Service difficulty report · Engine

Difficulty date
October 7, 2003
Submitted
January 5, 2004
Operation
General aviation
Engine
Pwa PT6A50
Part
Engine
Condition
Lightning Strike
Part time
27,101 hours, 33,901 cycles
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) AC WAS HIT BY LIGHTNING STRIKE. REVIEWED ENG ON GROUND AND RESIDUAL MAGNETISM WAS FOUND ON PROP SHAFT. IT WAS CONFIRMED THAT ENG DID SUFFER FROM LIGHTNING STRIKE, PARTS FOUND WITH HIGH MAGNETISM ON THEM. PRESENCE OF ARCING ON FRONT RED GB MAIN BEARINGS ARE TYPICAL RESULTS FROM LIGHTNING STIKES. ONE 1ST STG PLANET GEARS WAS FOUND WITH SPALLING ON ONE GEAR TOOTH. DETERMINED THAT THIS DAMAGE DID NOT COME FROM LIGHTNING STRIKE. NO OTHER MATING GEAR WAS FOUND WITH MATCHING DAM. THAT WOULD BE PRESENT IF SPALLING FROM AN ELEC DISCHARGE ARC. DAMAGE INDICATES IMPACT ON TIP OF TOOTH CAUSING MATERIAL DISPLACEMENT TOWARDS SPALLED SIDE. DISPLACEMENT INCREASED SURFACE STRESS CAUSING SURFACE TO FRACTURE AND SPALL.