# SDR UALA2011050202141

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 30, 2011
- Submitted: May 27, 2011
- Operation: Air carrier
- Aircraft: [N669UA](https://openairdocs.org/aircraft/N669UA), registered now
- Make and model: Boeing 767322
- Aircraft serial: 30025
- Aircraft time: 43,245 hours, 11,399 cycles
- Engine: Pwa PW4056
- System (JASC): [2421 · AC Generator-Alternator](https://openairdocs.org/jasc/2421)
- Part: Idg
- Part number: 745329F
- Part serial: 80986
- Condition: Faulty
- Location: Nr 1
- Stage of operation: DE
- How discovered: O
- Nature of condition: E
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UALA2011050202141

## Discrepancy

TWICE ON DESCENT WHEN REDUCING ENGINE POWER THERE WAS A STRONG VIBRATION AND RUMBLING SOUND.  VIBRATIONS IN YOKE AFTER POWER REDUCED FOR INITIAL DESCENT & FINAL APPROACH, DURATION OF 2-3 SECONDS TWICE AUTOPILOT WAS ENGAGED BOTH TIMES, ENGINE PARAMETERS NORMAL, NO STICK SHAKER WARNING NOTICED.  REPLACED NR 1 ENGINE IDG DUE TO INFORMATION WITHIN SERVICE TIP.  IDG REPLACED PER MM.

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