Service difficulty report · Structure · Boeing 7378H4

Difficulty date
March 27, 2023
Submitted
April 26, 2023
Operation
Air carrier
Aircraft
N8529Z
Make and model
Boeing 7378H4
Aircraft serial
36974
Aircraft time
19,992 hours, 9,666 cycles
Part
Structure
Condition
Corroded
Location
Zn 200 Fus Top
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 FWD SERVICE DOORWAY MOPSILL VERTICAL FLANGE; STA 310-331; RBL 58-59; WL 209 AND STA 327-329 ON HORIZONAL FLANGE; RBL 58 WL 208.<REMOVED CORROSION ON STEP 2;[04] ADDED BLEND TO STEP 1;[05] ADDED BLEND TO STEP 1;[06] REMOVED 26 EA FASTENERS ON FWD SERVICE DOORWAY MOPSILL VERTICAL FLANGE; STA 310-331; RBL 58-59; WL 209 AND STA 327-329 ON HORIZONAL FLANGE; RBL 58 WL 208 FOR ACCESS PER SRM 51-40-02-0G-0.;[07] VERIFIED CORRECTIVE ACTIONS 1-6.;[08] ACCOMPLISHED HFEC SURFACE SCAN IAW 737 NDTM PART 6 CHAPTER 51-00-00 PROCEDURE 23. NO CRACKS NOTED.ACCOMPLISHED UT THICKNESS MEASUREMENT IAW 737 NDTM PART 4 CHAPTER 51-00-00 PROCEDURE 2.<BR>MINIMUM REMAINING THICKNESS FOUND 0.074' ADJACENT TO 0.080' SEE ATTACHED GRID.<BR><BR>EQUIPMENT USED:<BR>-NORTEC 600 ID: ATS1465 CAL DUE: 09/2023<BR>-EPOCH 650 ID: ATS2342 CAL DUE: 07/2023;[09] MAX MATERIAL REMOVED WAS .006' FROM .080'. FOUND TO BE OUT OF LIMITS DUE TO BLEND GOES PAST THE 3 OUT OF TEN FASTENER LIMITS PER SRM 53-10-15-1A-2; STEP 4E; FIGURE 103 G.;INSTALLED 26 EA FASTENERS IN FWD SERVICE DOORWAY MOPSILL VERTICAL FLANGE; STA 310-331; RBL 58-59; WL 209 AND STA 327-329 ON HORIZONAL FLANGE; RBL 58 WL 208 PER SRM 51-40-02-0G-0; DWG# 141A8310; SHEETS 39; 46.;[14] VERIFIED CORRECTIVE ACTION 13.;[15] REPAIRED CORROSION DAMAGE ON FWD SERVICE DOORWAY MOPSILL VERTICAL FLANGE; STA 310-331; RBL 58-59; WL 209 AND STA 327-329 ON HORIZONAL FLANGE; RBL 58 WL 208. PER EA 23-153-01082

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