Service difficulty report · Fuel Control · Swrngn SA227AC

Difficulty date
April 26, 2012
Submitted
May 23, 2012
Operation
Air carrier
Aircraft
N685BA
Make and model
Swrngn SA227AC
Aircraft serial
AC685
Aircraft time
30,778 hours, 42,488 cycles
Engine
Garrtt TPE33111U
Engine time
27,049 hours, 37,393 cycles
Part
Fuel Control
Part number
8978014
Part serial
1708984
Condition
Defective
Location
Zone 500
Stage of operation
TX
How discovered
O
Nature of condition
J
Precautionary procedure
E

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

THE PILOT WAS ATTEMPTING TO START THE ENGINE WHEN THE EGT TEMP BEGAN TO ACCELERATE TO NEAR THE RED LINE INDICATION. HE ABORTED THE START AND NOTIFIED MX. MX PERSONELL MADE ANOTHER ATTEMPT TO START THE ENGINE BUT AGAIN, THE EGT TEMP BEGAN TO RISE RAPIDLY TO NEAR THE RED LINE SO THE START WAS ABORTED. THE END CAP OF THE P3 CHAMBER ON THE FCU WAS REMOVED AND CORROSION WAS EVIDENT ON THE CAP. UPON FURTHER INVESTIGATION IT WAS NOTED THAT THE TEFLON BACK-UP RING AND THE O-RING ON THE PISTON WERE DETERIORATING AND LEAVING PARTICLES ALONG THE CYLINDER WALL AND INTO THE BOTTOM OF THE CHAMBER. A SERVICEABLE FCU WAS INSTALLED WHICH CORRECTED THE PROBLEM. ENGINEERING WAS CONTACTED AND APPEARED INTERESTED IN INVESTIGATING THE CAUSE HOWEVER NO CONCLUSIONS HAVE BEEN MADE SO FAR.