result of instances where cracks have occurred in the aileron lever P / N 14WA199, the following inspection shall be accomplished within the next 50 hours' time in service after the effective date of this AD and thereafter at intervals not exceeding 50 hours' time in serv- ice and, in addition, prior to further flight if the aileron is removed for any reason. D E H A V H - L A N D D - l l (a) Visually inspect the aileron lever, P/N 14WA199 for cracks at the lugs for attach- ment of the connecting rod, in the region of the attaching pins for the mass balance weight tube and at the lower end of the lever counter bore. I f evidence of cracks is found, verify using dye penetrant or other F A A approved equivalent inspection method. (b) Replace cracked aileron levers prior to further flight. (c) When de Havilland Heron Modification 662, which incorporates a new forged lever P/N 14WA245, is installed, the inspections in (a) are no longer required. (de Havilland Technical News Sheet Heron (114) No. W3, Issue 2 dated January 1, 1962, covers this subject.) This directive effective July 20, 1962. 62-14-2 de Havilland Amdt. 454 Part 507 Federal Register June 20, 1962. Applies to A l l Model D.H. 104 Dove Aircraft. Compliance required as indicated. As a result of instances where cracks have occurred in the aileron lever, P/N 4WA315, the following inspection shall be accomplished within the next 50 hours' time in service after the effective date of this AD and thereafter at intervals not exceeding 50 hours' time in service and, in addition, prior to further flight if the aileron is removed for any reason. (a) Visually inspect the aileron lever, P/N 4WA315 for cracks at the lugs for the attach- ment of the connecting rod and in the counter- bored portion which receives the mass balance arm. I f evidence of cracks, is found, verify using dye penetrant or other F A A approved equivalent method. (b) Replace cracked aileron levers prior to further flight. (c) When de Havilland Dove Modification 967, which incorporates a forged lever, P/N 4WA491, is installed, the inspections in (a) are no longer required. (de Havilland Technical News Sheet C T (104) No. 151, Issue 3 dated January 1, 1962, covers this subject.) This directive effective July 20, 1962. D-14 D O U G L A S 2. Complete inspection as required by A above is conducted at intervals not to exceed 2,000 hours after the 16,000-hour inspection has been completed. 3. Canceled August 15,1955. D. Upon request of the operator, an F A A maintenance inspector, subject to approval of the Chief, Engineering and Manufacturing Branch, F A A Western Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established in- spection period of the operator if the request contains substantiating data to justify the in- crease for such operator. (Effective August 4, 1961.) 41-47-1 Douglas (Was Service Note 3 of AD-618-3 and Service Note 3 of AD-669-3.) Applies to A l l DC3 Series Aircraft. Each time a control surface is overhauled or repaired, the surface should be rebalanced. (Douglas Service Bulletin No. 207 contains instructions on rebalancing.) 43-12-1 Douglas (Was Service Note 4 of AD-669-3.) At each periodic inspection, check the elevator hinge brackets and if cracks are pres- ent the brackets should be replaced. Due to the possibility of vibration causing fatigue failures, continuous operation of the airplanes in the range of engine speeds between 1,300 and 1,600 r.p.m. should be avoided. A mini- mum engine speed of 1,700 r.p.m. during cruis- ing flight is recommended. (Douglas Service Letter dated January 15, 1943, covers this same subject.) 46-11-2 Douglas (Was Mandatory Note 1 of AD-762-7.) Applies to A l l C-54 Series Aircraft. To be accomplished not later than July 1, 1948. The copilot oxygen regulator must be relo- cated from its position below the autopilot con- trol handle to Station 101 aft of the windshield defroster control plate and knob, in order to eliminate a fire hazard and contamination of the oxygen regulator in the event hydraulic fluid drips on the regulator from the autopilot control valve. (Douglas Service Bulletin No. C-54-247 dated November 16, 1945, covers this same subject.) 46-11-3 Douglas (Was Mandatory Note 2 of AD-762-7.) Applies Only to A l l C54- D C (R5D) Airplanes Built at Santa Monica and to A l l C54A (R5D-1), C54B (R5D-2) and C54D-DC (R5D-3) Airplanes Built at Chicago Up to and Including C54D-DC A A F Serial Number 42-72698, and R5D-3 Navy Serial No. 56519. A l l Subsequent Air- planes Have Been Reworked Prior to Deliv- ery by the Dotiglas Co. To be accomplished not later than next engine change. Due to the possibility of the landing gear door stud shearing and preventing the landing gear from extending, the old thin stud, Douglas Drawing No. 1167048 should be replaced with the new thrick: stud, Douglas Drawing No. 1329227. In order to accomplish this change the thin stud should be removed from each land- ing gear door sleeve assembly, P/N 4167071. The existing stud hole should be drilled to ;!fff diameter and tapped 1^-20 NF-3 to a depth of y2 inch. The new thick stud, Douglas P/N 1329227 should be installed and locked in place with an 0.063-inch drill rod pin %-inch long pressed through the side of the sleeve assembly end, Drawing No. 2167063. (Douglas Service Bulletin No. C-54-275 dated January 21, 1946, covers this same subject.) 46-12-2 Douglas (Was Service Note 12 of AD-669-3.) Applies to DC3A Aircraft. Inspection required immediately and every 100 hours thereafter on all aircraft which have beryllium copper engine mount to firewall attach fittings installed. Inspect the engine mount to firewall at- tach fittings, P/N 5-81486-4 (with 4-power magnifying glass min.) in the fillet of the spot face for cracks or flaws in the material. I f evidence of defects are found, replace with P/N 1042764. I f cracks are not found, inspect every 100 hours until next engine change. P/N 5-81486-4 should be replaced with P/N 1042764 at engine change. (Douglas Service Bulletin No. 238 covers this same subject.) D-13 DOUGLAS 39-24-1 Douglas (Was Service Note 1 of AD-618-3 and Service Note 1 of AD-669-3). Applies to A l l DC3 Series Aircraft. A. I N S P E C T I O N 1. Attach Angles. Inspect wing attaching angles, P/N 570602-20 and -21, for cracks be- tween the attaching bolt holes. The inspection should be conducted with at least a 4-power magnifying glass at each periodic inspection not to exceed 450 hours flight time. A more detailed inspection should be made at the time of removal of the wings for the wing doubler inspection specified below. A l l paint should be removed from the angles at that time to permit examination with a high-power magni- fying glass. 2. Wing Doublers. Inspect the wing attach angle doublers for cracks along the bent-up flange portion at the wing attachment joint at the following intervals of wing doubler time: (a) On aircraft having less than 8,000 hours doubler flight time; inspect at 8,000 hours, or less, and at intervals not to exceed 4,000 hours thereafter. (b) On aircraft having more than 8,000 hours doubler flight time; where doublers have not been inspected during the last 4,000 hours, such doublers should be inspected immediately and intervals should not exceed 4,000 hours thereafter. Where doublers have been in- spected during the last 4,000 hours, inspection should be made at the next 4,000-hour period and at intervals not to exceed 4,000 hours thereafter. The wings should be completely removed to permit thorough cleaning of the doublers and inspection with a high-power glass. Dy-Chek may be used in lieu of a high-power glass in conducting the inspection. 3. Center Section Line in Outer Wing Joint. Inspection and rework should be made in accordance with the procedures outlined in AD 52-22-3. B . R E P L A C E M E N T R E Q U I R E D (Jig fixtures, Douglas Parts A652-5110506- 1-1F2 and A652-5110506-1F2 or equivalent, must be used to accomplish the replacement of the following attach angles and doublers.) 1. Defective Angles. I n case defective an- gles are found, they must be replaced by angles extruded 99° or the heavier type angles as out- lined in Douglas Service Bulletin No. 146, before allowing further operation. I n case defective angles are found and they are identi- fied as being angles extruded 99°, they must be replaced by the heavier type angles as out- lined in Douglas Service Bulletin No. 146 before allowing further operation. 2. Doublers. I n case cracked doublers are found at any of the specified inspections, they must be replaced. A l l lower surface outer panel wing attach angle doublers (P/N 570602- 206, -207, -208, and -209) must be replaced at or before 16,000 hours total doubler time. After October 15, 1944, no aircraft will be permitted to continue in operation having 16,000 hours total doubler time except as cov- ered under section C below. (Douglas Service Bulletin No, 220 dated March 11, 1944, contains information on ac- ceptable methods of accomplishing this rework.) After replacement of the doubler as de- scribed in the paragraph above, it will be satis- factory to add the auxiliary gussets and shims, as shown on Douglas Drawing 570602, change L L L . 3. Refer to AD 5^2-3. C. O U T E R W I N G H E A V Y D O U B L E R I N S T A L L A T I O N When the No. 570602-206 and -207 doublers have been replaced with 0.072 material instead of 0.064 material and the 570602-208 and -209 have been replaced with 0.064 material instead of 0.051 material as recommended in Douglas Service Bulletin DC3 No. 220, inspection is re- quired as outlined in paragraph A-2, but they need not be replaced at 16,000 hours provided the following are accomplished: 1. Complete inspection as required by A2 above is conducted at 16,000 hours and no cracks are found. D O U G L A S D - 1 5 4 6 - 1 3 - 4 Douglas ("Was Service Note 10 of AD-618-3 and Service Note 11 of AD- 669-3.) Applies to A l l DC3 Models Except Conversions From the C - 4 7 Series. 1. Inspect visually for cracks all landing gear rear brace strut fittings, P/N 230659, that have not been removed and magnetically in- spected at last airplane overhaul. This inspec- tion should be accomplished prior to next flight. 2. I f crack is less than }&-mch long it may be ground or filed out, being careful to remove all marks and scratches, without removing the fitting, until the next overhaul. I f cracks are found to be longer than y8 inch, the fitting must be removed and repaired in accordance with paragraph 3 below. 3. Cracks in weld area can be repaired by grinding away all existing weld and rewelding. I f cracks extend through spacer plate, the spacer plate may be cut back beyond the end of crack, all old weld removed, and a new section of spacer plate lap welded to the remaining portion of the spacer plate and then seam welded to the side plates. Cracks extending through the side plates for a maximum of Vi inch may be repaired by grinding a "V" on the outside surface of the plate to a minimum of Yie inch beyond the end of the crack and weld- ing. The weld must be ground smooth. 4. I f fitting is removed, rivets may be re- placed with spacers and %6 -inch AN bolts having a ream fit through the bulkhead and fitting in order to facilitate installation. 5. I n order to insure that parts in the air- plane continue to remain satisfactory for serv- ice, the following inspection procedure should be followed: (a) Visually inspect landing gear rear brace strut fitting at periods not to exceed 1,000 hours. (6) Remove and magnetically inspect rear brace strut fitting at each major overhaul. (The inspection and repair outlined above are covered by Douglas Service Bulletin No. 233, Section IV.) The inspections outlined above will not be necessary when the landing gear rear brace strut fitting, P/N 230659, is replaced by the new fitting, P/N 4341810. (Supplement to Douglas Service Bulletin No. 233, as revised October 24, 1946, covers this same subject.) 4 6 - 1 3 - 5 Douglas (Was Mandatory Note 10 of AD-618-3 and Mandatory Note 12 of AD-669-3.) Applies to A l l DC3 Aircraft. To be accomplished not later than April 1, 1947. Replace all canvas control boot assemblies either with the new rubber control column boot assemblies of the same part number (No. 5035184-16 and -17), as called for on Douglas Service-Bulletin No. 231, or with the follow- ing boot assemblies: (a) Thompson Co. (H. I. Thompson Co., 1733 Cordova St., Los Angeles 7, Calif.), No. 11-21001, change B, for Models DC3-C/C-47 and DC-3-D/C117A. (i) Thompson Co. No. 11-21002, change A, for Model DC3. (<;) American Airlines Drawing No. CDS-6132. Pending replacement, the canvas boots should be inspected prior to each flight to determine that the top of the boot is tight around the control assembly and the pocket around the base is eliminated. 4 6 - 2 4 - 2 Douglas (Was Mandatory Note 3 of AD-762-7.) Applies to C-54 Series Air- craft. To be accomplished not later than next periodic inspection. Revise the magneto wires forward of the fire- wall in accordance with Douglas Service Bul- letin No. C-54-283 dated March 19,1946. This is necessary to prevent burning of the magneto ground wire conduit which will cause the magneto to short out. 4 6 - 2 7 - 1 Douglas (Was Mandatory Note 5 of AD-762-7.) Applies to C-54 Series Air- craft. To be accomplished not later than Novem- ber 1,1946. Inspect immediately the spar webs in the wing integral tank area to ascertain if rein- forcements have been installed in accordance with Douglas Service Bulletin C-54-205 dated October 1, 1945. I f not already installed, re- inforcements must be added by November 1, 1946. Pending rework, airplanes which do not have reinforcements may be operated if daily inspection shows there is no leakage. Fuel should be carried in outer wing tanks as cracks may develop that might not be detected. D - 1 6 D O U G L A S 46-27-2 Douglas (Was Mandatory Note 4 of AD-762~7.) Applies to C-54 and DC-4 Aircraft. Inspection to be accomplished immediately and at periods not to exceed 35 hours there- after. Numerous reports have been received of cracks occurring in the nose wheel brace strut collar, P/N 5102824, in the region where the steering lugs meet the collar body. I f cracks are found, repairs should be made as outlined in Douglas Service Bulletin C-54-2Q9S (Sup- plement) dated May 31, 1946. After repairs have been accomplished, inspection must be continued at intervals not to exceed 35 hours. Douglas Service Bulletin C-54-209S (Sup- plement) dated August 12, 1946, contains the information which is included in the supple- ment dated May 31, 1946. I n addition, the later supplement outlines a method for the installation of steel brace rods to the nose wheel brace strut collar. Although the addition of the steel brace rods is not mandatory, it is recommended by the Douglas Co. I f the Steel brace rod installation has been incorporated in addition to the rework to the nose wheel brace strut collar which is required in the above paragraph, the 35-hour periodic inspections will not be required. 46-39-3 Douglas (Was Service Note 2 of AD-762-7.) Applies to C-54 Series Air- craft. Pending accomplishment of AD 46-24r-2, the magneto wires forward of the firewall must be inspected for chafing each 100 hours of operation. 46-39-4 Douglas (Was Mandatory Note 7 of AD-762-7.) Applies to C-54 Series Air- craft. To be accomplished not later than Novem- ber 15,1946. Instances of valve freezing, due to ice form- ing in the detent chamber, have been reported on fuel tank selector and crossfeed valves. To prevent valve freezing, the Parker and Hydro Aire valves must be reworked by filling the detent chamber with Dow Corning compound No. 4 and installing a washer to retain the compound and to act as a water shield. Douglas Drawings 4331597 and 2331524 cover this same subject.) 4 6 - 3 9 - 5 Douglas (Was Mandatory Note 6 of AD-762-7.) Applies Only to C-54B and Other C-54 Series Airplanes Having the C-54B Fuel System. To be accomplished not later than Decem- ber 1,1946. The main fuel line supporting brackets at wing Stations 357, 378, and 399 are subject to vibration failure and are to be replaced with redesigned brackets. In addition, the United Carr clips at wing Station 378 are to be re- placed by Adel clips. (Douglas Service Bulletin No. DC-4-5 cov- ers this same subject.) 4 6 - 4 3 - 1 Douglas (Was Service Note 1 3 of AD-669-3 and Service Note 11 of A D - 618-3.) Applies Only to DC3C and DC3D Series Airplanes and to DC3 Airplanes Hav- ing C-47 Type Outer Wings Installed. Inspection required at next periodic inspec- tion and at intervals not to exceed 450 hours thereafter. Inspect the outer wing attach angles for signs of corrosion. This corrosion may be found in the form of blisters on the surface of the angle with small cracks running across the surface of the blister. Cavities often exist under the blisters and if the corrosion has progressed sufficiently, may extend through the angle. This corrosion is intergranular in type and if found, the complete wing attach angle affected must be replaced. Evidence of the corrosion can be found on the outer surfaces of the angles; therefore, the wings need not be removed to complete the inspection. This in- spection may be accomplished at the same time as the attach angle inspection required in A D 39-24-1. (Douglas Service Bulletin No. 243 covers this same subject and gives additional informa- tion regarding the causes of this difficulty.) 4 6 - 4 3 - 2 Douglas (Was Mandatory Note 1 2 of AD-618-3 and Mandatory Note 13 of AD-669-3.) Applies Only to DC3 Series Aircraft Having the No. 4118923 Magnesium Alloy Casting Rudder Pedal Slide Tube Support. To be accomplished not later than January 1, 1947. Install a third A N 3-21 bolt in the existing hole between the two holes now having A N D O U G L A S D-17 3-21 bolts in. the attachment of the Rudder Pedal Slid& Tube Support, No. 4118923 and - I , to its Pedal Assembly (5118929, 5118931, and 5118928). I f necessary, to correct mis- alinement among the three holes, it is per- missible to use 24ST or 4130 bushing with i£2 -inch wall thickness. This additional bolt is necessary to insure the 100% margin of safety required on the magnesium casting. (Douglas Service Bulletin C-47-101 covers this same subject.) 47-2-1 Douglas (Was Mandatory Note 9 of AD-762-7.) Applies to 0-54 and DC-4 Aircraft. To be accomplished at next engine change. Replace present low carbon steel bolts and brass nuts on exhaust collector rings with stain- less steel bolts and nuts. This change is neces- sary in order to eliminate stretching of these bolts, corrosion, and other maintenance prob- lems connected with the present type bolts used in the exhaust collector system, (Douglas Service Bulletin DC-4 No. 10 cov- ers this same subject.) 47-2-2 Douglas (Was Mandatory Note 10 of AD-762-7.) Applies to All 0-54 Series Aircraft and DC-4 Aircraft, Serial Numbers 42904 to 42943, Inclusive; 42948 to 42952, Inclusive; 42982 to 42996, Inclusive; and 43065. To be accomplished not later than July 1, 1947. Inspect the clevis shear bolts in the vertical stabilizer forward attach fitting (Station 953), P / N 4106204 and -1, for loose or stretched bolts. I n some instances, the lower %6-inch bolts, when being checked for tightness, have broken. In order to overcome the difficulty, the stabilizer attaching fittings should be re- worked and bolts be replaced with high heat- treated bolts. (Douglas Service Bulletin DC-4 No. 11, cov- ers this same subject.) 47-2-3 Douglas (Was Mandatory Note 11 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. To be accomplished not later than August 1, 1947. Because of failures in service of the main 9-inch Douglas aluminum accumulators, it is necessary to replace these accumulators with dual 7i/£-inch accumulators. Bendix P / N 406920 or Vickers P / N A A 14308B. A single Vickers 10-inch accumulator Model AA-14310 may also be installed in place of the single Douglas accumulator. (Douglas Service Bulletin DC-4 No. 9, cov- ers this same subject.) 47-2-4 Douglas (Was Mandatory Note 12 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. Revised May 24, 1948. To be accomplished not later than March 15, 1947. Relocate engine primer solenoid to prevent fuel leaking into firewall junction box. This change shall be accomplished in accordance with item 25 of Douglas Service Bulletin C-54- 266, dated May 17, 1946, or part 2A, item 4; and part 2C, item 12 of Douglas Service Bul- letin DC-4 No. 66, dated June 18,1947. 47-2-5 Douglas (Was Mandatory Note 13 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. To be accomplished not later than next pe- riodic inspection. Inspect the entire electrical system for evi- dence of damage due to chafing, heat, or for- eign matter; and of loose terminals and con- nections. Pay particular attention to wiring subjected to heat from voltage regulators; the buss to the main cabin junction box; and any screws projecting into cable ducts. Correct any unsatisfactory conditions. 47-2-6 Douglas (Was Service Note 3 of AD-762-7.) Applies to C-54-DC Series Airplanes Incorporating Brake Pressure Accumulators and All DC-4's up to Serial Number 43065. Rework the hydraulic hand pump shutoff valve 5241991 by replacing the valve retainer, spring and plunger with a sleeve and new type packings. The existing P / N 5241991 and 4242103 are to be removed and Nos. 2343816-4 and 2343816-6 restamped on the valve assem- bly and valve body, respectively. Also, change placard at the hand pump shutoff valve con- trol to read "brakes, cowl flaps, nose wheel steering and windshield wiper" in the forward position and "landing gear, wing flaps, and main accumulator" in the rear position. D-18 D O U G L A S (Douglas Service Bulletin DC-4 No. 3, cov- ers this same subject.) 47-2-10 Douglas (Was Service Note 14 of AD-669-3.) Applies to A l l DC3C (C-47 Series) Aircraft and A l l DC3 Aircraft Hav- ing C-47 Elevators Installed. Reports have been received indicating that the 5115210-5 and 5115210-9 elevator ribs at the inboard and outboard ends of the trim tab cutout were found to be cracked on the left- hand elevator. A l l reports thus far were on surfaces which incorporated ribs made of 0.020 material. I n September 1944, the ribs were increased in gage to 0.040 for new production and so far no difficulties have been reported. I t is recommended that all 0.020 ribs be in- spected at intervals not to exceed 130 hours. These ribs can be reinforced by the addition of an 0.040 doubler as shown in Figure 1 of Doug- las Service Bulletin 244, Section I . After the doubler has been installed, these parts should be inspected at each engine change period. The elevators should be rebalanced after the reinforcing doublers have been installed. I t is also recommended that all surfaces incorporating 0.040 ribs be inspected at each engine change period in order to preclude the possibility of cracks occurring in these heavier ribs. (Douglas Service Bulletin No. 244, Section I , outlines the recommended doubler installa- tion mentioned above.) 47-6-7 Douglas (Was Service Note 12 of AD-618-3, Supplement 1; Service Note 15 of AD-669-3, Supplement 1.) Applies to A l l DC3 Series Aircraft. To be accomplished not later than the next periodic inspection, or in the case of sched- uled air carrier aircraft, at the next major inspection. Check the pull necessary to trip the trigger on the .C02 fire extinguishing system. I f the trigger pull exceeds 50 pounds due to wear of the aluminum conduit covering the fire extin- guisher release cable, this conduit must be replaced immediately. This procedure is to be repeated at each specified inspection period until such time as the aluminum cable conduit is replaced by stainless steel conduit. (Douglas Service Bulletin DC3 No. 246 dated November 22, 1946, covers this same subject.) 47-12-1 Douglas (Was Mandatory Note 14 of AD-762-7.) Applies to A l l C-54 and R5D Series Airplanes, and the Following DC^4 Airplanes: 42904 to 42943, Inclusive; 42948 to 42952, Inclusive; 42982 to 42996, Inclusive; 43065 to 43069, Inclusive; 43071; 43072; and 43102. DC-4 Production Airplanes Nos. 43070, 43090, and Subsequent Except 43102, as Noted Above, Will be Modified Prior to Delivery. To be accomplished not later than January 1, 1948. I f the clear-view panel in the windshield is opened in flight when the landing gear and flaps are extended, exhaust fumes enter the cabin. This causes considerable discomfort to passen- gers and may create a hazard which would af- fect the safe operation of the airplane. I n order to prevent the exhaust fumes from entering the cabin under these conditions, all openings around the control cables and flap buss system at the side of the fuselage must be sealed and and additional means for exhausting main cabin and cockpit ventilating air provided, unless tests made by the operator of the indi- vidual airplane show no unsatisfactory condi- tion of carbon monoxide entering cabin with open windows when landing gear down and flaps extended. (Douglas Service Bulletin No. DC-4, No. 32, covers this same subject.) 47-12-2 Douglas (Was Mandatory Note 15 of AD-762-7.) Applies Only to DC-4 and C-54 Series Airplanes Equipped With Pratt & Whitney R-200-11 Engines. To be accomplished not later than July 15, 1947. A considerable number of center main bear- ing failures have occurred in the R-2000-11 engine. These failures include roller bearing P/N 24966 and plain bearing P/N 97387 and 97387B. To remedy this unsatisfactory condition as soon as possible, the following shall be accom- plished : Remove from service at the first opportunity, but in no case later than July 15, 1947, all plain type center main bearings of the above D O U G L A S D-19 part numbers. Install either the superin- spected roller bearing (same part number as above) or incorporate the 2SD13-G or equiva- lent type main components of the power sec- tion crankcase, details of which can be obtained from Pratt & Whitney instructions dated Jan- uary 15, 1947 and entitled "Power Section Service F i x for R-2000-7 and R-2000-11 En- gines". Superinspected roller bearings may be procured through Pratt & Whitney or bearings in stock may become eligible if they are dis- assembled, inspected, and the inner race mag- nafluxed. I n cases where operating specifications do not so provide, main oil screen (on right side of rear accessory housing) checks will be ac- complished at each routine inspection or at least at every 75 hours of operation to detect failure of bearing. This precautionary inspec- tion must be conducted immediately and also after change to the superinspected roller bear- ing. However, this precautionary inspection is waived after complete modification has been accomplished to the 2SD13-G or equivalent type components in view of the greatly im- proved reliability and durability which these components have demonstrated in comparable service. 47-16-1 Douglas (Was Mandatory Note 16 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. To be complied with not later than Septem- ber 1,1947. A. I n those aircraft having the ammeter shunts in the positive generator leads, install two circuit breakers or circuit breaker switches in each nacelle junction box and reconnect each ammeter lead through one of these circuit breakers. Any type or variety of 10-ampere circuit break may be used, with the exception of the automatic-reset type. B. Install a circuit breaker or circuit breaker switch in the main junction box and connect in series with the voltmeter circuit wire PJ-34 at the (d. c.) buss. Any type or variety of 10-ampere circuit breaker may be used, with the exception of the automatic-reset type. The nonoverride variety of circuit breaker is preferable. C. Install for Heinemann type AM 1614- 15-28-2 or equivalent, 15-ampere circuit breaker switches or circuit breakers, at the reg- ulator location, in the leads to the B terminal of the voltage regulators; wires PA-530, PA- 531, PA-730, and PA-731. The usual thermal circuit breaker or fuse does not provide suffi- cient protection to meet the peculiar require- ments of a protective device for a generator field circuit application. Additional information on the foregoing changes are described by Douglas Drawing No. 4350951 entitled "Rework of Generator Field Lead and Volt-Ammeter Lead Circuit Protection". A Douglas Aircraft Service Bul- letin on this subject is also being issued. 47-16-2 Douglas (Was Mandatory Note 17 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. To be accomplished not later than June 1, 1947. I n case of leakage of the oil dilution sole- noid, fuel may flow down the flexible con- duit between the solenoid and the firewall junc- tion box and into the junction box, thus cre- ating a fire hazard. To correct this condition, remove the existing flexible conduit and wire between the solenoid and junction box and in- stall new 18-gage wire. Support wire with AN 755-4-4-8 clamps spaced approximately 10-inches apart. This change is similar to the removal of the flexible conduit for the primer solenoid as covered in item 25 of Douglas Service Bul- letin 266 in accordance with Note 47-2-4. (Part 2A, item 4 of Douglas Service Bul- letin DC-4, No. 66, dated June 18,1947, covers this same subject.) 47-27-2 Douglas (Was Service Note 4 of AD-762-7.) Applies to A l l C-54-DC Series and DC-4 Airplanes. Inspection required at intervals not to ex- ceed 170 hours. (Effective March 21, 1961.) Open the quick-opening type inspection doors in the bottom of the outer wing and center wing section surfaces forward of the front spar and aft of the center spar. Inspect spar web structure for loose rivets, cracks, or other irregularities. Pay particular attention in the fuel tank areas for evidence of fuel leaks which will indicate cracked spar webs or rivets and seam leaks. A l l spar web cracks which are found after accomplishment of AD 46-27-1 (Service Bulletin C-54r-205. "Rework—Integral Fuel D - 2 0 D O U G L A S Tanks") or cracks that are located in areas to which the Service Bulletin C-54-205 does not apply, should be repaired in accordance with Douglas Drawings No. 5354811, "Service Rework—Station 463, Outer Wing, Center Spar", and No. 3344236, "Repair—Integral Tank Spar Web Crack". 4 7 - 2 7 - 4 Douglas (Was Mandatory Note 18 of AD-762-7.) Applies to A l l C-54 and DC-4: Series Airplanes Having Exhaust Col- lector Rings Made Up of Top Segments P/N 5174842-56 L.H. and 5174529-56 R.H. To be accomplished not later than the first engine change subsequent to July 15, 1947, but in any event not later than October 15, 1947. Several reports have been received of crack- ing failure of the collector ring "Y" outlet assembly due to breathing of the exhaust stack. This induces failure which creates afirehazard. This type of exhaust collector "Y" is not rein- forced with a flange and is shown on page 4, Douglas Service Bulletin No. BC^A No. 31. To correct this condition weld a scalloped stiffener flange on the exhaust collector aft of the "Y" outlet assembly. (Douglas Service Bulletin No. DC-4 No. 68 covers this same subject.) Until this repair is accomplished, inspection for cracks should be made immediately and at periods not to exceed 50 hours of operation. 4 7 - 3 3 - 1 Douglas (Was Mandatory Note 19 of AD-762-7.) Applies to A l l DC-4 and C-54 Type Aircraft Except Production DC-4 Aircraft Serial Numbers 42952, 42992, and Subsequent. The following is to be accomplish to re- duce the possibility of wear of the outboard elevator hinge parts: Inspect immediately for wear, proper installation and operation unless already accomplished, and at periods there- after not to exceed 250 hours flight time, or in the case of Scheduled Air Carrier Operations, at each major inspection closest to 250 hours until the following mandatory rework is ac- complished. (This mandatory rework shall be accomplished not later than October 15, 1947.) (a) Each horizontal stabilizer outer hinge bracket P/N 5109899, must be reworked as follows: (1) Line ream 0.3745-0.3755-inch diameter holes through the two lugs at each hinge point. (2) Press in 3323406-A-2 bushings, two re- quired, made from %6 -inch diameter corrosion resistant steel bar, Spec. AN-QQ-S-771, Comp. FM, Cond. B., or bushing, P/N 1356866, which may be purchased from the airplane manufacturer. (3) Machine shoulders of bushings on in- side of lugs to obtain clearance for bearing in eyebolt of 0.563 inch, plus 0.005 inch and minus 0.001 inch. Minimum thickness of shoulder on each bushing after machining should not be less than 0.020 inch. (4) Line ream hole 0.3120-0.3140 inch in diameter through bushings after pressing into hinge fitting. (5) Remove outboard elevator hinge eye- bolt assembly, P/N 2110992, and install new assembly, P/N 2328991. (6) Reinstall elevators using 2357035-15 bolt through bushed hinge bracket and new eyebolt assembly, with 1357162 washer (two required—one under head of bolt and one un- der nut), AN B10-5 nut and AN 380-2-2 cotter pin. (&) The horizontal stabilizer outer hinge bracket, P/N 5109899, was replaced in later production aircraft and on some aircraft in the field with P/N 3323406. This latter bracket incorporates a % 6 - i n c h bolt with eye- bolt P/N 2328991, and must be reworked in accordance with parts 1, 2, 3, 4, and 6 of para- graph (a). (Douglas Service Bulletin DC-4, No. 73 dated September 23, 1947, covers this same subject. An earlier issue of this Service Bul- letin dated June 12, 1947, called for NAS 55- 15 bolts in paragraph (a) (6). I t is satisfac- tory to leave the NAS 55-15 bolts installed on airplanes reworked as per the original issue of the Service Bulletin.) 4 7 - 3 3 - 2 Douglas (Was Mandatory Note 14 of AD-618-3, Supplement 2; and Mandatory Note 15 of AD-669-3, Supplement 2.) Ap- plies to A l l DC3 Series Aircraft. To be accomplished not later than the first engine change after September 1, 1947, but in any event not later than December 1, 1947. I n order to preclude cowl flap hydraulic line failures and possible subsequent fires, re- place grommets and lines forward of the fire- D O U G L A S D-21 wall with AN 833-4 elbows and AN 924-4 nuts, or equivalent, and new fire resistant flexible hose assemblies of proper length. 47-36-1 Douglas (Was Mandatory Note 1 of AD-3L-1.) Applies to A-26B and A- 26C Aircraft. Compliance required prior to November 15, 1947, on all serial numbers. To reduce the possibility of failure of the wing bulkhead assemblies and subsequent loss of the ailerons: 1. Machine face of boss on fitting assem- blies P/N 4154028 and 4154028-1, to 0.335 inch, and ream bore to 0.9007 + 0.0000, -0.0005 inch, (See Figure 1.) Replace bearing AN 209K4A with self-alining bearing, P/N AN 200KS4 and stake in six places each side. In- stall reworked fitting assemblies, P/N 4154028 and 4154028-1, on original bulkheads as fol- lows: 0.437 FlGUKE 1 (a) On installations using two screws, P/N 1029421-416-11, or two bolts, P/N AN 4-6A, and three rivets, enlarge the rivet holes in the fitting and bulkhead to 0.191-inch di- ameter and countersink the holes in bulkhead 100°. Install fitting using two screws, P/N 1029421-416-11 or NAS 214-11, or two bolts, P/N AN 4-6A, originally installed, two wash- ers, P/N AN 960D416, and two nuts, AN 365- 428, in the top and bottom holes, and three screws, P/N S-1029421-10-12, three washers, P/N AN 960D10, and three nuts, P/N AN 365-1032, in the three remaining holes. (b) On installations using four or five screws, P/N S-1029421-10-12, reinstall fitting assemblies with original screws, washers, and nuts. 2. Inspect bulkhead assemblies, P/N 5153663 and 5153663-1, for cracks. I f cracks are found, replace bulkhead as follows: Remove damaged bulkhead by drilling out the attaching rivets. Using damaged bulkhead as a pattern, fabricate a new bulkhead from 0.081-inch 24SO aluminum alloy sheet, condi- tion A, annealed (Spec. No. QQ-A-362 or AN A-13.) After forming new bulkhead, heat- treat in accordance with AN 01-1 A - l , section V, then apply one coat of zinc chromate primer. Hold new bulkhead in place on the airplane and check for proper alinement between the upper and lower surfaces of the wing and wing tip. (Drill holes to match existing holes in the angle, skin, and fitting.) Install bulk- head using rivets, P/N AN 426AD-(0), length and diameter as required. Install reworked fitting assemblies on new bulkheads as follows: (a) For fitting assemblies which incor- porate two 14-inch bolt holes and three rivet holes, enlarge the rivet holes to 0.191-inch diameter. Drill corresponding holes in bulk- head and countersink 100°. Install fitting assembly using two screws, P/N 1029421-416- 11 or NAS214-11, two washers, P/N AN 960D416, two nuts, P/N AN 365-428, three screws, P/N S-1029421-10-12, three washers, P/N AN 960D10, and three nuts, P/N AN 365-1032. (b) For fitting assemblies which incor- porate four 0.191-inch diameter holes, drill corresponding holes in new bulkhead and countersink 100°. Install fitting assembly us- ing four screws, P/N S-1029421-10-12, four washers, P/N AN 960D10, and four nuts, P/N AN 365-1032. Reinstall aileron and check alinement of fitting assembly. Install washers, P/N AN 960D416 or AN 960A416L, or shim stock, as required, to take Up the end play between the bearing inner race and bracket assembly, ail- eron hinge support. (Army Technical Order 01-40AT-40 covers this same subject.) 47-36-2 Douglas (Was Mandatory Note 2 of AD-3L-1.) Applies to A-26B and A- 26C Aircraft. Compliance required prior to operation in cold weather and not later than next engine overhaul. D-22 D O U G L A S To preclude collapse of the oil screen dur- ing cold weather starting, replace oil screen assembly No. 51887 with oil screen assembly Nos. 51887M or 107547. P/N 51887 may be re- worked to P/N 51887M by incorporating re- inforcing spring No. 107542 and adding the letter "M" to the part number. 47-42-1 Douglas (Was Mandatory Note 20 of AD-762-7.) Applies to D C - 4 and C-54 Aircraft. To be accomplished not later than April 1, 1948. To prevent the possibility of the gust lock control becoming engaged in flight or dur- ing taxiing, a latch assembly must be installed to safety the control handle in the gust lock " O F T " position. Early aircraft incorporated a short gust lock control handle. I n later air- craft, the control handle design was changed and the length of the handle increased to pro- vide more leverage. On aircraft incorporating the short gust lock control handle, latch as- sembly, P/N 3356892, must be installed. I n aircraft incorporating the new and longer handle, latch assembly, P/N 4356957, must be installed and the gust lock handle link assem- bly, P/N 4248396, must be reworked by re- moving and replacing.the spring, P/N 2356732 (or 1248420), and plunger, P/N 1248421, with new bolt P/N 1356885. I n addition to the above, the elevator and rudder gust lock in the tail section and the aileron gust lock in the fuselage center section must be reworked by removing shaft, P/N 1165889, and replacing with new piston, P/N 2356840. After completing the rework, care must be exercised in properly rigging the gust lock control system. ( N O T E : Some operators have obtained ap- proval of a gust lock latch of their own de- sign. In such cases, the Douglas designed latch need not be installed, however, the re- mainder of the rework described above must be accomplished.) (Douglas Service Bulletin DC-4 No. 79 covers this same subject.) 47-42-2 Douglas (Was Mandatory Note 21 of AD-762-7.) Applies to C-54 and DC-4 Aircraft. To be accomplished as soon as possible but in any case not later than the first engine change after November 15, 1947. I t has been found that on some airplanes certain rework has been accomplished on the fire seal between the accessories section and the nacelle at the upper cowling former at tlie point where the carburetor airscoop skin rests on top of the firewall. This rework cre- ates a hazardous condition by providing an opening from the accessories section into the nacelle, through the hole under the non ram air intake fairing. Inspect all airplanes to ascertain that a fire seal is provided in this area. I f the cowling fire seal has been cut away it must be replaced either with the original type seal or with a new type seal. (Douglas Service Bulletin DCM No. 19 covers a new type fire seal.) 47-42-3 Douglas (Was Mandatory Note 22 of AD-762-7.) Applies to C-54 and DCM Aircraft. A l l the provisions of items A through O apply to airplanes used for carrying passen- gers under the provisions of Parts 41, 42 and 61 of the Civil A i r Regulations. On these air- planes the changes are to be accomplished not later than November 1,1948. Only items A, (12), A (15), C, D, F,J,K (1.), K (2), L, M, O (2), O (4), O (5), and O (7) apply to airplanes other than those indicated above. On these airplanes the changes are to be accomplished not later than the first engine change after November 1, 1948. As a result of investigation of powerplant fires which have occurred in this type air- craft, the following changes are to be accom- plished : A. 1. Seal all cracks and baffies in oil cooler fairing and provide additional drain holes. 2. Rework cowl tail pipe shroud to eliminate all cracks and gaps and seal shroud to cowl panel joint. 3. Seal inner ring corners at oil cooler joints. 4. Reinforce exhaust shroud to prevent damage when used as a step and seal same. 5. Provide accessory compartment vent opening in oil cooler fairing panel. 6. Seal joints between all engine ac- cessory sections cowling panels to prevent leakage of flame into aecesory section. D O U G L A S D-23 7. Eliminate engine accessory compart- ment vent opening in the side accessory section cowl panel. 8. Seal pressure transmitter and fire warning switch holes on firewall. 9. Close gap between aft oil cooler fair- ing and nacelle skin aft of firewall. 10.. Rework the hydraulic suction line connecting to the shutoff valve aft of the fire- wall to prevent failure at fittings due to rigid- ity of the line. 11. Relocate the hydraulic pressure and automatic pilot lines to move them farther away from the exhaust shroud. 12. Add a check valve in the automatic pilot delivery line behind the firewall. 15. Change the nacelle firewall miscel- laneous line connector assembly on the right side of the firewall from dural to steel. 16. Change carburetor air scoop adapter sleeve to provide a tight and flexible connection. 17. Replace exhaust stack nuts with spe- cial long-type nuts, extending past stud ends, on exhaust pipe attachments to engine and safety wire the nuts in place. 18. Change nuts and bolts used on the four-bolt flanges at the top of the exhaust collector ring to stainless steel. 19. Seal main landing gear door hinges on inboard nacelles. 20. Install means to prevent exhaust nipples from telescoping and pulling out of cylinder exhaust ports, in the event of exhaust port stud failure. (Douglas clamp assembly P/N 42440tf may be used.) (Douglas Service Bulletin C-54-250 covers the above items respectively. Items 13 and 14 of that Bulletin are not required by this Note.) B. Rework forward edge of exhaust shroud to eliminate gaps leading into engine accessory section. (Part I , Douglas Service Bulletin C-54-234, covers this same subject.) C. Add two fire detectors on forward face of firewall in vicinity of shutoff valve location. (Douglas Service Bulletin No. C-54-252 covers this same subject.) D. Relocate engine primer solenoid to pre- vent fuel from running into electrical junction box on rear face of firewall. (Item 12, Douglas Service Bulletin DC-4 No. 66, covers this same subject.) E . Install extended tail pipes on exhaust collectors. (Douglas Service Bulletin p~>54r-289 covers this same subject.) N O T E : Some of the above-mentioned changes were accomplished at the time Army or Navy airplanes were converted for civil certification. However, it will be necessary to check for compliance, in order to insure that items A to E, inclusive, are complied with. F. Improve the seal at the point where the top of the oil radiator duct fits against the cutout in the bottom of the accessories section diaphragm. (Part 1 of Douglas Service Bulletin DC-4 No. 49 covers this same subject.) G. Revise sealing of engine section drain line support adjacent to oil cooler shroud by in- stalling a drain manifold. (Part B of Douglas Service Bulletin DC-4 No. 66 covers this same subject.) H. Replace dural oil inlet elbow on oil cooler with new type steel elbow. (Part F, 9 of Douglas Service Bulletin DC-4 No. 66 covers this same subject.) I . Improve sealing of engine accessories sec- tion diaphragm at the four cutouts for the exhaust collector ring supports. (Part 2 of Douglas Service Bulletin DC-4 No. 49 covers this same subject.) J . Replace micarta fairleads with fairleads of fire resistant material for propeller governor and carburetor air preheat control cables on inner ring and for all engine control cables on firewall. (Douglas Service Bulletin DC-4 No. 55 cov- ers this same subject.) K. 1. Install seven fire-warning detectors in zone 1, (engine power section) on the cowl flap ring brackets and install separate set of warn- ing lights in the cockpit for each engine, 2. Add an additional fire warning detec- tor in zone 2, (engine accessories section) on top of the oil cooler housing at approximately the center of the section. (Douglas Service Bulletin DC-4 No. 57 cov- ers the above two items.) L. Replace open relays in junction box be- hind firewall with sealed relays and provide a drain for the junction box. D - 2 4 D O U G L A S (Douglas Service Bulletin DC-4 No. 61 cov- ers this same subject.) M. Attach nacelle junction box cover plate on forward face of firewall directly to firewall rather than to the junction box. (Douglas Service Bulletin DC-4 No. 65 cov- ers this same subject.) N. Inspect and seal all holes in the inner ring around the carburetor air preheat control and install fire resistant fairlead in retainer. (Douglas Service Bulletin DC-4 No. 55 cov- ers this same subject in part.) O. 1. Inspect and rework if necessary, inner ring cutouts for cowl flap actuating bellcranks to provide metal-to-metal contact between inner ring and cowl flap bellcrank bracket on aft side of inner ring. Dimple inner ring to accomplish metal-to-metal contact, or fill gap with washers made from Johns Manville No. 96 wire woven asbestos sheet impregnated with neoprene. 2. Inspect and rework diaphragm, inner ring and firewall for excess holes, gaps and rubber grommets. Close and seal all holes and gaps, and install fireproof grommets or equivalent. 3. Inspect and seal, with Johns Manville No. 96 or equivalent, gaps that may exist where the carburetor airscoop casting passes through the accessory section inner ring. 4. Inspect and seal with Johns Manville No. 96 split seal or equivalent the hole where the engine oil line (from the intermediate rear section to the main oil sump) passes through the plate in the accessory section diaphragm at the bottom of the engine. 5. Inspect and seal with Johns Manville No. 96 or equivalent any gaps that may exist where the plate mentioned in item 4, above, mates with the outer section of the accessory section diaphragm. 6. Inspect and seal gaps existing be- tween the diaphragm and the three engine crank case bosses. The magneto vent lines pass through the gaps around two of these bosses; the manifold pressure takeoff line at right top of engine being the-third. 7. Provide a fluid shutoff means at a point behind the firewall in the line-leading from the oil tank to the feathering pump on airplanes having the feathering pump located on the engine side of the firewall. This may be accomplished by a shutoff valve tied into the present shutoff valve linkage aft of the fire- wall, or a flapper type check valve. N O T E : Items 0-1 through 0-7 are to be developed and accomplished by the operators affected, since Douglas has not prepared Service Bulletins to cover these changes. 47-42-5 Douglas (Was Mandatory Note 2 of AD-781-1.) Applies to the Following DC-6 Airplanes: A A L Serial Numbers 42854 to 42865, Inclusive; Serial Numbers 42879 and 42880; U A L Serial Numbers 42866 to 42875, Inclusive; and Panagra Serial Num- bers 42876 to 42878, Inclusive. To be accomplished not later than August 1, 1948. I n order to prevent window curtain inter- ference when opening emergency exit doors, remove hook assemblies, 2346313, -500, from curtain track, 5337482, and from the window curtain assemblies, 3343932-512, and replace with new slides, 1335554 and hooks 1345849 on each side of the four forward and the two aft cabin emergency exit door window frames. (Douglas Service Bulletin DC-6 No. 15 cov- ers this same subject.) 47-42-^6 Douglas (Was Mandatory Note 3 of AD-781-1.) Applies to the Following DC-6 Airplanes: A A L Serial Numbers 42854 to 42865, Inclusive; Serial Numbers 42879, 42880 and 42882 to 42891, Inclusive; U A L Serial Numbers 42866 to 42875, Inclusive; and 43000 to 43009, Inclusive; Panagra Numbers 42876 to 42878, Inclusive; N A L Serial Numbers 43055 and 43056; and A A F Number 42881. To be accomplished not later than August 1, 1948. I n the main cabin, Station 890, stencil "Fire Extinguisher" on forward side of bulkhead 12 inches from the floor at the right-hand edge of the lounge door. (Douglas Service Bulletin DC-6 No. 18 cov- ers this same subject.) 47-42-7 Douglas (Was Mandatory Note 4 of AD-781-1.) Applies to the Following DC-6 Airplanes: A A L Serial Numbers 42855 to 42858, Inclusive; and U A L Serial Num- bers 42866 to 42869, Inclusive. DoTTGXAS D-25 To be accomplished not later than next engine change. I n order to prevent possible injury to flight crew members, it is necessary to install a spring in the handle operating mechanism of both windshield corner window assemblies. The purpose of the spring is to return the operating mechanism handle to a flush position when released in the open window position. To ac- complish this, remove the AN 393-35 pin and the NAS 75-3-007 bushings from the attaching point of 2335660 wedge and the upper end of 4335656 channel on 5243829 windshield corner window assembly. Install 5243829F-4 clips on the inside of each leg of channel. Rework 2335658F-6 link. Install 5243829F-2 spring to clips and eyebolt. Install wedge to upper end of channel. Repeat the foregoing opera- tions for removal and installation of identical parts to 5243829-1 windshield corner window assembly. (Douglas Service Bulletin DC-6 No. 19 cov- ers this same subject.) 47-42-8 Douglas (Was Mandatory Note 5 of AD-781-1.) Applies to DC-6 Airplane Serial Numbers 42854, 42855, 42857, 42858, 42860 to 42865, Inclusive; 42867, 42869 to 42880, Inclusive; 42882 to 42891, Inclusive; 43000, 43001, 43003 to 43009, Inclusive; 43055 and 43056. To be accomplished not later than next No. 3 inspection (or not later than next 150 hours for non-air-carrier operations). Certain cases have been found wherein the 5240452 horizontal stabilizers do not have the rivet pattern specified on Drawings Nos. 5248752 and 5249045. The following specific cases should be inspected and rivets should be added if the numbers are less than the following: Referring to Drawing 5248752. "Horizontal Stabilizer Rear Spar Assembly", zone 4, di- rectly outboard of Station 63: 1. There should be at least 12 ADS rivets top and bottom through the web and cap between the -14 and -12 stiffeners, not counting those through the stiffeners. 2. There should be at least 4 AD5 rivets through the -68 doubler, spar web and spar cap. 3. There should be at least 6 AD5 rivets top and bottom between the -12 stiffener and the -68 doubler through web and cap. With reference to Drawing No. 5249045 "Horizontal Stabilizer Panel and Spar Struc- ture Assembly", zone 3, section L-L, directly inboard of Station 69.5 both top and bottom, the existing rivet pattern of either y& or % 2 rivets should be continued inboard with AD5 rivets using the present pattern of % inch O. C. to within 3y1 6 inches from the end of the spar cap. Existing ^-inch rivets, are satisfactory. I t should be noted that the foregoing inspec- tions and riveting can be accomplished without removing the elevators. (Douglas Service Letter A-214-529.010/ RLT, and attached sketches, dated July 14, 1947, covers the same subject.) 47-42-9 Douglas (Was Mandatory Note 6 of AD-781-1.) Applies to DC-6 Serial Numbers 42854,42855,42858 Through 42865, 42869 Through 42880, 42882 Through 42891, 43000 Through 43009, 43055 and 43056. To be accomplished not later than next No. 3 inspection (or not later than next 150 hours for noncarrier operations). Certain cases have been found where the aileron hinge plates at wing Stations 421, 485, 585, and 675 were fabricated from overgage stock resulting in an interference fit between the plate and the clevis fitting. The following hinge plates and fittings should be inspected to determine whether or not they conform with the tolerances listed below. I f plates are found which exceed the widths noted below, they should be reworked with emery cloth to specified limits and touched up with zinc chro- mate primer. Fittings which have been in- stalled over an oversize plate should be anb- dized and carefully inspected before being reinstalled. Hinge Station No. 421 1 485 2 585 3 675 4 Thick- Plate ness 3320118 0.249 0.237 3323460 *0.238 0.243 3323461 0.311 0.297 Fitting Width 4334619 0.249 0.254 0.334 0.350 0.311 0.316 4345756 4345755 3323462 0.249 4345754 0.249 0.237 0.254 * T h i c k n e s s o f 0.093 a n g l e n o t i n c l u d e d . D-26 D O U G L A S Total thickness should not exceed 0.334. (Douglas Service Letter A-21^-529.004/RLT dated July 21, 1947,, and attached sketches cover this same subject.) 47-42-10 Douglas (Was Mandatory Note 7 of AD-781-1.) Applies to the Following DC-6 Airplanes: Serials 42854 Through 42887, Inclusive, and Serials 43000, 43001 and 43055. To be accomplished not later than January 1, 1948. Some operators have experienced malfunc- tioning of the DC-6 landing gear antiretract mechanism, thereby preventing retraction of the landing gear. Pending redesign of the antiretract. mechanism of the landing gear con- trol valve assembly, P/N 3319922, the anti- retract mechanism may be permanently discon- nected if desired, however, if connected, it must be revised in accordance with this note. I n order to correct this unsatisfactory con- dition, which is due to slippage and lost motion in the antiretract cable system, it is necessary to accomplish the following: 1. Remove clamp P/N 1338701 from Arens down-lock control cable assembly, P/N 4334802. Install 21-inch dural tube, P/N 1356157, around lower end of the Arens control cable (the upper end of the tube should be flanged). Install AN 735-7 clamp at lower end of tube. (Prior to installing dural tube push 4-inch (7 /16 I . D. x % 6 inch O. D.) syn- thetic rubber tube over lower end until it clears sufficiently to allow installation of clamp below it.) On upper end of dural tube, P/N 1356157, install trunnion, P/N 1356154, which incorpo- rates a bushing, P/N B-162-0688, and clips, P/N 1356156. Attach this assembly to the wheel well cover plate stiffener approximately 2 1 % inches below upper end of cover plate. Remove down-lock control cable climp^ P/N 1340559, located 4 % 6 inches from Station 114.5 and install new clamp, P/N 1356158, on angle, P/N 5249561-366, 1 % 6 inches from Station 114.5. (Douglas Drawing 5334338, Change "H" covers this modification.) 2. To correctly adjust the landing gear down-lock mechanism in order to maintain the required load of 100 pounds on the cable num- ber 108 with the oleo fully.extended, the oleo should be fully retracted into the shock strut cylinder and then permitted to fully extend, at least 8 to 10 times, checking and maintaining the 100-pound load after each operation. (Douglas Drawing 7354206, page 28, covers this same subject.) 47-42-11 Douglas (Was Mandatory Note 8 of AD-781-1.) Applies to the Following DC-6 Aircraft: Serial Numbers 42854 to 42894, Inclusive; 43000 to 43012, Inclusive; 43055,43056, and 43062. Rework to be accomplished not later than December 15, 1947. (See Note 47-42-19.) Cracks have been found near the ends of the tail stub extension of the horizontal stabilizer front spar caps, top and bottom, just inboard of the stabilizer joint. I n order to prevent cracks from traveling to a point which may impair the airworthiness of the aircraft, the rework described below shall be accomplished. Until such time as the rework is accomplished, inspect the area in question at every No. 2 inspection period according to instructions contained in Douglas Telegram A-214^529, 012/RLT, dated July 25,1947. A. Cut a %-inch diameter hole through skin and doubler only, 1 % 6 inches inboard and ^yS2 inch aft of inboard fitting attaching bolt. Use special tools furnished by Douglas Aircraft Co., being careful not to scratch the spar cap. Strip primer off %-inch diameter area on spar cap and inspect for cracks with high-power lens (40 power). I f cracks are found, make a record of the location and extent of crack. B. Drill 0.250-inch diameter stop hole through spar cap, l5 /ie inches inboard and 2 1 /3 2 inch aft of inboard fitting attaching bolt and burr, regardless of whether cracks are found. I f cracks are found that will extend inboard beyond the location of the stop hole, do not operate airplane until further salvage rework instructions have been obtained. Cover holes in skin and doubler with sheet metal plug and fabric patch cemented in place. (Douglas E . O. No. 5339013 (Salvage E . O. Serial No. 375) describes the rework of installing the stop hole.) D O U G L A S D - 2 7 47-42-12 Douglas (Was Mandatory Note 9 of AD-781-1.) Applies to DC-6 Serial Numbers 42866, and 42868 to 42875, Inclu- sive. To be accomplished not later than February 1,1948. I n order to provide adequate fastening of the rubber cushions on the reinforcing strap assembly of the astrodome, the following must be accomplished: 1. Remove the existing rubber strip cush- ions, P/N 5249604-36, all traces of cement and adhering rubber from reinforcing strap as- sembly, P/N 5249604-38. 2. Butt cushion assembly P/N 2356419 against pad P/N 5249604-42, locate and drill four No. 40 (0.098) holes through strap P/N 5249604-38 and attach with AN 426-AD-3-5 rivets. 3. Reinstall reinforcing strap assembly P/N 5249604-38, using eight AN 960-D-10L wash- ers and eight AN 365-1032 nuts. (Douglas Service Bulletin DC-6 No. 45 covers this same subject.) 47-42-13 Douglas (Was Mandatory Note 10 of AD-781-4.) Applies to DC-6 Serial Numbers 42854 to 42896, Inclusive; 43000 to 43018, Inclusive; 43035 to 43042, Inclusive; 43055 to 43057, Inclusive; 43062 to 43064, Inclusive; and 43105. To be accomplished not later than April 1, 1948. To prevent the possibility of the gust lock control becoming engaged during flight or in taxiing, a latch control assembly, P/N 4356957, is to be installed to safety the control handle in the gust lock "Off" position. The gust lock link assembly, P/N 4248396, must also be re- worked by removing and replacing spring, P/N 2356732, (or 1248420) and plunger, P/N 1248421, with new bolt P/N 1356885. I n addition to the above, the elevator and- rudder gust lock in the tail section and the aileron gust lock in the fuselage center section must be reworked by removing shaft, P/N 1165869, and replacing with new piston, P/N 2356840. After completing the rework, care must be exercised in properly rigging the gust lock control system. (Douglas Service Bulle- tin DC-6 No. 75 covers this same subject.) 4 7 - 4 2 - 1 4 Douglas (Was Mandatory Note 11 of AD-781-1.) Applies to DC-6 Serial Numbers 42854 to 42880, Inclusive; 42882 to 42884, Inclusive; 43000 and 43001. To be accomplished not later than first blower overhaul after January 1, 1948. To prevent bearing failures in the voltage regulator blowers, replace the bearings for- merly packed with lubricant Z815 with new bearings containing lubricant Z801. (Douglas Service Bulletin DC-6 No. 43 describes the complete rework.) 4 7 - 4 2 - 1 6 Douglas (Was Service Note 2 of AD-781-1.) Applies to DC-6 Aircraft. Remove combustion chamber of surface com- bustion Model 63A66 thermal anti-icing heaters and Model A63A68 cabin and thermal anti- icing heaters for inspection and pressure test at each 500-hour interval of heater operation. Also carefully inspect downstream end of the combustion chambers at each periodic inspection. 4 7 - 4 2 - 1 7 Douglas (Was Service Note 3 of AD-781-1.) Applies to the Following DC-6 Aircraft Serial Numbers: Douglas 43061; A A L 42854 to 42865, Inclusive; 42879 to 42880, Inclusive; 42882 to 42896, Inclu- sive; and 43035 to 43044, Inclusive; U A L 42866 to 42875, Inclusive; and43000 to 43024, Inclusive; Panagra 42876 to 42878, Inclu- sive; National 43055 to 43058, Inclusive; Sabena 43062 to 43064, Inclusive; Braniff 43105, 43106; K L M 43111 to 43112, Inclu- sive; and A A F 42881. Inspection required at each 300 hours (or at each 150 hours for non-air-carrier operations). Inspect the center spar web between Stations 167 and 184 for cracks in the web along the lower row of rivets which attach the spar web to the leg of the upper spar cap. For aircraft with the 10-tank fuel system this inspection can be properly made only by removing the fuel tank inspection opening near the affected area, since the spar web attaches to the forward side of the spar cap leg and small cracks in the web cannot be detected without close examina- tion: I f cracks are found during this inspec- tion or, if between the inspections, leaks occur which are caused by cracks in the center spar web between Stations 167 and 184? the spar web D-28 D O U G L A S must be reinforced by installing a doubler in accordance with Douglas Drawing 5356664. When the spar web reinforcement has been incorporated the special inspection required by this Note may be eliminated. A l l DO-6 air- craft not mentioned above will be reinforced at the factory. (Douglas Service Bulletin DC-6 No. 29, "Re- work Center Spar Web, Stations 167-184, Inte- gral Wing Fuel Tank DC-6 Airplane", covers the same reinforcement as described on Draw- ing 5356664.) 47-42-19 Douglas (Was Service Note 5 of AD-781-1.) Applies to the Following DC-6 Aircraft: Serial Numbers 42854 to 42894, Inclusive; 43000 to 43012, Inclusive; 43055, 43056,and 43062. Inspection required at every engine change. After the stop holes are drilled in the tail stub extension of the horizontal stabilizer front spar caps, as required by AD 47-42-11, inspect for signs of cracks, or progress of cracks, at each engine change period. I f the aircraft has been modified to incorporate the elevator fifth hinge modification, the inspection period may be extended to every other engine change pe- riod, but not to exceed 3,000 hours of airplane operation. I f cracks progress beyond the stop hole, operation of the airplane must be discon- tinued until additional corrective measures have been determined. 47-51-12 Douglas Applies to A l l Con- verted C-47 Series Aircraft With Ram Non- ram (Hydraulic) Type Carburetor Airscoop. To be accomplished not later than March 1, 1948. Compliance with the following items is nec- essary to preclude carburetor icing: 1. The carburetor alcohol system must be used. 2. The accessory cowling and engine fire seal must maintain not more than V4-inch clearance of the collector ring. 3. The cable system for operation of the hot air door must be rigged to 30 pounds tension. (Part B of Douglas Service Bulletin DC-3 No. 251 dated April 15, 1947, covers this same subject. Part A of the same Bulletin is not mandatory, but optional compliance may be accomplished when parts are available.) 47-51-15 Douglas Applies to DC-6 Serial Numbers 42854 . Through 42880 ; 42882 Through 42888; 42890; and 42891; 43000 Through 43003; 43005 Through 43009; 43055; and 43056. To be accomplished not later than next No. 3 inspection. I n order to prevent malfunctioning of the brakes, the original Raybestos brake lining, P/N 9520535 must be replaced with Good- year BL-56 lining, P/N 9521091. This new lining is identified with two yellow dote. (Douglas Service Bulletin DC-6 No. 1 covers this same subject.) 47-51-16 Douglas Applies to DC-6 Serial Numbers 42854 Through 42880, Inclusive; 42882 Through 42891, Inclusive^ 43000 Through 43009, Inclusive; 43055; and 43056. To be accomplished not later than August 1, 1948. I n order to increase the strength of the flap support assembly at wing Station 378 and to replace the temporary rework outlined in Douglas Co. Service Letter of May 12, 1947, which was necessitated by failure of the flap •hinge'.rsupport assembly on an airplane in flight, the following must be accomplished: (a) Remove the two Shafer bearings, P/N AB-4A from flap link assembly, P/N 4325008 and press in new Shafer bearings, P/N AB-5A and stake in place. (&) Remove outboard flap link support assembly, P/N 5107188, and line ream (0.312- 0.313) diameter through to permit use of % e - i n c h bolt for attachment of upper end of link assembly, P/N 4325008. Assembly, P / N 5107188 becomes P/N 5107188-500 after rework, (c) Press out old bushing, P/N 1338719, two places in flap hinge bracket assembly, P / N 3320998, and press in new bushings, P / N 1338719-500. (d) After replacing P/N 5107188-500 re- place P/N 4325008, using bolts, P/N 2356375- 22; washers, P/N 124682-5-12-6 and P/N AN 960-516;- nut, P/N AN 310-5 and cotter pin, P/N AN 380-2-3. (Douglas Service Bulletin DC-6 No. 66 cov- ers this same rework.) D O U G L A S D-29 48-1-1 Douglas Applies to C-54 and DC-4 Aircraft. Because of cracking and failure in the lock- ing groove of Goodyear Model 20DHBM wheels, Assembly No. 530402-M, resulting from the use of the old one-place flange and lock ring, the following must be accomplished: I. Not later than the next scheduled inspec- tion at which necessary facilities are available, and at each succeeding No. 3 inspection until I I is accomplished: (1) Remove the wheel-retaining flange from all wheels which are used with, or ever have been used with, the one-piece retaining flange P/N 511033 or 530405-M and lock ring P/N 511051-1. (2) Clean and etch the wheel lock ring groove and carefully inspect to determine if any cracking has started. Remove from serv- ice all wheels found to be cracked. (3) Measure the diameter of the lock ring groove at the locking surface. The nominal diameter is 0.440 inch + 0.002 inch. When the groove lias worn to more than 0.500-inch diameter and less than 0.563-inch, remove wheel from service until it has been reworked to provide a true radius in the outer side of the groove and the thrust surface is made parallel to the end of the wheel. This radius should be 0.220 inch + 0.001 inch. Wheels reworked in this manner must be inspected at each 500 hours or the closest major inspec- tion period thereto. Remove from service any wheels in which the groove has worn to a diam- eter equal to or exceeding 0.563-inch. I I . To be accomplished not later than Au- gust 1,1948. Remove from service all one-piece flanges and lock rings and replace by two-piece flange P/N 530735-M and studs P/N 511284-6. (Goodyear Service Bulletin No. 1 covers this same subject.) 48-2-2 Douglas Applies to C-54 and DC-4 Aircraft With Wilcolator Fire Detectors Installed in the Engine Power Section of the Nacelle. Compliance required by next engine change. Revise the method of attachment of the A-4981 Wilcolator fire detectors located on the cowl flap support wing in zone 1 by clamping the detector to its mounting plate with a re- tainer strip of 0.062-thickness low carbon steel sheet, cadmium plated, secured with the same screws which attach the detector to the support box. Failure of the supports is caused by vibration during engine operation. (Douglas Service Bulletin D 0 4 No. 75 cov- ers this same subject.) 48-2-4 Douglas Applies to DC-6 Serial Numbers 42854 Through 42880; 42882 Through 42896; 43000 Through 43017; 43035 Through 43038; 43055; 43056; 43062, and 43063. Compliance required by the next No. 3 inspection. To prevent the brake lining from becoming wedged between brake disc and housing, re- place the present adjustment pin Goodyear P/N 511940-1 and spring plate Goodyear P/N 512139 by the single piece adjusting pin Good- year P/N 9510744. (Douglas Service Bulletin DC-6 No. 90 cov- ers this same subject.) 48-2-5 Douglas Applies to DC-6 Serial Numbers 42854 Through 42880; 42882 Through 42884; 43000 and 43001. Compliance required by the first engine change after March 1,1948. To prevent the hot exhaust burning through the exhaust stack recess sheet on the upper and lower outboard accessory cowling, remove the present shield on the inboard side of the cowling and install a screw fastened exhaust chute of 0.042-thickness corrosion resistant steel sheet on the outboard side of the recess sheet. An air gap must exist between the ex- haust chute and the recess sheet to allow a flow of ram air for heat dissipation. (Douglas Service Bulletin DC-6 No. 30 cov- ers this same subject.) 48-2-6 Douglas Applies to DC-6 Serial Numbers 42854 Through 42896; 43000 Through 43018; 43025 ; 43055 Through 43057; 43062 Through 43064; and 43105. Compliance required by March 1,1948. As a fire protection measure, close off the dead air space between the upper and lower wing surfaces within the engine nacelle by installing cover plates over the open access hole in the lower surface of the wing in the right and left inboard nacelles between cen- D-30 D O U G L A S ter and front spars and between Stations 130 and 167. (Douglas Service Bulletin DC-6 No. 92 cov- ers this same subject.) 48-3-2 Douglas Applies to A l l Models C-54-DC and D 0 4 Aircraft. I n order to prevent the emergency air brake valve from seizing due to infrequent operation, the following should be conducted: At intervals not to exceed 1,000 hours, ex- cept at the discretion of the CAA Agent, the interval may be increased to coincide with a regular overhaul period, but should in no case exceed 1,700 hours. Connect a gage to one brake port on each side of the airplane and discharge the air brake cylinder from one of the flight compartment controls. The initial air pressure indications on the gages at the brakes should not be less than 400 p.s.i. Allow 5 minutes for change in pressure due to temperature and again note the air pressure indications on the gages at the brakes. These second observed pressure indi- cations should hold steadily for a period of at least 5 minutes. This will check the function- ing of oJie of the pull mechanisms, the air brake control valve, shuttle valve, lines and fittings. Push in the control to release air pressure on brakes and operate other air brake control to insure that both pull mechanisms are operating properly. 48-5-1 Douglas Applies to A l l DC3 Air- craft Equipped With Pacific Aviation Oil Shutoff Valves. Compliance required at first engine change after March 1, 1948, but not later than May 1, 1948. Replace the present "O" rings in the oil shut- off valves with rings of H222-90 high tempera- ture material or AMS-3228B material. There has been reported leakage attributed to the fact that the material in the "O" rings is not capable of withstanding the operating tem- perature of the oil. (Douglas Service Bulletin DC3 No. 256 covers this same subject.) 48-6-5 Douglas Applies to DC-4 and C-54 Aircraft. Compliance required by November 1,1948. To prevent failure of the aileron hinge eye- bolts and the rudder trim tab and elevator trim tab hinges and control horns, the following changes must be made: 1. On airplanes .having aileron assemblies P/N 5166075, -1, -500, -501, or -503, replace No. 3 hinge eyebolt P/N 1166013 with new eye- bolt P/N 1357234. Airplanes having aileron assemblies P/N 5078609, -1, -500, -501, -502, or -503, do not require this hinge replacement. 2. On elevator and rudder trim tabs replace all hinges and control horns with new parts made of steel. 3. Replace the standard AN bolts in elevator trim tab and rudder trim tab hinges and con- trol horns with new special close tolerance high strength bolts using new AN 310 type nuts, AN 960 washers and AN 380 cotter pins. Inspection should be accomplished in accord- ance with Note 51-9-2 except in the case of air- craft in which the standard AN rudder and elevator hinge bolts have not been replaced with new close tolerance high strength bolts using new AN 310 type nuts, AN 960 washers and AN 380 cotter pins. I n such cases, inspec- tion should be accomplished at intervals not to exceed 1,000 hours. (Douglas Service Bulletin DC-4 No. 83 cov- ers the above rework.) 48-7-2 Douglas Applies to DC-6 Serial Numbers 42854 Through 42896; 43000 Through 43024 ; 43035 Through 43064; and 43105 Through 43110. To be accomplished not later than the first engine change after March 1, 1948, but in any event not later than June 1,1948. To prevent failure in the engine super- charger control actuator when shifting from low to high blower and vice versa, it is neces- sary to provide overtravel in the engine super- charger control linkage by installing a new Geneva-Loc supercharger actuator lever, a new Bendix link-supercharger actuating link and a new four-hole mounting support bracket. (Douglas Service Bulletin DC-6 No. 127 covers this same subject.) 48-7-3 Douglas Applies to DC-6 Serial Numbers 42854 Through 42896; 43000 Through 43024; 43035 Through 43053; 43055 Through 43064; 43103 Through 43119; 43129 and 43132 (Note: Some of the Above Air- planes May Have Had Part of the Changes Installed Before Delivery From the Factory.) D O U G L A S D-31 Compliance required by September 15, 1948. To provide safer and more satisfactory oper- ation of all the doors, the following reworks must be accomplished: (1) Install new latch bolts on all emergency exit doors, main passenger door, crew door, heater compartment door, and belly cargo com- partment doors, to incorporate a notch which allows slow depressurization before the door can be fully opened in the event the handles are inadvertently turned toward the " O P E N " position while the cabin is pressurized. (2) Rework the operating and locking mechanisms of the passenger, crew, and emer- gency exit doors, to increase their strength and prevent malfunctioning. (3) Install visual inspection plugs in the passsenger, crew, and emergency exit doors to allow individual inspection of each lock bolt to determine if it is properly locked. (4) Install an assist handle above the main cabin door handle to prevent accidental grab- bing of the inside door handle. ( N O T E : Even in cases where the door handles have been changed so that the handle points downward when the door is closed and locked, it will still be necessary to install the assist handles.) 48-9-1 Douglas Applies to C-54 and DC-4 Aircraft. To be accomplished not later than April 15, 1948. Because of the hazards involved, the trans- fer of fuel between tanks must be prohibited. The following placard shall be installed in the cockpit in full view of the pilots: "Fuel cross-feed system not intended for transferring fuel from one tank to another and should not be used for this purpose. When using crossfeed system, turn off tank(s) not in use." I n addition to the placard, the F A A Ap- proved Flight Manual must be revised to in- corporate proper fuel system operation pro- cedures in accordance with the above placard. Approved Flight Manual pages may be ob- tained from the airplane manufacturer. 48-9-2 Douglas Applies to C-54 and DC-4 Aircraft. To preclude the probability of short cir- cuits occurring in the electrical distribution bus which runs from nacelles number one to four, and which is impracticable to protect by circuit protective devices, the following must be accomplished to assure that this bus will be in a fault-free condition. I . Inspection required by April 1, 1948, and thereafter at intervals not to exceed 400 hours (or in the case of scheduled air carrier opera- tors at each routine check period.) Determine that at least l/^-inch clearance is maintained between the bus and protuberances likely to "ground" the bus in the nacelle areas. Note particularly this clearance at the engine control pulleys and the pulley guide brackets. I I . Inspection required not later than July 1, 1948, and thereafter at intervals not to ex- ceed 8,000 hours. I n those installations where the large No. 1/0 nacelle-to-bus feeder cables are run in metallic conduit, such cables must be pulled out for inspection. Replace by new cable ANA Spec. ANJC48a or Douglas D E S SM-2001, where chafing or mechanical deterioration of the insulation is evident. ( N O T E : Oil-soaked insulation alone is not considered as sufficient cause to require the replacement of this cable.) I I I . Not later than June 1, 1948. Determine that the bus supporting brackets are of approved Douglas Aircraft Co. standard quality and that Adel or equivalent cushioned nongrounding type bus clamps are used for clamping the bus onto the brackets. Any substandard brackets and clamps must be re- placed. (Douglas Service Letter No. A214TS-1245/ SRD-530 dated October 10, 1947, covers this same subject.) 48-10-1 Douglas Applies to DC-6 Aircraft. To be accomplished prior to return to service in class A operation—with cabin supercharg- ing and thermal deicing operative (with the exception of heat windshield deicing) and with cabin heaters inoperative. Rework must be accomplished in accordance with the following Douglas Co. data: Service Bulletin DC-6 No. 204A. Procedure for Disconnecting No. 2 a n d No. 3 Alternate Fuel Cells, dated December 18,1947, or Service Bulletin DC-6 No. 204B, Fuel Tank Vent System Revision, as revised February 19, 1948. Service Bulletin DC-6 No. 200, Revised Heater Fuel Pressure Regulator Diaphragms, as revised Feb- ruary 26, 1948. D-32 D O U G L A S Service Bulletin DC-6 No. 201, Removal-Heater Fuel Pressure Regulator Static Balance Lines, dated December 6, 1947. Service Bulletin DC-6 No. 202, Heater Fuel Pump Check Valve—Rework, dated December 9, 1947. Service Bulletin DC-6 No. 208, Cabin Heater and De-icer Fuel System Revision, as revised February 20, 1948. Service Bulletin DC-6 No. 226, section I of V, Fire Extinguisher System for Boiler Room, as revised Feb- ruary 19, 1948. Service Bulletin DC-6 No. 226, section I I of V, C 0 2 Piping, as revised February 21, 1948. Service Bulletin DC-6 No. 226, section I I I of V, Installation Fire Detector Boxes and Conduit, dated February 12, 1948. Except that fire detectors in the under floor cargo compartments are not required since these compartments have been determined to comply with C A R 4b.383(d) requirements for Class "D" com- partments when they otherwise comply with this Air- worthiness Directive. Service Bulletin DC-6 No. 226, section I V of V, Electrical Rework, as revised Feb. 26, 1948. Service Bulletin DC-6 No. 226, section V of V, Sealing of Forward and Aft Baggage Compartment and Inverter Compartment Blower Duct, as revised February 24, 1948. Service Bulletin DC-6 No. 233, Fuel Overboard Drains for Wing Nose Area, dated January 14, 1948. Service Bulletin DC-6 No. 247, Drainage Holes and Dams for Fuselage and Wings, as revised Feb- ruary 18,1948. Service Bulletin DC-6 No. 252, Heater Exhaust Louver Removal, as revised February 17, 1948. Service Bulletin DC-6 No. 262, Installation of Com- bustion Heater Backfire Switches ,dated February 24, 1948. Superchargers with No. 7357594 stamped on gear- box housing and 5357091 stamped on the impeller housing (scroll) are satisfactory for A operation. These superchargers will be eligible for either A or C operation when reworked and identified as shown in Douglas Service Bulletin DC-6 No. 258. Service Bulletin DC-6 No. 225, Alcohol Windshield De-icing System, as revised February 24, 1948. Service Bulletin DC-6 No. 246, Relocation of Man- ual and Automatic Pressure Relief Valve, as revised February 17, 1948. Service Bulletin No. 224 canceled October 4, 1961. Service Bulletin DC-6 No. 217, Installation of Fire Axe, as revised Dec. 23,1947. Service Bulletin DC-6 No. 214, Modification of Main Junction Box and Annex, as revised February 16, 1948. Service Bulletin DC-6 No. 230, Rerouting of Heater Accessory Compartment Power Cables, as revised February 16, 1948. Service Bulletin DC-6 No, 149, Fuse Protection for Flight Instrument Transformers, dated December 5, 1947. Service Bulletin DC-6 No. 237, Addition of Fuse on Master Switch for Buffet, as revised February 21, 1948. Service Bulletin DC-6 No. 248, Conduit Clipping to Combustible Fluid Lines, as revised February 13, 1948, and Addendum dated February 13, 1948. Service Bulletin DC-6 No. 212, Protective Shield at Forward and Aft Cargo Compartment Lights, as revised January 7, 1948. Service Bulletin DC-6 No. 206, Rework of Battery Leads to Prevent Shorting, dated December 9, 1947. Service Bulletin DC-6 Jfo, 218, Addition of Phe- nolic Sheet Insulation to AC Circuit Breaker Guard Assembly, dated December 17, 1947. Service Bulletin DC-6 No. 221, Revision of Heater Fire Extinguisher Buttons, dated December 20, 1947. Service Bulletin DC-6 No. 210, Protection for Outer Wing Booster Pump Lead-in, as revised December 22, 1947. Service Bulletin DO-6 No. 213, Starter and Gen- erator Power Cable in Wing, as revised December 19, 1947. Service Bulletin DC-6 No. 242 .Relocation of T a i l Heater Control Can, as revised February 17, 1948. Service Bulletin DC-6 No. 203, Hand Fire Extin- guisher Support Bracket Revision, as revised Feb- ruary 17, 1948. Service Bulletin DC-6 No. 260, Installation of A A L Type Master Switch Arrangement and Emergency Inverter, as revised February 24, 1948. (This instal- lation not required on aircraft incorporating one set of vacuum operated flight instruments,) Service Bulletin DC-6 No. 267, Installation Heater Safety Relays, dated February 27, 1948. Service Bulletin DC-6 No. 205, Rework of D C - 6 Fuel Tank and Cell Vent Chambers, as revised Feb- ruary 23, 1948. Service Bulletin DC-6 No. 207, Guard for Fuel Booster Pump Switches, as revised December 19, 1947. Service Bulletin DC-6 No. 253, Fireproofing of Wing De-icer Ducts in Nacelles, as revised February 24, 1948. Service Bulletin DC-6 No. 219, Rework of Whit- taker Firewall Shut-Off Valves, dated December 19, 1947. Service Bulletin DO-6 No. 114, Fuel Flow Trans- mitter Line Replacement, dated October 29, 1947. Service Bulletin DC-6 No, 261, Installation of Oil Separator for Vacuum Pump Drain Lines, dated Feb- ruary 25, 1948. Service Bulletin DC-6 No. 249, Boiler Room Duct Revision, dated February 24, 1948. Service Bulletin DC-6 No, 232, Wing Heater E x - haust Insulation Cover, as revised February 16, 1948. Service Bulletin DC-6 No. 234, Tail Heater Ground Blower Check Valve Revision, as revised January 23, 1948. The rework outlined in the data listed above is based upon an airplane which incorporates certain production changes. Therefore, in or- der to satisfactorily complete the required re- D O U G L A S D - 3 3 work, some aircraft* must also be revised in accordance with the following: Service Bulletin DC-6 No. 62, Rework-Cabin Pres- sure Control Valve Linkage, dated September 2, 1947. Service Bulletin DC-6 No. I l l , Cabin Heater Fire Extinguisher Bottle, dated October 22, 1947. (Partial accomplishment only is required, which Is to include: Support No. 5333704-10, Pipe No. 5332568-518 and attaching parts.) Service Bulletin DC-6 No. 119, Aft Baggage Com- partment Smoke Detector Pick-Up Pipe Revision, dated December 6, 1947. (To be accomplished only if Modification Item 59 has not been accomplished.) Service Bulletin DC-6 No. 16, Installation of Ad- ditional Dams and Drain Plug in Fuselage Bottom, dated June 26,1947. Service Bulletin DC-6 No. 161, Rear Lounge Hot Air Supply Duct Sound Trap Installation, dated Jan- uary 30, 1948. (Need not be accomplished on Serial Nos. 42854 through 42891, 43000 through 43009, 43055, and 43081 until Service. Bulletin DC-6 No. 59, Im- proved Aft Lounge Heating, dated September 16, 1947, has been accomplished.) Service Bulletin DC-6 No. 95, Revision-Ground Blower Duct and Check Valve and Air Duct Connec- tion Improvement, dated October 21, 1947. (Accom- plish portion covered by Service Change No. 354 and that portion of Service Change No. 358 which includes cable assemblies 1342327-502 and -504s hook No. 1342315, latch assembly 1342314, AN 960-10L, wash- ers, AN 486-4 clevis, AN 393-11 and -13 pins, AN 380-2-2 cotters and AN 365-428 nuts.) I n addition to the above, the following must also be accomplished on all aircraft: 1. Inspect the wing structure around the fuel tanks in accordance with Douglas Serv- ice Letter to all operators dated December 29, 1947 (ref. A214TS-2521/SRD 529.37). Any damage found as a result of the inspection must be satisfactorily repaired. 2. The Airplane Flight Manual for each airplane must be revised to include FAA-ap- proved procedures covering "Fuel Useage," "Fire Fighting" and "Smoke Evacuation from the Cockpit." This information, pages 1 and 2 of Section I , and pages 31 through 65 of Sec- tion I I I , as revised February 26,1948, for air* craft incorporating Hamilton Standard Pro- pellers, or pages 1 and 2 of Section I , and pages 31 through 71 of Section I I I , as revised February 26, 1948, for aircraft incorporating •Serial numbers of airplanes affected by this rework are Hated on the pertinent Service Bulletin (s). Also, additional information may be obtained from the "Supplement" to "Cross Reference List-Service Changes and Modification Items" which has been prepared and revised by the Douglas Co. as of February 11, 1948. Curtiss Propellers, should be obtained from the Douglas Co. 3. Disconnect the cabin heater electrically and block off all fuel lines to this heater. 48-11-1 Douglas Applies to DC-6 Aircraft. To be accomplished prior to return to serv- ice in class B operation—with cabin heating and thermal deicing, including windshield, op- erative, but with cabin supercharging inopera- tive. Rework must be accomplished in accordance with the following Douglas Co. data: 1. Accomplish all rework covered by data listed in Note 48-10-1 for class A operation with the exception of the rework outlined in Service Bulletins No. 258, No. 225 and No. 230. Also accomplish paragraphs 1 and 2 but do not accomplish 3 of Note 48-10-1. 2. Rework in accordance with the following must also be accomplished: Service Bulletin DC-6 No, 223, Stainless Steel Heater Discharge Ducts and Windshield Anti-Icing Ducts, as revised February 24,1948. Service Bulletin DC-6 No. 38, Heater Fire Warn- ing Switch—Installation of, dated October 6,1947 Service Bulletin DC-6 No. 250, Cabin Heater Shut- Off Control, dated February 19,1948. Service Bulletin DC-6 No. 211, Main Cabin Heater Exhaust-^Revision of, as revised February 23, 1948. Service Bulletin DC-6 No. 227, Cabin Heater Scoop Segregation, as revised February 24, 1948. Service Bulletin DO-6 No. 243, Revise Cabin Heater Ignition Conduit in Boiler Room and Hell-Hole Area, as revised January 26,1948. Service Bulletin DC-6 No. 245, Heater and Buffet Power Cable Conduit, as revised February 24, 1948. The rework outlined in the data listed above is based upon an airplane which incorporates certain production changes. Therefore, in or- der to satisfactorily complete the rework re- quired, some aircraft* must also be revised in accordance with the following: Service Bulletin DC-6 No. 40, Heater Exhaust Fire Detector—Replacement of, dated September 3, 1947. (Accomplish partially*). Service Bulletin DC-6 No. 71, Installation—Oil Trap and Drain, Cabin Heater Combustion Air Duct, dated September 3, 1947. (Accomplish Electrical Phase of Service Bulletin only.) Service Bulletin DC-6 No. 96, Windshield De-Icing Air. Discharge Revision, dated December 22, 1947. Service Bulletin DC-6 No. 141, Improvements In DCMJ Cabin Pressure and Cabin Air Conditioning Systems, dated February 19,1948. Service Bulletin DC-6 No. 150, Revision—Cockpit and Windshield Heat Control System and Windshield Air Exhaust, dated December 11,1947. D-34 D O U G L A S Service Bulletin DC-6 No. 160, Cabin Air Mixing Valve Actuator, dated February 2,1948. Service Bulletin DC-6 No. 179, Ground Blower Elec- trical Wiring Revision, dated December 29, 1947. Service Bulletin DC-6 No. 28, Installation of Am- meter and Selector Switch for Functional Check of Pitot and Air Scoop Anti-Icing Heaters, dated August 20, 1947. (Must be accomplished completely except that P/N 3320167-5l'6 nameplate, 1 required, shall be deleted.) I n addition to the above, the following must also be accomplished in all aircraft: (a) Disconnect the superchargers and drain and flush supercharger oil system. 48-11-2 Douglas Applies to DC-6 Aircraft. To be accomplished prior to return to serv- ice in class C operation—with cabin super- charging, cabin heating, and thermal deicing including thermal windshield deicing, in opera- tion. Rework must be accomplished in accordance with the following Douglas Co. data: 1. Accomplish all rework covered by data listed in Notes 48-10-1 and 48-11-1 for classes A and B operation, including paragraphs 1 and 2 but excluding paragraph 3 of Note 48-10-1, and excluding paragraph (a) of Note 48-11-1. 2. Eework in accordance with the following must also be accomplished: Service Bulletin DC-6 No. 258, Cabin Supercharger Revisions and Bearing Oil Control, dated February 13, 1948. (Also, all superchargers must incorporate low speed drive shaft per Douglas Installation Drawing No. 5350684-C.) Service Bulletin DC-6 No. 257, Relocation of Cabin Supercharger Oil Cooler, as revised February 18, 1948, The rework outlined in the data listed above is based upon an airplane which incorporates certain production changes. Therefore, in or- der to satisfactorily complete the rework re- quired, some aircraft* must be revised in ac- cordance with the following: Service Bulletin DC-6 No. 13, Installation of an Oil Pressure Warning Switch for each Cabin Super- charger Gear Box, dated August 28,1947. 48-12-1 Douglas Applies to A l l C-54 and DC-4 Aircraft As Specified by Civil Air Reg- ulations Amendments 41-3,42-2, and 61-2. To be accomplished not later than the dates specified in the above amendments as revised by • S e r i a l n u m b e r s o f a i r p l a n e s a f f e c t e d b y t h i s r e w o r k a r e l i s t e d o n t h e p e r t i n e n t S e r v i c e B u i l e t i n ( s ) . A l s o , a d d i t i o n a l i n f o r m a t i o n m a y b e o b t a i n e d f r o m t h e " S u p p l e m e n t " t o " C r o s s R e f e r e n c e L i s t - S e r v i c e C h a n g e s a n d M o d i f i c a t i o n I t e m s " w h i c h h a s b e e n p r e p a r e d a n d r e v i s e d b y t h e D o u g l a s C o . as o f F e b r u a r y 11, 1948. special Civil A i r Regulations Serial Nos. 385, 390,390A, 390B and any subsequent regulations affecting these compliance dates. A l l air carrier aircraft must be modified to comply with the fire prevention requirements as outlined in C A R Amendments 41-3, 42-2, and 61-2. The modifications outlined in the following listed Douglas Service Bulletins and AD 47-42-3 are required for compliance with these amendments. Other modifications shown to be equivalent to those covered by the Service Bulletins will also be acceptable. Service Bulletin No. 62, Install Smoke De- tector in Belly Baggage Compartment; Service Bulletin No. 66, Engine Section Piping and F i t - ting Revision; Service Bulletin No. 69, Installa- tion of Enclosed Waste Container in Lavatory. I n addition to the above it will be neces- sary to ascertain that all interior materials and finishes comply with the applicable sections of CAR 4b. Safety Regulation Release 259 out- lines acceptable procedures for complying with these particular requirements. 48-12-2 Douglas Applies to A l l C54r-DC Series and the Following DC-4 Airplanes: 42904 Through 42943, 42948 Through 42952, 42982 Through 42996, 43065 Through 43068, 43071, 43072, 43093, 43094, and 43102. To be accomplished not later than the date established in accordance with the provisions of Special Civil A i r Regulation Serial Num- ber SR-329, or any subsequent regulation affecting this compliance date. As a result of investigation of heater fires, the following changes are to be accomplished in the nose and cabin heater installation: 1. Install steel firewall at Station 260 (cabin forward bulkhead) from ceiling level to top of bulkhead to provide isolation between heater compartment and the space between cabin ceil- ing and top of fuselage. Also, replace present wood panels under heaters with metal panels. (Douglas Service Bulletin DC-4 No. 47 cov- ers this same subject.) 2. (a) Install all heater control components in airtight steel containers. (&) Replace present heater fuel supply pumps with a single electric driven pump attached to No. 2 main fuel tank. (c) Provide shrouds around all heater fuel line fittings in fuselage. D O U G L A S D-35 (d) Install a fire detector and extin- guisher system for the nose heater and cabin heaters. (Douglas Service Bulletins D G 4 Nos. 64 and 64 addendum cover this same subject.) I n some cases, operators have obtained ap- proval from F A A Regional Offices for systems which differ in arrangement and detail from the above provisions. Designs which have been separately approved in this manner are considered to meet the intent of this Note. This supersedes AD 46-39-2. 48-14-4 Douglas Applies to A l l C-54 Se- ries Aircraft Prior to Model C-54G. Compliance required by November 1,1948. Because of fire hazard install a tailpipe shroud deflector on each tailpipe shroud assem- bly to prevent flame from a zone 1 fire enter- ing the engine accessory section through the space existing between the shroud and cowling. AN 3-3A bolts may be substituted for the AN 3C-3A bolts called out in the Service Bulletin. (Douglas Service Bulletin C-54r-289 adden- dum covers this same subject.) 48-15-3 Douglas Applies to C-54 and DC-4 Aircraft. Compliance required by November 1,1948. Because of service failures of hydraulic pres- sure regulator valves, the following must be accomplished: 1. (a) Modify Douglas hydraulic pressure regulator valve P/N 5104005, P/N 5231848, or P/N 5327293 to the equivalent of Douglas regu- lator P/N 5332857, or (5) Convert Douglas hydraulic pressure regulator valve P/N 5104005, P/N 5231848, or P/N 5327293 to Douglas regulator P/N 5332857, or (o) Install Douglas hydraulic pressure regulator P/N 5332857, or (d) Install Bendix hydraulic pressure regulator P/N 407484, or (e) Install Air Associates hydraulic pressure regulator valve P/N HC-3600, or (/) Install Vickers hydraulic pressure regulator valve P/N AA-34551, P/N A A - 34552, or P/N AA-34585 which must have the letter " C " or subsequent terminating the regulator serial number, i.e., "Serial No. 0000C," "Serial No. 0000D," etc. 2. Install a hydraulic fluid filter with Puio- lator core in regulators listed in 1, (a) through (Douglas Service Bulletin DC-4 No. 22, "Rework of Hydraulic Presssure Regulator Valve" with addendum, "Optional Installation of Hydraulic Pressure Regulators" covers part 1. Douglas Service Bulletin C-54-239, "In- stallation of Filter in Hydraulic Regulator Operating Line," covers part 2.) 48-17-1 Douglas Applies to A l l DC3 Se- ries Aircraft As Specified by Civil Air Regulations Amendments 41-3, 41-18, 42-2, 42-8, 61-2, and 61-16. To be accomplished not later than the dates specified in the above amendments and any subsequent regulations effecting these compli- ance dates. A l l air carrier aircraft must be modified to comply with the fire prevention requirements as outlined in CAR Amendments 41-3, 41-18, 42-2, 42-8, 61-2, and 61-16. The modifica- tion outlined in the following listed Douglas Service Bulletins are required for compliance with these amendments. Other modifications shown to be equivalent to those covered by the Service Bulletins will also be acceptable. DC3 No. 250, "Installation of Fire Detector in Engine Accessory Section and Smoke Detec- tor in Aft Cargo Compartment"; DC3 No. 252, "Rear Baggage Compartment Access Door and Vent"; DC3 No. 258, "Elimination of Holes in Firewall, Addition of Control Cable Seals, Re- placement of Dural Plates and Fittings With Steel Plates and Fittings. Replacement of Fluid Carrying Lines Forward of Firewall With Steel or Fire Resistant Flexible Hoses"; DC3 No. 259, "Installation of Shut-off Valves on Lines Carrying Combustible Fluids Into the Engine Accessory Section". (Installation of additional fuel valves listed on Page 2 of this Bulletin is recommended but is not manda- tory.) N O T E : I t will be noted that Service Bul- letins DC3 No. 258 and No. 259 apply to all DC3C and DC3D ((M7 and C-117) Series air- planes only with P&W R-1803 engines. Since there are various differences in early DC3 powerplant installations with P&W S1C3-G engines and Wright GR-1820 engines, it will be the operator's responsibility to use these two D-36 D O U G L A S Bulletins as a guide and develop the fire pre- vention items for other DC3 Series airplanes accordingly. I n addition to the above, it will be necessary to ascertain that all interior materials and fin- ishes comply with applicable sections of C A R 4b. Safety Regulation Release 259 outlines acceptable procedures for complying with these particular requirements. 48-17-4 Douglas Applies to A l l DC-4 and C-54 Aircraft Equipped With Pesco Vac- uum Pumps and Separators. To be accomplished not later than the date established in accordance with the provisions of special Civil A i r Regulation Serial Number SR-329, or any subsequent regulation affecting this compliance date. I n case of malfunctioning of vacuum pumps or other vacuum pump system components, fire can occur withing the lines and burn through the hose connections into the engine compart- ment. To prevent such occurrences a hose liner must be installed between the exhaust port vacuum pump fitting and the separator line or a stainless steel flexible hose must be installed between the pump and the separator. (Douglas Service Bulletin DC-4 No. 85 as revised March 10, 1948, covers this same sub- ject.) 48-19-3 Douglas Applies to DC-6 Serial Numbers 42854 Through 42896; 43000 Through 43024 ; 43035 Through 43052; 43055 Through 43058; 43061 Through 43064; and 43105 Through 43110. Compliance required by September 15, 1958. Due to two failures in flight and to reported excessive looseness in the elevator trim tab operating mechanism, the following must be accomplished: 1. Rework drum, P/N 4344461 into drum, P/N 4357010^, by boring hole in end of drum 0.8755-0.8745 diameter, 0.188-0.189 deep and concentric within 0.002 full indicator reading, and press in bushing 4357010-2 into hole. Re- move nut, P/N 2335472, press in nut, P/N 2357008, in place so that two holes in nut match two holes in drum, P/N 4357010-4, and insert two pins, P/N 1335480, and stake in place. This rework changes jackshaft mechanism assembly, P/N 434460, into P/N 4357010. 2. Rework push-pull tubes, P/N 2344790, into P/N 2357984-2 by cutting off swaged end of tube y 8 inch so that new tube length is 10 inches. Insert large end of plug, P/N 2357980, into tube 1 % inches, drill two 0.161 diameter holes (No. 20 drill) and attach plug to tube with two rivets, P/N AN 430 AD5-16. Ma- chine hex end on socket, P/N 2331924, and in- stall in end of the tube opposite to plug, P/N 2357980. Rework end assemblies, P/N 2331925 into end assemblies, P/N 2357983, and install with locknuts, P/N AN 316-5R and washer 1357982. Reassemble trim tab mechanism and install on aircraft. (Douglas Service Bulletin DC-6 No. 123 covers this same subject.) 48-22-1 See Pratt & Whitney Engines. 48-25-1 Douglas Applies to A l l C54-DC Series and DC-4 Airplanes Prior to Serial Numbers 43095, Operated in Scheduled and Nonscheduled Air Carrier Passenger Service. Compliance required by May 1, 1949. Because of previous fires and the fire hazard which exists in zone 3, it is necessary that the following be accomplished: 1. To increase the effectiveness of the fire warning system in the nacelles, seven fire de- tector units must be installed in the nacelle (zone 3) aft of the firewall at the following aproximate locations: (a) 1 unit at the top of nacelle approxi- mately 15 inches forward of the front spar. (&) 1 unit at each wing section fireseal. (c) 1 unit at the aft end of the nacelle area under the fuel tank and near the fuel supply lines. (d) 3 units on the aft face of the firewall (one near the top and one at each side.) These fire detectors should be connected into the existing engine accessory compartment fire detector circuit, and the entire system wired into the circuit of the audible warning system. (Douglas Service Bulletin DC-4 No. 60 covers this same subject.) 2. Revise the present fire extinguisher system in nose wheel well in order to install two addi- tional 15-pound C 0 2 bottles. Provide addi- tional plumbing aft of the firewall in each D O U G L A S D-37 nacelle by running a perforated line across the top of the nacelle directly aft of the oil tanks and then diagonally aft and down to a point under the bottom wing skin aft of the front spar, at which point it will cross the nacelle and run diagonally forward and up to the original starting point. The discharge pipes tee into the present % ring O. D. supply pipes for the accessory section. A l l aluminum C 0 2 supply pipes between firewall and front spar and between the inboard and outboard fireseal ribs of each nacelle are to be replaced with steel pipe. (Douglas Service Bulletin DC-4 No. 67 covers this same subject.) 48-28-2 Douglas Applies to C-54 and DC-4 Aircraft. To be accomplished not later than April 1, 1949. As a fire protection measure in order to pre- vent burn through, replace the present cabin heater combustion ducts with corrosion resist- ant steel ducts. (Douglas Service Bulletin DC-4 No. 89 covers this same subject.) 48-44-1 Douglas Applies to A l l C-54 and DC-4 Series Aircraft. To be accomplished not later than March 1, 1949. I n order to preclude nose gear retraction malfunction due to particles of disintegrated packing clogging the present upline orifice fit- ting, it is necessary to install an orifice fitting having a floating pin in the orifice hole and to replace the present packing used on the retract- ing cylinder with a more satisfactory packing. To accomplish this change: 1. Replace the present upline orifice fitting with a union fitting and rework the existing tee fitting to include an orifice fitting (0.063- inch diameter floating pin in 0.090-inch diam- eter orifice hole) in the pipe threaded end. 2. (a) Replace the existing chevron packing on the nose gear piston assembly with two syn- thetic chevron packings and two leather chev- rons. Install two dural packing rings on each respective end of the piston head. (5) Replace existing packing on the nose gear cylinder end assembly with one dural packing ring, three synthetic chevron packings, and one leather chevron packing. (<?) Install two new washers over the end of the cylinder barrel. (Douglas Service Bulletin DC-4 No. 78 dated May 4, 1948 covers this same subject.) 48-48-2 Douglas Applies to A l l DC-6 Air- craft Not Equipped With Steel Vacuum Pump Discharge Lines Aft of the Firewall and Chicago Metal Hose Assemblies From the Oil Separator to the Pesco Pump. To be accomplished as soon as practicable, but not later than May 1, 1949. In cases of malfunctioning of vacuum pumps or other vacuum pump system components, fire can occur within the lines and burn through the hose connection into the engine compart ment. To prevent such occurrences, replace the present Aeroquip Hose P/N 260-10WD- l S 1 ^ , existing between oil separator and Pesco vacuum pump, with a new Chicago Metal Hose Assembly No. 9273-1. (Douglas Service Bulletin No. 383 covers this same subject.) Also, to prevent fire from entering the zone behind the firewall, replace the dural vacuum pump discharge line, aft of the firewall, with a steel line. (Douglas Service Bulletin DC-6 No. 401 covers this same subject.) 48-49-3 Douglas Applies to A l l DC-6 Air- planes. Compliance required not later than March 1, 1949. To reduce the probability of a loss of power for electrical circuits considered to be essential in flight, these essential circuits were designed to be connected directly to the master bus. Other less essential circuits are connected to the master bus through a 500-ampere Burndy limiter (fuse). I n an undetermined number of aircraft some, of the essential circuits were inadvertently con- nected to the distribution bus rather than to the master bus. I t is necessary, therefore, that all DC-6 air- craft be inspected and such rewiring as neces- sary be done to assure that the following cir- cuit protectors are connected to the master bus: Radio Master (Bl-102),Fuel Booster Pumps (Bl-63, 97), Inverter Power (Bl-111, 116), Propeller Booster (Curtiss Propellers only, Fl-28,29), Propeller Control (Curtiss: Bl-141, 142, 143, 144. Hamilton Standard: Bl-188, D-38 D O U G L A S I 189, 190, 191), Propeller Synchronizer ( B l - 145), Governor Control (Hamilton Standard only, B l - 4 9 2 ) , Generator Control Panel (Eclipse Generator System only, Bl-246, 247, 248, 249. Reference Douglas Service Bulletin DC-6 No. 329). (Douglas Service Letter A214-T.3338/TFW dated October 2 2 , 1948 covers this same sub- ject.) 48- 52-1 Douglas Applies to A l l DC-6 Air- craft. To be accomplished not later than June 1, 1949. 1. Revise method of connecting power leads to main bus through Burndy limiters. 2 . Reroute generator and starter cables in No. 4 nacelle to eliminate possibility of abra- sion of power cables. 3. Install stainless steel combusion air intake ducting on all heaters. 4. Revise wing heater exhaust outlets to pre- clude nacelle fluids contacting exhaust piping. 5. Install expansion turbine oil drain and filling drain. 6. Install ducting from the wing and tail heater combustion air blowers to the outside skin of the nacelles and tail section. Ducting within the nacelles to be of stainless steel. 7. Delete present wing heater 1.4 pounds C 0 2 bottles and eject the fuselage nose C 0 3 banks to either wing heater. C 0 2 to go into the heater deicing and combustion air and into the area surrounding the heaters. Controls for the new system to be grouped with and worked in the same sequence as the tail and cabin heater fire extinguisher system. (Douglas DC-6 Service Bulletins No. 220, revised February 18,1948; 270, dated March 8, 1948; 231, revised January 19, 1948; 259, re- vised March 12,1948; 2 5 5 , revised February 26, 1948 ; 256, revised February 12, 1948; and 272, revised April 8, 1948; cover the above items consecutively.) 49- 6-2 Douglas Applies to DC-6 Aircraft. To be accomplished at every 8,000 hours of total flight time. Replace the following attachment bolts: ( 1 ) fuselage to center wing, ( 2 ) outer wing to center wing, (3) vertical stabilizer to fuse- lage, (4) horizontal stabilizer to fuselage and, ( 5 ) engine mount to firewall. The 8,000-hour period may be extended to 16,000 hours when studs 2325933 or 2340697, 2353832, 4329243 and 4333164 are replaced with studs 2361992, 2361993, 4361995 and 4361994, respectively, having letter "R" stamped on thread end and bolts in all other attachments listed are placed with NAS bolts with threads rolled after heat treatment. Bolts and studs removed from the airplane are to be scrapped and are not to be used again. (Douglas Service Bulletin DC-6 No. 410 con- tains a list of all studs and bolts affected and their replacements.) 49-27-3 Douglas Applies to A l l Models C54-DC and DCM Series Aircraft. To be accomplished as indicated below: 1. Prior to 5,000 hours total airplane time, or at next scheduled inspection at which neces- sary facilities are available, on airplanes with more than 5,000 hours total time, inspect nose gear yoke and fittings, P/N 5087950 and either 5087951 or 5180402 to determine if the i/2-inch radius fairs in properly with the journal. A l l parts having a poor radius condition must be replaced immediately with parts having the correct radius fairing into the journal. This inspection does not have to be repeated if al- ready accomplished. 2. Parts having a good radius must be re- placed at each 17,500 hours airplane operation time. I f the replacement parts have been shotpeened, as per Douglas Aircraft Co. rec- ommendations, the replacement time may be extended to 30,000 hours airplane operation time. 3. Unused parts having a poor radius may be used, after being reworked according to Douglas Aircraft Co. recommendations. 4. A l l used nose gear yoke end fittings hav- ing not more than 17,500 hours total time may be reinstalled and used for a total time of 30,000 hours if Zyglo inspection reveals no cracks; the radius of the journal is properly reworked to meet the limiting dimensions of Douglas E. C. 1361954 and the part is shot- peened in accordance with Douglas Aircraft Co. standards. 5. At the time of replacement of parts as per item 1, or at the next major aircraft overhaul period, rework bushing, P/N 1087938, to in- corporate a i^-inch radius Qir'the inside diam- D O T J G L A S D-39 eter at theflangedend of the bushing. Rework ring, P/N 2103390, by providing a 0.031-inch radius on the inside edges. (Douglas Service Letters A-214-T.51/WBM dated January 7, 1948; A-214 TS2249/WBM dated November 25,1947; and A-214-TS-1572/ WBM dated October 20,1947, cover the above.) This supersedes AD 48-24r-2. 49-30-1 See Curtiss Propellers, 49-33-1 Douglas Applies to A l l Model DC-6 Airplanes Eqiupped With Hamilton Stand- ard Model 43D60/6851A-0 Props. Compliance required not later than Septem- ber 10,1949. As a precautionary measure against fatigue failure, Hamilton Standard Model 43D60/ 6851A-0 propeller blades may not be operated in excess of 3,500 hours unless the taper-bores have been remachined and reshotpeened by the manufacturer. I n addition, any blades of this model which have sustained damage sufficient to change their face or edge alinement shall be withdrawn from service pending final results of manufacturer's test program. 49-38-2 Douglas Applies to A l l Models C-54 and DC-4 Aircraft. To be accomplished at every 9,000 hours of total airplane flight time. I n those cases where the pressent bolts have or will have accumulated more than 9,000 hours time prior to the next regular overhaul period, the first replacement time may be extended, at the discretion of the CAA Inspector, to coin- cide with a regular overhaul period but in no case should the adjustment time exceed 1,500 hours accumulated after January 26, 1948. Thereafter the bolt replacement shall be at the 9,000- or 18,000-hour period, whichever is ap- plicable. Replace the following bolts: Fuselage to Center Wing Attachment; Outer Wing to Cen- ter Wing Attachment; Vertical Stabilizer At- tachment to Fuselage Tail, Station 953; Engine Mount to Fire Wall Attachment; Horizontal Stabilizer to Fuselage T a i l Assembly Attach- ment. The 9,000-hour period may be extended to 18,000 hours when studs 4105725-1 and -2 in outer wing attachment have been replaced with special studs Nos. 4357723-1 and -2 having let- ter "R" stamped on thread end and bolts in all other attachments listed are replaced with NAS bolts with threads rolled after heat treat- ment. The bolt part numbers and the number of bolts required are shown on pages 4 and 5 of the Douglas Service Magazine of August 1947. Bolts removed from the airplane are to be scrapped and are not to be used again. (Douglas Service Letter No. 66, Supplement No. 2, dated July 18, 1951, covers this same subject relative to wing alinement at Station 421.) This supersedes AD 48-4-3. 49-46-1 Douglas Applies to A l l Models DC-4 and DC-6 Aircraft Equipped With Vacuum Systems, Incorporating Oil Sepa- rators Other Than the Type Mentioned in Item 2. To be accomplished not later than April 1, 1950. To guard against the possibility of excessive air temperatures in the vacuum system dis- charge line, one of the following modifications must be accomplished to this system: 1. Install a fusible plug in the side of the vacuum pump discharger port at the right angles to the axis of the discharge port boss. Some pumps incorporate a plugged hole in the discharge port which may be enlarged to a %-inch pipe tapped hole to accommodate the fusible plug. This plug should employ an AN 840-8D fitting with a binary eutectic mix- ture of 67.8 percent tin and 32.2 percent cad- mium, which has a melting point of 351° F. Figure 2 describes the design of such a plug. The %-inch fusible plug fitting is intended for pumps such as the Model 3P-211 and 3P- 32.Z% Cadmium, 67.8% Tin mixture poured to form _L" plug (5 grams) 4 V A C U U M S Y S T E M F U S I B L E P L U G F I G U R E 2 D-40 D O U G L A S 485. For smaller pumps such as the 3P-207, and AN 840-6D fitting, incorporating the same modification as shown below, should be used. Incorporation of an overboard drain line clamped to the fusible plug is recommended but is not mandatory. Brass fittings of the same design as the above dural fittings are acceptable. On in- stallations which do not use an overboard dis- charge line the possibility exists that the plug may damage other nacelle components if it can hit them upon being out of the adapter as high velocity. Therefore, if no overboard discharge line is provided, the installation must be made in such a manner that the plug will not be directed toward any vulnerable compo- nents when it issues from the adapter. 2. Replace the present oil separator with a new oil separator, Genisco No. 40081 or equiv- alent. The new separator incorporates a pres- sure relief valve and can be disassembled for cleaning. (Douglas Service Letter A-129-T-1271/ WB-ll-Q-4, dated April 1, 1949, covers this same modification.) 50-16-1 Douglas Applies to A l l Model DC-6 Airplanes Below Serial. Number 43149. Compliance required as soon as possible but in any event not later than January 1,1951. 1. Conduct electrical and mechanical func- tional check of propeller reverse mechanism, throttle system. 2. (a) Rework fish mouth in the 2345735 throttle latch assembly to assure a more posi- tive lock. (b) Rotate the 2333338 arm-throttle re- verse 20° clockwise on the shaft of the 4333339 lock assembly or replace with new 2333338 " F " change parts. (Douglas General Service Letters DC-6 No. 19, dated November 18, 1949, and DC-6 No. 23, dated January 20,1950, cover the above two items.) 50-18-2 Douglas Applies to A l l Model DC-6 Aircraft Equipped With Hamilton Standard 43D60/6841A-0, 6851A-0, and 6873A-0 Pro- peller Blades and R-2800-83AM4, R-2800- 83A Or CA Type Engines. To have been accomplished by April 28,1950. A recent propeller blade tip failure of a Hamilton Standard 43D60/6851A-0 propeller on a DC-6 powered with R-2800-CA-15 en- gines probably resulted from a worn P/2 order engine crankshaft torsional damper P/N 101169. Until further notice or until the en- gines are known definitely to comply with P&W Service Bulletin Nq, 1033 dated Novem- ber 30,1949, all DC-6 aircraft using Hamilton Standard 6841A-0, 6851A-0 and 6873A-0 blades and R^2800~83AM4 or CA type engines shall be placarded to avoid all operation be- tween 1,800 and 1,975, between 2,025 and 2,175 and between 2,225 and 2,450 r.p.m. Only ac- celeration and deceleration through placarded ranges shall be permitted. For gross weights above 80,000 pounds, 2,450 r.p.m. is permissible for normal climb. For gross weights below 80,000 pounds, climbing r.p.m. between 2,450 and 2,600 permissible. For gross weights above 80,000 pounds avoid operation above 2,450 r.p.m. except for takeoff and emergencies. For R-2800-83A engine installations, operating re- striction presently covered in Aircraft Speci- fication A781, Note 5C (1) applicable and until further notice operation between 1,800 and 1,975 and between 2,025 and 2,175 shall be prohibited. 50-23-2 Douglas Applies to A l l Model DC-6 Aircraft. To be accomplished as indicated below: 1. A l l P/N 5245424 and P/N 5248748 nose gear yoke end fittings which have not been shotpeened in the journal radius prior to origi- nal installation or by subsequent rework should be removed for inspection after being in serv- ice for a period not to exceed 6,000 hours. Nose gear yoke end fittings which have already accumulated service time in excess of 6,000 hours should be removed for inspection as soon as practical but not later than September 1, 1950. Shotpeening can be distinguished by the dull gray color and coarse surface of the shotpeened area. 2. Fittings removed at the 6,000-hour period may be used for an additional 4,000 hours or a total service life of 10,000 hours if inspected and reworked as follows: (a) Strip anodic surface from part, and subject to Zyglo inspection paying particular attention to the journal radius. I f no cracks are found, the radius should be polished to remove all blemishes and then shotpeened. This inspection and shotpeening must be done D O U G L A S D - 4 1 by the Douglas Aircraft Co., an agency ap- proved by that company, or by a method that has been substantiated as being equivalent to the procedure recommended by the Douglas Co. (b) Inspect the base radius of the spot faces of the six mounting holes. Parts having zero radius (sharp corner) to 0.031 radius at this point must be reworked to obtain an 0.062 spot face radius. I t will be permissible to increase the original spot face diameter of 1 % inches to 1*4 inches to obtain the 0.062 radius. Parts having 0.031 or better radius need not be reworked. Parts should be reanodized after completion of all work. (<?) Inspect the inside diameter of the 2103390 ring. A l l sharp edges should be given a 0.031 radius. (d) Inspect the inside diameter of the flanged end of the 2333253 bushing to see that it has a %-inch radius and rework if necessary. 3. Fittings shotpeened at time of original installation may be operated for a maximum service period of 10,000 hours provided they do not have the zero spot face radius at the mounting holes. Parts falling in this cate- gory should be removed at the normal gear overhaul period of 8,000 hours for rework of the spot face radius. 4. A l l fittings should be scrapped after reaching a total service life of 10,000 hours. (Douglas General Service Letter DC-6 No. 26 dated April 7, 1950, covers the same sub- ject.) 50-43-1 Douglas Applies to A l l Model DC-6 Aircraft. To be accomplished on or before the next major inspection where facilities are available and in any event by December 15, 1950, unless already accomplished at last previous tire change, and thereafter at the regular major inspection nearest to 330 hours. This inspec- tion period may be extended to tire replace- ment periods by the assigned CAA Agent when the airline's service experience indicates that a satisfactory level of safety is being maintained. Remove the tires from all Goodyear main wheels, Model L20HBMF, wheel assemblies 9540049 and 9540332, and thoroughly inspect by Zyglo or equivalent methods the critical areas of the wheel, such as: 1. Brake drive flange area. 2. Tire bead radius of the fixed flange. 3. Tire bead seat radius of the demountable flange. 4. Radius of the demountable flange step. 5. The flange returning ring groove in the wheel. I f cracks are found in any of the critical areas at one of these inspections, the wheel should be retired from service. 50-46-1 Douglas Applies to A l l Models DC3 and C-47 Series Aircraft Which Utilize a Standpipe in the Engine Oil Tank for Pro- peller Feathering Oil Reserve. Compliance required not later than the first engine change after December 1, 1950. There have been several cases of inability to feather the propeller due to inadequate feathering oil supply, following loss of engine oil. To correct this condition ascertain the quantity of oil retained in the tank by the propeller feathering standpipe with the air- plane in the level flight attitude. I f the quan- tity so retained is less than iy2 gallons, rework the standpipe so that at least this quantity is retained. Aircraft employing C-47 type oil tanks, Douglas P/N 5110511 with Douglas P/N 1355088 standpipe will be considered satis- factory. 5 0 - 5 2 - 1 See Hamilton Standard Propellers. 5 1 -1-1 Douglas Applies to A l l DC-6 Air- craft. To be accomplished as indicated below. (a) A l l airplanes at each 300 hours of flight time—Inspect for broken studs at the front spar lower and upper fittings at wing joint Station 421. Also inspect lower forward front spar fittings, P/N 4332884 and -1, and upper forward fittings, P/N 4332885 and - 1 , for cracks in area approximately 2 inches out- board of fitting face. (b) I f broken stud is found, replace both studs at spar fittings with parts having threads rolled after heat treat, install bolt with threads rolled after heat treat at center spar, and re- place lower fitting P/N 4332884 and - 1 and upper fitting P/N 4332885 and -1 with newly designed heavier fittings P/N 4397872 and -1 and P/N 4397873 and -1, respectively. Return of an airplane to service prior to the avail-