(b)
Shutoff test unit per instruction supplied with unit.
(c)
Closesuction-fill-drainvalve in airplane by placing control lever in down position and disconnectingtest unit hose from fitting. Install protective cap over fitting. Disconnectand remove test unit pressure hose from pressure fitting in airplane (if previously connected). Install the protective cap on the fitting.
(d)
Check fluid level in power pack reservoir.Check system for leaks.
(e)
Closeaccess in hydraulic components cover. Installaccess panel on right side of nose section.
14. Removal of Hydraulic Power Pack. (Figure401)
(a)
Remove right access panel at nose section between Stations 25.60 and 57.00. Completely remove hydraulic componentscoverby removing retaining strips from outer edges of cover.
(b)
Drainpower pack by removing both drain caps from end of suction; fill and drain plug installed inside access openingbehind hydraulic componentscover. Connect fluid line from fitting to container;raise lever to open valve and drain reservoir.
(c)
Disconnectelectrical connector at forward end of power pack.
(d)
Disconnect vent line from power pack.
(e)
Disconnect gear selector control cable from power pack control arm on outboard side of power pack.
(f)
Disconnectvarious hydraulic lines from power pack. Cap open lines to prevent contamination.
(g)
Cut safety wire and remove attachment bolts securing power pack to mounting brackets.
(h)
Move power packforward and out access opening.
15. Installation of Hydraulic Power Pack. (Figure401)
(a)
Positionpower pack in mounting brackets. Ensure power pack control arm is facing outboard; secure power pack and bracket supports to mounting brackets with bolts and safety.
(b)
Uncapand connect various hydraulic lines to power pack.
(c)
Connectelectrical connector to forward end of power pack and connect landing gear selector cable to selectorarm.
(d)
Fill power pack (refer to 12-10-00).
(e)
Bleedhydraulic system per instructions in this chapter.
(f)
Close hydraulic components cover. Replace access panel on side of airplane nose section.
NOTE: Readjust gear selector cable removed from support.
EFFECTIVITY:
040-999
Jan10/9029-10-00
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Main (continued)
5.
Power Pack Installation
Figure 401.
EFFECTIVITY: 040-999
0 PAGE
29-10-00 Jan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Main (continued)
1. Drain Fitting
2. Main Relief Valve
3. PriorityValve
4. Filter, Hand
Pump Suction
Pump Relief Valve
Time Delay Check Valve
Location of Power Pack Components
Figure 402
EFFECTIVITY:
040-999
Jan
Jan 10/901090 29-10-00
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Main (continued)
16. Disassembly of Power Pack. (Figure 403)
After power pack is removed from airplane and all ports are capped or plugged, spray with cleaning solvent (Federal Specifications P-S-661, or equivalent) to remove all accumulated dust or dirt. Dry with filtered compressed air. To disassemble unit, proceed as follows:
(a)
Remove wire, nut, reservoir cover, and O-ring. Since cover is a snug fit on reservoir, use soft malletand tap cover lightly to remove.
(b)
Removesnap ring from center stud. Remove baffle plate from reservoir. Drain remaining hydraulic fluid from reservoir.
(c)
Removereservoir and O-ring. Reservoir is a snug fit in body and requires hard pull to disengage.
(d)
Remove center stud and O-ring.
NOTE: All electrical wires are color coded. Ensure colored wires match when wires are reinstalled.
(e)
Removescrews, washers, switch assembly, and insulating plate. Switch will remain hanging from electrical wires (Figure 404).
(f)
Remove plastic strap attaching electrical wires to door solenoid valve. Remove safety wire from door solenoid valve (Figure 404).
(g)
Disconnect switch and door solenoid electrical wires from terminal block.
(h)
Remove four bolts attaching manifold assembly. Separate manifold assembly from power pack, being sure not to lose transfer sleeves between manifold and power pack (Figure 404).
(i)
Remove five transfer sleeves from manifold (Figure 404).
NOTE: When manifold is separated from power pack body, teeth on landing gear selector spool become disengaged from gear and permit selector spool to move. Never move selector spool to a position more than flush with manifold body at end opposite selector spool teeth. If moved beyond this position, an O-ring will get caught and selector spool will be difficult to remove.
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