Definition
A descent gradient expression meaning the aircraft loses 300 feet of altitude for every 1 nautical mile of forward distance flown. It is one way of describing the slope of a descent path, commonly used when planning or evaluating the rate of descent required on a nonprecision approach segment.
Plain English
For each mile you fly forward, you go down 300 feet. It's a way of stating how steep the descent needs to be.
Context Anchor
Seen when calculating or checking descent rates for a stable descent on a nonprecision instrument approach.
Why Pilots Care
Allows pilots to calculate a steady descent that keeps the aircraft on the published glidepath without overshooting or undershooting the runway.
Analogy
It is like saying a road drops 300 feet for every mile you drive forward. The number describes the slope, not just a single height or distance.
Grounding Statement
Picture the airplane moving one nautical mile closer to the runway while the altimeter shows about 300 feet less altitude.
Intuition Check
Do not read “300 feet to 1 NM” as a location or a limit. Here, “to” means “for every”: about 300 feet of descent for each 1 nautical mile traveled.
Example Sentence 1
The chart showed a descent gradient of 300 feet to 1 NM, so at a groundspeed of 90 knots the pilot set up a descent of about 450 feet per minute.
Example Sentence 2
The pilot adjusted the descent to maintain 300 feet to 1 NM after the FAF to reach the MDA at the correct point.