# SDR ASAA2017020619717

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 6, 2017
- Submitted: February 9, 2017
- Operation: Air carrier
- Aircraft: [N477AS](https://openairdocs.org/aircraft/N477AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 40716
- Aircraft time: 6,571 hours, 2,155 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Control Panel
- Part number: 8221567102
- Part serial: 45LX9C
- Condition: Faulty
- Location: Cockpit
- Part time: 6,598 hours, 2,165 cycles
- Stage of operation: NR
- How discovered: O
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2017020619717

## Discrepancy

ALTITUDE WINDOW DISPLAY HAS SEVERAL ANOMALIES. IT APPEARS THE IS A "MINUS" SIGN IN FRONT OF THE ALTITUDE. GROUNDED - YES. CONFIRMED ALTITUDE WINDOW DISPLAY IS DISPLAYING INCORRECT. REPLACED MCP AND RESET 9 C/B'S. OPS TEST NML. REF B737-900 AMM 22-11-34. ALL TEST PASS. GROUND VERIFICATION GOOD. ACCOMPLISHED DFCS LRU INTERFACE TEST MCP BITE GROUP 32 AND LAND VERIFY BITE GROUP #49. ALL TEST PASS. ALSO ACCOMPLISHED HGS SENSOR TEST FCC/AT. ALL TEST PASS. REF LWMP CHECKLIST AMM 22-00-01 AND SMM 34-36-00. A/C REMAINS CAT IIIA AUTOLAND AND HGS. A/C PLAC SCREW REFLECTS THE SAME. CLEARS MEL22-16K.

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