Service difficulty report · Strap · Boeing 747230B

Difficulty date
November 12, 2004
Submitted
November 24, 2004
Operation
Air carrier
Aircraft
N512MC
Make and model
Boeing 747230B
Aircraft serial
21220
Engine
Ge CF650E2
Part
Strap
Part number
65B94109
Condition
Cracked
Location
Nr 4 Pylon
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

DURING SCHEDULED MAINTENANCE, FOUND CRACK NR 4 PYLON AT AFT MOUNT BULKHEAD FRAME STRAP. SUBJECT CRACK WAS LOCATED ALONG THE STRUT UPPER SKIN ASSY LOWER EDGE. CRACK AFT END WAS CONTAINED WITH A STOP HOLE IN THE STRAP. THE REPAIR AREA WAS NDT INSPECTED, INCLUDING HFEC INSPECTION OF ALL REPAIR HOLES. THE AREA WAS REINFORCED WITH TWO EXTERIOR 0.063 INCH THICK LAYERS OF TITANIUM DOUBLERS WITH PROFILES TO MATCH THE BULKHEAD STRAP PROFILE AND SPAN ACROSS THE SUBJECT CRACK. THE REPAIR AREA IS TO BE REPEAT DETAIL VISUAL INSPECTED EVERY 18 MONTHS OR C-CHECK INTERVAL,