Engines

Propeller Shaft Bearing Wear

GARRETT, TPE331-11U-612G
SERVICE DIFFICULTY REPORT
(SDR) # 20110915001

SDR submitted:

After levelling off, the pilot got an engine chip light on the right engine; all other indications were normal. He decided to reroute to the airport for maintenance to have a look at it. Maintenance removed the chip detector and found evidence of metal. The engine was removed and forwarded to the engine shop for evaluation. The root cause of the metal on the chip detector was the propeller shaft aft bearing race. The engine was flushed of all metal and a new bearing was installed. The engine was test run on the test cell and the oil filter was pulled; no other evidence of metal was found. The engine was returned to service.

Propeller bearing race showing evidence of wear
Propeller bearing race showing evidence of wear

Transport Canada Comments:

Some bearing ‘mating’ is expected, however, when they start making metal, it can be an indication of a flaw in the part itself or the lubrication system of the engine. Close attention must be paid to the engine or batch from which the bearing was procured.

Auxiliary Power Unit Plenum Cracked

HAMILTON SUNDSTRAND, EQUIPMENT
(SDR) # 20110711019

SDR submitted:

During an unscheduled maintenance event, it was found that the turbine guide vane was rubbing on the turbine wheel. The turbine guide vane was found to be shifted. The unit was further disassembled and it was found that the air plenum and combustion liner was cracked and missing sections of metal. The unit was sent to the overhaul facility for repairs.

Cracked Auxiliary Power Unit plenum
Cracked Auxiliary Power Unit plenum

Transport Canada Comments:

An auxiliary power unit (APU) is a piece of equipment that can often be neglected (given minimum maintenance) until it fails and leaves an aeroplane stranded.

Date modified: