Broken wire.
Gaugeinoperative.
Incompleteground.
Vent holes in fuel transmitter clogged.
Fuel valve stuck.
No fuel in tanks.
Filters dirty.
Faulty fuel pressure gauge or
transducer.
MotivePort in Jet Transfer
pumpclogged.
InletPort screen clogged.
Frictionin meter movement causedby dirt or improper alignmentof meter pointer.
Metermovementcoil is open.
Defectivecomponenton printed circuit boards.
Aircraft connector not
connectedproperlyto
indicator.
Aircraftwiringdefective.
(Sheet1 of 2)
Remedy
Checkand reset.
Checkand repair.
Replace.
Checkgroundconnectionat gauge and at fuel transmitter in the wings.
Clear vent holes.
Check valve.
Checkandfill.
Clean filters.
Replacegaugeortransducer.
ServiceJetTransferPump.
Removeand clean affected item.
ReplaceFuel Quantity Indicator.
ReplaceFuelQuantityIndicator.
Replaceindicator.
Checkconnectorinstallation
at indicator.
Checkwiring,repairas required.
EFFECTIVITY:
040-999 2840-00 Jan1090
Jan 10/90
PIPER AIRCRAFT
PA-42-720(Advanced Trainer)
MAINTENANCEMANUAL
A. Indicating (continued)
2. Fault Isolation -Fuel System (continued)
CHART 1
FAULT ISOLATION (FUEL SYSTEM) (Sheet 2 of 2)
Fault Cause Remedy
Zero indication of Fuel QuantityIndicatoris Meter pointer out of balance. Replaceindicator.
out of tolerance.
Internal mechanical adjustmentof meter Replacei ndicator.
not set properly.
Externaladjustment incorrect. Adjust.
EFFECTIVITY:
040-999
Jan10/9028-40-00
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. Indicating (continued)
3.
Overhaul of Tank Sensor Units
Do not overhaul tank sensor units. If unit is found defective, replace it.
4.
Overhaul of Fuel Quantity Indicator
Do not overhaul fuel quantity indicator. Replace, if necessary.
5.
Removal of Tank Sensor Units
CAUTION: HANDLE SENSOR UNITS CAREFULLY. DAMAGING TUBES DESTROY ACCURACY OF THE UNIT.
(a) Nacelle Tank Sensor (mounted in upper portion of nacelle tank, inboard of filler cap):
(1.) Ensure enough fuel is drained from system to prevent spillover.
(2.) Remove access cover next to filler cap.
(3.) Disconnect and tag or mark leads to facilitate reconnection.
(4.) Remove screws attaching probe sensor to nacelle. Carefully remove probe sensor and
gasket.
(b) Main Outboard Fuel Sensor (mounted at Wing Station 102.0):
(1.) Remove access cover at Wing Station 102.0.
(2.) Ensure enough fuel is drained from system to prevent spillover.
(3.) Remove access cover next to filler cap.
(4.) Disconnect and tag or mark leads to facilitate reconnection.
(5.) Remove screws attaching probe sensor to fuel cell. Carefully remove probe sensor and
gasket.
(c) Aft Inboard Fuel Sensor (mounted at Wing Station 15.0):
(1.) Remove access cover at Wing Station 15.0.
(2.) Ensure enough fuel is drained from system to prevent spillover.
(3.) Remove access cover next to filler cap.
(4.) Disconnect and tag or mark leads to facilitate reconnection.
(5.) Remove screws attaching probe sensor to fuel cell. Carefully remove probe sensor and
gasket.
(d) Main Inboard Fuel Sensors (mounted at Wing Stations 13.3 and 36.0):
(1.) Remove access covers at Wing Stations 13.3 and 36.0.
(2.) Ensure enough fuel is drained from system to prevent spillover.
(3.) Remove access covers next to filler caps.
(4.) Disconnect and tag or mark leads to facilitate reconnection.
(5.) Remove screws attaching probe sensors to fuel cell. Carefully remove probe sensors and
gaskets.
EFFECTIVITY:
28-40-00
PAGE 5
28-40-00 Jan 10/90
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCE MANUAL
A. Indicating (continued)
(e)
WingTipTank Sensor:
(1)
Removebottom tank-wing fairing.
(2)
Ensure enough fuel is drained from system to prevent spillover.
(3.) Disconnect and tag or mark leads to facilitate reconnection.
(4.) Remove screwsattaching probe sensor to wing tip tank. Carefullyremoveprobe sensor
and gasket.
6. Installationof Tank Sensor Units
CAUTION: HANDLE SENSOR UNITS VERY CAREFULLY, AS DAMAGING TUBES DESTROYS ACCURACY OF UNITS.
(a) Nacelle Tank Sensor (mounted in upper portion of nacelle tank, inboard of filler cap):
(1.) Carefully install probe sensor and gasket. Install screws attaching probe sensor to
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