Which rotorcraft systems must be inspected according to the manufacturer's maintenance manual during a FAR Part 91 required inspection?

The correct answer emphasizes that the inspection protocols for rotorcraft are heavily dependent on manufacturer guidelines, particularly with components essential for flight safety. The main rotor, center section, drive shafts, and main rotor transmission gearbox are all critical systems that play vital roles in the flight operation and stability of a rotorcraft.

The main rotor is responsible for generating lift, while the center section contributes to structural integrity and stability during flight. The drive shafts transmit power from the engine to the rotor systems, which is fundamental for controlling the rotorcraft’s movement. Finally, the main rotor transmission gearbox is crucial for converting the engine's rotational energy into the speed and torque necessary for rotor operations.

Regular inspection of these components is vital for ensuring overall safety, compliance with regulatory requirements, and adherence to the manufacturer’s maintenance manual. Each of these systems is complex and interconnected, making their careful monitoring essential for safe flight operations. The critical nature of these components underscores why they are prioritized in scheduled inspections under FAR Part 91.