# SDR ASAA2017011519360

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 15, 2017
- Submitted: January 18, 2017
- Operation: Air carrier
- Aircraft: [N477AS](https://openairdocs.org/aircraft/N477AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 40716
- Aircraft time: 6,334 hours, 2,069 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Circuit Breaker
- Condition: Tripped
- Location: Autopilot B
- 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/ASAA2017011519360

## Discrepancy

AUTO PILOT B INOPERATIVE,  WOULD NOT ENGAGE. CIRCUIT BREAKER P6-2 B4 TRIPPED.  ACFT GROUNDED.  DIGITAL FLIGHT CONTROL SYSTEM (DFCS) BITE PROCEDURE IAW AMM 22-11-00. NO AUTO PILOT DISCONNECT FAULTS FOUND. DUE TO AFCS SYSTEM B ENGAGE INTERLOCK CIRCUIT BREAKER FOUND OPEN. ACCOMPLISHED DFCS OPS TEST IAW AMM 22-11-00. ACCOMPLISHED MCP CMD/CWS INTERLOCK BITE TEST 60.58, DISENGAGE BITE LIBRARY 60.62, MACH TRIM 60.33, SPEED / STAB TRIM BITE 60.32. ALL TESTS PASSED.

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