# SDR 0202079976

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: June 22, 2002
- Submitted: June 27, 2002
- Operation: Air carrier
- Aircraft: N9340
- Make and model: Doug DC-9-31
- Registry model: [Doug DC-9-31](https://openairdocs.org/model/douglas-dc-9-31) (OpenAirDocs)
- Aircraft serial: 47389
- Aircraft time: 82,988 hours, 90,593 cycles
- System (JASC): [2910 · Hydraulic System, Main](https://openairdocs.org/jasc/2910)
- Part: O-Ring
- Condition: Damaged
- Location: Hyd System
- Stage of operation: CL
- How discovered: O
- Nature of condition: K, J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/0202079976

## Discrepancy

LEFT HYDRAULIC PRESSURE AND QUANTITY WENT TO ZERO.  COMPLIED WITH COM PROCEDURES AND THE LEFT QUANTITY RETURNED TO 5 QUARTS BUT PRESSURE REMAINED AT ZERO.  FLIGHT RETURNED TO A SAFE UNEVENTFUL LANDING BACK TO DTW.  MAINTENANCE FOUND THE RESERVOIR EMPTY AND FOUND A LEAK DUE TO A BAD O-RING ON THE CHECK VALVE AT THE LEFT THRUST REVERSER CONTROL VALVE.  THE O-RING AND THE ENGINE DRIVEN HYDRAULIC PUMP WERE REPLACED.  ALSO, NEW FILTERS AND CHECK VALVE WERE INSTALLED.  AIRCRAFT RETURNED TO SERVICE.

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