Refer to figure.
A clutch is a mechanical device used to connect and disconnect the power transmission from the engine to the main rotor gearbox (MGB) in helicopters. It allows the engine to be started without turning the MGB and rotating assemblies, thereby reducing the load on the engine and starter.

There are different types of clutches, such as centrifugal clutches, which use a set of shoes and a drum to engage the drive as engine speed increases. Additionally, some systems use a belt with tighteners as a clutch, which requires manual or electrical engagement by the pilot.

1. “If the main rotor run-down time is much longer than usual after engine shutdown, the clutch connecting the engine to the main rotor drive system requires maintenance” → CORRECT.

If the main rotor run-down time is much longer than usual after engine shutdown, it may indicate an issue with the clutch connecting the engine to the main rotor drive system, and maintenance may be required. This is because the clutch should disengage the engine from the rotor, to allow it to stop in a timely manner. If this does not happen, it suggests that the clutch may not be functioning properly. Additionally, if there are issues with the clutch, you might experience symptoms, such as erratic rotor behaviour or unusual noises during operation. This can cause excessive wear on the rotor system and potentially lead to more severe mechanical failures.

2. If the main rotor is engaged at a higher engine RPM than usual, it means that the springs in the centrifugal clutch are too weak → INCORRECT.

A centrifugal clutch is an automatic system using a set of shoes and a drum. The shoes are splined to the drive from the engine. As the engine speed increases, the shoes are moved outward by centrifugal forces, making contact with the drum, which drives the transmission. In case the springs in the centrifugal clutch are too weak, then they will provide less resistance to the outward movement of the shoes. As centrifugal forces increase with engine RPM, the weaker springs will be overcome sooner. So, the shoes will contact the drum and transmit torque at a lower engine RPM, thus the main rotor is engaged earlier.

If the springs are too strong, the main rotor will be engaged at a higher engine RPM, indicating excessive wear or glazing of the shoes, and contamination or oil on the friction surfaces.