# SDR USAA2009051491168

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 13, 2009
- Submitted: May 19, 2009
- Operation: Air carrier
- Aircraft: [N196UW](https://openairdocs.org/aircraft/N196UW), registered now
- Make and model: Airbus A321-211
- Registry model: [Airbus A321-211](https://openairdocs.org/model/airbus-a321-211) (OpenAirDocs)
- Aircraft serial: 3879
- Aircraft time: 145 hours, 62 cycles
- Engine: Cfmint CFM565B3P
- System (JASC): [7321 · Fuel Control/Turbine Engines](https://openairdocs.org/jasc/7321)
- Part: Hydromech Unit
- Part number: 8061536
- Part serial: WYGC6570
- Condition: Defective
- Location: Nr 1 Engine
- Part time: 145 hours, 62 cycles
- Stage of operation: TO
- How discovered: O
- Nature of condition: O
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/USAA2009051491168

## Discrepancy

LOG PAGE 8429793 - FLT 771 CLT-SFO - RETURN TO FIELD - SHORTLY AFTER DEPARTURE, CREW SENT ACARS MESSAGE INDICATING THEY HEARD POPPING AND GRINDING NOISES DIRECTLY BELOW THE COCKPIT AND THOUGHT THEY HAD LOST THE NOSE GEAR. . PASSENGERS REPORTED HEARING BANGS AND FLASHES FROM THE NO. 1 ENGINE. AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO CLT LANDING WITHOUT INCIDENT.  MAINTENANCE PERFORMED EXTENSION/RETRACTION CHECK OF NOSE LANDING GEAR WITH NO FAULTS FOUND. ACCOMPLISHED BORESCOPE OF NO. 1 ENGINE AND REPLACED THE HYDRO MECHANICAL UNIT (HMU). ALL OPERATIONAL CHECKS WERE GOOD.

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