040-999
12-10-00 9
PAGE
12-10-00 Jan 10/90
PIPER AIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
U. EngineOil Chip Detector
The magnetic chip detector, located in the sameplace as the drain plug on the reduction gearbox, is connectedelectricallyto the annunciator panel lights. Illuminationof chip detect light on annunciator indicatesmetal contamination in oil system. If chip detect light illuminates,removechipdetectorand inspectmagneticpole pieces for contaminate. Refer to Pratt & Whitney PT6A-61Maintenance Manual,P/N 3034342, Chapter79.
NOTE: Whenchip detector is removed for inspection, alsoinspectoil filter.
1. Removal of ChipDetector
(a)
Removewiringfromchip detector.
(b)
Removechip detector from gearbox anddiscardpreformedpacking.
2. Inspectionof Chip Detector
(a)
If a single chain of magnetic particlesbridgesgapacross detector poles and particles consists of small slivers, cleanchipdetectorby wiping with lint-free cloth and reinstall.
(b)
If more than 10 pieces of small, nugget shaped magneticmaterialsexiston detector, send engine to overhaulfacilityfor inspection.
(c)
If small amount of fuzz (powered material)exists, clean detectorand reinstall. Recheck for continuityafter 10 hours of operation.
(d)
If same amount of fuzz is found again, clean detector,reinstall, and make another continuity checkafter another 10 hours of operation.
(e)
If fuzz is found a third time with similar or greater quantities, ship engine to overhaul facility for inspection.
3. Installationof Chip Detector
(a)
Installchip detector with new preformed packing in boss on reduction gearbox.
(b)
Tightenand torque the detector to 45 -55 inch-pounds.
(c)
Connectplug and safety.
V.
DrainingEngineOil
1.
Removeenginecowling and place suitable containeror drip pan under engine.
2.
Removechip detector at 6 o'clock positionon front case of reduction gearbox.
3.
Removedrainplug at 6 o'clock positionon accessory drive gearbox.
4.
Removedrainplug from oil tank drain line.
NOTE: Whenoperating engine on oil which differs from that previously used, or if oil system is contaminatedby other metallic matter, proceedwith steps 5 through 18. If using same oil and no contaminationexists, proceed only with steps7, 8, 17, and 18.
EFFECTIVITY: 040-999
Jan 10/90
Jan 10/90 12-10-00
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
V. DrainingEngineOil (continued)
5. Remove drain plug from oil-to-fuel heater.
CAUTION: LIMIT ENGINE ROTATION TO MINIMUM TIME REQUIRED TO ACCOMPLISH COMPLETE DRAINING. DO NOT EXCEED STARTER TIME LIMITS (30 SECONDS ON, 1 MINUTE OFF, 30 SECONDS ON, 1 MINUTE OFF, 30 SECONDS ON, 30 MINUTES OFF).
6.
With drains open and ignition and condition lever off, motor engine with starter only; allow scavenger pumps to clear all lubricating oil.
7.
Install new preformed packings on chip detector and plugs.
8.
Reinstall chip detector and drain plugs. (Refer to t00-00 for torque values.)
9.
Refill oil tank with specified oil. (See latest revision of Pratt & Whitney Service Bulletin 13001.) Normal oil lever is one quart below maximum level (hot). Over filling causes excess oil to flow through accessory gearbox breather.
10.
Start engine and run at idle speed for minimum 2 minutes.
11.
Feather propeller and shut down engine.
12.
Repeat steps 1 through 6.
13.
Remove and clean main oil filter.
14.
Remove and clean reduction gearbox oil strainer.
15.
Reinstall all engine drain plugs and chip detector; tighten, torque, and lockwire. (Refer to 91-00-00 for torque values.)
16.
Repeat steps 7 through 10.
17.
Check oil level; replenish as required.
18.
Install filler cap and dipstick assembly in filler tube. Ensure cap is correctly installed and locked securely.
W. Servicing Oil Filter Elements
CAUTION: PLUG BOTH ENDS OF FILTER ELEMENT BEFORE SUBMERGING IN VARSOL CLEANER. THE ELEMENT MUST NEVER BE ULTRASONICALLY CLEANED, PRESSURE FLUSHED, OR DRIED WITH COMPRESSED AIR CAUSING DAMAGE TO FILTER MEDIA.
Oil filter elements must be cleaned every 100 hours. Remove and inspect for foreign material and handflush in petroleum solvent (AMS 3160 Varsol) bath to remove light contaminants collected on external protective screening. Service life of filter element is 1000 hours.
If cleaning method previously described proves ineffective, clean filter element electrosonically.
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