# SDR ASAA2017121722924

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 17, 2017
- Submitted: December 19, 2017
- Operation: Air carrier
- Aircraft: [N494AS](https://openairdocs.org/aircraft/N494AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 41729
- Aircraft time: 7,388 hours, 2,422 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Computer
- Condition: Malfunctioned
- Location: Llm
- Stage of operation: IN
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2017121722924

## Discrepancy

WHILE ACCOMPLISHING LLM UPDATE BITE LIBRARY TEST FOR AILERON FAILED. 2 FAULTS AIL POS FAIL & R SENSOR EXC INV CHANNEL B. REPEATED TEST, NO HELP. CHANNEL A TEST PASSED.  ACFT GROUNDED.  TROUBLESHOT IAW FIM 22-12 TASK 813. NO MAINTENANCE MESSAGES SHOWN AFTER DFCS BITE CHECK ACCOMPLISHED. PERFORMED DFCS LRU REPLACEMENT TEST FOR FCC IAW AMM 22-11-33, LAND VERIFY TEST IAW AMM 22-11-00/201 BOTH TESTS PASSED. NO HISTORY LAST 30 DAYS.

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