Service difficulty report · Gear

Difficulty date
March 17, 1998
Submitted
March 26, 2000
Operation
General aviation
Engine
Pwa PW120A
Part
Gear
Part number
311468201
Condition
Spalled
Location
Rgb
Part time
17,412 hours
Stage of operation
IN
Nature of condition
O
Precautionary procedure
K

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

What was found

(CAN) REDUCTION GEARBOX (RGB) WAS SENT FOR INVESTIGATION AFTER REPORTS THE RGB WAS MAKING METAL. DISASSEMBLY OF THE RGB FOUND THE SOURCE OF THE METAL WAS THE SPALLING OF THE FIRST STAGE GEARS. THERE WAS NO CONTRIBUTING FACTORS TO THE SPALLING OF THE FIRST STAGE GEARS, HOWEVER, THE RGB INPUT SHAFT HAD 2501.5 HOURS AND THE 1ST STAGE HELICAL GEARS EACH HAD 17,411.8 HOURS. ONCE THE 1ST STAGE HELICAL GEARS FAILED, THE RGB INPUT SHAFT WOULD SUFFER SECONDARY TOOTH DAMAGE. SECONDARY DAMAGE WAS ALSO SUFFERED TO THE NR 11 BEARING. THE NR 8 AND NR 9 BEARINGS WERE ALSO REPLACED AS A PRECAUTIONARY MEASURE.