Definition
A standard climb gradient expressing 1,000 feet of altitude gained for every nautical mile of horizontal distance flown. It is the minimum climb gradient assumed for a standard instrument departure unless the procedure specifies a higher value.
Plain English
For every nautical mile you travel forward over the ground, you must climb at least 1,000 feet upward. It is a slope, not a rate -- it ties altitude gained to distance covered, not to time.
Context Anchor
Seen on instrument procedure charts and in discussions of required climb or descent gradients.
Derivation
The notation reads 'one thousand feet per nautical mile.' 'Per' (the slash) means 'for each.' So the figure describes a ratio: feet of climb for each unit of distance traveled.
Why Pilots Care
Ensures required obstacle clearance is achieved during climbs in instrument conditions.
Analogy
It is like saying a road rises 1,000 feet for every mile you drive. The number describes the steepness of the path, not how fast you are driving.
Grounding Statement
Picture a runway extending 1 NM ahead of you; by the time you reach that point on the ground, you must be 1,000 feet above where you started.
Intuition Check
Do not read 1000 ft/NM as 1,000 feet per minute. It is 1,000 feet per nautical mile, so it depends on distance traveled, not time.
Example Sentence 1
The departure procedure required a climb gradient of 1,000 ft/NM to 3,500 feet, so the pilot calculated whether the aircraft could meet it at the planned takeoff weight.
Example Sentence 2
The aircraft maintained 1000 ft/NM to provide terrain clearance over the ridge.