# SDR AALA202605073935

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 3, 2026
- Submitted: May 7, 2026
- Operation: Air carrier
- Aircraft: [N913NN](https://openairdocs.org/aircraft/N913NN), registered now
- Make and model: Boeing 737823
- Aircraft serial: 29571
- Aircraft time: 39,062 hours, 17,052 cycles
- Engine: Cfmint CFM567B24E
- System (JASC): [7320 · Fuel Controlling System](https://openairdocs.org/jasc/7320)
- Part: Hmu
- Part number: 1853M56P16
- Part serial: BECW9851
- Condition: Defective
- Location: Nr 1 Engine
- Part time: 40,565 hours, 17,717 cycles
- Stage of operation: AP
- How discovered: O
- Nature of condition: E, K, J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA202605073935

## Discrepancy

AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: AT LEVEL OFF ENGINE NUMBER 1 EXPERIENCED HARD SHUDDER AND N1; DROP OF 25% FOR APPROXIMATELY 4 SECONDS. ALSO, NOTICED A 500 LB IMBALANCE SUDDENLY WITH LEFT TANK LOW. AIRCRAFT EMERGENCY LANDED SAFELY AT MSY. TROUBLESHOT ENGINE NUMBER 1 PER FIM TASK 71-05-00-810-805-F00.  FOUND HMU TO BE DEFECTIVE, REMOVED AND REPLACED HMU, PER WC 08L40073001. OPS CHECK AND LEAK CHECK GOOD.

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