# SDR AALA20060111

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 14, 2006
- Submitted: March 16, 2006
- Operation: Air carrier
- Aircraft: [N973AN](https://openairdocs.org/aircraft/N973AN), registered now
- Make and model: Boeing 737823
- Aircraft serial: 29548
- System (JASC): [3460 · Flight Management Computing Hardware System](https://openairdocs.org/jasc/3460)
- Part: Acquisition Unit
- Part number: 22330008161
- Condition: Vibration
- Location: Lt Engine
- Stage of operation: CL
- How discovered: O
- Nature of condition: E
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/AALA20060111

## Discrepancy

MIA - LEFT ENGINE VIBRATION INCREASED TO 4.3 AT 100 PERCENT N1.  HIGH FREQUENCY VIBRATION FELT IN ENTIRE COCKPIT WITH LOUD HUMMING NOISE.  REMOVED AIRCRAFT FROM SERVICE.  ENGINEERING ORDERED FLIGHT DATA RECORDER DOWNLOAD.  ACCOMPLISHED LEFT HAND ENGINE FAN BALANCE.  REPLACED DIGITAL FLIGHT DATA ACQUISITION UNIT AND INSTALLED SOFTWARE.  SYSTEM GROUND CHECKED NORMAL OPERATION.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.