Which component is essential in a helicopter flight crew?

In a helicopter flight crew, the role of the pilot or co-pilot is essential because they are responsible for the operation and control of the aircraft. The pilot leads the crew in executing flight maneuvers, ensuring the safety of the aircraft and its passengers, and navigating through different flight conditions. The co-pilot supports the pilot in these tasks, helping to manage various systems and assist with situational awareness. Without either a pilot or co-pilot, the helicopter would lack the necessary expertise required to operate safely, making their presence a critical component of any flight crew.