In a dual-hydraulic landing gear system, what happens if one hydraulic path becomes unavailable?

• A. The system automatically seals the affected path and stops gear operation.
• B. The other path is shut down to prevent crossflow.
• C. The gear will fail to extend due to loss of crossfeed.
• D. Crossfeed lines allow pressure to reach all actuators even if one path is unavailable.

Answer: (D)

In a dual-hydraulic landing gear system, two independent hydraulic paths power the gear, and crossfeed lines connect the two sides so pressure can be routed to all actuators even if one path fails. This means that if one hydraulic path becomes unavailable, the remaining path can still supply pressure to the gear actuators through the crossfeed, allowing extension or retraction to proceed. The crossfeed is specifically there to keep the system operable despite a failure in one line or pump, so the gear doesn’t lock up or quit working. The other scenarios describe automatic sealing, shutting down the other path, or loss of crossfeed, which aren’t how a properly designed dual-hydraulic system maintains operation.