Definition
The runway length declared available and suitable for the landing ground run of an aircraft, measured from the threshold (or displaced threshold, if applicable) to the end of the usable landing surface. It is used in the context of Land and Hold Short Operations (LAHSO), where ALD is the distance from the landing threshold to the hold-short point on the runway.
Plain English
The amount of runway you actually have to land on and stop, especially when air traffic control asks you to land and stop short of an intersecting runway or taxiway.
Context Anchor
You will see ALD in airport and ATC information connected with Land and Hold Short Operations, especially when deciding whether you can accept a clearance to land and stop before a specific point.
Why Pilots Care
Confirms whether the runway meets the aircraft's landing distance needs before touchdown.
Intuition Check
Do not assume Available Landing Distance means the full runway length. In this use, it means only the measured distance from the landing threshold to the hold-short point.
Example Sentence 1
Tower issued a LAHSO clearance with an ALD of 4,500 feet, which was well within our aircraft's required landing distance for the conditions.
Example Sentence 2
A tailwind increased the required landing distance, making the published ALD the deciding factor for the approach.