Definition
Describing an airplane equipped with one powerplant (engine). Used to classify aircraft for training, certification, and operational purposes, and to distinguish them from multi-engine airplanes which have two or more engines.
Plain English
An airplane that has just one engine.
Context Anchor
Seen in airplane descriptions, training discussions, and handbook sections about how an airplane handles, stalls, climbs, glides, or recovers using power.
Why Pilots Care
Determines the specific emergency procedures, performance data, and pilot certification requirements that apply when the single power source fails.
Intuition Check
Do not read single-engine as meaning simple, small, or easy to fly. It only tells you the airplane has one engine.
Example Sentence 1
Most primary flight training is done in a single-engine airplane such as a Cessna 172 or Piper Cherokee.
Example Sentence 2
Single-engine pilots practice engine-out landings as a standard part of their training.