An unstable approach is an approach during which an aircraft does not maintain certain essential flight parameters within reasonable limits.^[1][2] This usually includes at least one of the following variables stable: speed, descent rate, vertical/lateral flight path and in landing configuration, or receive a landing clearance by a certain altitude. Unstabilized approaches account for most approach and landing accidents. For this reason, an approach should be stabilized by 1,000 feet (305 m) above runway altitude. Otherwise, a go-around should be executed by the pilot.

For example, the 2016 Magdalen Islands Mitsubishi MU-2 crash was blamed on an unstabilized approach.^[3]