Casualties unknown

Pilot Reports Downdraft Encounters and Power Loss During Takeoff from Gravel Airstrip (N4062H)

Chickaloon, AK, US

On June 14, 2003, a Longren CENTAUR L-13 (registration N4062H) operated by Ben Stevenson was involved in an aviation accident near Chickaloon, AK. Investigators recorded the probable cause as: The loss of engine power during the takeoff initial climb for an undetermined reason, which resulted in an in-flight collision with water. 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 2026-06-10Data APIEditorial standards

A pilot attempting takeoff from a gravel airstrip after a thunderstorm reported encountering downdrafts, touching down on river sandbars, and eventually nosing over in the river. The pilot later noted a mysterious loss of power.

Accident Sequence

According to a telephone interview conducted the day after the accident, the pilot waited on a gravel airstrip for a thunderstorm and associated rain to pass before attempting a takeoff. During the takeoff roll, the pilot reported calm winds. However, during the initial climb, the airplane encountered a downdraft and descended, touching down on a sandbar in a river adjacent to the airstrip. The airplane started to climb again, but was forced down by another downdraft, touching down on another sandbar. After a third attempt to climb, the airplane was forced down into the river, where it nosed over.

Pilot Statements

In a subsequent written statement, the pilot wrote, "in retrospect, it appears there was a mysterious loss of power." The pilot further noted that two witnesses stated there was little or no wind, and that the airplane sounded like a normally powered takeoff, but the sound quickly dwindled, as if the throttle was pulled back to abort the takeoff. The pilot's written statement did not provide further explanation for the loss of power.

Environment

The accident occurred on a gravel airstrip near a river. A thunderstorm and associated rain had passed shortly before the takeoff attempt. Winds were reported as calm by the pilot during the takeoff roll, and witnesses described little or no wind at the time.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20030618X00904. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.