# SDR 0102516306

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 17, 2001
- Submitted: July 18, 2001
- Operation: Air carrier
- Aircraft: N666US
- Make and model: Boeing 747451
- Aircraft serial: 23821
- Aircraft time: 50,033 hours, 6,214 cycles
- System (JASC): [2913 · Hydraulic Pump (Electric/Engine), Main](https://openairdocs.org/jasc/2913)
- Component: Hyd Pump, Vickers, 3508806
- Stage of operation: UK
- Nature of condition: K
- Precautionary procedure: H
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/0102516306

## Discrepancy

DURING FLIGHT, RECEIVED "HYD PRES ENG 4" AND "HYD QTY LOW" MESSAGES. THE HYDRAULIC FLUID QUANTITY IN THE NBR 4 SYSTEM INDICATED ZERO. TURNED OFF THE HYDRAULIC PUMPS FOR THE NBR 4 SYSTEM AND THE CREW DECLARED AN EMERGENCY. ALTERNATE EXTENDED THE LANDING GEAR AND THE AIRCRAFT LANDED WITHOUT INCIDENT.    REPLACED THE ENGINE DRIVEN HYDRAULIC PUMP. OPERATIONAL CHECK GOOD.

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