Which items are included in a towbar inspection?

The correct choice for the items included in a towbar inspection is indeed focused on the tow bar head, wheels, hydraulic system, and shear pin.

When inspecting a towbar, it is crucial to check the tow bar head, as this is the connection point between the towbar and the aircraft. A malfunction at this point can lead to significant safety issues during ground operations. The wheels are also key components since they need to be in good condition to allow for smooth movement and maneuverability when towing the aircraft.

Additionally, the hydraulic system of the towbar, if applicable, must be inspected to ensure that it functions correctly. This system helps in adjusting the angle and ensuring proper engagement with the aircraft. Finally, the shear pin is a safety feature designed to prevent excessive force from damaging the towing system. If the towing force exceeds a safe limit, the shear pin will break, thus preventing damage to the towbar and the aircraft.

In summary, the inclusion of these specific components in the towing inspection underscores the importance of ensuring that all elements involved in the towing process are functioning properly and safely to prevent accidents and ensure efficient operations.