Accident Overview
On October 25, 2009, at approximately 1733 central daylight time, a Bell 206B-3 helicopter, registration N57PH, operated by Provine Helicopter Service, Inc., was destroyed after a forced autorotation following a total loss of engine power near Eupora, Mississippi. The certificated commercial pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the aerial application flight conducted under 14 CFR Part 137.
Flight Details
The pilot performed a preflight inspection of the helicopter at about 0700. He drained approximately one quart of Jet-A fuel to check for water and contaminants, finding the fuel clean and free of water. The helicopter initially would not start, prompting the pilot to contact the company's mechanic, who performed maintenance that morning. Afterward, the helicopter was fueled with 16.7 gallons of Jet A. Around 1300, the pilot departed to the job site, a tract of land to the northeast, for aerial application flights.
The pilot began applications about 1400, treating approximately 115 acres with about 1,725 gallons of herbicide before the accident. During the operation, the helicopter was refueled three to four times, each with about 15 gallons of Jet-A fuel from a fuel truck located at the application site. The fuel truck also carried herbicide in a separate tank. After refilling the spray tank with approximately 90 gallons of herbicide, the pilot began his first turn at the edge of the land tract when the engine "completely lost power." The pilot radioed that he was "going down and needed help" and attempted to guide the helicopter to a clearing. He stated that the rotor "stopped turning completely" approximately 50 feet above the ground, after which the helicopter dropped "straight down" and landed on its skids.
Ground Support
A member of the ground crew, who drove the fuel truck and serviced the helicopter with fuel and herbicide, stated that he began his day with a pre-trip inspection of the truck shortly after 0500. He drained about one-half gallon of Jet-A fuel from the 500-gallon fuel tank and inspected it with a flashlight, repeating the procedure with about a quart from the fuel filter. Both samples showed no water or debris. Later, after learning of the pilot's starting difficulties, the crewman again drained samples from the fuel tank and filter, again noting no debris.
Examination Findings
A Federal Aviation Administration (FAA) inspector reported that the helicopter came to rest upright with extensive crush damage to the fuselage.
A fuel sample obtained from the airframe fuel filter contained a mixture of fuel and a brown contaminant. When placed in a jar, the contaminant and fuel separated, with the contaminant settling to the bottom. Similar brown contaminant was observed in the engine fuel pump filter, the fuel control unit screen, and the engine fuel nozzle screen.
The fuel truck, owned by the operator, had a 500-gallon fuel tank at the forward end and a tank for mixing water and spray chemical at the aft end. A common trough ran along the top of both tanks, designed to retain over-fill of water or fuel, with two small drain holes at the forward end. Examination of the fuel tank cap revealed that the o-ring seal and the fuel vent were deteriorated, and the seals were not continuous. The fuel tank was configured so that fuel was taken directly from the lowest point and pumped through a filter to the fuel filler hose; no standpipe prevented collected water from entering the filter, and no pressure gauges were installed before or after the filter.
Water was detected in the truck-based fuel tank using water-finding paste on a dip stick. The fuel filter between the tank and delivery hose was removed and found to have a "bulged" element with water present. The brown contaminant was present throughout the paper folds of the filter and collected along its interior.
According to the operator, the fuel truck's Jet-A fuel tank was last serviced with 198 gallons of fuel from the operator's fueling station the day before the accident.
Pilot Information
The pilot held a commercial pilot certificate with a helicopter rating and reported approximately 2,600 hours in the accident helicopter make and model. His most recent second-class FAA medical certificate was issued in February 2008.
Weather Conditions
The nearest weather reporting station, approximately 45 nautical miles from the accident location, reported clear skies, 10 statute miles visibility, and calm winds around the time of the accident.