Definition
A unit of speed expressing the number of feet an object travels in one second. In aviation performance work, fps is used when calculations require speed in consistent units with other terms measured in feet, such as radius of turn or rate of climb derivations.
Plain English
How many feet something moves in one second. If a plane is going 100 feet per second, it covers 100 feet of ground (or air) every second.
Context Anchor
Seen in performance and maneuvering calculations, such as radius-of-turn discussions where speed must be placed into a formula using feet and seconds.
Why Pilots Care
Most cockpit speeds are shown in knots or miles per hour, but turn-radius and similar formulas use fps. Knowing how to convert keeps the math honest. A handy rule: knots × 1.69 ≈ fps.
Intuition Check
Do not treat fps as the same as knots. fps is feet traveled each second; knots are nautical miles traveled each hour.
Example Sentence 1
To calculate the radius of turn, the pilot first converted the airspeed from knots to fps.
Example Sentence 2
The formula used fps to calculate the radius required for a standard-rate turn.