# SDR ASAA2020083173111

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 27, 2020
- Submitted: August 31, 2020
- Operation: Air carrier
- Aircraft: [N570AS](https://openairdocs.org/aircraft/N570AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35185
- Aircraft time: 50,502 hours, 15,066 cycles
- System (JASC): [3460 · Flight Management Computing Hardware System](https://openairdocs.org/jasc/3460)
- Part: Fmc
- Condition: Malfunctioned
- Location: Right
- Stage of operation: CR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2020083173111

## Discrepancy

IN OCEANIC AIRSPACE A MOMENTARY ANP SPIKE CAUSED THE ANP FIELD TO TURN AMBER, RNP WENT TO 10.  LNAV AND VNAV REVERTED TO CWS ROLL AND ALTITUDE HOLD.  GROUNDED - YES.  REF B737-800 FIM 22-11 TASK 811, 22-11 TASK 801, 34-61 TASK 801.  FMC-L FLIGHT 1 SHOWS: FMC-R PRES LAT.  DFCS BITE SHOWS NO CURRENT FAULTS ON BOTH, CH A +B.  CH-B SHOWS MSG: 22-11822, 22-11071 ON LEG 01.  NO CURRENT FAULTS OR IN HISTORY FOR ADIRU 1 + 2.  DFCS TESTS GOOD.  ALL REQUIRED TESTS PASSED.

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