Which item is NOT listed as a common cause of problems in hydraulic actuators?

Which item is NOT listed as a common cause of problems in hydraulic actuators?

• A. Overheating
• B. External leakage
• C. Internal leakage
• D. Sluggish operation

Answer: (A)

Understanding why hydraulics fail involves separating direct fault causes from conditions that worsen things. External leakage and internal leakage describe actual faults in seals and connections that let fluid escape or bypass where it shouldn’t, directly impairing performance and efficiency. Sluggish operation signals that something is hindering flow—perhaps a worn seal, contamination, or a restriction in the circuit—again pointing to a concrete fault or fault-family. Overheating, while harmful, is usually treated as a condition that develops from other issues (like excessive load, inadequate cooling, or continuous high friction) rather than a primary fault category listed in standard fault trees. It can worsen problems by degrading oil viscosity and seals, but it’s not typically listed as a common, stand-alone cause of actuator problems.