# SDR ASAA2018043024551

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 30, 2018
- Submitted: June 20, 2018
- Operation: Air carrier
- Aircraft: [N464AS](https://openairdocs.org/aircraft/N464AS), registered now
- Make and model: Boeing 737990ER
- Aircraft serial: 40714
- Aircraft time: 16,051 hours, 5,245 cycles
- System (JASC): [7321 · Fuel Control/Turbine Engines](https://openairdocs.org/jasc/7321)
- Part: Hmu
- Part number: 1853M56P16
- Part serial: BECWB796
- Condition: Faulty
- Location: Nr 2 Engine
- Part time: 16,485 hours, 5,380 cycles
- Stage of operation: IN
- How discovered: O
- Nature of condition: J
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2018043024551

## Discrepancy

WHILE ACCOMPLISHING T/C 78273000 FAULT CODE APPEARED ON NR 2 ENGINE, FAULT CODE 73-31162, THE MECHANICAL OVERSPEED PROTECTION SIGNAL IS OUT OF RANGE, LONG TIME. MUST BE CORRECTED IN 450 HRS. GROUNDED - YES. REMOVED AND REPLACED HMU ON NR 2 ENGINE IAW T/C'S N8473000 AND N8473001. RAN ENGINE, NO LEAKS NOTED AND GROUND VERIFICATION CONFIRMED NO FAULTS NOTED.

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