What happens when the left engine flames out at FL270 with AP/AT engaged in speed mode?

When the left engine flames out at FL270 with the autopilot (AP) and autothrottle (AT) engaged in speed mode, selecting engine out mode is crucial for effective response and management of the situation. In this scenario, the autothrottle is designed to maintain a specific airspeed, and the loss of engine power would significantly affect the aircraft's ability to maintain that speed.

By selecting engine out mode, the autothrottle adjusts its parameters to account for the asymmetric thrust condition created by the loss of one engine. This adjustment helps to stabilize the aircraft and allows the pilot to control the airplane more effectively using the remaining engine. Hence, engaging the engine out mode is essential for managing the engine failure situation optimally.

In this case, if the pilot does not select the engine out mode, the autothrottle might not compensate appropriately for the lost thrust, leading to potential issues with aircraft control and performance. This highlights the importance of pilot intervention in configuring the aircraft systems correctly after an engine failure, which ultimately aids in ensuring safety and stabilizing flight.