Definition
Rate of Climb is the vertical speed at which an aircraft gains altitude, expressed in feet per minute (fpm). It is the result of excess power available beyond what is required to maintain level flight at a given airspeed and configuration.
Plain English
How fast the aircraft is going up, measured in feet per minute. If your ROC is 500 fpm, you are gaining 500 feet of altitude every minute.
Context Anchor
Seen in climb performance discussions, takeoff planning, and cockpit instruments that show how quickly the airplane is gaining altitude.
Derivation
Rate' comes from Latin 'ratus' meaning a reckoned or fixed amount; 'climb' comes from Old English 'climban' meaning to ascend. The combination names the measured upward speed.
Why Pilots Care
It tells the pilot whether the aircraft can clear terrain or obstacles and is essential for safe departure and go-around planning.
Analogy
ROC is like a speed reading for upward movement instead of forward movement.
Intuition Check
ROC is not how steep the airplane’s path looks. It is how much altitude the airplane gains over time.
Example Sentence 1
At full power and best rate of climb speed, the aircraft showed a steady ROC of 700 feet per minute on the VSI.
Example Sentence 2
On the missed approach the aircraft established a positive rate of climb before the pilot called for gear retraction.