Service difficulty report · Bolt

Difficulty date
November 15, 2007
Submitted
January 21, 2008
Operation
General aviation
Engine
Allsn 250C20J
Part
Bolt
Part number
6871259
Condition
Cracked
Location
Compressor
Part time
3,486 hours
Component
Compressor · Allsn
Component part number
C20J
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) COMPRESSOR TIEBOLT S/N KU506716 FOUND CRACKED AXIALLY UPON REWORK AT MPI AFTER REMOVAL OF SILVER PLATING ON EXTERIOR OF PART. PART SCRAPPED. CRACK WAS NOT DISCOVERED UPON INITIAL MPI, MOST LIKELY BECAUSE OF THE SILVER PLATE BRIDGING THE CRACK SURFACE. SEM EVALUATION OF CRACK INDICATED A DEPTH OF APPROXIMATELY 600 MICRO METERS RADIALLY . EDS EVALUATION OF THE CRACK INDICATED THAT THE CRACK WAS FULL TO EXTREMITIES WITH IRON OXIDE. THIS APPEARS TO BE A MANUFACTURING DEFECT. NO ASSOCIATED DAMAGE OR SERVICE ISSUES NOTED ON REMAINDER OF COMPRESSOR ASSEMBLY. HARDNESS OF MATERIAL WAS WITHIN SPECIFICATIONS. FAILURE OF BOLT WOULD BE CATASTROPHIC. (TC NR 20071115003)