Service difficulty report · Skin · Boeing 74747UF

Difficulty date
October 18, 2010
Submitted
October 19, 2010
Operation
Air carrier
Aircraft
N498MC
Make and model
Boeing 74747UF
Aircraft serial
29259
Aircraft time
48,208 hours, 7,309 cycles
Engine
Ge CF680
Part
Skin
Condition
Damaged
Location
Rt Wing Te Flap
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 A3 CHECK INSP OF ACFT, MX FOUND 4 EA CHAFE MARKS ON THE RT INBD AFT FLAP UPPER EXTERNAL SKIN CAUSED BY BOTTOM OF SCREWS THAT SECURE AFT SECTION OF COVE PANEL. AFTER BLENDOUT AREAS 1-4 FOUND BEYOND ALLOWABLE DAMAGE LIMITS IAW SRM 57-53-01, FIG 101, DETAIL II (SHEETS 1, 2 AND 3). THE UPPER PANEL ASSY - OUTER SKIN IS MADE FROM 0.125 IN. 7075-T6 (CHEMMILLED TO 0.012 IN MIN) ALUMINUM HONEYCOMB IAW BMS 4-4, TYPE 3-15. DETAIL DAMAGE AS FOLLOWS: WBL139.682 - 6.0 IN. LONG X 2.5 IN. WIDE X 0.016 IN. DEPTH. WBL208.682 - 6.0 IN. LONG X 3.5 IN. WIDE X 0.035 IN. DEPTH. WBL229.142 - 4.5 IN. LONG X 3.0 IN. WIDE X 0.044 IN. DEPTH. WBL359.186 - 5.0 IN. LONG X 3.75 IN. WIDE X 0.065 IN. DEPTH. HFEC INSP PERFORMED TO THE DAMAGED AREAS 1-4 IAW NDT MANUAL, PART 6 51-00-00, FIG 4, OR 23 WITH CRACK FREE CONDITION ON AREAS 1 - 3. AREA 4 (WBL359.186) REVEALED 2 EA CRACKS, REMOVED WITH A 0.5 IN. DIAM HOLE. DISPOSITION WAS MADE TO PERFORM A TIME LIMITED REPAIR AS DESCRIBED IN PART 1 WORK INSTRUCTIONS, DVI INSPECTIONS AT EVERY 1,000 FH (FLIGHT HOURS) UNTIL ACCOMPLISHMENT OF PERMANENT REPAIR PRIOR TO, OR AT THE NEXT C CHECK AFTER PART 1.

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