Service difficulty report · Beam · Boeing 747243F

Difficulty date
March 26, 2010
Submitted
March 30, 2010
Operation
Air carrier
Aircraft
N540MC
Make and model
Boeing 747243F
Aircraft serial
22508
Aircraft time
106,156 hours, 18,652 cycles
Engine
Ge CF650E2
Part
Beam
Condition
Damaged
Location
Cargo Doorway
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

DURING C-CHECK, DAMAGE WAS FOUND IN THE 65B04721-2 AFT LOWER CARGO DOOR LOWER BEAM WEB BETWEEN BS 1840 TO 1852. DAMAGE WAS TRIMMED OUT AND REPAIRED IAW NRC 786 AND SRM 51-40-03, FIG 1. THE 65B04721-2 WEB IS MADE FROM 0.125 INCH THICK 7075-0 SHEET IAW QQ-A-250/12 HEAT TREATED TO T62 AFTER FORMING. THE REPAIR CONSISTS OF AN 0.125 INCH THICK DOUBLER THAT MEASURES 6.0 INCHES BY 16.0 INCHES MADE FROM 7075-0 ALUMINUM SHEET HEAT TREATED TO T6 AFTER FORMING INSTALLED USING HL18PB6-4 HI-LOKS WITH HL70-6 COLLARS. REPAIR IAW PART 1 AND SRM 51-40-03, FIG 1 IS INSTALLED ON FATIGUE CRITICAL BASELINE STRUCTURE (FCBS) AND A DAMAGE TOLERANCE EVALUATION (DTE) IS NECESSARY. A DAMAGE TOLERANCE INSP (DTI) INCLUDES AN INSP THRESHOLD, INSP INTERVALS, AND INSP PROCEDURES AND METHODS. IF THE DTI IS NOT AVAILABLE WHEN THE AIRPLANE RETURNS TO SERVICE, THE REPAIR IS APPROVED FOR 24 MONTHS. THIS REPAIR HAS BEEN SUBMITTED TO MFG FOR DTI ON SR 1-1554670751. THE REPAIR ACCOMPLISHED IAW PART 1 IS FAA APPROVED IAW SRM 51-40-03, FIGURE 1. THE PART 2 INSP WILL BE FAA APPROVED AT THE TIME IT IS PROVIDED BY MFG, EO 4752A163.