Service difficulty report · Spar · Boeing 7377H4

Difficulty date
April 3, 2023
Submitted
April 28, 2023
Operation
Air carrier
Aircraft
N412WN
Make and model
Boeing 7377H4
Aircraft serial
29818
Aircraft time
71,376 hours, 42,351 cycles
System (JASC)
5711 · Wing Spar
Part
Spar
Condition
Corroded
Location
Zn 500 Left Wing
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 LEFT WING REAR SPAR AROUND BOOST PUMP UPPER BONDING JUMPER IRSS145.<REMOVED CORROSION ON LEFT WING REAR SPAR WEB AROUND BOOST PUMP UPPER BONDING JUMPER IRSS145 IAW SRM 57-20-10-1A-3. ALLOWABLE DAMAGE 3 STEP 2.B.(1 - 3) ON BLENDED AREA NOTED ON STEP 6 BY NDI. VERIFY ALLOWABLE DAMAGE LIMITS AFTER ACCOMPLISHMENT OF UT THICKNESS MEASUREMENTS ON STEP 12 ABOVE; ORIGINAL MATERIAL THICKNESS = 0.680' THICK; DEEPEST MATERIAL LOSS = 0.102' THICK; MATERIAL REMAINING AT DEEPEST MATERIAL LOSS = 0.578' THICK IS OUT OF LIMITS IAW SRM 57-20-10-1A-3 ALLOWABLE DAMAGE 3 STEP 4.A TABLE 101.;[14] VERIFIED CORRECTIVE ACTION 13.;[15] REQUESTED HFEC INSPECTION OF REWORKED SURFACES ON LEFT WING REAR SPAR WEB AROUND BOOST PUMP UPPER BONDING JUMPER IRSS145 TO VERIFY CRACK FREE CONDITION.;[16] ACCOMPLISHED HFEC INSPECTION OF BLEND AREA NO CRACK NOTED IAW 737 NDTM PART 6; 51-00-00 PROCEDURE 23 TOOL# IS000680 CAL. DUE 04/2023.;[17] REFER TO FAULT TTG8Q00K84NB WHERE EA 23-157-01162 WAS ADDED AS A SUBTASK.;[18] VERIFIED CORRECTIVE ACTION 17 AND MEASUREMENT TABLE

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