Definition
The Approach End of Runway (AER) is the threshold of the runway being used for takeoff or landing — that is, the end of the runway nearest the aircraft on approach, or the end from which a departing aircraft begins its takeoff roll. In departure procedure design, the AER is the reference point from which climb gradients, distances, and obstacle clearance calculations begin.
Plain English
The start of the runway you are using — where landing aircraft first touch down, or where departing aircraft begin rolling. It's the point distances and climb requirements are measured from.
Context Anchor
Seen in instrument procedure and departure procedure diagrams where runway reference points are used to describe obstacle-clearance surfaces or procedure design.
Why Pilots Care
Establishes the exact starting point for climb gradients and required obstacle clearance on departures.
Intuition Check
“Approach end” does not simply mean the end you are flying toward in a casual sense. In this context, it means the runway’s landing-threshold end for a specific runway direction.
Example Sentence 1
The departure procedure required a climb gradient of 250 feet per nautical mile measured from the AER.
Example Sentence 2
Identify the AER on the airport diagram before applying the published departure instructions.