8.
Nose Gear Up Lock 22. Shuttle Valve -Right Main Gear
9.
Nose Gear Actuator 23. Left Main Gear
10.Nose Gear 24. Left Main Gear Door
11.
Main Gear Bottle -Left 25. Left Main Gear Door Actuator
12.
Main Gear Bottle -Right 26. Right Main Gear Door Actuator
13.
ShuttleValve -Left Main Gear 27. Right Main Gear Door
14.
Unlock Actuator -Left Main 28. Right Main Gear
EmergencyExtensionSystem Operational Schematic
Figure 301
EFFECTIVITY: 040-999
32-30-00 PAGE
Jan 10/90 7
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Extensionand Retraction (continued)
4. FunctionalProofPressureand Leak Test For EES (continued)
(k)
Using the test cart, cycle the gear six times with the first cycle in the DOWN position initiating the shuttle valve into the hydraulic position. This ensuresthe system and shuttle valve is in the full hydraulic mode.
(I)
Retightencap on the tee test port.
(m)Performsame test on other gear.
(n)
Reconnectandrig gear doors.
(o)
Functionallytest hydraulic system.
CAUTION: THOUGHTHE GEAR IS ALREADY DOWNAND LOCKED AFTERPNEUMATIC EXTENSION,THE GEAR HANDLE MUST BE MOVED TO THE DOWN POSITIONAND THE SYSTEM HYDRAULIC PRESSURE ALLOWED TO BUILD UP. OTHERWISE, THE PNEUMATIC LINEAND THE UP LOCK HOOK RELEASE ACTUATOR WILLBE FILLED WITH HYDRAULIC FLUID.
5. Testing of Emergency BlowdownSystem
The blowdown system,whichconsists of three individual blowdownsystems,musthaveeach unit individuallytested.
(a) With the airplane firmly jacked up, disconnect appropriateactuatorfrom the gear system linkage to be tested.
(b)Disconnectwires from squib unit to be tested. Ensure the two squib wires are interconnected with either a U-clip oraluminumfoil.
(c) Connecta multimeter to leads coming from the aircraft system.
(d)Turn on master switch. Ensure all other gears are locked in the DOWN position.
(e) While observing the meter, activate the blowdown switch and check for proper
voltage/amperage.
6. Testing of Explosive Valve
CAUTION: THE MINIMUM CIRCUITRESISTANCEFOR THE SQUIB IS 0.6 TO 1.2 OHMS, BUT MAXIMUM CONTINUITY TEST CURRENTALLOWED IS 0.01 AMPS. DO NOT EXCEED 10 MILLI AMPS.
(a) Using an ohmmeter with a 4 1/2 digit reader, which doesnt exceed 10 milli amps, test squib circuitfor 0.6 to 1.2 ohms.
EFFECTIVITY:
PAGE8 Jan 10/90 32-30-00
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Extension and Retraction (continued)
7. Removal of Main Gear Actuating Cylinders
(a)
Place airplane on jacks.
(b)
Disconnect hydraulic line and shuttle valve from actuating cylinder. Cover open line ends to preventcontamination.
(c)
Disconnect cylinder operating rod end from link assembly.
(d)
Disconnect attachment end of cylinder by removing bolt securing the cylinder and main gear up lock crank assembly.
(e)
Removecylinderfrom wheel well.
8. Disassemblyof Main Gear Actuating Cylinders (refer to 32-30-00 Figure 401)
(a)
Before disassembly, establish rod end engagement distance to air in preliminary assembly of actuating cylinder.
(b)
Withcylinder removed from the airplane, remove safety wire attached to end cap and cylinder body.
(c)
Loosen nut and remove key and rod end.
(d)
Unscrew end cap from cylinder body.
(e)
Drawpiston from cylinder body.
9. Assemblyof Main Gear Actuating Cylinders (refer to 32-30-00 Figure 401)
Lubricate all parts with hydraulic fluid (MIL-H-5606) prior to assembly.
(a)
Install GT-ring on piston.
(b)
InstallO-ring and back up on exterior of end cap.
(c)
Install GT-ring and scraper on interior of end cap.
(d)
Slideend cap on piston and screw end cap into piston. Torque end cap to 65 + 15 inch-pounds.
(e)
Install nut and key on rod end.
(f)
Adjust rod end to length obtained before disassembly. Refer to Adjustment of Main Landing Gear for final adjustments. Torquenut to 85 + 15 inch-pounds.
(g)
Reconnectsafetywire.
10. Installation of Main Gear Actuating Cylinders
(a)
Positionattachmentend of cylinder and up lock crank assembly on their mounting brackets. Install attachment bolts and secure.
(b)
Connect operating rod end of cylinder to the gear link assembly.
(c)
Connect hydraulic lines to cylinder.
(d)
Check operation of installation and landing gear rigging.
(e)
Removeairplanefrom jacks.
11. Inspection of Main Gear Actuating Cylinders
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