# SDR ASAA2023011741522

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 14, 2023
- Submitted: January 17, 2023
- Operation: Air carrier
- Aircraft: [N442AS](https://openairdocs.org/aircraft/N442AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 43293
- Aircraft time: 33,920 hours, 10,732 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Control Panel
- Part number: 8221567102
- Part serial: 1RDWR
- Condition: Faulted
- Location: Dfcs
- Part time: 58,006 hours, 18,313 cycles
- Stage of operation: AP
- How discovered: O
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2023011741522

## Discrepancy

WHEN ON DOG LEG TO FINAL HEADING SELECT KNOB WOULD NOT CHANGE THE HEADING IN THE WINDOW. WHEN ON FINAL IT WORKED AGAIN. GROUNDED - YES. DUPLICATED PROBLEM, HEADING KNOB INTERMITTANT. REMOVED/REPLACED DFCS MODE CONT PNL PER B737-900 AMM 22-11-34, SYS OPS CKS NML PER SAME, GND VERIFICATION SUCCESSFUL.

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