# SDR ASAA2017070121253

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 1, 2017
- Submitted: July 5, 2017
- Operation: Air carrier
- Aircraft: [N579AS](https://openairdocs.org/aircraft/N579AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35187
- Aircraft time: 39,351 hours, 11,726 cycles
- Engine: Cfmint CFM567B27
- System (JASC): [7714 · Engine RPM Indicating System](https://openairdocs.org/jasc/7714)
- Part: Sensor
- Part number: 3205490050
- Part serial: EM173382W
- Condition: Failed
- Location: N2 Speed
- Part time: 12,387 hours, 3,717 cycles
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2017070121253

## Discrepancy

NR 1 ENGINE VIBRATION INDICATOR INTERMITTENTLY BLANKS OUT AND THEN REAPPEARS.  ACFT GROUNDED.  CONFIRMED FAULT, M1240 ENGINE VIBRATION SIGNAL CONDITIONER, VIBROMETER BITE IAW FIM 77-05 TASK 804, SHOWS ENGINE NR 1 N2 TACHO LOSS E1 MESSAGES LAST 32 FLIGHTS.  ACCOMPLISHED FIM 77-31 TASK 805, TROUBLESHOT TO DEFECTIVE N2 SPEED SENSOR. REMOVED & REPLACED N2 SPEED SENSOR IAW AMM 77-11-02,  GROUND FUNCTIONAL CHECK NORMAL IAW AMM 77-00-00.

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