Service difficulty report · Sidewall Support · Boeing 7377H4

Difficulty date
March 31, 2022
Submitted
May 2, 2022
Operation
Air carrier
Aircraft
N475WN
Make and model
Boeing 7377H4
Aircraft serial
32474
Aircraft time
59,744 hours, 35,276 cycles
Part
Sidewall Support
Condition
Corroded
Location
Aft Cargo Bay
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

CORROSION ON AFT CARGO BAY FLOOR TO SIDEWALL SUPPORT AT RBL 21 BS 727D+18; BS 727E+3; BS 727E+6; BS 727E+10; BS 747+3; BS 747+12; BS 747+15. / [01] SRM 53-60-53-0I-2 IDENTIFICATION AND SRM 53-00-53-1A-2 ALLOWABLE DAMAGE ARE APPLICABLE<BR><BR>REMOVED CORROSION BY BLENDING FLOOR TO SIDEWALL SUPPORT UPPER SURFACE AT MULTIPLE AREAS PER SRM 51-10-02. MAXIMUM MATERIAL LOSS L=6.8'; W=0.9'; D=0.011'. ORIGINAL THICKNESS 0.040'; REMAINING THICKNESS 0.029'. FOUND TO BE OUT OF LIMITS PER SRM 53-00-53-1A-2 FIGURE 103 DETAIL E.<BR>GAGE: ATS1672; S/N:65092939; DUE DATE 03/2023;[02] VERIFIED CORRECTIVE ACTION 1- BLEND IS OUT OF LIMITS;[03] LOCATED AND DRILLED FLOOR TO SIDEWALL SUPPORT FROM BS 727+4 TO BS 767; RBL 21 PER SRM 51-40-05 AND DWG# 146A7500. FROM EXTRUSION BAC1496-377#7075T62 LOT #1477731-1. OK TO TREAT AND PRIME;[04] VERIFIED CORRECTIVE ACTION 3.;[05] TREATED AND PRIMED FLOOR TO SIDEWALL SUPORT SECTION PER SRM 51-20-01 AND SOPM 20-41-02;[06] VERIFIED CORRECTIVE ACTION 5.;[07] UPDATED MEASUREMENTS;[08] FABRICATED FLOOR TO SIDEWALL SUPPORT FROM BS 727+4 TO BS 767; RBL 21 PER SRM 51-40-05 AND DWG# 146A7500. FROM EXTRUSION BAC1496-377#7075T62 LOT #1477731-1.;[09] VERIFIED CORRECTIVE ACTION 8.

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