What are common hydraulic system failure modes and their effects on flight controls?

What are common hydraulic system failure modes and their effects on flight controls?

• A. Overheating due to fuel.
• B. Ice buildup in ducts.
• C. Leaks, pump failure, ruptured lines; loss of pressure degrades or defeats actuator control of surfaces.
• D. Electrical failures shutting down avionics.

Answer: (C)

Hydraulic flight control systems rely on pressurized fluid to move actuators that position the control surfaces. The most common failure modes are leaks, pump failure, and ruptured lines, all of which cause a loss or drop in pressure. When pressure falls, the actuators can’t deliver the required force, so surfaces become sluggish, unresponsive, or may drift to a neutral or stuck position, degrading or defeating pilot input control. In contrast, overheating, ice in ducts, or electrical failures affecting avionics describe issues outside the hydraulic pressure pathway and don’t directly explain how hydraulic control surfaces lose effectiveness.

Hydraulic flight control systems rely on pressurized fluid to move actuators that position the control surfaces. The most common failure modes are leaks, pump failure, and ruptured lines, all of which cause a loss or drop in pressure. When pressure falls, the actuators can’t deliver the required force, so surfaces become sluggish, unresponsive, or may drift to a neutral or stuck position, degrading or defeating pilot input control. In contrast, overheating, ice in ducts, or electrical failures affecting avionics describe issues outside the hydraulic pressure pathway and don’t directly explain how hydraulic control surfaces lose effectiveness.