Definition
The initial portion of the available landing runway, measured from the threshold to a point one-third of the runway's total usable length. In flight training, it is the target touchdown zone for normal landings, indicating that the aircraft has been brought to the runway with appropriate energy management and approach accuracy.
Plain English
The first one-third of the runway, measured from the start where you cross the threshold. It is the area where a well-flown landing should touch down.
Context Anchor
Used during landing training, especially when deciding whether a landing is stabilized and whether there is enough runway left to land safely.
Why Pilots Care
Touching down here leaves the longest possible runway remaining for safe deceleration and reduces the chance of a runway overrun.
Grounding Statement
Picture the runway divided into three equal parts from the landing end to the far end; the first part is the first third of the runway.
Intuition Check
Do not measure the first third from wherever the airplane happens to be over the runway. Measure it from the landing threshold, in the direction you are landing.
Example Sentence 1
The instructor reminded the student that a normal landing should touch down within the first third of the runway, not float halfway down it.
Example Sentence 2
Touching down past the first third leaves less runway for braking and increases the risk of going off the end.