What is one maintenance function a flight engineer may perform according to regulations?

A flight engineer is responsible for ensuring that the aircraft's systems are operating correctly, and one of the critical maintenance functions they can perform is replenishing hydraulic fluid. This task is important for maintaining proper system functionality and safety, as hydraulic systems are integral to aircraft operation, controlling critical components such as landing gear, brakes, and flight control surfaces.

The regulations outline that flight engineers can perform specific maintenance functions within the guidelines of the Federal Aviation Regulations (FARs) and the procedures established by the certificate holder's manuals. Replenishing hydraulic fluid fits this description as it is a routine maintenance operation that supports the ongoing airworthiness of the aircraft.

Other tasks listed, such as replacing cockpit instruments or calibrating navigational equipment, typically require more specialized maintenance and would be managed by qualified maintenance personnel or technicians with the appropriate certifications. Conducting pre-flight inspections is indeed a vital safety activity but often falls under the pilot's responsibilities rather than a maintenance function specifically handled by flight engineers. Hence, replenishing hydraulic fluid is a clear example of a maintenance function aligned with the regulatory framework governing a flight engineer's duties.