What is a common error when executing the FTI engine failure procedures?

Lowering takeoff flaps at low key is considered a common error during the execution of engine failure procedures because it can significantly affect the aircraft's performance and handling characteristics at a critical phase of flight. The low key position is typically used during traffic pattern operations and represents the point where the aircraft is on a descending leg of the traffic pattern in preparation for landing.

By lowering the flaps too early or at an inappropriate altitude, the pilot may inadvertently disrupt the desired glide slope or airspeed. Flap deployment alters the lift-to-drag ratio and can lead to undesired changes in pitch and airflow over the control surfaces. This could result in a stall or inadequate control of the aircraft during a phase when maintaining optimal glide performance is essential for a successful engine-out landing.

In contrast, delaying flap extension or managing power and altitude during an engine failure is typically more critical to ensure an appropriate approach is maintained. Thus, piloting skills focus on optimal airspeed management, proper flap usage, and effective glide attitude to safely navigate the situation.