# SDR 99UAL900069

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 2, 1999
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: N990UA
- Make and model: Boeing 737291
- Aircraft serial: 21980
- Engine: Pwa JT8D17
- System (JASC): [2780 · Leading Edge Slat Control System](https://openairdocs.org/jasc/2780)
- Part: Valve
- Condition: Failed
- Location: Le Flap
- Component: Waterman, 1121S10100
- Stage of operation: LD
- Nature of condition: K, J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/99UAL900069

## Discrepancy

LOST A SYSTEM HYDRAULIC QUANTITY AND PRESSURE AFTER GEAR EXTENSION AND DURING FLAP OPERATION. *S/D* FOUND THE FLAP FLOW LIMITING VALVE LEAKING. THIS UNIT WAS LEAKING BECAUSE THE BODY SEPARATED INTERNALLY. THE UNIT CONTAINS A FLOW RING WHICH FAILED DUE TO FATIGUE.    THE UNIT ALSO HAD SEVERE EROSION IN A METERING ORIFICE HOLE.  THE VALVE WAS REPLACED PER MM 27-53-03, OPS CHECK OK.

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