Definition
The vertical distance, in feet, between the Minimum Descent Altitude (MDA) on a non-precision instrument approach and the published airport elevation. HAA is used on circling approach procedures and is referenced to the highest point on any usable runway at the airport.
Plain English
How far above the airport's ground level you are when you reach the lowest altitude allowed on a circling approach. It tells you, in feet, how much room you have above the airport itself before you need to see the runway and land.
Context Anchor
Seen on instrument approach charts, especially in the minimums section for circling to land.
Derivation
Formed directly from the descriptive words height, above, and airport to specify the exact reference point for the measurement.
Why Pilots Care
Sets the minimum altitude a pilot must maintain during a circling approach to stay clear of obstacles.
Grounding Statement
On the chart, HAA answers: at the minimum descent altitude, how high are you above the airport elevation?
Intuition Check
HAA does not mean your airplane’s current height above the airport. It is a published chart value that compares the minimum descent altitude to the airport elevation.
Example Sentence 1
The circling minimums on this approach show an MDA of 1,420 feet with an HAA of 543 feet.
Example Sentence 2
The pilot climbed to maintain the required HAA while circling to the runway.