25Q1A - PP215-5 - Turbine Engine Troubleshooting

If the engine data is incomplete, unclear, or conflicting, what action can be done to rectify the problem?

Run the engine

what consideration should be taken when deciding whether or not to run the engine?

If it will cause further damage to the engine

what publication can be used to determine if there is an actual problem with the engine?

Operations Manual, Maintenace Manual

when troubleshooting, what is the first thing that should be accomplished?

ensure the engine and discrepancy data is complete and accurate

when trouble shooting, isolation of the fault is accomplished by first listing what? Then performing test.

Possible Causes of the Problem

Define - No Start

engine spools but fuel and air mix does not light off

Define - Hot Start

Excessive EGT during starting procedure

Define - Hung Start

Engine lights off but fails to reach idle RPM

how can you identify an indication problem?

Deviation in one indication only

The flight log reads: Oil pressure became very low and fluctuated prior to inflight shut down

Clue: Oil Temp. Increased but within limits. Vibration Normal, No evidence of oil leak noted.

Bad internal seal

The flight log reads: Oil Pressure follows through movement an is higher than normal at takeoff power.

Clue: Oil Temp and quantity normal

Regulator

The flight log reads: Engine start aborted due to no evidence of engine rotation on RPM gauge. Bleed duct pressure did not change

Starter Failure

The flight log reads: Engine hot started on first start of the day, Bleed duct pressure normal

Fuel on before proper RPM

The flight log reads: The engine lights off but fails to reach ground idle. Electrical load draw normal throughout start attempt.

Insufficient start fuel flow

The flight log reads: Engine slow to light off. Fuel flow and RPM normal. Snapping/popping of igniters heard by ground crew.

Igniter immersion depth

The flight log reads: Engine would not start. No fuel flow indication on gauge an no fuel evident in hot section during inspection.

Faulty fuel shutoff in fuel control

The flight log reads: Engine would not start. RPM and WF normal. Evidence of fuel in tail pipe

Faulty ignition system

The flight log reads: No engine rotation evident on RPM gauge during start. Did not hear engine spooling noise. Current draw did not increase on amp gauge

Starter Solenoid

The flight log reads: Engine acceleration slow compared to throttle movements. Take off power good with normal N1 an N2 RPM, WF and EGT. Throttle levers aligned.

Improperly rigged stator vanes or bleed valves

The flight log reads: Takeoff EPR low with throttle levers aligned. All other parameters normal.

Damaged/Faulty Pt7 (Engine exhaust probe)

The flight log reads: Unable to make takeoff EPR or RPM before EGT limit reached. Engine seems slow to spool up to power compare to other engine.

damaged turbine

The flight log reads: Unable to make takeoff EPR without N2 Overspeed, WF normal.

Damaged Variable Stator Vanes

The flight log reads: Throttle lever hits forward stop prior to takeoff EPR being reached. All other parameters are low but within limits

Rerig throttle system

The flight log reads: Engine hot started on 3rd flight of the day

failure to spool engine to reduce EGT to acceptable value

The flight log reads: Oil consumption exceed tolerances. Evidence of oil in compressor during inspection

internal seal leaking

The flight log reads: Oil consumption excessively high. Oil found coming from accessory drain in bottom of cowl.

Leak in accessory drive seals

The flight log reads: Throttle lever split in excess of 1 1/2" with engines set at takeoff power. Both engines within normal tolerances with no indication of overspeed or overtemp

throttle linkage system mis-rigged

The flight log reads: Engine surge above idle during taxing. Engine produces full power with all parameters normal.

HIgh crosswind at inlet

The flight log reads: Engine surged while acceleration to take off power. Take off power parameters normal with no split between levers

bad inlet guide vanes, stator vanes

The flight log reads: Engine surged at takeoff power.

Compressor FOD

The flight log reads: Main engine oil filter bypass warning light came on in flight. Neither chip detector nor Delta P lights came on but tested good. All other oil and engine parameters normal.

bad bypass valve or faulty light switch

The flight log reads: Oil temperature excessively high oil pressure low but within limits. All other parameters normal.

Oil cooler thermostatic valve

The flight log reads: Shut down engine in flight because oil Delta P, chip indicater an oil filter bypass warning lights came on. Oil temperature an engine vibration high

internal engine failure

The flight log reads: Oil pressure dropped below acceptable value in flight. Oil temp an quantity normal. Delta P and filter bypass lights did not come on an tested good.

oil pressure regulator