# SDR P5CA9500804

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 7, 1995
- Submitted: March 26, 2000
- Operation: Air carrier
- Aircraft: [N850FT](https://openairdocs.org/aircraft/N850FT), registered now
- Make and model: Boeing 747122
- Aircraft serial: 19755
- System (JASC): [2910 · Hydraulic System, Main](https://openairdocs.org/jasc/2910)
- Part: Check Valve
- Part number: 2720021
- Condition: Failed
- Location: Nr 3 Hyd Adp
- Stage of operation: TX
- Nature of condition: K, J
- Precautionary procedure: D
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/P5CA9500804

## Discrepancy

DURING CONTROL CHECK ON TAXI OUT, NR 3 HYDRAULIC PRESS LIGHT ILLUMINATED WITH SUBSEQUENT LOSS OF TOTAL SYSTEM QUANTITY.  DEPRESSURIZED SYSTEM AND RETURNED TO BLOCKS.  FOUND NR 3 HYDRAULIC CHECK VALVE FAILED, VALVE CRACKED AT THREADS.  REMOVED REMAINING THREADED SECTION, INSPECTED MODULE THREADS, INSTALLED NEW CHECK VALVE.  LEAK AND OP CHECK NORMAL PER MM 29-11-40.

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