Definition
A sudden increase or decrease in the speed of the aircraft through the air, occurring quickly enough to be felt by the pilot and reflected by an immediate movement of the airspeed indicator needle. In instrument flying, such a change is treated as a flight cue indicating an unintended pitch or power deviation that requires correction.
Plain English
The airplane's speed through the air is changing fast enough that you can see the airspeed needle moving noticeably, not just drifting slowly.
Context Anchor
Seen in airspeed indicator discussions, especially when learning how the instrument responds while the aircraft is accelerating, slowing down, or changing configuration.
Why Pilots Care
Signals possible wind shear or severe turbulence that can affect aircraft control and performance.
Analogy
It is like a car speedometer during hard acceleration: the number is moving because the car is changing speed, so you watch the trend and let it settle instead of reacting to every tiny movement.
Grounding Statement
Picture lowering the nose or reducing power: the airplane’s speed changes quickly, and the airspeed indication may move before it becomes steady again.
Intuition Check
Do not read this as simply “high airspeed.” A rapid change in airspeed means the speed is changing quickly, either faster or slower.
Example Sentence 1
A rapid change in airspeed during level flight usually means the pilot has unintentionally let the nose pitch up or down.
Example Sentence 2
Turbulence caused a rapid change in airspeed that the pilot corrected with power adjustments.