# SDR AALA20140119001

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 13, 2014
- Submitted: January 27, 2014
- Operation: Air carrier
- Aircraft: [N642AA](https://openairdocs.org/aircraft/N642AA), registered now
- Make and model: Boeing 757223
- Aircraft serial: 24600
- Aircraft time: 70,525 hours, 24,975 cycles
- System (JASC): [5412 · Nacelle/Pylon, Bulkhead/Firewall](https://openairdocs.org/jasc/5412)
- Part: Bulkhead
- Condition: Cracked
- Location: Nr 1 Pylon
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA20140119001

## Discrepancy

NR 1 PYLON, INBD MID BULKHEAD HALF WAS BEING REPLACED DUE TO CRACK.  THE FWD FASTENER HOLE COMMON TO THE MID BULKHEAD & THE LOWER SPAR CHORD WAS FOUND TO BE AT .415 INCHES WHICH IS BEYOND THE LIMITS SPECIFIED IN SB 757-54A0039 OF .3911INCHES MAXIMUM.  ENGINEERING  AUTHORIZATION B757-54-033265 DATED 01/17/2014 WAS ISSUED TO INCREASE THE HOLE SIZE TO .4990 INCHES.  INSTALLED A FREEZE PLUG IN THE LOWER SPAR CHORD & INSTALLED FASTENER.

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