Service difficulty report · Drive Shaft · Bell 206B1

Difficulty date
October 30, 2008
Submitted
December 18, 2008
Operation
General aviation
Make and model
Bell 206B1
Aircraft time
14,282 hours
Engine
Allsn 250C20B
Part
Drive Shaft
Part number
23076061
Condition
Failed
Location
Turbine Governor
Part time
2,021 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

(CAN) DURING REMOVAL OF THE GOVERNOR FOR SCHEDULED OVERHAUL, AT REMOVAL FROM ENGINE GEARBOX, THE CLIP THAT RETAINS THE DRIVEGEAR ON THE PT SHAFT WAS NOT LOCATED IN THE GROOVE ON THE SHAFT, AND THE WASHERS THAT ARE RETAINED BY THE CLIP AND SET AGAINST THE DRIVE GEAR, WERE FOUND SITTING IN THE MALE SPLINE OF THE GEARBOX DRIVE. IT APPEARS AS THOUGH THE END OF THE DRIVESHAFT WAS WORN DOWN TO ALLOW THE CIRCLIP TO BECOME DISLODGED FROM THE GROOVE AND WORK IT`S WAY OFF THE SHAFT, HOWEVER THE DAMAGE TO THE SHAFT COULD HAVE BEEN DUE TO THE DISLODGED WASHERS SITTING IN THE DRIVE SPLINE. THE ONLY ITEM FOUND RETAINING THE DRIVEGEAR WAS THE SPRING ON THE BACK SIDE OF IT. THE ENGINEER INSPECTED THE GEARBOX DRIVE BUT WAS UNABLE TO LOCATE THE CLIP. NO PREVIOUS HISTORY OF FAULTY GOVERNOR OPERATION OR ABNORMAL SOUNDS WERE NOTED. CHIP PLUGS WERE INSPECTED - NOTHING FOUND. GEARBOX DRIVE GEARS INSPECTED FOR DAMAGE, NONE FOUND. O/H UNIT INSTALLED AND GROUND RUN - SATISFACTORY.