Casualties unknown

Helicopter Loses Power After Pikes Peak Takeoff, Collides with Trees and Rolls Over; Fuel Contaminants Found in Post-Accident Analysis (N99TV)

Cascade, CO, US

On September 8, 1994, an Eurocopter AS-350-B2 (registration N99TV) was involved in an aviation accident near Cascade, CO. Investigators recorded the probable cause as: A POWER LOSS DUE TO CONTAMINATED FUEL FROM AN UNKNOWN SOURCE THAT CLOGGED THE FUEL FILTER AND INTERNALLY DAMAGED THE FUEL CONTROL UNIT. A FACTOR WAS UNSUITABLE TERRAIN FOR A FORCED LANDING. 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

Shortly after takeoff from Pikes Peak, a helicopter's engine lost power. The pilot autorotated but the helicopter collided with trees and rolled over. Post-accident fuel samples contained visible contaminants including filter material and metallic particles.

Accident Details

A helicopter experienced a loss of engine power shortly after takeoff from the summit of Pikes Peak. The pilot executed an autorotation straight ahead, but the aircraft collided with trees and subsequently rolled over.

Post-Accident Examination

Fuel samples taken after the accident were found to contain visible contaminants. Laboratory analysis identified the contaminants as filter material and particles of metal, glass, sand, and plastic. The metallic particles were composed of copper, iron, nickel, and chromium.

During post-accident testing, the fuel control unit (FCU) was unable to attain the target fuel flow. Disassembly of the FCU revealed a clogged amplifier piston filter, a scored isochronous piston, and a collapsed temperature compensator.

Manufacturer Assessment

According to the engine manufacturer, the presence of fuel contaminants could disturb FCU operation. The manufacturer further stated that the scored piston was "evidence of an operation with polluted fuel."

Origin of Contaminants

The source of the contaminants was not determined. No reports of fuel contamination were received from other pilots who used the same fuel vendor.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001206X02236. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.