# SDR ASAA2021072435499

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 24, 2021
- Submitted: July 26, 2021
- Operation: Air carrier
- Aircraft: [N428AS](https://openairdocs.org/aircraft/N428AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36353
- Aircraft time: 20,284 hours, 6,428 cycles
- System (JASC): [3460 · Flight Management Computing Hardware System](https://openairdocs.org/jasc/3460)
- Part: Fmc
- Condition: Failed
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021072435499

## Discrepancy

DURING CRUISE IN STRAIGHT AND LEVEL FLIGHT F/O PR GOT VTK AND DUAL FMC FAIL, DROPPED OUT OF LNAV/VNAV AFTER ABOLUT 45 SECONDS BOTH FMC RETURNED BUT ALL DATA WAS BLANK. GROUNDED - YES. FMC BITE SHOWS FMC-L RESYNC MSG ON PREVIOUS FLT LEG. ACCOMPLISHED B737-800 FIM 34-61 TASK 832 VERIFIED OP PROGRAM & ALL SOFTWARE SAME.

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