Definition

An event occurring during an approach to landing that results in an inadvertent landing or contact with the ground or an object short of the runway or intended landing area. Normally undershoots occur due to misjudgment of distance, speed, and/or altitude on final approach. It does not include occurrences in which the aircraft could not have reached the intended landing area; i.e., after loss of engine power. The undershoot distance is described by the longitudinal distance by which the aircraft undershoots the intended runway approach end.

Source: ACRP Report 3: Analysis of Aircraft Overruns and Undershoots for Runway Safety Areas