A pilot flying an aircraft equipped with what can receive directional finding assistance?

The choice of a radio as the correct answer is based on its role in aviation communications and navigation. Aircraft radios are vital components that allow pilots to communicate with air traffic control and receive various navigational aids. Directional finding assistance typically involves the use of VHF or HF radios equipped with specific navigational capabilities, such as VOR (VHF Omnidirectional Range) or NDB (Non-Directional Beacon) systems.

When a flight is in need of directional finding, the radio can pick up signals broadcast from these navigational aids, helping the pilot determine their position relative to the beacon. This capability is essential for safe navigation, particularly in areas with poor visibility or unreliable visual references.

Other options like a transponder, while important for air traffic surveillance, only transmit information but do not receive directional signals. An altimeter measures altitude but does not provide directional information. An autopilot system helps in aircraft control but lacks the capability to receive any directional finding assistance. Hence, the radio is the device that enables the pilot to access and utilize directional finding services effectively.