Service difficulty report · Bearing

Difficulty date
November 28, 1997
Submitted
March 26, 2000
Operation
General aviation
Engine
Pwa PW120A
Part
Bearing
Part number
310703301
Condition
Spalled
Location
Rgb Nr 15
Part time
24,835 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 SENT FOR INSP AND REPAIR AFTER OPERATOR NOTED A LARGE NUMBER OF SHINY METAL FLAKES IN RGB SCAVENGE FILTER AND ON RGB CHIP DETECTOR. DISASSEMBLY OF ENG REVEALED SOURCE OF METAL CONTAM WAS SPALLING OF NR 15 BEARING. NR 15 BEARING ROLLERS AND UNDAMAGED PORTION OF OUTER RACE HAD CHAINS OF ELECTRICAL DISCHARGE PITTING WHICH APPEAR TO BE CAUSE OF THE SPALLED BEARING. SECONDARY DAMAGE FROM THE SPALLED BEARING LIMITED TO NR 13 LT BEARING. THERE IS SOME DETECTABLE MAGNETISM ON A RANDOM SCATTERING OF STEEL COMPONENTS. THIS PATTERN IS NOT TYPICAL OF A LIGHTNING STRIKE, SO A LIGHTNING STRIKE IS NOT THOUGHT TO BE A CAUSE OF NR 15 BEARING FAILURE. PART TC: 34,042.