Piper Twin Comanche C Owner's Handbook

distribution to the cylinders is accomplished by a fuel flow divider. Fuel pressure regulation by means of the servo valve causes a minimal. drop in fuel pressure throughout the metering system. Metering pressure is maintained above vapor forming conditions while fuel inlet pressure is low enough to allow the use of a diaphragm pump. Vapor lock and associated problems of difficult starting are thus eliminated. ' Incorporated in the servo regulator is the airflow sensing system which contains a throttle valve and venturi. The differ- ential pressure between the entrance and the throat of the venturi is the measurement of air entering the engine. These pressures are applied across an air diaphragm in the regulator. A change in power changes the a1rflow to the engine and across the diaphragm in the. regulator.- Mounted on top of the engine is the ported fuel flow divider with four nozzle lines routed to the cylinders. The divider con- tains a spring loaded positive shut-off valve. Within éach cylinder are continuous flow air bleed nozzles with provisions to eliminate the adverse effects of low manifold pressure when idling. Since fuel ‘metering is provided by the servo regulator rather than the nozzles, more uniform cylinder head temperatures result and a longer engine life is possible. Induction air for the engine enters the opening in the nose cowl and is picked up by a large air duct at the right rear baffle. The air is directed through a filter .and on to the servo regulator. Analternaté air source for the induction system contains a spring loaded door at the throat of the servo regulator. This door op- erates -automatically if primary source is obstructed or manually by the push-pull control on the right side of thé power control quadrent. The primary system should always be used for take-off. 7 681101 TWIN COMANCHE “'C" SECTION II STRUCTURES Structutes are of sheet aluminum construction and are de- signed to ultimate load factors well in excess of normal require- ments. All components. are completely zinc chromate primed and exterior surfaces are coated with acrylic lacquer. The main spars of the wings are joined with high strength butt fittings in the center of the fuselage, making in effect a continuous main spar. The spars are attached to the fuselage at the side of the fuselage and in the center of the structure; wings are also attached at the rear spar and at an auxiliary front spar. The wing airfoil section is a laminar flow type, NACA- 642A215, with maximum thickness about 40%¢ aft of the leading edge. This permits the main spar, located at the point of max- imum thickness, to pass through the cabin under the rear seat, providing unobstructed cabin floor space ahead of the seat. LANDING GEAR The nose gear is steerable with the rudder pedals through a 40 degree arc. During retraction of the gear, the steering mecha- nism is disconnected automatically to reduce rudder pedal loads in flight. The nose gear is equipped with a hydraulic shimmy dampener. ’ Retraction of the landing gear is accomplished through the use of an electric motor and gear train, actuating push-pull cables to each of the main gear and a tube to the nose gear. The landing gear motor is beneath the center floor panel and the selector switch on the instrument panel to the left of the power control quadrant.. To guard against inadvertent movement of the landing gear selector on the ground, the handle must also be pulled aft before ‘moving it upward. The gear selector has the shape of a wheel to 681101 8 SECTION Il TWIN COMANCHE *‘C”" distinguish it from the elecfric flap control which has an air- foil shape. As an added safety LANDING feature, the warning horn is GEAR connected to the gear selector switch. The horn will then op- erate if the selector is moved to the UP: position with the master switch on and the weight of the airplane on the landing gear. To prevent gear retraction on the ground, an anti-retraction switch is in- Gear Selector Switch stalled on the left main gear. This prevents the completion . of the electric circuit to the landing gear motor until the gear strut is within 3/4 inch of fullextension. The gear indicating lights are located conveniently by the gear selector switch. The green indicating light below the selec- tor switch shows that all gear are down and locked. The amber light above the gear selector switch is the gear up indication: it will flash if the power of one engine is reduced below 12 inches of manifold pressure while the gear is up and locked. The white light indicates that the landing gear is in transit. The gear up _warning horn will sound when power is reduced (below approx- imately 12 inches of manifold pressure) on both engines and the gearis not down and locked. The pilotshould become familiar with the gear warning horn to distinguish it from the stall warning horn. GEAR INDICATION LIGHTS ARE DIMMED WHILE THE INSTRU- ‘MENT LIGHTS ARE ON. The brakes are-actuated by toe brake pedals mounted on the left set of the rudder pedals. Hydraulic brake cylinders above the brake pedals are accessible in the cockpit for servicing. Parking brake valves are incorporated in each cylinder and have two cables attached from the parking brake ‘“T'’’ handle. To pre- vent inadvertent application of the parking brake in flight, a safety lock is' incorporated in the valves, thus eliminating the.possi- bility of pulling out the ‘“T”’ handle until pressute is applied by 9 700110 TWIN COMANCHE “‘C”’ SECTION I use of the toe brakes. Toe brakes. for the right side are available as optional equipment. A tow baris provided with each aircraft. When not in use it is stowed next to the main spar. It may be removed by lifting the flap covering the forward side of the spar and removing the bar from its fasteners.- When towing with power equipment, caution should be used not to turn the nose gear beyond its 40 degree arc as this may cause damage to the nose gear and steering mechanism. CONTROL SYSTEM Dual flight controls are Cables connect the movable pedals and control columns. Directional and longitudi- nal trim is provided by an adjustable trim mechanism for the rmudder and stabilator. The manual rudder trim control is located to the right of the throttle quadrant. Max-Lift electncally op- erated flaps are used on the Twin Comanche. The flaps are operated by an electric motor; . they can be lowered 700110 Tow Bar Stowage provided as standard equipment. control surfaces with the rudder COWL FLAP Rudder Trim and Flap Controls 10 SECTION 11 TWIN COMANCHE *‘C"’ and stopped in any desired position. The airfoil shaped flap con- trol is to the right of the power control quadrant. Located on the instrument panel is a flap position indicator marked to show the position of the flap relative to the wing. A range for take-off operation is also shown. ’ Located in the inboard end of the right flap is a lock which holds the flap in the UP position so that it can be used as a step for entry or exit. A second lock is incorporated to prevent the flap from going full down in case a step load is applied and the up lock is not fully engaged. FUEL SYSTEM The fuel is carried in four integral fuel cells located in the leading edge sections of the wings. Capacity of the two main fuel cells is 30 gallons each, .of which 27 gallons is usable. The auxiliary fuel system consists of two 15 gallon cells (all usable) installed in the wings just outboard of the main fuel cells. Wing tip tanks are available as optional equipment. Auxil- iary fuel and tip tank fuel is to be used in level flight only. The cells should be kept full of fuel during storage of the airplane to prevent accumulation of moisture and deterioration of the cells. For storage of more than ten days without fuel,the cells ‘should be coated with light engine oil to prevent excessive drying. During normal operation use the engine driven fuel pump to draw fuel from the cell directly adjacent to that engine. How- ever, fuel can be drawn from any cell to both engines through use of the engine driven fuel pump or the electric auxiliary fuel pump. For emergency single engine operation a crossfeed is pro- vided to increase the range. When using fuel from tanks on the same side as the operating engine, the position of the fuel se- lector will remain the same as for normal operation with the n 700110 TWIN COMANCHE “‘C" ~ SECTION Ii WaLSAS T13nd 12 681101 SECTION Il TWIN COMANCHE ‘‘C”’ augiliary fuel pump off unless the engine driven pump is inoper- ative. NOTE Do not put both fuel selectors in the crossfeed position at the same time. When using fuel from cells on the opposite side of the oper-~ ating engine, move the fuel selector for the inoperative engine to the main or auxiliary position; then move the fuel selector for the operating engine to the crossfeed position. For single engine landing, fuel must be pumped from the .main cell on the same side as the operating engine. The fuel strainers for the system are located beneath the floor panel in the center section of the fuselage. Daily draining of the strainers may be accomplished in the cockpit by opening the hinged access door located in the floor panel just aft of the fuel selector handles and pulhng up on the knob located in the center of the selector valve. The general procedure for draining the fuel system is to open the strainer quick drain for several seconds with the fuel cell selector on the main cell, then to change the selector to the auxiliary cell and repeat the process. Allow enough fuel flow to clear the lines as well as the strainer. Positive fuel flow shut-off can be observed through the clear plastic tube that carries the fuel overboard. Located inside the fuel valves is a by-pass valve which will open at 1/2 psi differ- ential pressure if the strainer screen becomes blocked. ' Fuel quantity is indicated by two electric gauges located be- low the instrument cluster. The instruments are connected to a transmitter unit located in each fuel cell. The gauges will indi- cate the emount of fuel available in the cells that are selected. 13 700110 TWIN COMANCHE “‘C” SECTION I ELECTRICAL SYSTEM _ Electrical power is supplied by two 12 volt 70 ampere alter- nators and a 35 ampere-hour battery. The battery is located in the fuselage nose sectionin a sealed stainless steel battery box. Refer to the Maintenance Section for servicing of the battery. The alternators ate paralleled by the use of one voltage tegulator to control the field voltage of both units. Also incor- porated into the system is an overvoltage relay. Its function is to open the field circuit and temove the field voltage from the unregulated alternators in the event of a failure of the voltage regulator, thus -preventing an overvoltage condition which could damage the electrical equipment. In the event of a voltage regulating system fallure an aux- iliary regulating system may be switched into use. Abnormal system operation may be indicated by zero output on both alter- nator test positions and a discharge indication for the battery. NOTE Use of the voltage regulator selector switchshould be limited to the above condition unless the Service Manual is consulted. An ammeter, in conjunction with alternator push-to-test switches,is used to check the electrical system output. All three of these items are located on the pilot’s instrument panel. The ammeter normally indicates battery charge or discharge current. Depressing either of the push-to-test switches will cause the ammeter to indicate the respective alternator output current, Electrical switches for the various systems are located pri- marily in the lower left sub-panel. Rheostat switches control the interior lighting: the instrument post light switch is on the left sub-panel just below the parking brake handle, the map light switch is just to the right of the brake handle and the switch for back lighting of the radio selector panel is centrally located at the top of the radio stack. The instrument panel can be illuminated from the cabin ceiling by turning the switch in the center of the over- - 700110 14 SECTION Hi TWIN COMANCHE “‘C" T RIGHTALT. S0 ANP MASTER SWITCH TO MASTER YOLTAGE REGULATOR SELECTOR SWITCH QVERVOLT. OVERVOLT. RIGHT AMMETER RELAY RELAY SHITCH WAIN VOLTAGE = = AUX.VOLTAGE REGULATOR BOKX ASSEMBLY REGULATOR LEFT ALTERNATOR ELECTRICAL SCHEMATIC TWIN COMANCHE “‘C"’ | SECTION II head light panel. The alternator shunt fuses and spare fuses are located under the floor panel access door aft of the nose wheel well. The circuit breakers are located on the lower right sub-panel and automatically break the electrical circuit if an overload occurs. It may be necessary to allow approximately two minutes for the circuit breakers to cool before resetting them if an overload occurs. Corrective action should be taken in event of continual circuit breaker popping. It is possible to trip the breaker manually by pull-' ing out the reset button. Do not open alternator switches in flight unless an emergency arises. If power loss occurs, reduce elec- trical loadto a minimum and terminate flight as soon as practical. VACUUM SYSTEM Suction for the vacuum operated gyro instruments is supplied by two engine driven (dry type) vacuum pumps, interconnected to form a single system. Either vacuum pump has sufficient capacity to operate the gyro insttuments. If suction is lost from one or the other side a check valve automatically closes and suction is supplied by the remaining system. A vacuum gauge is installed in the instrument panel to pro- vide a constant indication of vacuum source. Incorporated in the instrument are two red indicators (right and left systems). During normal operation the indicators are not visible, but if vacuum is lost, for example on the right side, then the right indicator will be visible. Suctionis indicated onthe gauge in inches of mercury; normal operating range is 4.8 to 5.1 inches. The system is con- trolled by two adjustable regulators, one located in each engine nacelle. After initial adjustment the regulators require very little attention. 700110 16 SECTICN Il TWIN COMANCHE “‘C" VACUUM MANIFOLD CHECK VALVES CENTRAL AIRFILTER ARTIFICIAL DIRECTIONAL _HoRIZON | | ovRo REGULATOR VACUUM GAGE LEFT ENGINE RIGHT ENGINE VACUUM PUNMP VACUUM PUMP INSTRUMENT PANEL The instrument panel is designed to accommodate the cus- tomary advanced flight instruments on the left side in front of the pilot and engine instruments on the right side. The optional in- struments such as the gyro instruments of the flight group are shock mounted. The Artificial Horizon and Directional Gyro in this group are operated by an optional vacuum pump on each engine. The vacuum system standby is the optional, electrically operated Rate of Turn Indicator. 7 700110 TWIN COMANCHE “‘C"’ SECTION I 1. RATE OF TURN INDICATOR S, /S COUPLER LIGHT 2, AIRSPEED INDICATOR 6. DIRECTIONAL GYRO 3. STALL WARNING LIGHT 7. ALTIMETER 4. GYRO HORIZON 8. RATE OF CLIMB 9. 10. r. 12. OMNI BEARING SELECTOR 13, MARKER BEACON 14, TRANSPONDER 15. RADIO SELECTOR PANEL 16, 21, 22, 23, 24, 25. 26. DME MASTER SWITCH VOLT.REG. SEL. SWITCH NAV LIGHTS ROTATING BEACON PARKING BRAKE' U5 %2 27. 28, 29, 30. 31, 32. POST LIGHTS SWITCH LANDING LIGHT L LANDING LIGHT R GYRO SUCTION GAUGE PITOT HEAT MAP LIGHT SWITCH B B3NN U OB BA = Wk AMMETER NAY. SELECTOR SWITCH + LANDING GEAR SELECTOR AUTOFLITE ALTERNATOR TEST BUTTONS « MIXTURE CONTROL INDICATOR ADF RADIO COMM /NAY TIRANSCEIVERS ALTIMATIC INID ‘LEFT TACHOMETER A A a0, 40, 41, 42, 43, a4, Yo o Avyymancul . S "5 e 17, 8. 9. 20, MANIFOLD PRESSURE GAUGE RIGHT TACHOMETER FUEL FLOW INDICATOR FUEL AND ENOINE 0AUGES 18 o 414 &| . «ap » | (] Five PLAD [RDICATOR NAV/ARPROAGI COUPLER FLAR ACTUATOR RUDDER THIM ALTERNATE AIR L =R COWL FLAFE 1,»R S00PETE0 e Dvl TARER ey JalojolololelC 45, « 0} a7. 48. 49, 50. Al L DE CHRCUIT BREAKER PANEL C/jB IN HEAT CONTROLS s ey 50 . TERNATOR SWITCHES YGEN CONTROL CHTER LFROSTER CONTROL 681101 18 SECTION 1 TWIN COMANCHE *‘C”’ n 4 o o - x 8 - w e - W e o0 o o= kO Cw m <lél‘ll - o ags I<a g = faorx WG eXZao uuuuu uuuuuuu < = U< ......... ~ 0o X n:;“ < = “en T w> nvE< Wwazx e W x [ zZZT X o oo < € vouou TteEB " HEATING ARND VENTILATING SYSTEM 19 681101 TWIN COMANCHE “‘C” SECTION Il INSTRUMENT STATIC PRESSURE SYSTEM Static air for the airspeed" indicator, altimeter and vertical speéd indicator is supplied from two static ports, one located on- each side of the aft fuselage section. An optional, alternate static source is available to provide’ continuous operation of the pitot static instruments should the static system ports or lines become obstructed. The alternate static source is located in the cabin on the lower left side of the control quadrant. _ If incorrect instrument readings are suspected the alternate static source valve should be opened, venting the static system to cabin pressure. Cabin pressure will vary, however with cabin ventilators open, cabin heater operating and various airspeeds. Use of the alternate static source may result in the following instrument indications: The altimeter reads higher than normal; md1cated airspeed greater than normal; and the vertlcal velocity indicator monentarily shows a climb. _ The - following table shows airspeed corrections for the standard static system and the alternate static system: Standard Alternate Gear and Static System Static System’ Flaps IAS CAS CAS "MPH MPH MPH 80 82 81 Retracted 88 90 91 120 121 113 160 160 148 200 197 185 220 216 204 80 © 80 81 91 90 91 100 98 97 Extended 120 117 113 700110 20 SECTION I TWIN COMANCHE ““C"’ HEATING AND VENTILATING SYSTEM The flow of air for heating and defrosting is taken through an inlet located in the nose and regulated by controls located in the lower right side of the instrument panel. Heated air for the cabin and windshield defrosting is pro- vided by a Janitrol heater installed in the nose section. . Operation of the heater is controlled by a three position switch, labeled FAN, OFF and HEAT. The FAN position will operate the vent blower only and may be used for cabin venti- lation on the ground or for windshield defogging when heat is not desired. ' For heat the manual heater fuel valve must be on and the three position switch turned to HEAT. This will start fuel flow and ignite the burner simultaneously. With instant starting and no need for priming, heat should be felt within a few seconds. Regulation of heat, airflow and defroster operation is con- trolled by levers on the heater control console. The top control regulates a thermostat and provides a wide range of temperatute selections. Adjustable heat deflectors are on the cabin wall beneath the instrument panel to provide additional comfort. Cabin temperature and air circulation can be maintained by using various combinations of lever settings, to suit individual desires. To minimize the feeling of drafts, a low airflow high heat combination may be used. Windshield defrosting may be regulated by various settings of the defroster lever and in severe windshield fogging or icing conditions, it may be desirable to restrict the heater air, since this will drive more air through the defrosters. Heat may be supplied to warm the cabin before flight by turning on the master switch, the right auxiliary fuel pump, and starting the heater. The cabin heater uses gasoline from the fuel injector on the right engine. If the right fuel selector is in the off position the heater is inoperative. In case of right engine failure the heater can be operated by leaving the fuel selector on and closing the 21 700110 TWIN COMANCHE “‘C” SECTION Il mixture control while operating the auxiliary fuel pump. Before the heater is operated under these conditions, determine that no fuel leaks are present between the tank and engine. Located in the heater is a heat limit switch, which acts as a safety device to render the heater system inoperative if a mal- function should occur causing excessively high temperatures. This control is located in the downstream end of the vent jacket, with the teset button on the heater shroud. It is reached only through the nose section to insure that the malfunction causing the overheat condition is corrected prior to future heater op- eration. _ ) To prevent activation of the overheat control during landing roll or while taxiing, turn the three position switch to FAN. Duting ground operation the manual switch should be on FAN for several minutes to cool the heater before turning to the OFF position. Ventilating air for the cabin interior is obtained from the two ventilators located at each side of the instrument panel. The rear seat area is furnished with air by overhead vents from the dorsal fin scoop. Each individual vent is adjustable for the desired air- flow. Located in the aft section of the cabin is an exhaust vent to improve the circulation of air in the cabin interior. SEATS The front and rear re- clining seats are adjustable fore and aft to provide comfort for pilot and passengers. Seat backs may be tipped forward to facilitate ease of entry and exit from the aircraft. They are’ easily removed by taking out the stops at the end of the mounting tracks and sliding the seats from their tracks. Seat Adjustments 700110 22 SECTION 1 TWIN COMANCHE *‘C”’ The optional family seat(s) may be removed to allow more baggage area and access to the rear fuselage panel. Release the snap fasteners that attach the seat backs to the hat shelf and turn the wing fasteners at the back of the seat cushions. Verti- cally adjustable pilots’ seats are offered as optional equipment. FINISH All aluminum sheet components are carefully finished inside and outside to assure maximum service life. Both sides of all pieces are alodine treated. External surfaces are coated with durable acrylic lacquer in attractive high gloss colors. The application of primer to interior surfaces prevents corrosion of structural and non-structural parts on the inside of the aitplane. BAGGAGE AREA Maximum \'Jveight in the baggage area, including bag- gage, passengers and family ‘seats is 250 pounds, with up to 20 cubic feet of available space. Baggage may be placed in the aircraft through a 19 x 21 inch door or through the passenger entrance. Tie-down straps are available for se- curing baggage when the family seats are not installed. Baggage-Emergency Door The baggage door may also be used as an emergency exit. 1t is opened by holding the inside door knob up while turning the latch clockwise. For additional baggage compartment loading information refer to page 51. 23 700110 TWIN COMANCHE “‘C" SECTION i STALL WARNING SYSTEM An approaching stall is indicated by both a stall warning light and horn, activated by a lift detector installed on the left wing outboard of the engine nacelle. This warning horn is separate and operated by a different system from the gear warning horn mentioned on page 9. 700110 24 SECTION 1| OPERATING INSTRUCTIONS Preflight . . . . . . . Starting Engines . . . . . . Flooded Start . . . . . Warm-Up and Ground Check . Electrical Power . . . e Taxiing and Pte-Take—Off P Take-Off and Climb, . . . . . . . Wing Flaps . . . . . e Short and Soft Field Take-Offs . Landing Gear Retraction . DeicerBoots . . . . . Vmc oA e e & e e s . e s e Stalls . . . . . . . Spins . . . . . . Spin Recovery Techruque Cruising . . . . . Fuel Manegement . . . . . . . . Approach and Landing., . . Post Landing, . . . . . , Emergency Procedures.: . . . . . Vmc Demonstration. . . Vme and Stall Speed Mooring Loading and Wexght and Balance OperatingTips . . . . . Flight Conditions Diving Spiral., . Radio Operation. 763773 731116 25 27 27 28 29 29 31 31 32 33 33 33 34 35 36 36 37 39 42 42 49 S0 50 50 52 53 55 55 TWIN COMANCHE “‘C” SECTION i SECTION Il OPERATING INSTRUCTIONS PREFLIGHT The following safety procedure instructions must become an integral part of the pilot’s operational routine and preflight inspection. Begin the preflight inspection in the cockpit. Check that the landing gear selector switch is in the down position. Turn master switch on and check that the green landing gear indicator light is on., If the green light is not on, make sure that the instrument panel light switch is turned to the OFF position, The landing -- S — - . - bl - - - _________ ________ -------- _______ 700710 25 SECTION Il TWIN-COMANCHE ‘'C" gear indicator light is automatically dimmed and is difficult to see in the daytime if the instrument lights are on. Drain about a quarter of a pint of fuel from each tank with the cockpit drains before doing the external preflight check. During the extemal check, determine that the fuel has stopped draining. During the external preflight check see that the baggage- emergency door is properly secured. Prior to flight, passengers should be briefed about seat belts, the use of oxygen when appli- cable, how to evacuate the airplane, and advised not to smoke . during take-off or landing. They should be cautioned against handling or interfering with essential equipment and flight con- trols, fuel valves, switches, circuit breakers, trim knobs or cranks, radios etc. ' 1. Ignition and master switches - OFF. 2. Fuel strainer sump - drained and not leaking. 3. Fuel selectors on main cells. 4. Control surfaces, wing, fuselage - no damage or oper- ational interference. 5. Control surface - free of obstructions, ice and snow, 6. Fuel supply - adequate. 7. Fuel cell caps - secure. 8. Fuel system vents - open. 9. Landing gear struts ~ 2-3/4" piston exposed under static 10. Tires - inflated and not excessively worn. 11. Cowling, landing gear doors, oil and inspection covers - 12. . Propellers - check. 13. 0il supply - adequate. 14, Leaks - absent. 15. Windshield - clean and secure. 16. Dorsal fin air scoop - free of obstruction. 17. Control locks - detached. 18, Baggage door - secure. 19. Tow bar - stowed. _ 20. Cabin controls - operative. 2% 700110 TWIN COMANCHE “C” | SECTION Il * 21. Gear selector switch - down. 22. Required papers - in order. 23. Turn master switch on - check stall warning system. 24, Check navigation lights. 25. Fasten safety belts. STARTING ENGINES 1. Master switch- on. 2. Gear lights- check green. 3. Fuel quantity- check gauge readmg 4. Cowl flaps- open. 5. Trim tabs - set. 6. Throttles - open 1/2 inch, 7. Propeller controls - forward. 8. Mixtures - rich. ) 9. Electric fuel pumps-on till indication on fuel flow gauge. 10. Mixtures - idle cut-off. 11. Magneto switches - on. 12, Propellers - clear. 13. Starters - engage. 14. Mixtures - advance. 15. 0il, fuel pressure - check. FLOODED START Magneto switches - on. Throttles - open, Mixtures - idle cut-off, Electric fuel pumps - off. Starters- engage. , (When engine fires, retard throttle and advance mxxture ) A Cranking periods should be limited to 30 seconds with a two minute interval. Longer cranking periods shorten the life of the starter. Do not engage the starter immediately after releasing it as the starter mechanism may be damaged. 753773 27 731116 SECTION il TWIN COMANCHE “‘C"’ WARM-UP AND GROUND CHECK Check the oil pressure as soon as the engines start. If no pressure is indicated within thirty seconds, stop the engine and determine the trouble. If cold temperatures exist (10°F or be- low), a longer period of time will be necessary before an indi- cation is received. Warm-up the engines at 1000 to 1400 RPM for not more than two minutes in warm weather and four minutes in cold. The en- gines are warm enough for take-off when no faltering occurs with the throttle opened. Avoid prolonged idling at low RPM to prevent fouled spark plugs. Check the magnetos with the propeller in low pitch and the engine running at 2200 RPM. The maximum drop on each magneto should not exceed 175 RPM while the differential drop between them should not exceed 50 RPM. Operation on one magneto should not exceed 10 seconds. Move the propeller controls through their complete range to check feathering action, then leave them in the full forward low pitch position. Feathering action can be checked by running the engine between 1000 and 1500 RPM and pulling the prop control into feather position momentarily, Do not allow a drop of more than 500 RPM and do not feather the propeller when operating at a high menifold pressure with the aircraft on the ground. Pro- pellers should be cycled three times in cold weather. Cowl flaps permit cooling of the engines by manual control during ground operations or special conditions- of flight. It is recommended that cylinder head temperature not exceed 400° F and the oil temperature should not exceed 245°F. Turn off the electric fuel pumps after starting to make sure that the engine driven pumps are operating. The electric fuel pumps should be on during take-off, landing and when changing fuel selector positions to prevent loss of power at critical times. 28 700110 TWIN COMANCHE “C" SECTION Il ELECTRICAL POWER Do not attempt flight with a very low charged battery. If the battery charge is too low, the alternator voltage control may become erratic. CAUTION Be sure to have the alternators turned on. If the battery charge is low and alternators are not operating, an inadvertent gear-up landing. is possible because the warning horn and flashing light will not operate and the landing gear can- not be extended electrically. Manual extension of the landing .gear is required under these circumstances. ’ ; TAXIING AND PRE-TAKE-OFF Start to move the airplane forward. During initial taxiing, throttle back and apply brakes to check their operation. Use differential power and nose wheel steering rather than brakes when taxiing. Retard the throttle to the engine on the inside of turn and advance the throttle to the engine on the outside of the turn. . The autopilot should be off before take-off. On a cold day test defroster and cabin heaterbefore take-off, Do not fly in cold weather when the heater is inoperative, as the windshield may become frosted. 700110 29 SECTION Il TWIN COMANCHE “‘C" Lock the door before take-off. If this item is neglected and the door comes open after take-off, maintain normal climb and airspeed until sufficient tetrain clearance is obtained. (Do not risk loss of control of the airplane to close the door. It is pos- sible to continue safely for extended periods with the door un- latched.) When it is impossible to land straight ahead, the door may sometimes be closed by the following procedure: slow the airplane to 100 miles per hour; lower landing gear and wing flaps; open the small window to the left of the pilot; pull the door shut and lock it. Check list: 1. Parking brake - on. 2. Engine run-up (a) Mixture controls - forward. (b) Propeller controls - forward. (c) Throttle controls - forward (1500 rpm). (d) Propeller controls - exercise. Check feather; 500 rpm maximum decrease. (e) Throttle controls - forward (2200 rpm). (f) Magnetos - check. Normal drop - 100 tpm Maximum drop - 175 pm Differential drop left to right - 50 rpm 3. Engine gauges - check green., 4. Lights (as required) - on. 5. Pitot heat (as required) - on. 6. Transponder - stand-by. 7. Flaps - set. 8. Gyro pressure - 4.8 to 5.1 in. Hg. 9. Directional Gyro - set. 10. Turn & Bank - operating. 11. Altimeter - set. 12. Clock - wind & set. 13. Altemator output - check. 14. Electric fuel pumps - on. 15. Door - locked. I 16. Safety belts - fastened. 753773 30 731116 TWIN COMANCHE *‘'C"” SECTION 111 The normally recommended setting for sea level take-off is full throttle at 2700 RPM. The slightly rich mixture for this sefting aids in cooling the engine. TAKE-OFF AND CLIMB 1. Parking brake - off 8. Flaps - retracted 2. Mixtwes - forward 9. Climb power - set 3. Propellers - forward (At approx. 400 AGL) 4. Throttles - forward 10. Cowl flaps - set 5. Accelerate to - 90 MPH (Maintain cyl. hd. temp. (Prior to climb) at or below max) 6. Landing gear - retract 11. Oxygen - no smoking - on 7. Accelerate to - 112 MPH (10,000 ft & above) (Best R/C speed) During take-off roll apply light back pressure to the control wheel to avoid porpoising during the take-off run. Accelerate to sipgle engine minimum control speed (Vyc) before -applying stronger back pressure for rotation. During normal conditions, retraction of the landing gear should occur when a gear down landing is no longer possible on the runway. Attain the best rate of climb speed and at least 400 feet above ground level before reducing power. WING FLAPS Wing flaps are not necessary for take-off except when operating from a short or soft field, The use of wing flaps during take-off in a lightly loaded airplane may cause the airplane to lift-off the runway before Vp. is attained. An effort to hold the airplane on the runway too 700110 3 SECTION 1l TWIN COMANCHE “C"_ long may result in a ‘‘wheelbarrowing tendency’’ with most of the weight on the nose wheel. " Wing flaps are not normally used during a crosswind take-off. After lift-off set up the required crab angle, retract the gear at a safe altitude and continue climb out. An en route climbing speed of 130 miles per hour is : recommended for increased forward visibility during continuous climb. SHORT AND SOFT FIELD TAKE-OFFS If it is necessary to get the airplane off the runway in the shortest possible distance, set take-off wing flaps (with the flap position needle at the bottom of the white .arc on the flap indicator). With brakes set, run up engines" to maximum power and check instruments. If the airplane - is off the runway at less than 90 miles per hour, it is essential to fly level a few feet off the runway immedi- ately after lift-off until reaching 90 mph. After airspeed has increased, initiate a climb at the best angle of climb . . speed (90 mph at sea level) if an obstacle is to be cleared, or at the best rate of climb speed (112 mph at sea level) if a normal climb out is desired. Since the airplane cannot be controlled in flight below Ve in the event of the sudden power loss in one engine, be reedy to reduce power promptly. NOTE Take-off at high altitude (density altitude), from a soft, wet, rough or grassy field, or with an uphill gradient or tail wind component results in greatly reduced take-off performance. During take-off roll, check to be sure the airspeed indicator is operating properly. The needle should indicate zero when the airplane is at rest. 32 700110 TWIN COMANCHE “‘C**~ SECTION i LANDING GEAR RETRACTION . Make sure the aitcraft has sufficient altitude and airspeed with no chance of settling back on the runway before retracting the gear. When taking off from a long runway, retract the landing gear when it would no longer " be possible to land straight ahead. DEICER BOOTS If your Twin Comanche is equipped with deicer boots, they should not be operating during take-off since inflated boots can change the stall characteristics of the airplane. YMC Vme (Velocity minimum control) is the calibrated airspeed, determined by FAA test pilots, below which a twin engine aircraft cannot be-controlled in flight with one engine operating at take-off power and the other engine windmilling. The Vmc which the FAA has determined for the Twin Comanche is 90 mph CAS. Calibrated airspeedis equal tothe airspeed indicator reading corrected for position and instrument error, Since calibrated air- speed and density altitude and pilot flight techniques vary, it is best, especially when heavily loaded or on a cold day, to fly the aircraft as though Vg were slightly higher. Under no circumstances should the aircraft be flown below the Vypc of the aircraft with one engine operating at maximum power and the other engine windmilling. When operating under single engine flight conditions, either in training or in emergency situations, maintain indicated airspeed above 97 mph. APPROACH YMc WITH CAUTION ~ On take-off the aircraft should be kept either on, or near the runway, until reaching V. After Ve has been reached the air- 711229 33 SECTION Iif TWIN COMANCHE ‘C" craft should be accelerated as rapidly as possible to the bestrate of climb speed (112 mph) if there are no obstacles ahead. If there are obstacles ahead maintain the best angle of climb speed (90 mph). The applicable speed should be maintained until all obsta- cles are cleared and the airplane gains sufficient altitude. *STALLS WARNING Do not petform asymmetric power stalls.or single engine stalls. Do not perform symmetrical power-on stalls unless maneuver is initiated at least 5000 feet above terrain and with not more than pilot and copilot aboard except during flight checks. The left wing on the Twin Comanche with clock- wise rotating propellers will, generally speaking, under conditions of moderate symmetrical power, stall more rapidly than the right wing, and if re- covery is not promptly initiated, the airplane will have a tendency to roll to the left. As in any multi-engine aircraft, stall recovery in the Twin Comanche should be initiated at the first indication of a pre-stall buffet, warning light or horn. The aircraft should not be permitted to develop into a full stall. 34 711229 TWIN COMANCHE “‘C” SECTION 1)l N CAUTION, Use controls promptly to counteract any rolling or yawing action of the airplane during the approach to and recovery from the stall. The stall warning system is inoperative if the master switch is off. NOTE An increase in bank angle increases the stalling speed. ’ STALL SPEED TABLE (CAS) Angle of Bank Gear & Flaps Up Gear & Flaps Down 0° 76 69 20° 79 71 400 87 79 50° 108 98 [These figures are at gross weight of 3600 pounds with power off. SPINS Tl}e Twin Comanche is FAA approved in the normal category, and in this category all intentional acrobatic maneuvers, in- cluding spins, are prohibited. Spins and other intentional acrobatic "maneuvers, may subject the airplane to stresses beyond which it was designed. 700110 35 SECTION Il TWIN COMANCHE ““C”’ - SPIN RECOVERY TECHNIQUE . In the event of an inadvertent spin, recovery can be accomplished in the following manner: 1. Retard both throttles to idle position. 2. Applyfull rudder in the opposite direction to the spin. 3. Push control wheel full forward. While it is not necessary for recovery, the use of ailerons against the turn (ie. right aileron if spin is to left) will expedite re- covery. Maintain controls in these positions until the spin stops. Then, neutralize rudder and ailerons. 4. Recover from dive with smooth back pressure on control wheel, No abrupt control movement should be used during recovery from the dive. NOTE ‘Altitude loss in a spin may be in excess of 2000 feet. Avoid any maneuver which might result in a spin at’low altitude. The more rapidly spin recov- ery is begun the more prompt the recovery will be, -~ CRUISING The cruise power concept now possible with Lycoming en- gines permits more efficient use of the available horsepower. Simplified power matagement allows a more constant manifold presswre and eliminates continual reference to power charts. Refer to Power and Performance charts for power settings. Do not exceed 28 inches of manifold pressure below 2400 RPM. To INCREASE power, first increase RPM; then increase manifold pressure. To DECREASE power, first decrease manifold pressure; 36 700110 TWIN COMANCHE "'C”’ SECTION HI then decrease RPM. \ To obtain the desired cruise, set the manifold pressure and RPM according to the power setting table. For information on leaning procedure see Avco-Lycoming Operator’s Manual and current Avco-Lycoming Service Instructions. During climbing operation the servo regulator will sense the change in altitude and will automatically lean the mixture. For better economy, manual leaning with the mixture control can be accomplished. ' FUEL MANAGEMENT Fuel should be used from the main fuel cells during take-off, landing, climb and descent. Auxiliary fuel and tip tank fuel is to be used in level flight only. The electric fuel pumps should be on during take-off, landing and while switching tanks in order to prevent loss of power at critical times. In turning off the electric fuel pumps allow a time delay of approximately 20 seconds between switching each of the fuel pumps off in order to insure that the engine driven pumps are operating properly. Since a fuel injected engine such as is used on the Twin Comanche takes an appreciable length of time to start after fuel starvation, it is recommended that you avoid emptying a fuel cell to depletion, If the engine should stop because a fuel cell is depleted of fuel be prepared to wait a while for the engine to start after changing to a fuel cell with fuelin it. If it is necessary to use all the fuel in a fuel cell, carefully monitor the fuel flow meter and quickly change the fuel valve position at the first indication of a decrease in fuel flow. This will enable you to keep the engine operating while using all of the fuel in the fuel cell. ~— 700110 a7 SECTION Iil TWIN COMANCHE"‘C'" N CAUTION If tiptanks are installed on the airplane and if the tip tanks have been run completely dry in flight, air may be trapped in the line from tip tank to solenoid valve when tip tanks are subsequently filled. The air pocket in the line may prevent im- mediate feeding of fuel from tip tanks. To avoid this condition, purge air from lines prior to starting of aircraft. 1. Turn fuel selector valve to ‘“‘AUX’’ po- sition, 2. Turn on aircraft master switch and place ‘tip tank fuel selector switch to tip tank position. Ascertain that tip tank solenoid switch, under fuel console, is operating by listening for a shghtchck when switch is operated. 3. Lift up appropriate fuel drain valve and allow fuel to drain. Observe for flow in clear plastic tube, followed by interrupted flow of no fuel for a few seconds, further followed by a bubbling flow then full flow. Total drain time should not be less than 30 seconds. 4. Procedure shall be accomphshed for each tip tank separately. 5. In addition to above procedure operate the the power plant from each wingtip separately until steady fuel flow is assured during ground runup prior to flight. i "If not properly inspected and maintained, the bladder-like fuel cells of the airplane could partially collapse, causing the fuel gauging system to be inaccurate. The tanks and gauging system, therefore, should be inspected in accordance with Piper service instructions and kept in good condition. During flight, keep account of time and fuel used in connec- tion with power settings to determine how the fuel flow and fuel 38 700110 TWiN COMANCHE “‘C”’ SECTION (i quantity gauging systems are operating. If the fuel flow indication iM considerably higher than the fuel actually being consumed or un asymmetric flow gauge indication is observed, you may have u clogged fuel nozzle which should be cleaneci‘\. APPROACH AND LANDING. Prior to extending the landing gear for landing, retard both throttle controls to check that the landing gear warning horn is operating. Flying the airplane with the horn inoperative is not permitted. It can lead to a gear up landing as it is easy to forget the landing géar when approaching for a single engine landing when other equipment is inoperative or when attention is drawn to events outside of the cockpit. Therefore it is especially im- portant to check that the-landing gear is down when there is any distraction in the landing situation. - Lower the .gear at speeds below 150 miles per hour and the flaps at speeds below 125 an hour. CAUTION Maintain sufficientspeed during turns in thetraffic pattern. It is a good practice to trim the aircraft to establish a speed of at least 115 miles per hour on the downwind leg and 110 miles an hour on the base leg. Hold 110 miles per hour until the turn onto final approach has been completed. Then reduce to a final approach speed at 100 miles per hour. ' Set the propeller ata high cruising RPM of at least -2400 RPM for ample power ifa go-around is neces- sary. Mixture control should be in the full rich 700110 39 SECTION Ili TWIN COMANCHE ““C”’ position unless density altitude or conditions of high temperature and humidity dictate otherwise. Avoid steep turns at low airspeeds or at low alti- tudes, particularly during the turn from base leg to final approach. Ascertain the landing gear is down and locked on base leg or final approach, by checking the green indicator light on the instrument panel and the external mirror to make sure the nose landing gear is extended. ' The degree of wing flap extension and touch down .speed vary with conditions, but under normal conditions full wing flaps (27 degrees)should be used during the final approach and landing to reduce stall speed and to permit contact with the runway at a slower speed. ' . Contact the ground at the minimum speed consistent with landing conditions. For short, slow iandings under normal conditions use full wing flaps, partial power, and hold the nose up as long as possible before and after contacting the ground with the main wheels. In high winds and crosswinds, it is desirable to approach a landing at higher than normal speeds with half or no wing flaps. If a go-around is necessary apply full throttle, retract the landing gear, and slowly retract the wing flaps a few degrees at a time, During a crosswind approach hold a crabbed angle.into the wind until ready to flare out for the landing. Then lower the wing that is into the wind, reduce crabbed angle, and keep the wheels aligned to the runway using rudder. NOTE Landings with a crosswind component greater than 20 miles per hour should be avoided. When extending or retracting wing flaps, do so a few degrees at a time to avoid' an asymmetrical flight condition which would 40 ' 711229 TWIN COMANCHE “‘C"’ result if one wing flap should stick. Do not side slip with wing flaps extended. Avoid prolonged side slip with a fue! selector set to a fuel cell with low fuel indication. Prior to landing and early in the roll out the brakes should be checked for operation. After landing maximum braking is achieved by retracting wing flaps and pulling back on the con- trol wheel as wheel brakes are applied. CAUTION - It is possible for a pilot to inadvertently reach for the landing gear selector switch instead of the wing flap switch while there is still enough lift on the wings to keep full weight of the airplane off the wheels and thus prevent the actuation of the landing gear safety mechanism, causing retraction during the landing roll. If additional braking is not needed, the wing flaps should be retracted after the airplane has been maneuvered to a stop off the runway. If a landing mustbe made without wheel brakes the air- plane should be flown to contact the ground at a slower speed and landed short on the longest available runway. SECTION 11l The procedure for manually lowering the landing gear should be memorized and understood completely so that it can be ac- complished quickly in an emergency situation, such as a single engine landing. (Refer to Emergency Procedures, in this section for manually lowering the landing gear.) Landing check list: NP U A LOE 753 773 731116 Mixtures - rich. Electric fuel pumps - on. Fuel selectors on proper tanks. Propellers at high cruising rpm. Landing gear - down (under 150 mph) - check green. Flaps (under 125 mph)- set, Safety belts- fastened. 41 SECTION Il TWIN COMANCHE ‘‘C"’ POST LANDING Check list: - 1. Flaps - retract 3. Electric fuel pump - off 2. Cowl flaps - open 4. Prop controls - forward When completely stopped in a parking spot, check the follow- ing items for shut down: ) * 1. Radio & elec. equip. - off 5. Master switch - off 2. Heater (if used) fan - off 6. Parking brake - on 3. Mixtures - idle cut-off 7. Main volt reg. - on 4. Magneto switches - off 8. Alternators - on I control locks are not available and the airplane is to be left for more than a few minutes, secure the control wheel with- the safety belt strap. Chock the wheels and secure tie downs at appropriate places. EMERGENCY PROCEDURES 1. Engine Failure: (a) During Take-off Or After Lift-off: " If an engine failure occurs during take-off run prior to lift- off with adequate stopping distance remaining, reduce the power on both engines and -stop the airplane straight ahead. ' If an engine failure occurs after lift-off with adequate- landing distance ahead, immediately reduce the power on both engines and effect a landing. If engine failure occurs during. climb out after take-off, maintain directional control with rudder and ailerons, and estab-: lish the best single engine rate of climb airspeed (105 mph at sea level). Speeds below or above the best rate of climb speed’ will result in lower than optimum rate of climb. Check that mix- 42 700110 TWIN COMANCHE “‘C"’ SECTION {1l (ure, propeller and throttle controls ate full forward and landing gear and wing flaps are up. If enough altitude has been reached before the failure occurred, or if performance is satisfactory for reaching the airport with landing gear extended, leave the landing gear in the down position. Make positive identification of inoperative engine by gently throttling back on suspected engine. If no effective power is being delivered by that engine, feather the propeller, and trim directionally with rudder trim. Climb straight ahead to traffic pattern altitude and return to airport for landing. Do not try to turn or climb too sharply. Turns, however, can be made toward the inoperative engine if necessary. NOTE A climbing turn toward an inoperative engine is more critical than a gliding turn toward an in- operative engine because there is more asymmetric thrust with the power setting used for climb. Trim directionally with rudder trim. (b) During Cruise Flight: If engine failure occurs during cruise flight, maintain air- speed and directional control of airplane; immediately advance mixture, propeller and throttle controls. The airplane wiil yaw in the d1rect1on of the inoperative engine. It will rarely be possible to 1mmed1ately locate the inoperative engine by viewing the manifold pressure gauge. This yaw in the direction of the in- operative engine can be corrected with rudder and rudder trim. " Carefully retard the throttle control of the suspected in- opetative engine in order to identify the malfunctioning engine and verify that it is not producing power. Turn on fuel pumps, check ignition switches, fuel gauges and fuel cell selectors and try to determine cause of the engine failure. If power cannot be regained, the propeller on the inoperative: engine should be feathered by retarding the throttle to the idle position and moving 700110 43 SECTION 1l TWIN COMANCHE “‘C”’ the propeller pitch control into the feather position. The mixture should then be moved to idle cut-off and ignition turned ‘off. Reduce power on the operating engine if altitude and loading are such that adequate performance can be maintained on one engine and then reduce the electrical load. Best single engine performance will be obtained with the wing on the side having the inoperative engine held about three to five degrees higher than level to help counteract the tendency to turn in that direction. Rudder trim may be used to cormect for additional control pressure needed in single engine flight. - (c) Single Engine Approach: As the airport is approached for landing, reduce power on the operative engine and gradually retrim the rudder. When it is obvious that the airport can be reached, lower the landing gear and check the indicators to make sure landing gear is down and locked. . During a single engine approach the landing gear should not be lowered until landing is assured. It is important, however, to extend the landing gear soon enough that there will be time to lower it manually in the event of a landing gear malfunction, and also so there will be no great change in airplane conflguranon just prior to landing,. Maintain additional altitude and speed durmg approach, keeping in mind that landing should be made right the first time and that a go-around may require the use of full power on the operating engine, making control more difficult. A final approach speed of 105 miles per hour and the use of half rather than full wing flaps will place the airplane in the best configuration for a go-around should this be necessary, but it should be avoided if at all possible, It is essential to land the airplane the first time on a single engine approach in order to avoid the need for a go-around. Under some conditions of loading: or density altitude a.go-around may be 1mposs1ble, and in any event the sudden application of power during single engine operation may cause control difficulties. 44 700110 TWIN COMANCHE *‘C” SECTION 111 If single engine go-around cannot be avoided, the landing peitir and wing flaps should be retracted as soon as possible uller application of full power, since under most conditions, climb, or even level flight, is impossible during single engine operation with landing gear and wing flaps extended. CAUTION If rudder.trim has been used to ease single engine control pressures, the trim should be adjusted as the throttle control is retarded for final approach and landing. RECOMMENDED PRACTICE When operating single engine maintain speed above 97 mph. This speed, 97 mph, will not provide optimum single engine climb petformance, Optimum single engine climb is obtained at the best single engine rate of climb speed, 105 mph, with the operating engine at full throttle, 2700 rpm and the inoperative engine propeller feathered and cowl flap closed. The gear and flaps must be retracted. 700110 45 SECTION i# TWIN COMANCHE 'C"’ 2. Feathering: The Hartzell HC-E2YL-2 feathering propellers can be feath- ered only while the engine is rotating above 1000 RPM. Loss of centrifugal force due to slowing RPM will actuate a stop pin that keeps the propeller from feathering each time the engine is stopped on the ground. If an engine freezes up, it will be im- possible to feather its propeller. Single engine flight with the propeller of the inoperative engine unfeathered will decrease single engine performance. 3. Unfeathering: It is not recommended that propeller feathering and un- feathering be practiced on the ground because of the excessive vibration that occurs in the engine installation. In flight, feath- ering should be practiced only to familiarize the pilot with the proper procedures. To unfeather a propellerin flight,the following technique is recommended: Ignition switches ON. Mixture RICH. Throttle open about 1/2 inch. Prop control at cruise setting. Engage starter until engine starts. f. Allow engine to idle at 1000 to 1500 RPM until oil temper- ature begins to rise. Adjust to cruising powerwhen engine warms. The Twin Comanche, operating under optimum conditions of turbulence and pilot technique, and under standard conditions of temperature and pressure, has a single engine service ceiling of 5800 feet at 3600 pounds gross weight and maximum con- tinuous power. - During initial multi-engine training and in order to maintain subsequent proficiency, it is desirable to practice single-engine flight. Such practice is not advisable with passengers aboard the airplane, with a heavy load, or with extreme rearward center of gravity. In no case should single-engine operation be practiced without having in one of the pilot’s seats a well-qualified twin- rRrRopyp 46 700110 TWIN COMANCHE “C"” . . SECTION 1l ongine rated pilot who is familiar with the Twin Comanche char~ acteristics and procedures. For most single-engine practice it is recommended that the reduction of drag accomplished by feathering a propeller be simulated by a power setting of 10 inches of manifold pressure and 2200 RPM. This will accomplish a zero thrust on the selected engine. Under the proper conditions, actual propeller feathering may be practiced. The following precautions should be exerc1sed' when an engine is feathered for practice. a. Do not feather a propeller for practice if you think the engine may be difficult to restart. b. Do not feather a propeller for practice at a low altitude above the ground. ' c. Do not feather a propeller for practice with a low charged battery, as it takes electrical power to get the engine started. d. Do not feather a propeller for practice unless you are within reasonable distance of an aitport. e. Do not feather a propeller for practice in conditions of temperature, altitude, weight or turbulence which may prevent single-engine flightat altitudes well above the ground elevations. 4, Manual Gear Extension: Manual extension of the landing gear is accomplished with the emergency disengage control located under the floor panel cover between the pilots’ seats. The gear cannot be retracted manually once it is in the down and locked position. Check the following before extending the gear manually. a. Gear circuit breakers - IN. b. Master switch - ON. c. Instrument lights - OFF (daytime). To extend the gear, remove the plate covering the emergency disengage control and proceed in these steps as listed on the underside of the cover plate: a. Reduce power - airspeed not to exceed 100 MPH. b. Place landing gear selector-switch in ‘‘gear down locked”’ position. 711229 A7 SECTION ilI TWIN COMANCHE /'C"’ c. Disengage motor - raise motor release arm and push for- ward through full travel. ' d. Remove gear extension handle from stowage. If left socket is not in clear position, place handle in right socket. Engage slot and twist clockwise to secure handle. Extend handle and rotate forward until left socket is in clear position. Remove handle and place in left socket and secure. Extend handle. Rotate handle “full forward to extend landing gear and to engage emergency safety lock. Pull aft on the handle to check that the safety lock has engaged. e. Handle locked in full forward position indicates landing .gear is down and emergency safety lock engaged. Gear ‘‘down locked’’ indicator light should be ON. If the gear selector switch is moved to the up position with the emergency safety lock en- gaged, the white light will indicate that the gear is in transit although the gear will remain down and locked as indicated by the green light. NOTE Reducing power and rocking gear extension handle will aid in manually extending the landing gear. DO NOT RETRACT WITH HANDLE IN SOCKET. DO NOT RE-ENGAGE MOTOR IN FLIGHT. Procedure for returning the gear to electric operation: a. Place the airplane on jacks. b. Be sure the landing gear circuit breaker is disengaged and release the landing gear safety lock assembly. c. Partially retract the gear by pulling the extension handle halfway back. ' d. Re-engage the circuit breaker and align the slot in the electric motor drive shaft with the mating pin on the torque tube by using the landing gear control lever. e. Engage the torque tube pin with the slot in the drive shaft by moving the extension handle. 48 700110 TWIN COMANCHE ““C” SECTION Il f. Push torque tube and drive shaft together, then lock by pulling the motor release arm back to normally locked position. g. Disengage the extension handle and return it to stowage. Check the landing gear operation. 5. Gear-Up Landing: ‘An emergency gear-up landing may be necessary under the following conditions: a. If surface is too soft or rough for gear down landing. b. When the field is too short for a gear down landing. c. When a water landing is necessary. During a gear-up landing use a normal flaps up approach. During flare out close the throttles, shut off the master and ignition switches, turn fuel selectors off and contact the ground at minimum speed. Vmc DEMONSTRATION WARNING The engine-out minimum control speed demon- stration required for the FAA flight test for the multi-engine rating approaches “an uncontrolled flight condition with power reduced on one engine, The demonstration should not be performed at an altitude of less than 3500 feet above the ground. APPROACH Vyc WITH CAUTION. Initiate re- covery during the demonstration by immediately reducing power on the operating engine and promptly lowering the nose of the airplane. 700110 49 SECTION iii TWIN COMANCHE ““C*" 2! Vuc AND STALL SPEED More power is available on the operating engine at lower altitudes (if the engine is normally aspirated)and hence there can be more asymmetric thrust. The Vpc is highest at low altitudes. The Vpc decreases with altitude and at higher altitudes the air- plane will approach a stall speed before reaching Vpmc. The most critical situation occurs at the altitude where the stall speed and Vmc speed coincide. Care should be taken to avoid this flight condition because at this point loss of directional control could lead to a spin. MOORING The airplane should be moved on the ground with the aid of the nose wheel towing bar provided with each plane. The tow bar is stowed on the forward side of the main spar within the cabin. Tie down ropes for mooring the airplane can be fastened to the wing tie down rings and tail skid. The aileron and stabilator controls should be secured by means of a safety belt or control locks to prevent control surface damage. The rudder is held in position by its connections with the steerable nose wheel and does not need to be secured except under unusually high wind conditions. LOADING AND WEIGHT AND BALANCE CAUTION It is the responsibility of the owner and pilot to determine that the gross weight of the airplane is not exceeded and to determine that the airplane 50 700110 TWIN COMANCHE “‘C"' 700110 remains within the allowable weight vs center of gravity envelope while in flight. The owner or pilot must determine before each flight that the gross weight is not exceeded and that the center of gravity is within allowable limits. For weight and balance see the Airplane Flight Manual and Weight and Balance form supplied with each air- plane. ' Weight and balance determination should be ac- complished with the Weight and Balance Plotter supplied with the airplane. The airplane can carry six passengers with less than the full fuel capacity of 90 gallons (without wing tip tanks) and less than the allowable bag- gage. The two rear family seats, if installed, are designed and placarded to carry not more than 235 lbs. total. With theseé two rear family seats re- moved, the area remaining (baggage) will carry up to 250 lbs. depending upon airplane loading. It will carry fewer passengers and baggage with fuil fuel tanks. As with any airplane, improper loading will cause undesirable flight characteristics if the airplane approaches a critical or marginal flight condition. Make sure that baggage and/or cargo are secured properly with tie down straps to avoid an acciden- tal in-flight shift of the center of gravity or injury to passengers. With tip tanks installed, the airplane has an allowable gross weight of 3725 pounds. It is important to remember that any weight in excess of 3600 pounds however, must be in the form of fuel in the tip tanks. SECTION 11 51 SECTION ifi TWIN COMANCHE “C’® OPERATING TIPS - 1. Trim for takeoff so that a light back pressure on the control wheel allows the airplane to lift from the runway. . 2. When checking the propeller feathering action, it is necessary to move the propeller control rapidly in and out of feathered position to prevent a drop of more than 500 RPM. Excessive manifold pressure will occur if the RPM count falls below 1000 during this check.. 3. Do not retract the landing gear prematurely on takeoff. 4. To reduce wing flap operating loads, lower the wing flaps at airspeeds well below 125 miles per hour. 5. Determine the position of the landing gear by checking the gear position lights. 6. During landing, allow the main wheels to contact the ground while centering the rudder pedals. Apply additional back pressure to the contro]l wheel and retract the wing flaps for good directional control and maximum effectiveness of brakes during landing roll. "7. When the instrument hghts are on, the gear position lights are dimmed for night flight. 8. Be sure that all radio switches, light sthchcs and pitot heat switch are in the off position before starting engines. 9. Due to the responsive trim tab controls, a small adjustment in trim gives a rapid change in attitude. 10. Engine shut down by use of the mixture controls may cause a rough stop during high ambient temperature conditions. A spring loaded device on the throttle will shut down the engines by closing the throttle valves and shutting off air to the engines. As this mechanism is connected to and operated by the last 1/8 inch travel of the throttles, a stop on the quadrant prevents the throttles from being pulled fully aft and closing the throttle valves. This throttle cut-off is not intended to_be used in lieu of the mixture control for engme shut down: it is to be used only when the mixture control is placed in idle cut-off and there is mdxcatlon of a rough stop. 11. During single engine flights be sure that the gear and flaps are fully retracted when climbing at the best single engine climb speed. Speeds above or below the best single engine climb speed will decrease climb performance. Close the cowl flap on the inoperative engine and trim the airplane to reduce drag. 52 763773 731116 TWIN COMANCHE *‘'C"* SECTION Il 12. Fuel from auxiliary cells and from optional wing tip tanks is to he used in level flight only. Takeoffs should not be made using fuel from the auxiliary cells or tip tanks or with the main cells less than one-quarter full. Certain maneuvers should be avoided. These maneuvers could cause fuel to move sway from fuel cell outlets. If the outlet is uncovered, the flow of fuel will be interrupted and a temporary loss of power may result. ~ Running turning takeoffs, prolonged slips or skids in any pitch - attitude, or any unusual or abrupt maneuvers which could cause uncovering of the fuel outlet should be avoided. 13. The rudder pedals are suspended from a torque tube which extends across the fuselage. The pilot should become familiar with the proper positioning of his feet on the rudder pedals so as to avoid interference with the torque tube when moving the rudder pedals or operating the toe brakes. 14. Anti-collision lights should not be operated in heavy haze or clouds, since reflected light can produce spacial disorientation. Show courtesy for other pilots by not operating strobe lights while taxiing in the vicinity of other aircraft. FLIGHT CONDITIONS Do not fly into marginal or deteriorating weather unless you ute equipped and qualified to fly as an instrument rated pilot under instrument conditions. Before taking off on an instrument flight, or a flight at night or in marginal conditions, make sure ull instruments and equipment are operating propetly. In mountainous terrain, maintain proper distance from the mountains, especially in strong winds, which may cause extreme downdrafts and turbulence. Flight should be planned to avoid thunderstorm areas. In conditions of extreme turbulence, reduce power to slow the air- plane below the design maneuvering speed of 162 miles per hour. A further reduction of power will ease the stress to which the airplane is subjected by virtue of turbulence. When flying In extreme turbulence or strong vertical currents, using the auto- pllot, the altitude-hold mode should not be used. 763773 53 731116 SECTION Ill TWIN COMANCHE “C* . . ¢ Secure safety belts in severe turbulence. Flying over 10,000 feet without using supplemental oxygen should be avoided. Do not take off with ice or frost on the wings, as ice ot frost will radically change the flight conditions of the airplane. The deicing equipment on light twins, if installed, is de- signed to allow the pilot to fly out of inadvertent icing situations, not to handle heavy icing. Even if the airplane is equipped with _deicing equipment, do not plan to fly it in any icing condition. Deicing equipment should be checked in accordance with the Airplane Flight Manual instructions prior to entering known icing conditions. ' When flying in wet, heavy snow or other conditions where the induction air filters may become clogged, monitor the manifold pressure gauge. A decrease in manifold pressure may indicate a clogged filter. If the decrease is followed by a slight increase in manifold ptessure, this will then indicate that the automatic alternate induction air system is in operation, and the manifold pressure may then be brought back to the desired level with the throttle control. A continued drop in manifold pressure would. indicate that the automatic induction air system was not working, In this case, actuate the manual alternate air control, which serves as a back- up for the automatic system. A partial regain of manifold pressure will indicate that the manual alternate air induction system is operating. Throttle controls may be advanced to gain additional manifold pressure. The manual alternate air control should not be actuated on the ground with the engines operating, because the engines would then be supplied with unfiltered air. "54 ‘763773 731116 TWIN COMANCHE *'C” SECTION [l DIVING SPIRAL At night or during instrument flying conditions, it is possible for a pilot not proficient at instrument flying to get into an in- advertent steep diving spiral. If a spiral should develop, recover In the following manner: a. Reduce power. b. Level the wings. c. Bring the nose of the airplane to the horizon. RADIO OPERATION Communication and navigational equipment controls are lo- cated in the center of the instrument panel. Associated switches are located in a junction box above the radio stack. Circuit breakers for the radios are located on the lower right sub-panel. All sets are turned on by the switch in the control head of each unit. After power is supplied, either one of the transmitters may e operated by moving the selector switch tothe desired position. 763773 55 731116 SECTION IV PERFORMANCE CHARTS Take-off Ground Run Distance ., . Take-off Distance Over 50-Foot Obstacle . . Multi-Engine Climb Rate and Airspeed . Single-Engine Climb Rate and Airspeed Altitud;e Conversion Chart . Range vs Density Altitude . True Airspeed vs Density Altitude Landing Distance vs Density Altitude Landing Distance Over 50-Foot Obstacle (Short Field) . Part Throttle Fuel Consumption Power Setting Table . 56 . 57 - 59 60 . 61 ) - 63 65 . .66 - 67 TWIN COMANCHE 'C"" SECTION IV TWIN COMANCHE C 1T 7T VTP T T 17T 17T 1T 171 — TAKE-OFF GROUND RUM DISTANCE — | AT VYARIOUS ALTITUDES, | TEMPERATURES, WEIGHTS, AW@ WI]N@S FLAP SETTING- 15° LIFT- OFF SPEED- 80 MPH. IAS PAVED LEYEL RI.IINVMIY [T 1T 1 | | T ATT SR e avruoe a4 — égsfl E&mEFE%%NCET gh TOC AT - i;'i';"a"fim‘“fi;mz s e roe ] [ ZIN\ \ < 2400 ‘x'\(\“‘/ . \\‘ \ “@S\\“ /// \ \ \\ 2000 smh// / //\\ A \ N K = -6000 \/ /, FA RN \\\\\ \\ 1600 § 1000 //, /F"”‘\S N \x\\\\- "2 | 20001 )< \‘\\—\\ NN 100 2 =SB ENSESSONN i -~ 1= \Q% \f:.w g l RN | N 20 40 60 B0 3500 3408 3200 3008 2600 0 10 20 30 4 TEMI’ERATI.IIIE °F WEIGHT- LBS.” ~ HEADWIND - MPH. 700110 56 SECTION IV TWIN COMANCHE ““C"’ 7 TWIN COMANCHE C T T T T T T T T T T T — TAKE-OFF DISTANCE ~ = - - OVER 50 FOOT OBSTACLE AT VARIOUS ALTITUDES, T‘ TEMPERATURES, WEIGHTS, AND WiNDS FLAP SETTING- 15° = ATTAIN 91 MPH 1AS AT 50 FT. — PAVED LEVEL RUNWAY ] NOTE: THE TAKE - OFF DATA SHOWN BELOW WAS . B PREPARED IN ACCORDANCE WITH CIVIL AIR REGULATION 3.84 T T R | 1 N AN RMRRNL sw0 &= &8 TAKE - OFF DISTANCE - [/ 1/ / // &% N SN \\ DS NI NI 000 L - / /) / ~\ 4000 2000 I N AN N N S [ . Bl « L i / I |l J / o ] (el /Y AAA 1000 1 / 0 20 4D 60 80 3BN0 340 3200 3088 280 O 18 20 38 TEMPERATURE - °F WEIGHT - LBS. HEADWIND - MPH. 57 700110 COMANCHE “‘C*” SECTION IV This page intentionally left blank. 58 DENSITY ALTITUBE - FEET SECTION IV TWIN COMANCHE “¢ TWIN COMANCHE C 1T 7 T 17T T 17 17 1T 17T T°717°1 — MULTI-ENGINE CLIMB RATE AND SPEED — L_ S _ DENSITY ALTITUDE AND WEIGHT | GEAR AND FLAPS RETRACTED COWL FLAPS OPEN EXCEPT AS NOTED i 24000 \ \ i \%\ \ NN 12000 %‘%\%@? \ % TN \ 8000 VAN x4000 \q%é \fEx Xi\, \ \° \V\ \\ \ st \ \& \ 0 480 808 1200 1608 2000 S0 100 1o RATE OF CLIMB FT. /MIN. BEST RATE OF CLIMG SPEED MPH 59 7001] TWIN COMANCHE “C’" , SECTION IV TWIN COMANCHE C T T SINGLE EN@UN%SIBA?E OF CLIMB ALTITUDE AND WEIGHT LEFT ENGINE INOPERATIVE COWL FLAP OPEN GEAR AND FLAPS RETRACTED ” 2000 \\\ 8000 }_\ \\"’ % |4 el N N | wl T INCNL TN \ NN N 1 N\ \\ { e 100 200 400 w 500 80 100 110 RATE OF CLIMB FT./MIN. ' BEST RATE OF CLEMB SPEED NPH et | BHGT aTE - 700110 60 SECTION IV TWIN COMANCHE *‘C" TWIN COMANCHE C T T T T T T T T 17 ALTITUDE CONVERSION CHART THIS CHART SHOULD BE USED T0 DETERMINE DENSITY ALTITUDE FROM EXISTING TEMPERATURE AND PRESSURE ALTITUDE CONDITIONS FOR USE WITH PERFORMANCE CHARTS. s T\ 24000 |—— 20000 " 12600 / DENSITY ALTITUDE - FT. L~ A L '\ 200! 110 L L ..IH/‘ A » 60 80 100 TEMPERATURE - °F ~N 2 - »N 2 61 e 700110 TWIN COMANCHE “‘C”’ SECTION IV TWIN COMANCHE C T T 17T 17T 1777 RANGE Vs - DENSITY ALTITUDE GROSS WEIGHT 3600 LBS. FUEL - 90 GAL TOTAL 84 GAL USABLE Wo.{ cauise [gew [wp. [ ARROR | wrxvure NORMAL [2400] 26 | .80 | BEST POWER INTERMEDIATE {2400| 24 | 7.70 | BEST ECONOMY " | ECONOMY 2200| 24 | 6.90 BEST ECONOMY LONG RANGE [2200{ 20 | S5.80 BEST ECONONY -~ N F o f‘,“lzooo #noe : 'J’ [ / I ANEaHY i ll ! ll / ! / / 900 0 800 90 1000 1100 1200 1380 RANGE - STATUTE MILES - NO RESERVE ————~45 MIN RESERVE 8 I - = e — — e —— 400p 1 ‘\ S~ e 62 SECTION IV TWIN COMANCHE “‘C"" ~ TWIN COMANCHE € TRUE AIRSPEED Vs DENSITY ALTITUDE GROSS WEIGHT 3600 LBS. COWL FLAPS CLOSED 20000 16000 12000 DENSITY ALTITUDE - FT 4000 SL 120 140 160 100 200 20 TRUE AfRSPEED - MPH 63 700110 TWIN COMANCHE *‘C" SECTION IV TWIN COMANCHE C GROUND RUN DISTANCE - FT. T T 77T 7T 717 1T T 1T 1771 ~ LANDING GROUND RUN DISTANCE -AT YARIOUS ALTITUDES, TEMPERATURES, | WEIGHTS, AND WINDS ] ‘ FLAP SETTING - 27° - TOUCH-DOWN 76 MPH IAS PAVED LEVEL RUNWAY f“mm | L 1000 “tss\\“““‘w / \\\\ ::r , L~ "“J’?/ii\ \\\ \ - 800 NN ST oo SIS — - TEMP. e S EN r 00 E T~ Xv '\ é \\ ‘\ 400 ! N\ ' N . 200 8 20 40 60 90 3600 34003200 3008 2000 & 19 20 30 TEMPERATURE - °F WEIGHT - LBS. READWIND - MPH. 700110 64 SECTION IV TWIN COMANCHE “C'*- 65 TWIN COMANCHE C T r T T T T T T — LANDING DISTANCE @VEE’% 50 FOOT . | OBSTACLE AT VARIOUS ALTITUDES, — | TEMPERATURES, WEIGHTS, AND WINDS _ | FLAP SETTING- 27° — PUWEH OFF- APPROACH SPEED- 90 MPH IAS — e PAVED LEVEL RUNWAY _ NOTE: THE LANDING DATA SHOWN | BELOW WAS PREPARED IN ACCORDANCE WITH CIVIL AIR REGULATION 3.86. - { l‘\_ ) S R j \.\ k - 8000 3 :/s \\ \ 2400 . X A’V.}\\N\x\ L\ Zflgl | r’e: \\fiiégfik‘\}k \\ 2000 STD.¢ 3 TE_IrP: \¥\ \K\} - - Q\ N Q\ 1000 | E \\\\\V 1200 i N: y 08 i . ) TEMPERATURE - °F 20 40 GO0 BO 3600 3480 3200 3900 2800 0 10 20 HEADWIND- WEIGHT - LBS. 1 MPH, 700110 LANDING DISTANCE - FT “OH NI - 3UNSSTUd GI0JINVA SECTION IV 66 FUEL CONSUMPTION - BAL/HR EACH TWIN COMANCHE C 92 62 "7 £Z T 1z 0z 61 L m =z Lo e " \ MI. = T — | 1 = | m o = =15 - \_\ ] \\ \\ = = L T B e | W L ] \_\ 7 7 Y\ "QHVONYLS MOTIE I'Y'0 HO4 \ 0¥ J4NLYHIANIL JONLILTY TEYONVLS L~ | 1™ WOR3 NOLLYINYA 4o OF HOVA ¥4 W/ V3 > L0° NOILdWRSNOJ TInd 3HI 1934400 2 " “13A31 ¥3S 3A04Y J0NLILTY FENSSTHA = . 40 1334 0001 HIV Ho4 :cEI:.m:nu . . TINA 13AT1 VIS u-.._. 01 HH/T¥9 60" OOV "1 *SILON ) QYYONYLS - 13837 ¥3S ) Yig&-0Z€-01 ININ0IAT NOILINASNGD T2A4 TLLO¥HL LEVd bbb g TWIN COMANCHE “‘C" 700110 TWIN COMANCHE “C" SECTION IV €168009 V¢SO0 0€2 "18YD vondunsuo) [3ng 03 9591 sAuryes 1amod 995Y) 10§ UoHdWNSUOD [aNy BUIMIAP O °Z "PIepus}s mojaq samjeiadwa) i0j Joelgns ‘prepuels aaoqe samjeladwa} e 1oy amssaxd plojluew ppy ‘amjesadws) apnjijfe prepue)s woly ainjeradwa) T8 UOTIONPUL UI UOTETIBA d o0T yoma 103 *8H ,,LT1°0 Ajojewrxoidde amssaid piojiuew 3951100 ‘1amod Juejsuod utejurew oy, ‘I €61 00€c SCe oore 0°vC (1] 74 0’02 00T cee 00cc Ly 00¢¢ 9'0C 001¢ 0'vC 0022 9'st 00ze 9 00+ dw. Wdd dW Wdy dW Wdd dW Wdy asing as1017) es1nid) . 851y abuny Bue Awouoogy aojpawsau| |pwioN aui3u3 4 091 ‘8-0Z¢-0I [apow Buiwodky - (asinig) ajqe] Buinag Jamog 700110 67 TWIN COMANCHE “‘C" SECTION IV NOTES 700110 ou SECTION V GENERAL MAINTENANCE Tire Inflation. Battery Service . Brake Service Landing Gear Setvice . Fuel and Qil Requirements Care of Air Filter Care of Windshield and Windows Serial Number Plate Propeller Service Fuel System . . 69 . 69 . 7Q .71 .71 .72 .72 .75 .75 .76 TWIN COMANCHE *‘C"’ SECTION V SECTION v GENERAL MAINTENANCE This section contains information on preventive maintenance.. Refer to the Twin Comanche Service Manual for farther main- tenance. Any complex repair or modification should be accom- plished by a Piper Certified Service Center. TIRE INFLATION For maximum service from the tires, keep them inflated to the proper pressure of 42 psi. Interchange the tires periodically for even wear. All wheels and tires are balanced before original installation, and the relationship of tire, tube and wheel should be maintained upon reinstallation. In the installation of new components, it may be necessary to rebalance the wheels with the tires mounted. Out of balance wheels can cause extreme vibration in the landing gear. BATTERY SERVICE Access to the 12-volt 35 ampere hour battery is geined through the top panel of the fuselage nose section. The stainlesg mteel battery container has a plastic drain tube which is normally closed off with a clamp that should be opened occasionally to drain off any accumulation of fluid. The battery fluid level must not be brought above the baffle 700110 69 "SECTION V TWIN COMANCHE “‘C"’ plates. It should be checked frequently to determine that -the fluid level is proper and the connections are tight and free of corrosion. If the battery is not properly charged, recharge it starting with a rate of 4 amperes and finishing with a rate of 2 amperes. Quick charges are not recommended. The external power recep- tacle, if installed, is located Battery Installation on the left side of the nose section. Be sure that master switch is off while inserting or removing a plug at this receptacle. BRAKE SERVICE The brake system is filled with MIL-H-5606 (petroleum base) hydraulic brake fluid. This should be checked at every 100 hour inspection and replenished when necessary. Refill the brake reservoir on the aft bulkhead of the nose section to the indicated level. ' No adjustment of brake clearance is necessary. If the brake blocks become wom to 1/64 inch minimum lining, replace them with new brake segments. Remove the four cap bolts that join the brake cylinder housing end lining back plate assemblies, then remove the back plates. from between the brake disc and wheel. Slide the brake cylinder housing from the torque plate and slide the pressure plate and lining from the anchor bolts of the cylinder housing. Remove the lining by prying it from the presswe plate. and back plates. With the four cap bolts 70 ‘700110 TWIN COMANCHE “‘C”’ SECTION V removed, it is possible to remove the main wheels by taking off the dust cover and axle nut. LANDING GEAR SERVICE To raise the aircraft for servicing, use two hydraulic jacks aitl a tail support. Place about 300 pounds of ballast on the base ul the tail support before jacking the aircraft. Landing gear oleos should be serviced according to instruc- flon on the units. All three oleos should be extended until about iwo and three-quarter inches of oleo strut extenmsion is exposed In slatic position. To add air to the oleo struts, attach a strut pump to the air vulve and pump the oleo up to the proper position. To add oil, tnlease the air through the strut valve, and allow the strut to sxlend fully. Remove the air valve and fill the unit through its opening., Compress the oleo to within one-quarter inch of full compression, allowing air and excess oil to escape. Reinsert the vulve core and pump up the strut. FUEL AND OIL REQUIREMENTS A minimum octane of 91/96 Aviation Grade fuel mustbe used tu the Twin Comanche. Since the use of lower grades of fuel can rullse serious engine damage in a shott period of time, the engine wurranty is invalidated by use of lower octanes. » The oil capacity of the Lycoming I0-320-B is 8 quarts with s minimum safe quantity of 2 quarts. It is recommended that wipine oil be changed every 50 hours ot sconer under unfavorable conditions. Intervals between oil changes can be increased as 190110 - n SECTION V TWIN COMANCHE *‘'C"’ much as 100% on engines equipped with full flow cartridge type type oil filters provided the element is replaced each 50 hours of operation. The following grades are required for the specified temperatures: Temperatures above 60° F S.A.E. 50 Temperatures between 30° F and 90°F S.A.E. 40 Temperatutes between 0° F and 70°F S.A.E. 30 Temperatures below 10°F S.A.E. 20 CARE OF FILTER The induction air filters must be cleaned at least once every fifty hours. Depending on the type of condition existing, it may be necessary to clean the filters more often. The following cleaning procedure is recommended by the manufacturer of the filter: 1. Remove the filter from the engine compartment. 2. Tap filter gently to remove dirt particles. Do not use compressed air or cleaning solvents. 3. Reinstall air filter. CARE OF WINDSHIELD AND WINDOWS The following procedure is recommended for care of .the plexiglas windows: 1. Flush with clean water and dislodge excess dirt and mud by hand. " 2. Wash with mild soap and warm water, using a soft cloth or sponge. Do not rub. 72 ' 700110 '\N COMANCHE “'C"”’ SECTION V SKETCH E SKETCH F FREQUENCY = METHOD g 1O <> O A A t oHAKD oy EREASE SPRAY HYDRAULIC 50 W s As | Ty BRUSH DAILY REQURED | phtk CAN GUN OAN FLUD . 7. LUBRICATING OIL — INTERVALS BETWEIH O3l GHANGES CAN BE oo e o SPECIAL STRUGTIONS et s B R RSe O SPECIFICATION e 1, AIR FILTER - TO CLEAN FILTER, TAP GENTLY TO RENOVE IS REPLACED EACH 50 HOURS OF oru‘lnnnt IRT PARTICLES, DO NOT BUOW GUT WITH COAPRESSHD AfRt OR 6. LUBRICATE FLAP TRACK WITH DUFGHT'S AV POSE SLIP A MIL-L7870 LUBRICATING OIL, GENERAL PURPOSE, USE SOLYENT, REPLACE F {F PUNCTURED Oit DAWAGHD, SPRAY #6611 FLAPS REQUIRE CLEANM(} AWt LUBRICATION LOX TEMPERATURE TURBOCHARGED ENGINES — CLEAN FILTER [N SOLYEHT AND AFTER EXPOSURE TO AN ABNORMAL UHIAN 11 WATER. ALLOY TO DRY. DIP [K SAE 12 0IL AND ALLOY TO DRAIN FOiR FLAPS WITH NYLON ROLLERS WILL HOT Kith LUBRICATION 8 MIL-L082 LUBRICATING OIL, AIRCRAFT RECIPRO- HOURS, ON EITHER FLAP \ CATING ENGINE (PISTON) GRADE AS 2, BEARINGS ANO BUSHINGS — CLEAK EXTERION WITIHA DRY TYPE | 9. OVERHEAD TRIN PULLEYS — LUBRICATN l“ll BXTENDED SPECIFIED SOLVEHT BN ORE RELUBRICATING. TO 250 HOURS WNEN DUSTY CONOITIONS AN AT A HINIWUM. SAE 50 ABOYE &0~ ¥ AIR YEMP, 3, LANDING GEAR AND FLAP TRANSMISSIONS AND SCRENS, TRIX SAE 40 30 TO 90+ F AIR TEKP. SCKENS AHD WHEEL BEARINGS - DISASSEMILL] AND €1 AN NOTES SAE 30 0~ TO 70 F AIR TEMP, ¥ITH A DRY TYPE SOLVENT.[WHEN REASSENBLING TRANS . SAE20BELOY 10« F AIR TEMP, NISSIONS, FILL WITH LUBRICENT AND APPLY A THIN COATIHG I Bmeols'u ?‘EE%NAG'{ :m&a CLEAL£ Amg:‘o‘ Im ?hc‘fim APTER c MIL-H-5606 HYDRAULIC FLUID, PETROLEUN BASE 4, OLFD STRUTS AND BRAKE R Lmwon < FILL PER (RSTRUCYIONS | 2. SEE LYCOKING SERVICE (NSTRUCTIONS i, 1614 FOR USE OF OH UNIT OR CONTAINER, OR REFER YO SERYICL HAHUAL, LETERGENT OIL, 0 MIL-G-23827 GREASE, AIRCRAFT AND INSTRUMENT, SECTION I, CAUTIONS GEAR AND ACTUATOR SCREW 3, PROPALLER - REMOVE ONE DF THE TWO GRFASH FITTIHGS LUBRICATION I'GR EACIY BLAOE. APPLY GKEASE TRROUGH IV 1 TIHt UNT I, 1, DO HOT USE HYDRAULIC FLUID WATIY A FAV) R O, OR ESTER E NILG-3545 GREASE, AIRCRAFT, HIGH TEWPERATURE| FRMSH GRIFASE APPEARS AT HOLE OF REMOVED FIT IING, s 6 LUBRICATION POINTS — WIPE ALL LUBRICAYION MOINTS €1 FAN 7. DO HOT OVER-LUBRICATE COCKPIT r’omn'“ C HA@? PA-ZS@ F 'A.l&'- 62';"’0!5 SLIP SPRAY DUFONT O OLD GREASE, OIL DIRT, ETC., BEFORL NFLUMKKATING, 3, DO HOT APPLY LUBRICANT TO RUODLH FAN e ‘ _ am e e - - 73/74 TWIN COMANCHE “C”’ SECTION V 3. Remove oil, grease or sealing compounds with a cloth soaked in kerosene. 4. After cleaning, apply a thin coat of hard ‘polishing wax. Rub lightly with a soft dry cloth. ) 5. A severe scratch or mar can be removed by using jow~ eler’s rouge. After the flaw has been removed apply wax to the fArea. SERIAL NUMBER PLATE The Manufacturer’s Association Plate is located on the for- ward side of the forward cabin builkhead. A second plate con- taining only the serial number is located to the left of the tail nkid. The serial number should always be used in service or warranty matters. PROPELLER SERVICE The air charge in the propeller cylinder should be kept at the Pressure specified on the placard located in the spinner cap. The pressure in the cylinder will increase about one-third psi for every I‘ahrenheit degree increase in temperature. This effect should be considered when checking pressure. The charge maintained must be sccurate and free of excessive moisture since moisture may freeze the piston during cold weather. Dry nitrogen gas is recommended, See appropriate service manual for service instructions. 711229 I “TWIN COMANCHE “‘C"' SECTION V FUEL SYSTEM The fuel screens in the strainers require cleaning at fifty hour or ninety day intervals whichever first occurs. The fuel strainers beneath the floor panel are accessible through a plate in the underside center of the fuselage. The fuel injector screen is located in the housing where the fuel inlet line connects to the injector. This screen should be cleaned every fifty hours of operation, ' 76 711229 TWIN COMANCHE “‘C"” SECTION V NOTES 700110 1 INDEX SECTION | Specifications: . . . . . Performance . . . . . . Weights . . . . . . . Power Plant . . . ., . . Fueland Qil. . . . . . Baggage Area . . . . . Dimensions . . Landing Gear . . . . . SECTION I1 Design Information: . . . Engine and Propeller . . . Fuel Injection . . . Structures. . . . . . . Larding Gear . . . . . Control System . . . . . Fuel System . . . . . Electrical System . . Vecuum System . . . . . Instrument Panel . . . . Instrument Static Pressure System . Heating and Ventilating System. Seats . . ... . . . Finish. . .. . . . Baggage Area . . . Stall Warning System SECTION I Operating Instructions: . Preflight . . . . . . . Starting Engines. . . . 700110 Page B W WM = 25 47 INDEX' (cont) -SECTION 11l (cont) Flooded Start . . C e e e Warm-Up and Ground Check e e e e Electrical Power . Taxiing and Pre-Take-off Take-Off and Climb . . . Wing Flaps . . Short and Soft Field Take-Offs Landing Gear Retraction . . . . ..-. Deicer Boots Vmc e e s v s s e e v s Stalls . . . . . . . . . . Spins . . v : Spin Recovery Techmque Cruising. Fuel Management . Approachand Landing Post Landing . Emergency Procedures . Vme Demonstration . e e e Vmc and Stall Speed . . . . . . Mooring. . . o Loading and Weight and Balance Operating Tips Tl e e e . Flight Conditions, . . .. . , . . Diving Spiral Radio Operation . . . . . . . . SECTION IV Performance Charts; . Take-Off Ground Run Dlstance . . Take-Off Distance Over 50-Foof Obstacle . Multi-Engine Climb Rate and Airspeed . Page 27. . .56 56 57 59 753 773 731116 INDEX (cont) SECTION 1V (cont) Single-Engine Climb Rate and Airspeed . Altitude Conversion Chart . . . . Range vs Density Altitude . True Airspeed vs Density Altitude . Landing Distance vs Density Altitude. Landing Distance Over 50-Foot Obstacle (Short Field) Part Throttle Fuel Consumption Power Setting Table . . . SECTION V General Maintenance: . . . . . . . Tite Inflation. . . . . . . . . Battery Service . . . . . . . Brake Service . . . . . . . . Landing Gear Service . . . . . . Fuel and Oil Requirements . . . . Care of Air Filter . . . . . Care of Windshield and Windows Serial Number Plate Proper Service . . . . Fuel System . ., 700110 . I'nyw 0l Ol 62 63 65 66 67