# SDR 0300996638

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 18, 2003
- Submitted: May 20, 2003
- Operation: Air carrier
- Aircraft: N638US
- Make and model: Boeing 747251B
- Aircraft serial: 23549
- Aircraft time: 69,572 hours, 9,115 cycles
- System (JASC): [2913 · Hydraulic Pump (Electric/Engine), Main](https://openairdocs.org/jasc/2913)
- Part: Pump
- Part number: 3508806
- Part serial: MX312947
- Condition: Leaking
- Location: Hyd System
- Part time: 1,748 hours
- Stage of operation: CR
- How discovered: O
- Nature of condition: K, J
- Precautionary procedure: H
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/0300996638

## Discrepancy

DURING CRUISE THE HYDRAULIC FLUID QUANTITY IN THE NR 4 SYSTEM INDICATED ZERO.  AIRCRAFT CONTINUED TO DESTINATION, ALTERNATELY EXTENDED THE LANDING GEAR AND LANDED WITHOUT FURTHER INCIDENT.  REPLACED THE NR 4 ENGINE DRIVEN HYDRAULIC PUMP.  OPERATIONAL CHECK GOOD.

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