Multi Engine Terminology

CRITICAL ENGINE
The engine that if failed will have the most adverse affect on the control and performance of the aircraft.
A Breakdown of the Critical Engine...

Vmc
The speed at which the rudder no longer has the authority to overcome the yaw caused by the critical engine being inoperative, under specific criteria.
A Breakdown of Vmc...

ACCELERATE STOP DISTANCE
The distance required to accelerate to rotation speed, and assuming an engine failure at rotation, bring the aircraft to a stop. This is the maximum runway required for an aborted takeoff since an engine failure after rotation will be handled airborne.

ACCELERATE GO DISTANCE
The distance required to accelerate to rotation speed, and assuming an engine failure at rotation, climb to 35’ above the departure end.

SERVICE CEILING
The density altitude which will produce a 100 foot per minute climb when flying in a clean configuration, at the best rate of climb airspeed with both engines at maximum continuous power.

SINGLE ENGINE SERVICE CEILING
The density altitude which will produce a 50 foot per minute climb when flying in a clean configuration, at the best rate of climb airspeed with one engine at maximum continuous power and the other engine feathered.

ABSOLUTE CEILING
The highest altitude at which an airplane can sustain level flight with both engines operating (this altitude will never be reached in flight except during flight testing).

SINGLE ENGINE ABSOLUTE CEILING
The highest altitude at which an airplane can sustain level flight with one engine operating. This altitude will only be reached if flying above the single engine absolute ceiling when the engine is lost and the aircraft drifts down to the SE absolute ceiling.

CRITICAL ALTITUDE
The maximum altitude under standard atmospheric conditions at which a turbocharged engine can produce its rated horsepower. Above this altitude, the engine‘s performance will begin to decrease.

Vyse
The best rate of climb airspeed during single engine operations.

Vsse
The safe single engine speed. It is unsafe to intentionally fail an engine below this airspeed.