Emergency Descent Mode will engage automatically under which condition?

• A. Autopilot on and cabin altitude above 20,000 ft
• B. Autopilot off and cabin altitude above 20,000 ft
• C. Autopilot on and cabin altitude below 10,000 ft
• D. During normal cruise when altitude reaches 30,000 ft

Answer: (A)

Emergency Descent Mode is a protective, automated response to loss of pressurization. It is designed to rapidly reduce cabin altitude to a breathable level by taking control of the descent, but it relies on the autopilot to execute that descent smoothly. The system triggers only when the autopilot is engaged and the cabin altitude climbs above about 20,000 feet. At that point, continuing manual control would be slower and risk hypoxia, so EDM steps in to descend to a safer altitude automatically. If the autopilot isn’t on, EDM won’t engage on its own. It also wouldn’t activate at low cabin altitude or during normal cruise because those conditions don’t present the same pressurization risk. Once engaged, it flies a controlled descent to reach a safe altitude with breathable cabin air, after which the crew can assume manual control and continue the approach.