Service difficulty report · Stiffener · Boeing 74747UF

Difficulty date
June 6, 2011
Submitted
June 11, 2011
Operation
Air carrier
Aircraft
N493MC
Make and model
Boeing 74747UF
Aircraft serial
29254
Aircraft time
52,204 hours, 8,360 cycles
Engine
Ge CF680C2B1F
Part
Stiffener
Condition
Deformed
Location
Bs 1393.5
Stage of operation
IN
How discovered
V
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

DURING A C3-CHECK INSP, THE MLG W/W TOP PRESSURE DECK STIFFENERS AT BS 1393.5 & NBSP; LOWER FLANGE WERE FOUND DEFORMED AT RBL 46 AND RBL 45.5 RESPECTIVELY AS SHOWN ON FIG 1. AT BS1393.5 THE DEFORMATION IS APPROX BETWEEN RBL 44 AND RBL 48. THE WEB IS ALSO DEFORMED. (HAECO REPORTED THAT NO APPLICABLE SRM REPAIR CAN BE FOUND FOR THESE DAMAGES AND PROPOSES TO REPAIR THE DAMAGE BASED ON SRM 51-70-12, REPAIR 2 BY TRIMMING OUT THE DEFORMED LOWER FLANGE AND WEB AND INSTALLING A MACHINED REPAIR ANGLE AS SHOWN IN FIG 2. THE TRIM EDGES AND VICINITY WILL BE HFEC INSPECTED TO CONFIRM NO CRACK OR OTHER DEFECTS EXIST.)

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