What action should be taken concerning the cabin air during an engine fire in flight?

In the event of an engine fire in flight, turning off cabin heat and air is the recommended action. This is crucial because hot air and fumes from the burning engine can be drawn into the cabin if the heating system is operational, thereby exposing the crew and passengers to smoke or toxic gases. By shutting off these systems, you mitigate the risk of inhaling harmful substances, which is critical for maintaining the safety and well-being of everyone on board.

Additionally, the priority during an engine fire is to execute emergency procedures that focus on controlling the situation and preparing for a potential forced landing. Ensuring that the cabin environment is as safe as possible is part of managing that emergency effectively. Shutting off cabin heat and air minimizes the potential for smoke or fire spreading into the cabin, allowing the pilot to concentrate on flying the aircraft and managing the emergency.