Definition
The rate at which a freely falling object speeds up as it falls toward the Earth, equal to approximately 32.2 feet per second per second (9.81 meters per second per second) at sea level. This value is represented by the symbol g and is used as the standard reference for measuring G-forces in flight.
Plain English
Gravity pulls everything toward the Earth, and as something falls, it speeds up. Each second it falls, it goes about 32 feet per second faster than the second before. That rate of speeding up is what this term describes, and it's the baseline pilots use to talk about the forces they feel in maneuvers.
Context Anchor
Seen in basic aerodynamics, aircraft performance, weight, and discussions of g forces in turns or maneuvers.
Derivation
From Latin accelerare, 'to hasten,' and gravis, 'heavy.' Acceleration means a change in speed over time, not just speed itself. Knowing that helps the term make sense: it isn't how fast something falls, it's how quickly that fall keeps getting faster.
Why Pilots Care
It forms the reference for weight, lift requirements, rate of descent, and load-factor calculations in all phases of flight.
Analogy
If you drop a ball, it does not fall at one steady speed. It keeps speeding up as gravity pulls it downward; that speeding up is acceleration caused by gravity.
Grounding Statement
Drop a wrench from a hover: after one second it's falling at about 32 feet per second; after two seconds, about 64 feet per second. That steady increase is acceleration caused by gravity.
Intuition Check
Do not read this as just “gravity” or just “falling.” The key idea is the rate at which gravity makes speed increase.
Example Sentence 1
The load factor felt during a steep turn is measured in multiples of the acceleration caused by gravity.
Example Sentence 2
In a level turn the wings must produce extra lift to offset both the aircraft weight and the acceleration caused by gravity.