What is the typical effect of hydraulic fluid contamination on landing gear operation?

• A. Sticking actuators, erratic extension/retraction, reduced braking efficiency, and potential gear jam.
• B. Faster gear extension.
• C. No effect.
• D. Increased braking efficiency.

Answer: (A)

Contaminated hydraulic fluid disrupts the precise hydraulic control that moves and locks the landing gear. Particles and degraded fluid can score seals, clog valves, and cause nondeterministic pressure delivery, leading to sticking actuators and irregular extension or retraction. The braking system, which depends on clean fluid to transmit pressure reliably, loses braking efficiency when contaminants impair pressure transmission and valve function. In extreme cases, debris can jam an actuator or valve body, preventing gear movement or secure positioning.

If the fluid were contaminated to this degree, you wouldn’t expect faster gear extension, and there would be a noticeable effect on operation, not none. Increased braking efficiency wouldn’t occur because contaminants generally hinder, not enhance, hydraulic performance.