Definition
A height measurement taken from the surface of the ground directly beneath the aircraft, rather than from sea level. An aircraft at 1,000 feet AGL is one thousand feet above the terrain it is currently flying over.
Plain English
How high you are above the ground right below you. If the ground rises, your AGL height drops, even if the aircraft hasn't climbed or descended.
Context Anchor
Seen in airspace descriptions, weather reports, obstacle information, and altitude limits where the height above the local ground matters.
Why Pilots Care
Pilots use AGL to confirm they are meeting terrain clearance and regulatory altitude limits, especially when flying under instrument flight rules.
Analogy
AGL is like measuring how high a ceiling is above the floor you are standing on, not how high that ceiling is above sea level.
Grounding Statement
If an aircraft is 1,000 feet AGL, it is about 1,000 feet above the ground in that area.
Intuition Check
Do not assume AGL means the altitude shown on the altimeter. AGL means height above the local ground; an altimeter normally shows height referenced to sea level when set correctly.
Example Sentence 1
The standard traffic pattern altitude at most airports is 1,000 feet AGL.
Example Sentence 2
We maintained 800 feet AGL until reaching the final approach fix.