Definition
On a multi-engine airplane, the technique of applying unequal thrust to the left and right engines to assist with turning the airplane on the ground. Adding power on one side and reducing it on the other produces an asymmetric pull that pivots the airplane in the desired direction.
Plain English
Using more power on one engine than the other to help steer the airplane while taxiing.
Context Anchor
Encountered during ground operations and taxi discussions for multi-engine airplanes, especially when turning in tight spaces or maintaining control at low speed.
Derivation
Differential' comes from the Latin differre, meaning 'to differ' or 'to set apart.' In this context, it simply means the two engines are set to different power levels rather than matched.
Why Pilots Care
It allows tighter, more precise turns on the ground while reducing brake wear and improving control on slippery surfaces.
Analogy
Like paddling harder on one side of a canoe to swing it around.
Intuition Check
Differential power does not mean a special kind of engine power. It means a difference in power between engines on opposite sides of the airplane.
Example Sentence 1
During the tight turn onto the run-up pad, the pilot used a small amount of differential power, adding throttle on the left engine to help the airplane pivot to the right.
Example Sentence 2
During a tight ramp turn, differential power combined with light brake pressure kept the turn smooth and controlled.