(c.) Differential pressure reading in psid.
NOTE: Cabin differential pressure must not exceed 6.4 psi and cabin altitude must not be less than 2,000 feet.
(6.) If system is operating satisfactorily, proceed to next test procedure.
(e) Descentand Negative Relief Check Procedure
(1.) While maintaining 18,000 feet and cruise, proceed with the following steps: (a.) Set cabin rate control fully counterclockwise (decrease). (b.) Set cabin altitude control knob to 10,000 feet. (c.) Set slowly rotate cabin rate control clockwise to maximum rate (no climb will be
observedfor approximately 1 minute). When cabin stabilizes at 10,000 feet, proceed to next step.
(2.) Initiate normal descent, maintaining sufficient power to maintain pressurization (until below 10,000 feet) and observe the following: (a.) At 18,000 feet, the cabin must be at 10,000 feet and remain constant until aircraft
reaches 10,000 foot altitude. (b.) Below 10,000 feet, cabin rate of descent must be approximately the same as airplane.
NOTE: When airplane goes through 10,000 feet, differential between cabin altitude and aircraft altitudemust not exceed ± 1,000 feet.
NOTE: Do not land with more than 0.3 psi cabin differential. Dump pressure and control airplane descent to airplane altitude does not catch up with cabin altitude during rate operation.
(3.) Prior to landing, perform the following steps:
(a) Resetcabin altitude selector to field elevation plus 500 feet, descent position.
(b.) Adjust rate of change controlto comfortable rate of descent.
(c.) Observe cabin differential pressureindicator.When airplane reaches pattern altitude,
cabin differential pressure must be nearly equalized.
EFFECTIVITY: 040-999
Jan 21-30-00
Jan 10/9021-30-00
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. PressurizationControl(continued)
CHART 2 CABIN ALTITUDE VS. AIRPLANE ALTITUDE
16,000
14,000
12,000
U
uJ10,000
LL
0
8,000
m
6,000
4,000
2,000
SEA LEVEL 0 4 8 12 16 24 32333435
EFFECTIVITY:
040-999
21-30-00 PAGE23
Jan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Pressurization Control (continued)
Windshield Defog Control Lever
ManualTemperature Control
CabinFan Control
ECS Mode
Control
Automatic Temperature Selector
Pressurization/
Rate of Test/DumpChange Altitude SwitchControl Controller
CabinPressurization and ECS Control Panel
Figure 5
EFFECTIVITY:
040-999
PAGE2421-30-00Jan10/90 21-30-00
PIPERAIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
A. PressurizationControl (continued)
8. AbsolutePressure Regulator Removal
(a)
Remove trim panel in front of pressure regulator (located on rear pressure bulkhead).
(b)
Disconnect lines from regulator.
(c)
Remove three attaching screws from regulator.
(d)
Remove regulator from mounting bracket.
9. Absolute Pressure Regulator Installation
(a)
Install regulator into mounting bracket.
(b)
Installthree attaching screws and tighten.
(c)
Connectlines removed from regulator.
(d)
Install trim panel on rear pressure bulkhead.
CABIN INBLEED
BELLOW
CONTROL PORT
AbsolutePressure Regulator
Figure 6
EFFECTIVITY:
040-999
21-30-00 Jan 10/90
21-30-00 Jan 10/90
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Pressurization
Control(continued)
10. OutflowandSafetyValve Removal
(a)
Removetrim panel infront of safetyandoutflow valves (locatedin rear pressurebulkhead).
(b)
Removeaccesspanelon left sideof tail section, just aftof entrance door,if safety valve is beingremoved,or remove accesspanelon right side if outflow valve is beingremoved.
(c)
Disconnectlinesto valve being removed.
(d)
Workingthroughtailsectionaccesshole, remove threelocknuts securing valve.
(e)
Removevalvefrompressurebulkhead.
11.OutflowandSafetyValveInstallation
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本文链接地址：夏延飞机维护手册 Cheyenne IIIA PA-42-720 AMM 1(64)
