Service difficulty report · Bolt · Boeing 747*

Difficulty date
February 1, 2010
Submitted
February 12, 2010
Operation
General aviation
Make and model
Boeing 747*
Part
Bolt
Part number
65B054544
Part serial
SS118
Condition
Cracked
Location
Nlg Component
Part time
17,808 hours
Component
Nlg
Component part number
65B014659
Stage of operation
IN
How discovered
9
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

BOLT IS CRACKED, VISIBLE IN THE INNER BORE PROGRESSING FROM A SMALL LUBE HOLE. BOLT WAS GOING THROUGH A NORMAL O/H PROCES. INITIAL FLUORESCENT MAGNETIC PENETRANT INSP (FMPI) DID NOT REVEAL CRACK. BOLT WAS SUBSEQUENTLY MACHINED TO REMOVE CORROSION FROM THE NSIDE FACE OF BOLT HEAD. BOLT WAS INITAL ETCH INSPECTED AND STRESSED RELIEVED FOR 4 HRS AT 375 DEGREES F =/-25 DEGREES F. BOLT WAS FMPI PRIOR TO SHOTPEEN WHEN CRACK WAS DISCOVERED. CRACK PROGRESSES IN BOTH DIRECTION FROM A LUBE HOLE LOCATED APPROX 2.275 INCHES FROM THE THREADED END OF THE BOLT. THE CRACK RUNS APPROX 1 INCH FROM THE LUBE HOLE TOWARD THE THEADED END OF THE BOLT AND APPROX .250 INCH, 180 DEGREES IN THE OPPOSITE DIRECTION. BOLT IS A LIFE LIMITED COMPONENT: LIFE LIMIT 50430 CYCLES. CYCLES SINCE NEW=17808