THE FOLLOWING EXCERPT IS FROM A FAA PAMPHLET
FLYING LIGHT TWINS SAFELY
The major difference between flying a twin-engine and a single-engine airplane is knowing how to manage
the flight if one engine loses power for any reason. Safe flight with one engine out requires an
understanding of the basic aerodynamics involved-as well as proficiency in engine-out procedures.
LOSS OF POWER ON ONE SIDE
Loss of power from one engine affects both climb performance and controllability of any light twin.
Climb performance depends on an excess of power over that required for level flight. Loss of power from
one engine obviously represents a 50% loss of power, but in virtually all light twins climb performance is
reduced by at least 80%. (See Figure E-1.)
The amount of power required for level flight depends on how much drag must be "overcome" to sustain
level flight. It is obvious if drag is increased because the gear and flaps are down and the prop
windmilling, more power will be required. Not so obvious, however, is the fact drag also increases at the
square of the airspeed while power required to maintain that speed increases as the cube of the airspeed.
(See Figure E-2.)
Climb performance depends on four factors:
Airspeed-too little or too much will decrease climb performance.
Drag-gear, flaps, cowl flaps, prop and speed.
Power-amount available in excess of that needed for level flight.
Weight-passengers, baggage and fuel load greatly affect climb performance