In addition to the pilot, what key role is part of the helicopter flight crew?

The key role that is part of the helicopter flight crew, in addition to the pilot, is the co-pilot. The co-pilot assists the pilot in operating the aircraft and can take control if necessary. This role is critical for ensuring safety and efficiency during flight operations, especially in complex missions where additional oversight and support are required.

The co-pilot's responsibilities may include monitoring instruments, communicating with air traffic control, managing navigation systems, and performing checklists and protocols. This position allows for a collaborative environment in the cockpit, enhancing situational awareness and decision-making during flights.

The other roles mentioned, while important in various operational contexts, do not serve as direct members of the flight crew in the cockpit during flight.