SERVICE BULLETIN NUMBER M20-208B
MOONEY M20F · Service Bulletins
Overview
This service bulletin outlines inspection procedures for the fuselage tubular structure of Mooney M20 series aircraft, particularly addressing corrosion issues. It specifies compliance timelines and detailed steps for inspection and maintenance for affected models.
- Applicable to all M20 Series aircraft manufactured before Jan. 1, 1976, excluding certain S/Ns.
- Corrosion in tubular structure is a concern, especially for aircraft in coastal areas.
- Inspection is required at the next annual or 100-hour inspection.
- Detailed steps for inspection and maintenance are provided in two parts.
- Mooney will cover up to 10 hours of labor under warranty for repairs.
- New foam insulation is recommended for installation after inspection.
- Ultrasonic testing is suggested for suspected internal corrosion.
- Compliance notes must be entered into the aircraft log book.
Summary written by AI from the source document. Check the original before relying on it. See which parts of Sprinkle are written by AI.
Reference only, not for flight. Use the current approved manual for your aircraft. See terms, section 5.
Document
Source
Copy found at mooney201.de. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type ·
- Service Bulletins
- Year ·
- 1989
- File size ·
- 53 KB
- Copy found at ·
- mooney201.de
- Language ·
- en
What is the SERVICE BULLETIN NUMBER M20-208B?
The SERVICE BULLETIN NUMBER M20-208B is a service bulletins for the MOONEY M20F, dated 1989.
What year was the SERVICE BULLETIN NUMBER M20-208B published?
The SERVICE BULLETIN NUMBER M20-208B — the MOONEY M20F service bulletins on file — is dated 1989.
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- Pilot's Operating Handbook / AFM
- Checklist
- Maintenance Manual
- Parts Catalog (IPC)
- Systems & Wiring
- Service Bulletins on file
- Type Certificate (TCDS)
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In this document
Introduction
The bulletin addresses corrosion in the fuselage structure, particularly in coastal areas, and outlines the need for inspections.
Instructions (Part A)
Part A details the removal of interior components for inspection and the steps to check for corrosion and moisture.
Instructions (Part B)
Part B provides further inspection steps, including checking insulation and probing for internal corrosion.
Warranty
Mooney Aircraft Corporation offers warranty coverage for labor and parts needed for repairs related to this bulletin.
Parts List
A list of parts required for the inspection and repair process is provided, including insulation kits.
Figures/Tables
Figures and tables for tube identification and inspection areas are referenced for detailed guidance.
Summary written by AI from the source document. Check the original before relying on it. See which parts of Sprinkle are written by AI.
Safety notes
- Corrosion may not be easily detected due to its location.
- Do not remove foam insulation at subsequent inspection periods unless damaged.
- Use caution with MEK to avoid damage to painted areas.
- Ensure all repaired areas are properly secured and painted before reinstalling panels.
- Ultrasonic testing is recommended for suspected internal corrosion.
Summary written by AI from the source document. Check the original before relying on it. See which parts of Sprinkle are written by AI.
Full document text
SERVICE BULLETIN NUMBER M20-208B DATE: 8-18-89 THIS BULLETIN IS FAA APPROVED FOR ENGINEERING DESIGN SUBJECT: INSPECTION OF FUSELAGE TUBULAR STRUCTURE MODELS AFFECTED:Part A only All M20 Series aircraft manufactured prior to Jan.1, 1976 excluding S/N’s listed under Part B. Part B only M20C S/N 20-1186 thru 20-1258; M20F S/N 22-1246, 22-1306 thru 22-1438; M20J S/N 24-0001 thru 24-1607, 24-3000 thru 24-3017; M20K S/N 25-0001 thru 25-1093. (All “flush window” aircraft) TIME OF COMPLIANCE: Part A At the next annual or 100 Hr. Inspection, whichever comes first, and only annually thereafter. Part B For Part B effectivity aircraft in excess of 18 months from date of manu- only facture and annually thereafter. INTRODUCTION: There have been reports of corrosion in the tubular fuselage structure, particu larly on aircraft operated in sea coast areas. Attention is being called to this situation because corrosion present in these areas is not easily detected due to its location. NOTE: Revision B has been prepared to clarify criteria and procedures of earlier issues of this Service Bulletin. The changes are indicated by a vertical black line in the margin. INSTRUCTIONS (PART A): 1. Remove seats - front and rear. 2. Remove ABS vinyl kick panels located in forward lower pilot/copilot leg area. 3. Remove interior ABS vinyl side panels (window trim) and carpet side panels, LH and RH. 4. Remove carpeted spar closeout panel (fwd. face of main spar). 5. Remove duct tape from tubular structure in areas where required (wing root/fuselage mating area in particular) to enable thorough inspection of weld joints and bottom side of any tubular structure member. 6. The entire side of the aircraft (LH & RH) should now be open from the firewall, below instrument panel back to the baggage compartment bulkhead. Before continuing with step-by-step inspection per this S.B., conduct a general inspec- tion of the following: (1) Inspect insulation for dampness, check areas under windows particularly, but inspect entire area for any dampness. (2) Inspect for signs of water leaks between side windows and aluminum skin. (3) Inspect for signs of corrosion on any part of tubular structure, ie., paint missing, rust scale, etc. If NO VISIBLE SIGNS of any of the above condition exist, proceed to Step 9 (Part A) and complete required maintenance action. If any one of the three conditions in Step 6 are found, proceed with complete inspection per Steps 7 through 10 for all Part A aircraft affected. 7. Proceed to step-by-step inspections as shown in Instructions Part B, Steps 7 through 20. 8. Reinstall old fiberglass insulation blankets if thoroughly dry or install new foam insu- lation per Steps 21 and 22 of Part B. 9. Proceed with instructions per Part B Steps 23 through 27. 10. Enter Compliance Note into Aircraft Log Book and return aircraft to service. INSTRUCTIONS (Part B): 1. Remove seats - front and rear. 2. Remove ABS vinyl kick panels located in forward lower pilot/copilot leg area. 3. Remove interior ABS vinyl side panels (window trim) and carpet side panels, LH & RH. 4. Remove carpeted spar closeout panel (fwd. face of main spar). 5. Remove duct tape from tubular structure in areas where required to enable thor- ough inspection of weld joints and bottom side of any tubular structure member (wing root/fuselage mating area in particular). 6. Before continuing with step-by-step inspection, inspect the now opened area for general conditions: (1) Inspect fiberglass insulation for dampness, (2) Inspect for signs of water leaks between side windows and aluminum skin (the fiberglass insula- tion may need to be removed from the window /skin area being inspected), (3) Spray water over exterior surface of aircraft concentrating on areas where side windows and aluminum skin overlap. If water is observed to leak from outside to inside of any side window/skin lap area,see Steps 18 and 19 for detailed action recommended. (4) Visually inspect all tubular structure (ref. Figure S.B. M20-208-1) for signs of cor- rosion, i.e., paint flaking, paint missing, rust scale, etc. If NO VISIBLE SIGNS of any of the above 4 conditions are found, proceed to Step 23 and complete the mainte- nance action. If evidence of any one of the four conditions in Step 6 are found, complete all remain- ing maintenance action steps. 7. Remove all existing fiberglass insulation blankets now exposed on sides of cabin and discard if desired. Fiberglass blankets may be THOROUGHLY dried out and rein- stalled if desired; however the new foam insulation is recommended. (Exclude: fire- wall, baggage area and overhead insulation). NOTE: DO NOT REMOVE FOAM INSULATION AT SUBSEQUENT INSPECTION PERIODS UN- LESS DAMAGED OR AS REQUIRED TO TAKE CORRECTIVE ACTION. 8. Visually inspect tubes and weld joints for signs of corrosion or moisture (ref. Fig. S.B. M20-208-1 for tubes to be inspected). Special attention should be directed to areas where the insulation was in direct contact with tubular structure members. 9. Use an awl, screwdriver or sharp punch to probe suspect tubes at points of insula- tion contact, and/or on bottom and lower ends of vertical structure, (where water most likely would be located, if present) to determine if tube wall has corroded from the inside. Probe along the entire length of horizontal tubes and around the circumference of any verti- cal or angled tube at lower end. Repair or replace any tube where internal corrosion is found. Refer to AC 43.13.1 (*) for recommended testing and repair for welded tubes. NOTE: ULTRASONIC TEST EQUIPMENT IS RECOMMENDED TO CHECK TUBE WALL THICK- NESS IF IT IS SUSPECTED OF HAVING ANY INTERIOR CORROSION. REF. FIG. SB-M20- 208-2 FOR TUBE O.D. AND WALL THICKNESS: TUBE P/N MUST BE IDENTIFIED USING APPROPRIATE MOONEY ILLUSTRATED PARTS CATALOG. 10. If a tube has exterior surface corrosion that cannot be polished smooth with “00 steel wool” or cannot be polished out within 10% of wall thickness in localized areas
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with the corrosion cumulative length not to exceed 10% of the total length of the tube, and the cumulative corrosion not to exceed 25% of the circumference of this 10% of the tube length. Refer to Figure S.B. M20-208-2 for table of Part Numbers vs. Outside Tube Diameter (O.D.) and minimum wall thickness for replacement tubes. 11. Any replaced or repaired tubes that have screw holes in it for attaching bracket, etc. should have a moisture displacing fluid, i.e., LPS-1, sprayed into hole or holes to displace any moisture and coat the interior walls after all welding has been com- pleted. 12. If a tube is replaced or repaired that later has to be drilled for P.K. screws to at- tach brackets, it is recommended that each P.K. screw be coated with PR1422-B2 or equivalent sealant prior to installation. NOTE: (*) equates to latest revision. S.B. M20-208B Page 2 of 6 Instructions (Part B) con’t. 13. Remove rear seat bottom trim panels (if installed) to gain access to aluminum seat bottom skin. Remove forward, outboard, taped-on covers, left and right, to ex- pose access holes in aluminum seat bottom skin. This should allow access to the ten- sion bolts connecting wing and fuselage. 14. Cut safety wire that holds tension bolts. AN7H-17A, located at A , Figure S.B. M20-208-1. 15. Remove tension bolts from fitting/spar attach point, LH side - then RH side. Care- fully pass a small pencil magnet on a long flexible shaft up through threaded portion of tension fitting and into tube interior at least 12 - 15 inches, withdraw magnet and observe if any metal (rust flakes) adhere to the magnet. Bright metal, indicating no corrosion, should be on the magnet along with rust flakes (if any). Repeat this process until rust flakes are removed. When all metal (if any) is pulled from the tube, spray moisture displacement fluid, ie., LPS-1, through tension fitting into the interior of the tube, both sides of the aircraft. 16. Reinstall tension bolt, AN7H-17A, torque to 450 - 500 inch pounds per AC 43- 13.1(*) Chapter 5, Section I, paragraph 227, e, (2) - (5) and safety each bolt as it was before removal. 17. Repair any corroded tubular structure area per AC 43-13.1(*). Reference Figure S.B. M20-208-2 for tube part numbers vs. outside diameters and wall thickness re- quired for the various locations, Identify the tubes from the appropriate Mooney Il- lustrated Parts Catalog figures. 18. Remove side windows per appropriate Mooney Service and Maintenance Manual. 19. Thoroughly clean all old sealant from acrylic windows, structural contact areas and aluminum skin contact areas. Use anhydrous isopropyl alcohol or denatured ethyl alcohol to clean acrylic windows and MEK to clean aluminum areas. Care should be taken to keep MEK from painted areas. Wipe wet MEK from surface before it dries with a dry cloth, otherwise any contaminants will be redistributed over the area. Allow 5 to 10 minutes before sealant application. Reinstall side windows per appropriate Mooney SErvice and Maintenance Manual. Apply a uniform thickness of PR1403-G-B2 sealant to the skin, window area and re- tainers where window overlaps skin and retainers. Sufficient sealant should be used to cause sealant to extrude from all edges of window/skin lap, both inside and out- side, (approx. 5 (3.5 oz.) tubes for 4 windows). Allow sealant to cure, then trim ex- cess from outside window area with non-metallic sharpened tool. Refer to fuel tank section of appropriate Mooney Service and Maintenance Manual for sealant mixing and cure times. 20. Inspect forward bottom cap stripes on main spar under carpet where floorboard and spar meet (at rear passenger’s footrest area) for corrosion caused by any mois- ture retained by the carpet. Repair as needed if corrosion is detected, Reference AC 43-13.1 (*). 21. The new foam insulation material is available as precut pieces to be applied to proper locations on the aircraft. (See location view pages supplied with parts kit for foam insulation). Identify each trimmed/fitted piece prior to removing protective backing an applying to aircraft skin. NOTE: THE AREA BETWEEN THE FUSELAGE TUBULAR STRUCTURE AND THE WING ROOT RIB THAT CONTAINS FUEL QUANTITY SENDER AND FUEL OUT FITTING FROM FUEL TANK DOES NOT REQUIRE FOAM INSULATION. 22. Bond new foam insulation to proper locations on skin. When locating insulation pieces, they should not come in contact with tubular steel structure. Allow approxi- mately 1/4 inch clearance around all tubular structure if possible. 23. If any forward Wemac air valves are attached to interior panels, remove the We- macs from panels and seal Wemac air valves against aluminum pan with PR1422-B2 prior to installation of interior side panels. Trim holes in panels as needed to fit over Wemac. 24. Retape all areas where duct tape was removed for inspection. 25. Verify all repaired areas are properly secured and painted before installing inte- rior panels. Epoxy primer is recommended for all areas to be repainted. 26. Reinstall all interior side and seat trim panels, carpeting, seats, etc. 27. Enter Compliance Note into Aircraft Log Book and return aircraft to service. S.B. M20-208B Page 3 of 6 WARRANTY: Mooney Aircraft Corporation will allow up to 10.0 hours labor and provide the parts as needed for repair of aircraft under warranty at date of Rev. A of Service Bulletin and accomplished within 1 year of issue date of Rev. A. REFERENCE DATA: N/A PARTS LIST: KIT P/N: S.B. 208A-1 P/N . . . . . . . DESCRIPTION . . . . . QTY 170018-901 . . . . . INSULATION, FOAM, LH . . . 1 set 170018-902 . . . . . INSULATION, FOAM, RH . . . 1 set (Material P/N S404, Specialty Composite Corp.) FIGURE/TABLES: SEE PAGES 5 & 6 FOR TUBE IDENTIFICATION & INSPECTION AREAS. S.B. M20-208B Page 4 of 6 S.B. M20-208B Page 5 of 6 TUBE P/N MODEL O.D. WALL THK. TUBE P/N MODEL O.D. WALL THK. ------------------------------------------------------------------------------------------------------------------------------------------------------------- 340117-035 J/K 5/8 .083 340155-007 J/K 7/8 .058 340117-085 68/76 ½ .028 340155-009 J/K ¾ .058 340117-086 68/76 ½ .028 340155-011 J/K ¾ .058 340117-087 68/76 ½ .028 340155-021 J/K 1.0 .035 340117-088 68/76 ½ .028 340155-029 J/K 7/8 .058 340117-089 68/76 ½ .035 340155-030 J/K 7/8 .058 340117-090 68/76 ½ .035 340155-031 68/76 1.0 .063 340117-093 68/76 ¾ .035 340155-032 68/76 1.0 .063 340117-095 68/76 1.0 .035 340155-035 68-86 7/8 .035 340117-097 J/K 7/8 .035 340155-051 J/K 5/8 .035 340117-099 68/76 7/8 .035 340155-052 J/K 5/8 .035 340117-101 68/76 7/8 .035 340155-053 J/K 5/8 .035 340117-102 68/76 7/8 .035 340155-054 J/K 5/8 .035 340117-103 68/76 3/8 .058 340155-061 J/K ¾ .035 340117-107 68/76 1.0 .058 340155-063 J/K 5/8 .035 340117-108 68/76 1.0 .058 340155-064 J/K 5/8 .035 340117-113 68/76 ¾ .058 340155-069 J/K ¾ .035 340117-115 J/K 7/8 .058 340155-077 J/K 1.0 .049 340117-117 J/K 1-1/8 .035 340155-135 J/K 7/8 .049 340117-119 68/79 7/8 .035 340155-173 J/K 1-1/8 .035 340117-121 J/K 5/8 .058 340155-175 J/K 5/8 .058 340117-123 J/K ½ .035 340155-176 J/K 5/8 .058 340117-125 J/K ¾ .058 340155-179 J/K ¾ .058 340117-135 J/K ½ .120 340155-189 J/K ¾ .035 340117-141 J/K ¾ .035 340155-193 J/K ¾ .058 340117-145 J/K ¾ .058 340155-195 J/K ¾ .028 340117-157 J/K ¾ .028 340155-215 J/K 7/8 .035 340155-216 J/K 7/8 .035 340155-219 J/K ½ .065 340008-001 68/76 ¾ .035 340155-067 J/K ½ .035 340008-501 J/K ¾ .058 340031-007 68-86 5/8 .058 340031-008 68-86 5/8 .058 340031-009 68-86 5/8 .058 -------------------------------------------------------------------------------------------------------------------------------------------------------------- NOTE: ALL TUBING IS CHROME MOLY 4130, COND. N. FIGURE S.B. M20-208-1 S.B. M20-208B Page 6 of 6 FIGURE S.B. M20-208-2