SDR UE5R201201170001

Service difficulty report · Gear Set · Dhav DHC6*

Difficulty date: January 17, 2012
Submitted: January 17, 2012
Operation: General aviation
Make and model: Dhav DHC6*
Engine: Pwa PT6A27
System (JASC): 7210 · Turbine Engine Reduction Gear
Part: Gear Set
Part number: E310145502
Part serial: EE074
Condition: Misaligned
Location: Reduction G/B
Part time: 2,250 hours
Stage of operation: IN
How discovered: V
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

WHILE REPLACING THE 1ST STAGE SUN GEAR AND PLANET GEAR SET TO COMPLY WITH AD 2011-25-12 AND SB-804 REV B, A DEFECT WAS FOUND IN THE BEARINGS INSTALLED IN THE REMOVED PLANET GEARS. THE BRONZE SLEEVE OF THE BEARINGS HAD ROTATED AND ALSO STARTED TO MOVE OUT OF THE GEAR. IN ONE OF THE GEAR BEARINGS, THE BRONZE SLEEVE HAD MOVED OUT APPROX .1250". THE BRONZE SLEEVE OF THE BEARING SHOULD NOT MOVE DURING A TYPICAL SERVICE LIFE OF A FIRST STAGE PLANET GEAR.