# SDR AALA201907189007

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 17, 2019
- Submitted: July 18, 2019
- Operation: Air carrier
- Aircraft: [N900UW](https://openairdocs.org/aircraft/N900UW), registered now
- Make and model: Airbus A321-231
- Registry model: [Airbus A321-231](https://openairdocs.org/model/airbus-a321-231) (OpenAirDocs)
- Aircraft serial: 7617
- Aircraft time: 7,736 hours, 2,978 cycles
- System (JASC): [3430 · Landing and Taxi Aids](https://openairdocs.org/jasc/3430)
- Part: Mmr
- Part number: 8221821430
- Part serial: 49G06C
- Condition: Faulty
- Location: Zone 100
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA201907189007

## Discrepancy

AIRCRAFT NOT GROUNDED: PILOT REPORTS DURING DEPARTURE WHILE LEVEL AT 10,000. FMC REVERTED TO HDG MODE. RE-ENGAGED NAV, DROPPED BACK TO HDG MODE AGAIN DURING CLIMB TO 17,000. RE-ENAGED NAV AGAIN AND RECEIVED UNCOMMANDED TURN TO THE RIGHT MCDU SCRATCH PAD SHOWED FM PREDICTIONS LOST MESSAGE. RE-ENGANGED NAV A THIRD TIME AND ALL OPS NORMAL. MAINTENANCE PERFORMED POST FLIGHT REPORT FAIL MSG. MMR1 GPSSU1 T/S IAW TSM 34-14-00. FOUND #1 MMR AT FAULT. REPLACED MMR #1 IAW AMM 34-36-31. OPS AND BITE CHECKS NORMAL. RETURN TO SERVICE PROCEDURE PASSED IAW AMM 22-97-00.

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