Definition
The buffer of airspeed, altitude, or aircraft performance held in reserve above the minimum required to keep the airplane flying safely under current conditions. In stall awareness, it specifically refers to the airspeed cushion above stall speed that protects the airplane from an inadvertent stall during maneuvering, configuration changes, or gusty conditions.
Plain English
The cushion you keep between how the airplane is flying right now and the point where something bad would happen. The bigger the cushion, the more room you have to react if something changes.
Context Anchor
You will see this term in stall awareness, slow flight, approach, and maneuvering discussions, especially when the handbook is explaining why a pilot should avoid flying too close to stall conditions.
Derivation
Margin comes from a word meaning edge or border. Safety means being protected from harm. Together, margin of safety means the space you keep between normal operation and the dangerous edge.
Why Pilots Care
An adequate margin prevents loss-of-control accidents that occur when pilots allow airspeed to decay too close to stall speed during maneuvering or approach.
Analogy
It is like not walking right along the edge of a drop-off. You leave some space so a small mistake or gust of wind does not immediately put you in danger.
Intuition Check
Do not read margin of safety as a guarantee that nothing can go wrong. Here it means a practical buffer: extra room between how the airplane is flying now and the point where it could stall.
Example Sentence 1
Adding a few extra knots on final in gusty wind preserves the margin of safety above stall speed.
Example Sentence 2
During steep turns the pilot watched the airspeed indicator to preserve at least a fifteen-knot margin of safety above stall.