EFFECTIVITY:
04-999
36-10-00 Jan10/90
A. Distribution (continued)
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
1.Engine Bleed Air Ports
2. Bleed Air Shutoff Valve
3. Ground BypassValve
Showing Disconneted Bleed LinesView Showing Disconnected Bleed Lines
7. Nitrogen Bottle
6. Nitrogen SupplyRegulator 5. Manual Shutoff (Test Only) 4. Pressure Gauge (Test Only) View Showing N2 Connection —9.BleedAir Lines ECU 12. Pressure Cap -SupplyLines I Sta. 57.00
8. Intercooler 11. Check
Proof Pressure and Leakage Test Setup
Figure 501 (Sheet 1 of 2)
EFFECTIVITY:
040-999
Jan 10/90 36-10-00
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Distribution(continued)
ENGINELEFT SIDE
Pressure LEFTSIDE-FORWARDFUSELAGE
Proof Pressure and Leakage Test Setup
Figure501 (Sheet2 of 2)
EFFECTIVITY: 040-999
36-10-00JPAGE9
36-10-00Jan 10/90
PIPER AIRCRAFT PA-42-720 (Advanced Trainer) MAINTENANCE MANUAL
CHAPTER 37
LIST OF EFFECTIVE PAGES
CHAPTER SECTION PAGE DATE CHAPTER SECTION PAGE DATE
37-EFFECTIVITY 37-CONTENTS 37-00-00 37-10-00 37-10-00 37-10-00 1 1 1 1 2 3 Jan 10/90 Jan 10/90 Jan 10/90 Jan 10/90 Jan 10/90 Jan 10/90
LIST OF EFFECTIVE PAGESan 10/90
SUBJECT
Descriptionand Operation FaultIsolation
Distribution VacuumSystemTest VacuumRegulatorAdjustment
PIPER AIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
CHAPTER 37- VACUUM
TABLE OF CONTENTS
CHAPTER PAGE
37-00-00
1
1
37-10-00
1
2
3
EFFECTIVITY: 040-999
CONTENTSan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
VacuumSystem
A Descriptionand Operation
Thegyro-vacuumsystemfunctionsbybleedairbeingforcedthroughaventuridevicecalledan ejector. Astheprimarybleedairflowisforcedthroughtheejector,adecreasein pressuredevelopsproviding thesecondaryflow.Thesecondaryflowactsasthesourceof airtothesystem.(Shownin Figure1)
The inletfor secondaryflow is locatedbehindthe instrumentpanel. Attachedtothe inlet,a filtercleans
air downto 0.3 micronparticleswith a 99%efficiency.
Thevacuumis controlledon the vacuumsideof the instrumentsbya vacuumregulatorandcheck
valve. Theregulatormaintainsvacuumbetween4.5and 5.2 inchmercury,relativeto cabinpressure.
Onthe vacuumsideof the regulator,a checkvalveisbuilt intothe line,preventingreverseflow to gyro
instruments.
Thevacuumsystemoperatesthepilotsturnandbankindicator.A suctiongauge,locatedonthelower
leftofthepilot'sinstrumentpanel,indicatesnegativepressureinthevacuumsystem.
CHART 1
FAULT ISOLATION (VACUUM SYSTEM)
Fault Cause Remedy
SuctionGauge-pressure drop. (PressureGauge-mayincrease.)Pilot'sturn andbankbecomes inaccurate. Blockedbleedair nozzleto Ejectorfails. CheckValvefailsclosed. VacuumRegulatorfails openorclosed,orthe inletfilteriscloggedor blocked. RemoveEjectorandblow out nozzle. ReplaceCheckValve. ReplaceRegulatorand/ or cleanInletFilter.
Tubingfrom Ejectorto vacuumregulatorfailed openorclosed. RepairorreplaceTubing.
Specificvacuuminstruments tumble. Thetubingto thespecific instrumentsfailedopen or closed. Replaceor repairtubing.
EFFECTIVITY:
37-00-00Jan
10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Distribution
Figure 1 gives a schematic descriptionof how the vacuum system is arranged in the aircraft.
Pilot's Turn and Bank Indicator
Engine EngineBleed
Inlet Filter BleedSuction
Bleed Air Directional Gyro
Check and
Pressure Gauge GyroHorizonShutoff
Valve VacuumRegulator
(4.2to 5.2 in. Hg Intercooler
Bleed Air
Overtemp-
erature
Switch
(N.O.)
Pressure -
Switch
(N.O.)
15+ 1 PSI
Door Seal Valve (N.C.)
Solenoid Valve (N.C.)
Deice Boots
A. VacuumLineto Cabin Pressure Control System
B. To Bleed Air and Cabin Pressure System
Vacuum System Schematic Figure1
EFFECTIVITY:
040-999
37-10-00 PAGE
Jan10/901
PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Distribution
1. Vacuum System Test (Figure 501)
(a)
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