# SDR 2002UALA01498

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 27, 2002
- Submitted: November 12, 2002
- Operation: Air carrier
- Aircraft: [N791UA](https://openairdocs.org/aircraft/N791UA), registered now
- Make and model: Boeing 777222
- Aircraft serial: 26933
- Aircraft time: 23,228 hours, 3,641 cycles
- Engine: Pwa PW4090
- Engine time: 20,719 hours, 3,207 cycles
- System (JASC): [7230 · Turbine Engine Compressor Section](https://openairdocs.org/jasc/7230)
- Part: Bearing
- Part number: 50B927
- Part serial: 1023
- Condition: Failed
- Location: Lt Engine
- Part time: 20,719 hours, 3,207 cycles
- Stage of operation: CR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2002UALA01498

## Discrepancy

LEFT ENGINE OIL FILTER DIFFERENTIAL WARNING EICAS ILLUMINATED.  REPLACED ENGINE.  SUBSEQUENT SHOP TEARDOWN REVEALED FAILURE OF THE NR 1 BEARING.  BOTH OF THE BEARING'S INNER RACEWAY HALVES HAD MACHINED THE CAGE INNER DIAMETER 360 DEGREES.

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