Definition
A power-control concept in instrument flying which states that as the airspeed (A/S) approaches the value the pilot wants, the throttle (power) becomes the primary instrument control used to capture and hold that target airspeed. In level flight at a constant altitude, once airspeed has nearly stabilized at the desired figure, small power adjustments — rather than pitch changes — are used to fine-tune and maintain it.
Plain English
When the airspeed is getting close to the number you want, use the throttle to settle it onto that exact speed. Power becomes the main tool for nailing the target airspeed at the end of the change.
Context Anchor
Seen in instrument flying diagrams that show which control becomes most important during an airspeed change.
Why Pilots Care
Prevents over-controlling pitch near the target airspeed, reducing altitude excursions and stabilizing the aircraft more smoothly.
Grounding Statement
Picture reducing or adding power just before the airspeed needle reaches the target number so the needle stops on that number instead of drifting through it.
Intuition Check
“Primary” does not mean power is the only control being used. It means power is the main control to watch and adjust for airspeed at that moment.
Example Sentence 1
As the airspeed neared 90 knots, the instructor reminded the student that power was now primary for capturing the target speed, so only small throttle adjustments were needed.
Example Sentence 2
In level cruise, once airspeed stabilizes near the desired value, primary power keeps the speed constant without constant attitude changes.