Casualties unknown

1985-01-09: Fairchild Hiller FH-1100 (N5056F) — Gulkana Air Service — Glennallen, AK

Glennallen, AK, US

On January 9, 1985, a Fairchild Hiller FH-1100 (registration N5056F) operated by Gulkana Air Service was involved in an aviation accident near Glennallen, AK. Investigators recorded the probable cause as: The pilot's inability to maintain control due to downdrafts and variable wind gusts while attempting to hover on upsloping terrain. 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 1781061362Data APIEditorial standards

A helicopter experienced difficulty hovering due to downdrafts and variable wind gusts shortly after liftoff, causing it to settle onto upsloping terrain and roll over.

What happened

Shortly after liftoff, the pilot encountered significant downdrafts and variable wind gusts. The pilot decided to set the helicopter back down approximately 100 yards from the point of takeoff. Hovering proved very difficult under these conditions, and the helicopter settled onto upsloping terrain. The aircraft slid to the right, down the slope, and rolled over. A fire erupted from the engine after impact, destroying the helicopter.

The investigation

The investigation focused on the immediate environmental factors and mechanical response during the incident. The pilot reported that hovering was extremely difficult due to the weather conditions. The helicopter's movement was influenced by the terrain, sliding to the right and rolling over before the fire began.

Findings

The primary contributing factor was the variable wind gusts and downdrafts encountered shortly after takeoff. These conditions made hovering difficult and led to the loss of control as the aircraft settled on the upsloping terrain. The helicopter was destroyed by impact and subsequent fire.

Safety message

Pilots should be aware of the potential for downdrafts and variable wind gusts in certain terrain conditions, which can make hovering difficult and lead to loss of control.

Probable cause

The pilot's inability to maintain control due to downdrafts and variable wind gusts while attempting to hover on upsloping terrain.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001214X35453. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.