Service difficulty report · Bushing · Dhav DHC6300

Difficulty date
July 2, 2014
Submitted
July 18, 2014
Operation
General aviation
Filed by
QOWR001Y
Southwest Airmotive Corporation
Aircraft
N148SA
Make and model
Dhav DHC6300
Aircraft serial
409
Engine
Pwa PT6A27
Part
Bushing
Part number
3037305
Part serial
PKAAA473790
Condition
Failed
Location
Rgb Gear
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

MFG INSTALLED NEW FIRST STAGE SUN GEAR, WITH NEW 1ST STAGE PLANET GEAR SET ASSY. ONE OF THE GEARS, HAD A BUSHING FAILURE, CAUSING THE GEAR TO SPIN AROUND. CAUSING CONTAMINATION OF THE OIL SYSTEM. GEAR HAD FOUR HRS OF TEST TIME ONLY SINCE NEW. REPAIR STATION INSTALLED THE GEARS DURING O/H AND DID NOT NOTICE ANY DEFECT IN THE GEAR AT THE TIME OF INSTALLATION. BUSHING FAILURE OCCURRED AFTER CUSTOMER INSTALLED THE ENGINE AND WAS PERFORMING A GROUND PERFORMANCE RUN. DURING THE PERFORMANCE RUN, THE OIL PRESSURE DROPPED TO 80 PSI. SHUTDOWN THE ENGINE AND REMOVED THE FILTER HOUSING TO ADJUST THE OIL PRESSURE. AT THIS TIME THEY NOTICED BRONZE-LIKE FLAKES IN THE OIL FILTER. THE CHIP DETECTOR WAS PULLED AND A SIGNIFICANT AMOUNT OF DEBRIS WAS NOTED. THE ENGINE WAS RETURNED TO THIS REPAIR STATION AND AN INVESTIGATION REVEALED THE BUSHING HAD SPUN IN THE GEAR CAUSING OIL CONTAMINATION. NO OIL STARVATION WAS OBSERVED IN ANY OF THE GEARS WITHIN THE RGB/AGB, ELIMINATING THE POSSIBILITY OF GROUND CREW NOT PUTTING OIL IN THE ENGINE PRIOR TO START.