Casualties unknown

Pilot Veers Off Highway After Traffic Encounter During Canyon Emergency Landing Attempt (N4016F)

Ten Sleep, WY, US

On August 9, 1986, a Cessna 172 (registration N4016F) operated by John W. Dunn was involved in an aviation accident near Ten Sleep, WY. 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 2026-07-04Data APIEditorial standards

A pilot, lost and disoriented, attempted to land on a highway at 7,500 feet MSL after entering a narrow canyon in a mountain pass. On short final, vehicular traffic forced a veer-off, leading to impact with steep, rocky terrain.

Incident Overview

A pilot, having become lost and disoriented, inadvertently entered a narrow canyon within a mountain pass. As the aircraft progressed, it became apparent that the climb rate was insufficient to clear rapidly rising terrain, and reversing course within the confined space was not feasible. The pilot then attempted to land on a public highway at an elevation of 7,500 feet MSL.

Sequence of Events

During the approach, on short final, the pilot observed vehicular traffic approaching from around a switchback curve on the highway. In response, the pilot veered off the roadway. The aircraft subsequently impacted steep, rocky terrain adjacent to the highway.

Environmental Context

The incident occurred in a mountainous area characterized by narrow passes and canyons. The highway served as a potential landing site but was compromised by unexpected traffic. The terrain off the highway consisted of steep, rocky slopes.

Investigation Findings

No probable cause has been stated in the official report. The investigation determined that the pilot was lost and disoriented prior to entering the canyon, which led to the attempted highway landing. The presence of vehicular traffic necessitated the diversion from the landing area.

All Cessna 172 accidents →

Frequently asked questions

What happened in the 9 Aug 1986 Cessna 172 accident near Ten Sleep, WY?

A pilot, lost and disoriented, attempted to land on a highway at 7,500 feet MSL after entering a narrow canyon in a mountain pass. On short final, vehicular traffic forced a veer-off, leading to impact with steep, rocky terrain.

What aircraft was involved and where did it happen?

The accident on 9 Aug 1986 involved a Cessna 172, registration N4016F, operated by John W. Dunn, at Ten Sleep, WY.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X34447. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.