What three systems does the firewall shutoff handle cut off?

The firewall shutoff handle is a crucial safety feature within an aircraft's systems, particularly in emergency situations. It is designed to cut off key systems to prevent further fuel supply and mitigate the risk of fire or explosion.

The correct answer specifies that the systems involved are the fuel system, hydraulic system, and bleed air.

1. The fuel system is cut off to stop any potential fuel flow to the engine in the event of a fire or an emergency, drastically reducing the risk of a fire igniting or spreading.

2. The hydraulic system is similarly crucial because hydraulic fluid is essential for the functioning of flight controls and landing gear. By shutting this off, the potential for hydraulic fluid fires or malfunctions is minimized.

3. Bleed air is used in various aircraft systems, including cabin ventilation and engine starting. Cutting off bleed air helps prevent any heated air from fueling a fire or affecting other critical systems.

This combination of systems ensures that the aircraft can respond effectively to emergencies, prioritizing the safety of passengers and crew while addressing potential hazards in flight. The other options presented do not accurately reflect the systems the firewall shutoff handle addresses, leaving out one or more critical elements involved in safety management.