Casualties unknown

1991-09-17: Aeronca 7DC (N9654H) — Steven G. Joachim — Yellow Pine, ID

Yellow Pine, ID, US

On September 17, 1991, an Aeronca 7DC (registration N9654H) operated by Steven G. Joachim was involved in an aviation accident near Yellow Pine, ID. Investigators recorded the probable cause as: The pilot's inadvertent entry into a box canyon with rising terrain that exceeded the aircraft's climb capability at a high density altitude. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

A pilot inadvertently entered a box canyon with rising terrain that exceeded the aircraft's climb capability at a density altitude of approximately 7600 feet, resulting in a crash into trees.

What happened

The pilot was operating an aircraft from a remote strip located within mountainous terrain. Following takeoff, the pilot inadvertently entered a box canyon. The terrain within the canyon rose rapidly, creating conditions that exceeded the climb capability of the aircraft given the environmental factors.

Due to the inability to gain sufficient altitude to clear the rising ground, the aircraft impacted trees and was subsequently destroyed. The density altitude at the site of the accident was approximately 7600 feet, which likely contributed to the reduced performance of the aircraft in the high-altitude environment.

The investigation

The investigation focused on the flight path and environmental conditions at the time of the accident. Key findings included the box canyon topography and the density altitude of 7600 feet. The terrain profile was identified as the primary constraint on the aircraft's ability to continue the climb.

Findings

The primary factor in this accident was the climb capability limitation of the aircraft relative to the rising terrain. The combination of high density altitude and confined canyon geography prevented the pilot from maintaining a safe flight path. No mechanical failure or pilot error other than the inadvertent entry into the canyon was identified as a contributing cause.

Safety message

Pilots operating in mountainous terrain should be aware that remote strips may have limited options for escape or diversion. Understanding density altitude and its effect on aircraft performance is critical when flying in confined valleys or canyons where rising terrain can quickly exceed climb limits.

Probable cause

The pilot's inadvertent entry into a box canyon with rising terrain that exceeded the aircraft's climb capability at a high density altitude.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X18203. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.