# SDR ASAA2018011223154

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 12, 2018
- Submitted: January 17, 2018
- Operation: Air carrier
- Aircraft: [N461AS](https://openairdocs.org/aircraft/N461AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 36363
- Aircraft time: 15,130 hours, 4,989 cycles
- System (JASC): [2210 · Autopilot System](https://openairdocs.org/jasc/2210)
- Part: Warning Light
- Condition: False Activation
- Stage of operation: NR
- How discovered: O
- Nature of condition: N
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2018011223154

## Discrepancy

MACH TRIM FAIL LIGHT ILLUMINATES WITH MASTER CAUTION RECALL AND EXTINGUISHES WHEN MASTER CAUTION IS RESET.  ACFT GROUNDED.  PERFORMED FIM 22-11 TASK 801,  FAULT HISTORY SHOWED FCC-A MACH TRIM 28 VDC FAULT LAST FLIGHT.  CURRENT STATUS TEST FAILS MACH TRIM ON A CHANNEL,  PASSED ON B CHANNEL.  REMOVED MAINTENANCE PROCEDURES,  TWO CIRCUIT BREAKERS RESET, COLLARS REMOVED.  ACFT CONFIGURATION RETURNED TO NORMAL.  PERFORMED FIM 22-11 TASK 801, CURRENT STATUS, MACH TRIM BITES 13.33 AND 60.33.   TESTS OPS NORMAL NUMEROUS TIMES. NO HISTORY LAST 90 DAYS PLUS.

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