Pt6A-21/27 ENGINE RIGGING&

TROUBLE SHOOTING

Dade Sobarna®2009

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1. Trouble Shooting Quick Reference

COMPRESSORSYMPTOM CAUSE FIX

Hooting Sound. Irregular air control at BOV. Switch bleed valve or swap to otherside.

Growling sound and #1 bearing support and Replace support and adapter assy.possibly vibration. adapter out of round.

BLEED VALVESYMPTOM CAUSE FIX

Very high T5. Open bleed valve or late Clean mettering orifice, change closure of BOV. diaphragm, or switch bleed valve.

Surging Compressor . Bleed Valve closing early. Clean the C-D orifice Switch bleed valve.

Rumbling Compressor. Fluttering bleed valve. Switch bleed valve Hot start, hung start, BOV on wrong side of engine. Swap BOV to other side. choking/stall.

T5 SYSTEMSYMPTOM CAUSE FIX

Erratic T5 reading. Loose trim stick terminals. Repair terminal block. High T5 Corroded trim resistor Clean connection.

connection. Low T5 Several burnt thermocouples Replace trim stick

or corroded trim probes lead. Replace thermocouples T5 Difference between Engine with different Check T5 gauges* by switching from both engine. temperature profiles. side-to-side, verify trim stick by

comparing log book trim value to that on stick. If OK, no further action required.

No reading after repair. Thermocouples lockwired to Remove lockwire and correct. ground.

TORQUE SYSTEMSYMPTOM CAUSE FIX

High torque reading Stuck T/M control valve Apply Nitrogen to T/M oil pressure(return spring or sleeve valve) port to engine & rock prop. Shaft

T/M reading levels off but Leakage from the aft sealing Replace T/M sealing ring. actual torque stil l increasing ring Check for potential overtorque. Dropping torque pressure Worn T/M Seal Increase oil pressure (within limits).

If pressure continues to drop, replace seal.

Fluctuating T/M pressure Fluctuating oil pressure or Replace pressure regulating valve or undersize T/M valve replace T/M valve

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SECONDARY AIR SYSTEM & BREATHERSYMPTOM CAUSE FIX

Oil in compressor Oversized #1 bearing Replace labyrinth seal (or at bleed valve) labyrinth seal Oil smell in the cabin Oversized #2 bearing rear Replace labyrinth seal

labyrinth seal Smoke at start up and/or Oversized #2 bearing front Replace labyrinth seal shutdown. Burnt oil on turbine labyrinth seal Black exhaust smoke during Oversized #3 bearing Replace labyrinth seal. operation. labyrinth seal. Oil mist in overboard Broken carbon seal Replace starter-generator carbon breathing. seal Erratic oil pressure at altitude. Low static pressure in oil tank. Check for proper operation of the

tank pressurizing valve. Change O-ring on oil filter housing.

OIL SYSTEMSYMPTOM CAUSE FIX

Oil leaking at compressor Check valve stuck open. Remove the housing and clean. Let inlet or #1 bearing. sit for 10 minutes. If oil present,

repair or replace check valve. If oil not present, check and replace the filter housing O-ring, the center tube O-ring, or the pressure pump drive shaft diaphragm seal.

Fluctuating oil pressure. Clogged or damage oil filter element, broken check valve Check the oil filter element, check spring, or scored pressure valve, and pressure relief valve. relief valve.

Increase in oil temperature. Stuck check valve causing bypassing of oil past the Remove and replace the check valve. relief valve.

Oil leaking out of bleed valve. Static leak from oil tank. Check O-ring on oil filter housing. Low oil pressure. Blocked oil filter. Clean or replace oil filter. High fluctuation of oil pressure High tank air pressure Change O-ring on oil filter housing. at high altitude. differential. Check tank pressurizing valve. Oil smell in the cabin. Excessive oil crossing the Remove and repair gas gen section.

#1 labyrinth seal. Oil smell in the cabin and Excessive oil crossing the Remove and repair gas gen section. oily diffuser pipes. #2 rear labyrinth seal. 24 psi decrease in oil pressure. Oil filter is bypass due to Install oil filter correctly.

backwards oil filter. High oil temperature Diverter valve not diverting Check diverter valve operation.

oil to oil cooler Oil pressure increase with Ng Cracked main oil pressure Replace main oil pressure pump. speed. pump housing. High oil consumption. Oil leaking from oil-to-fuel Replace oil-to-fuel heater.

heater, mixing with fuel and burning. © Dade Sobarna