If an electrical problem prevents gear extension, gear can still be extended using:

• A. Pneumatic backup extension
• B. Electrical back-up drive
• C. Gravity-assisted extension
• D. Hydraulic manual override valves

Answer: (D)

When the electrical system won’t allow the gear to extend, the gear can still come down through hydraulic control that bypasses the normal electrical path. The hydraulic manual override valves provide a direct route for hydraulic fluid to the gear actuators, allowing the crew to extend and lock the gear even with an electrical fault. This is the intended emergency extension method because it uses the same hydraulic power that normally moves the gear, but without relying on the failed electrical controls. Pneumatic or gravity methods aren’t standard, and an electrical backup would still depend on power, so they wouldn’t reliably guarantee extension in this scenario.