Casualties unknown

Light Aircraft Crashes Short of Runway After Encountering Severe Downdraft (N99946)

Boynton Beach, FL, US

On May 4, 1992, a Let L-13 (registration N99946) operated by Willis, B.n. was involved in an aviation accident near Boynton Beach, FL. Investigators recorded the probable cause as: Encounter with a severe downdraft during final approach, which resulted in impact with terrain short of the runway. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive; 1 related events involving the same aircraft type or operator are linked below.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 2026-06-10Data APIEditorial standards

A light aircraft crashed into trees approximately 300 feet short of the runway after encountering a severe downdraft during final approach, despite the pilot's attempt to retract partial spoilers.

What happened

The flight crew initiated a turn to base leg with the aircraft's spoilers partially extended. As the aircraft transitioned to the final approach phase, it encountered a severe downdraft. The pilot attempted to mitigate the descent by retracting the spoilers; however, the downward momentum continued unabated. The aircraft impacted a line of trees approximately 300 feet short of the runway threshold.

The investigation

Examination of the pilot's recent flight history revealed limited experience with the specific make and model of the aircraft. In the 30 days preceding the accident, the pilot had accumulated only three hours of total time in that specific type. This experience was derived from eight dual instruction flights and twelve solo flights.

Findings

The primary factor contributing to the accident was the encounter with a severe downdraft during the critical final approach phase. The aircraft's inability to maintain altitude despite spoiler retraction indicates the intensity of the weather phenomenon relative to the aircraft's performance envelope at that moment.

Probable cause

Encounter with a severe downdraft during final approach, which resulted in impact with terrain short of the runway.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X14707. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.