158 Hydraulic Power (ATA 29) service difficulty reports for the Boeing 747 — 0.6% of all reported difficulties.
Most reported components
- PUMP 28
- LINE 23
- HYDRAULIC LINE 23
- HYDRAULIC SYSTEM 9
- HOSE 7
- UNKNOWN 7
- TRANSMITTER 7
- TUBE 5
- CIRCUIT CARD 5
- B-NUT 4
- CONNECTOR 3
- WIRE 3
- O-RING 2
- FUSE 2
- PACKING 2
Report counts reflect fleet size and reporting activity, not relative safety or reliability. Source: FAA Service Difficulty Reporting System (public domain).