# SDR USAA2012090400020

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 17, 2012
- Submitted: September 4, 2012
- Operation: Air carrier
- Aircraft: [N749US](https://openairdocs.org/aircraft/N749US), registered now
- Make and model: Airbus A319-112
- Registry model: [Airbus A319-112](https://openairdocs.org/model/airbus-industrie-a319-112) (OpenAirDocs)
- Aircraft serial: 1313
- Aircraft time: 32,279 hours, 20,913 cycles
- System (JASC): [2720 · Rudder Control System](https://openairdocs.org/jasc/2720)
- Part: Crystal
- Part number: A1217675
- Condition: Defective
- Location: Computer
- Component: Fac, Thales
- Component part number: B397BAM0513
- Stage of operation: CL
- How discovered: O
- Nature of condition: F
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAA2012090400020

## Discrepancy

FLIGHT CREW REPORTED UNCOMMANDED RUDDER MOVEMENTS ON CLIMB, AT LEAST SIX TIMES, ON BOTH AUTO PILOTS 1 AND 2, IN LEVEL FLIGHT AND TURNS.  DECLARED AN EMERGENCY AND RETURNED TO BOS.  REMOVED AND REPLACED BOTH LEFT AND RIGHT FLIGHT AUGMENTATION COMPUTERS AND BOTH AILERON/ELEVATOR COMPUTERS.  PER VENDOR TEARDOWN REPORT, THE NR 1 FLIGHT AUGMENTATION COMPUTER FAILED PT. 10 DURING STRESS TESTING.  REPLACED IC10 AND Y1 ON A52 PCB TO CORRECT FAULTS.

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