# SDR UALA2013052903741

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 25, 2013
- Submitted: July 26, 2013
- Operation: Air carrier
- Aircraft: [N776UA](https://openairdocs.org/aircraft/N776UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 26937
- Aircraft time: 70,592 hours, 12,434 cycles
- Engine: Pwa PW4077
- System (JASC): [4950 · APU Bleed Air System](https://openairdocs.org/jasc/4950)
- Part: Pressure Switch
- Part number: 38762191
- Part serial: 65242195
- Condition: Failed
- Location: Apu Bleed
- Stage of operation: NR
- How discovered: 9
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UALA2013052903741

## Discrepancy

APUC DETECTED LOSS OF ABILITY TO PNEUMATICALLY LOAD APU.  MESSAGE IS TRIGGERED BY IGV OR SURGE CONTROL SYS FAULTS.   REPLACED DIFFERENTIAL PRESSURE SWITCH.  OP CHECKED GOOD.  STATUS MESSAGE CLEARED.

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