# SDR ASAA2016080717638

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 7, 2016
- Submitted: August 9, 2016
- Operation: Air carrier
- Aircraft: [N563AS](https://openairdocs.org/aircraft/N563AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35180
- Aircraft time: 37,489 hours, 11,297 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Control Panel
- Part number: 8221567102
- Part serial: 17YY1G
- Condition: Failed
- Location: Altitude
- Part time: 22,102 hours, 7,152 cycles
- Stage of operation: NR
- 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/ASAA2016080717638

## Discrepancy

MCP ALTITUDE SELECTORS IS NOT WORKING PROPER AND CHANGING ALTITUDE ON ITS OWN. DIFFICULT OR IMPOSSIBLE TO MAKE SELECTIONS.  ACFT GROUNDED.  ACCOMPLISHED DFCS BITE TEST, NO FAULTS LOGGED.  REMOVED & REPLACED DFCS MCP AS A PRECAUTION, IAW AMM 22-11-34/401.  ACCOMPLISHED DFCS LRU INTERFACE TEST FOR MCP, IAW  AMM 22-11-34/501 (GP 32), DFCS LAND VERIFY TEST, IAW AMM 22-11-00/201 (GP 49), AND HGS SYSTEM/SENSOR TEST, IAW SMM 34-36-00, OPS CHECKED NORMAL.  ACFT LWMP STATUS REMAINS UPGRADED AT CAT3A AUTOLAND & HGS, CAT STATUS SCREW REFLECT SAME.

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