Which rotorcraft system must be inspected according to the manufacturer's maintenance manual under 14 CFR Part 43?

The correct choice is based on the requirements set forth by 14 CFR Part 43, which outlines maintenance, preventive maintenance, and alterations for aircraft, including rotorcraft. According to these regulations, manufacturers often provide specific maintenance manuals that detail the necessary inspections and intervals for various components of the aircraft.

The drive shaft is a crucial component of the rotorcraft's power transmission system. It connects the engine to the rotor system, and any malfunction or degradation in this part can significantly impact the aircraft's performance and safety. Given its critical role and the potential consequences of failure, inspections of the drive shaft must follow the detailed criteria established in the manufacturer's maintenance manual to ensure that it is functioning safely and effectively.

In contrast, while the engine, flight controls, and fuel system are all essential systems that require regular inspections, the drive shaft stands out in this context due to its specific oversight under the manufacturer's directives stated in the regulations. Each of these other systems is also subject to inspection, but the drive shaft particularly emphasizes the importance of following manufacturer guidelines to maintain the integrity and safety of rotorcraft operations.