EFFECTIVITY:
040-999
36-10-00Jan10/90
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Distribution (continued)
18. Check Valve Removal
(a)
Remove center instrument panel for access to check valve.
(b)
Remove clamps securing valve in position. Removelines from valve.
(c)
Remove check valve.
19. Check Valve Installation
(a)
Install new valve.
(b)
Connect and secure lines to valve.
(c)
Replace center instrument panel. Reinstall other hardware removed.
20. Vacuum Regulator Removal
(a)
Remove or hand copilot's instrument panel to gain access to regulator.
(b)
Disconnect all lines from vacuum regulator.
(c)
Remove vacuum regulator.
21. Vacuum Regulator Installation
(a)
Install vacuum regulator.
(b)
Connect all lines to vacuum regulator.
(c)
Replace copilot's instrument panel and other hardware removed. Refer to 37-20-00 for adjustment procedure.
22. Gyro Central Air Inlet Filter Removal
(a)
Removeor hang copilot's instrument panel to gain access to inlet filter.
(b)
Disconnectlinesfrom inlet filter.
(c)
Remove inlet filter by removing central retaining bolt retaining filter to bracket.
23. Gyro Central Air Inlet Filter Installation
(a)
Install central air filter in position. Secure with washer and nut previouslyremoved.
(b)
Connect all lines to inlet filter.
EFFECTIVITY: 040-999
36-10-00
Jan 10/90
PIPER AIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
A. Distribution(continued)
24. Proof Pressure and Leakage Test of Pneumatic Lines
CAUTION: PRIOR TO PERFORMING THE PROOF PRESSURE AND LEAKAGE TEST, PERFORM THE STATIC SYSTEM TESTS IN 34-00-00, TO ENSURE NO PITOT-STATIC SYSTEM LEAKS EXISTS. CONDUCTING CABIN PRESSURE TESTS WITH A LEAKING PITOT-STATIC SYSTEM COULD DAMAGE DELICATE INSTRUMENTS.
(a)
Remove upper and lower engine cowling from left engine. (Described in 71-00-00.)
(b)
On left and right sides, disconnect engine primary bleed air line at bleed air shutoff valve (Figure 501, Item 2) and ground bypass valve outlets (Item 3). Disconnect secondary bleed air line from ground bypass lines.
(c)
Connect nitrogen bottle (Figure 501, Item 7) with regulator (range 0-500 psig) (Item 6), a pressure gauge (range 0-500 psig) (Item 4), and a manual shutoff valve (range 0-500 psig) (Item 5) to disconnected lines.
(d)
Remove ECU access panel from forward left side of fuselage.
(e)
Disconnect bleed air supply line forward of station 57.00 pressure bulkhead and cap the line (Figure 501, Item 12).
(f)
Disconnect the secondary bleed air line from the emergency pressurization shut-off valve in the right hand wing root and cap the line (Figure 501, Item 12).
(g)
Cap bleed air line at bleed air valve and ground bypass valve outlet. (Figure 501, Item 12)
(h)
Remove fuselage floorboards at F.S. 146.00.
(i)
Disconnect two pneumatic supply lines to check valves (Figure 501, Item 11) and cap the supply lines (Figure 501, Item 12).
WARNING: BEFORE APPLYING HIGH PRESSURE TO THE BLEED AIR SYSTEM, ENSURE ALL PERSONNELARE CLEAR, ALL CONNECTIONSARE TIGHT, AND HOSE ENDS ARE SECURED TO ENGINE MOUNT WITH ROPE OR SAFETY WIRE.
(j)
Slowly open regulator valve on nitrogen bottle until test pressure gauge (Figure 501, Item 7) reads 300 psig (room temperature).
(k)
Apply nitrogen pressure at 300 psig (room temperature)to disconnected primary and secondary bleed air lines in left nacelle for 5 minutes.
(I)
Conduct a complete inspection of bleed air and pneumatic supply ducting (including bleed air/ram air intercooler -Figure 501, Item 6) for leakage and deformation.
(m)Components showing permanent deformation (indicated by loosened mounts, clamps, or distorted tubing) must be replaced.
(n)
Using manual shutoff valve, close valve to isolate nitrogen bottle from the system.
(o)
With test pressure of 300 psig trapped in ducts, monitor gauge for pressure drop.
NOTE: Pressure drop cannot exceed 50 psig over five minutes.
(p)
Repeat steps (a) thru (o) for right hand supply ducts.
(q)
Upon completion of test, relieve pressure from system, remove nitrogen supply, shutoff valve and gauge, reconnect engine bleed air lines, and install cowling.
(r)
Remove all pressure caps (installed for test only) and test equipment. Reconnect all lines and install all floorboards and access panels previously removed.
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