# SDR ASAA2016030315758

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 3, 2016
- Submitted: March 7, 2016
- Operation: Air carrier
- Aircraft: [N477AS](https://openairdocs.org/aircraft/N477AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 40716
- Aircraft time: 2,872 hours, 933 cycles
- System (JASC): [3460 · Flight Management Computing Hardware System](https://openairdocs.org/jasc/3460)
- Part: Warning Light
- Condition: False Activation
- Stage of operation: CR
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2016030315758

## Discrepancy

ATTEMPTED MLP IN NR 1 FMC APPROXIMATELY 1 HR INTO FLT, RECEIVED A ROUTE MOD UNABLE MESSAGE IN SCRATCHPAD.  NR 1 FMC SCREEN WENT BLANK AND NR 1 MAP DISPLAYED VTK W/NO NAVIGATION DATA.  NR 2 FMC MAP SUBSEQUENTLY FAILED BEFORE WE COULD RUN QRH.  NR 2 FMC RETURNED FOLLOWED BY NR 1.  HOWEVER RECEIVED SAME RT MOD UNABLE MESSAGE WHETHER WE TRIED MLP IN NR 1 OR NR 2 FMC.  BOTH FMCS SUBSEQUENTLY FAILED AGAIN BUT QUICKLY RETURNED NR 2 FIRST THEN NR 1.  FINALLY ABLE TO INPUT MLP.  ACFT GROUNDED.  LT FMC LOGGED PGM FAULT & LOC DEV SSM FAULT.  PERFORMED FIM 34-61, TASK 807 & 823, ALL TESTS PASSED AND FMC LT BITE CHECK GOOD, REF FIM 34-61, TASK 801.  RT FMC LOGGED PRESSURE POSITION LAT, RATE AND LOCATION DEV SSM FAULT.  PERFORMED FIM 34-61, TASK 824 & 823.  ALL TESTS PASSED, RT FMC BITE CHECK PASSED, REF FIM 34-61, TASK 801.

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