Service difficulty report · Spur Gear · Dhav DHC8102

Difficulty date
March 11, 2000
Submitted
January 22, 2001
Operation
General aviation
Make and model
Dhav DHC8102
Aircraft time
28,664 hours
Engine
Pwa PW120A
Propeller
Hamstd 14SF7
Part
Spur Gear
Part number
312137201
Condition
Worn
Location
Accessory Drive
Part time
15,076 hours, 16,087 cycles
Component
Acc.Dr.Spur Gear · Pwa · PW120A
Stage of operation
CR
How discovered
O
Nature of condition
O
Precautionary procedure
E

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

What was found

(CAN) EXAMINATION OF AGB BREATHER GEAR SHOWED THAT ALL OF DRIVE TEETH FOR FUEL PUMP GEAR HAD FRACTURED FROM ROOT WITH EXCEPTION OF 5 TEETH. THESE 5 TEETH DISPLAYED SEVERE WEAR PATTERN ON TOOTH FLANK, MAINLY BELOW PITCH LINE. IN-FLT SHUT DOWN CAUSED BY LOSS OF FUEL PUMP DRIVE DUE TO AGB BREATHER & FUEL PUMP GEARS TEETH FRACTURE: THE TEETH FRACTURE OF ACCESSORY DRIVE BREATHER GEAR OCCURED FROM FATIGUE, WHICH ORIGINATED AT TEETH ROOT RADIUS BELOW TEETH WEAR. HIGH STRESS CONTACT FATIGUE COMBINED WITH HIGH HRS OF OP ON GEARS PROBABLY CAUSED TEETH WEAR AT PITCH LINE.