Definition
The vertical speed at which an aircraft is losing altitude, expressed in feet per minute (fpm). It is read directly from the vertical speed indicator and is calculated during descent planning by multiplying groundspeed (in nautical miles per minute) by the required descent gradient (in feet per nautical mile).
Plain English
How fast the aircraft is going down, measured in feet per minute. A 500 fpm rate-of-descent means the aircraft is losing 500 feet of altitude every minute.
Context Anchor
Used in instrument descent planning, approach briefings, and cockpit monitoring when deciding whether the airplane is descending fast enough, too fast, or too slowly to meet an altitude target.
Derivation
Rate means an amount of change over time, and descent means moving downward from a higher altitude to a lower altitude. Together, rate-of-descent means how fast the airplane is going downward over time, not just that it is going down.
Why Pilots Care
Controls energy management and ensures compliance with published descent gradients and crossing altitudes.
Grounding Statement
If the altimeter is unwinding quickly, the ROD is high; if it is unwinding slowly, the ROD is low.
Intuition Check
ROD is not the same as forward speed or the steepness of the flight path. It is the downward loss of altitude per minute.
Example Sentence 1
To meet the crossing restriction, the crew calculated a 700 fpm rate-of-descent based on their current groundspeed.
Example Sentence 2
A higher ROD reduced the time spent in icing conditions during the approach.