# SDR ASAA2021092036008

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 20, 2021
- Submitted: September 21, 2021
- Operation: Air carrier
- Aircraft: [N506AS](https://openairdocs.org/aircraft/N506AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35690
- Aircraft time: 48,399 hours, 14,632 cycles
- Engine: Ge
- System (JASC): [3460 · Flight Management Computing Hardware System](https://openairdocs.org/jasc/3460)
- Part: Unknown
- Part number: UNKNOWN
- Condition: Unknown
- Location: Unknown
- Stage of operation: NR
- How discovered: V
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021092036008

## Discrepancy

MOMENTARY VTK FLAG ON CAPTAINS ND WITH LOSS OF LNAV/VNAV, THEN RESET ITSELF. GROUNDED - YES. NO VTK FLAG NOTED AT THIS TIME & NOTED RECOVERY OF SYSTEM & VTK EXTINGUISHED. CREW NOTED F/OS NAV DISPLAY SHOWED NO FLAG. CONSIDERED NUISANCE ERROR REF B737-800 AMM 34-61-00. NO HISTORY 30 DAYS & CREW NOTED THERE WAS NO SOURCE SELECT SWITCHING ACCOMPLISHED.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.