Casualties unknown

1999-07-17: Bell 47G-3B-1 (N4002G) — Sour Lake, TX

Sour Lake, TX, US

On July 17, 1999, a Bell 47G-3B-1 (registration N4002G) was involved in an aviation accident near Sour Lake, TX. Investigators recorded the probable cause as: Engine power loss due to contaminated fuel. 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 commercial helicopter lost engine power during takeoff after being refueled with water-contaminated fuel. The pilot found 20 gallons of water in the fuel tank and a crack in the fueling truck tank.

Incident Overview

A commercial helicopter experienced a loss of engine power during takeoff as a result of contaminated fuel. The pilot performed an autorotation landing.

Pilot's Account

According to the pilot, the fueling truck was inspected the night before the accident. The truck contained separate tanks for water, chemicals, and fuel. At that time, the fuel appeared normal. The following day, prior to the accident flight, the helicopter was refueled without sumping the tanks. During takeoff, the engine lost power at an altitude of about 50 feet above ground and an airspeed of 30 miles per hour.

Emergency Landing

The pilot executed an autorotation to the ground. During the landing, the main rotor blades struck the tail boom, and the tail rotor blades contacted the ground.

Post-Accident Investigation

After the accident, the pilot reported finding 20 gallons of water in the helicopter's fuel tank. Further inspection revealed that the fueling truck had a crack between the water and fuel tanks, which allowed approximately 80 gallons of water to leak into the truck's fuel tank. Additionally, the truck was supposed to be equipped with an aqua stop filter designed to prevent pumping if water was present; however, the wrong filter had been installed.

Probable cause

Engine power loss due to contaminated fuel.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001212X19285. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.