Service difficulty report · Bolt

Difficulty date
July 22, 2004
Submitted
February 8, 2005
Operation
General aviation
System (JASC)
1430 · Fasteners
Part
Bolt
Part number
SL12596
Condition
Mismanufactured
Location
Connecting Rod
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

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

What was found

THE CONNECTING ROD BOLT, PN SL12596, LOT NR 575765, WAS FOUND TOO SHORT FOR PROPER INSTALLATION. THE FREE LENGTH OF THE BOLTS IN QUESTION WERE 2.2485 TO 2.2491. MFG SL1458B REQUIRES A TWO STEP TORQUE PROCESS. FIRST, TORQUE BOLTS TO 35 FT LBS AND MEASURE, IF THE BOLT IS SHORTER THAN 2.255, THE BOLT IS REJECTED. SECOND, THE BOLT MUST NOT EXCEED LENGTH OF 2.256 AT THE FINAL TORQUE OF 55 FT LBS. THE SUSPECT BOLTS WOULD NOT ATTAIN REQUIRED LENGTH AT 35 FT LBS. THE DEFECT IS CAUSED BY GRINDING THE BOLT TOO SHORT OF A DIMENSION AT MFG. AN INSPECTION RATE WOULD NEED TO BE INREASED TO A LEVEL THAT WOULD ENSURE PROPER QUALITY CONTROL. (K)