(a)
Unwanted material that is in the engine from the time of its assembly (called build debris) and pieces from a repair. 1) Remaining material from repairs are, for example, small
pieces of gaskets or preformed packing, sealing compound, or pieces of metal seal rings. This contamination is usually caught in the oil filter after the first engine operation after the repair.
2) These pieces are frequently not metallic. 3) If the pieces are metallic, they are frequently larger than the particles that come from a bearing or gear.
(b) Metal particles from a bearing or gear.
1) Metal particle contamination is a bad problem that is caused, for example, by bearings and gears that are worn too much.
2) The particle source must be found and the condition must be corrected before the subsequent flight.
CAUTION: IF THE OIL IS BLACK, IT CAN BE THE RESULT OF OIL
_______ TEMPERATURES THAT WERE HIGHER THAN THE USUAL OIL TEMPERATURES (SEE FIM 71-00-00/101, HIGH OIL TEMPERATURE). BLACK OIL CAN ALSO BE A SIGN OF OTHER DAMAGE OR CONTAMINATION. IF HIGH OIL TEMPERATURE HAS NOT OCCURRED, CONTINUE WITH THE STEPS BELOW.
(c) Hydraulic fluid (Skydrol is an example)
1) Hydraulic fluid contamination can cause bad problems in the oil system. During usual engine operation temperatures, hydraulic fluid makes the synthetic engine oils become black, thick, and tacky.
2) This oil stops or badly decreases the oil flow through the jets, the nozzles, and the small-mesh screens.
3) Oil that has hydraulic fluid in it can cause damage to packings. The quantity of damage is in proportion to the quantity, temperature, and length of time of contamination. If packings have damage, leaks and corrosion of oil system parts are possible.
4) Hydraulic fluid can get into the oil system through a hydraulic pump seal failure or when hydraulic fluid is accidentally added to the oil tank.
(d) Jet Fuel.
1) Jet fuel contamination can cause bad problems in the oil system.
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BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
////////////////////////A / PW4000 SERIES /747-400 / ENGINES/MAINTENANCE MANUAL ////////////////////////
No. 8 - Oil System Contamination Inspection
___________________________________________
2) If oil has jet fuel in it, you can smell the fuel. Also, the viscosity of oil that has jet fuel in it is less than for oil without fuel in it.
3) Signs of jet fuel contamination are high oil temperature and too much oil in the oil tank.
4) Oil with jet fuel contamination causes damage to packings. Damaged packings cause oil leaks in the gearbox accessory seals. The quantity of damage to the bearings is in proportion to the quantity, and length of time of contamination.
5) It is possible that an internal leak in the fuel/oil cooler is the cause or fuel contamination.
B. Equipment
(1)
PWA 86018 - Adapter, Oil Sample, Pratt & Whitney, Commercial
Products Division, 400 Main street, East Hartford, CT
06108
C.
References
(1)
AMM 12-22-03/301, Engine Oil Servicing
(2)
AMM 29-11-05/401, Engine Driven (Hydraulic) Pump
(3)
AMM 71-00-00/201, Power Plant
(4)
AMM 71-11-04/201, Fan Cowl Panels
(5)
AMM 71-11-06/201, Core Cowl Panels
(6)
AMM 72-61-07/401, Hydraulic Pump Drive Oil Seal
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