Plain English Meaning

If one engine quits in a twin, VYSE is the speed that lets the airplane climb the most feet in the shortest amount of time on the remaining engine. It is the speed you fly to gain altitude fastest after losing an engine.

Full Definition

VYSE is the airspeed that produces the greatest gain in altitude per unit of time when a multi-engine airplane is operating with one engine inoperative, at maximum gross weight and sea level conditions. It is published in the Pilot's Operating Handbook and is marked on the airspeed indicator of most twin-engine airplanes by a blue radial line, which is why pilots commonly call it 'blue line' speed.

Context Anchor

Seen in multiengine airplane , , , and on the airspeed indicator as the blue-line speed.