In the event of engine failure above the OEI ceiling, what is the best speed for a twin-engine jet airplane to descend?

In the event of engine failure above the single-engine out-climb (OEI) ceiling, the optimal speed for a twin-engine jet airplane to descend is indeed the best angle of climb speed. This speed maximizes the aircraft's horizontal distance covered during the descent, which is critical for safety and operational efficiency.

The best angle of climb speed (often denoted as Vx) allows the aircraft to achieve the maximum altitude gain for the distance traveled, which is particularly advantageous in situations where the aircraft must maintain control and navigate safely, especially during an emergency descent. At this speed, the aircraft is able to maintain the best performance in terms of lift-to-drag ratio while still ensuring stable flight characteristics.

In scenario emergencies such as an engine failure, the goal is to control the aircraft and manage the descent effectively, which is why this speed is the preferred choice. It allows for better handling and control while maximizing the distance covered per unit of altitude lost, thus enhancing the chances of a safe recovery or controlled landing.