NTSB Factual Report

On June 6, 2002, about 1845 Alaska daylight time, a skid-equipped Robinson R-44 helicopter, N7130G, was destroyed by fire after landing about 5 miles east of Galena, Alaska. The helicopter was being operated as a visual flight rules (VFR) on-demand passenger flight under Title 14, CFR Part 135, when the accident occurred. The helicopter was operated by Quicksilver Air Inc., Fairbanks, Alaska. The commercial certificated pilot, and two ground personnel, were not injured. Visual meteorological conditions prevailed. VFR company flight following procedures were in effect.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on June 7, the director of operations for the operator reported the pilot landed in an area of brush/grass to pick up two passengers who had been conducting a ground survey. The pilot stayed at the controls of the helicopter, and reduced the engine rpm to 70 percent as the ground personnel were loading their equipment into external baskets on the helicopter. The pilot told the director of operations that he smelled smoke, and the passengers noticed flames under the helicopter. The director of operations said that the pilot attempted to regain full engine rpm to lift-off from the landing area, but was unable to do so because the engine quit. The pilot exited the helicopter, and along with the ground personnel, attempted to extinguish the flames on the ground. They were unsuccessful, and the pilot attempted to restart the helicopter. It would not start. The fire consumed the helicopter, and about 60 acres of brush/grass.

According to statements provided by the ground personnel, they indicated that after the helicopter landed, they began to load packs and a chain saw while the pilot remained at the controls. The ground personnel reported that the chain saw had not been used in the previous hour, and the engine was cold. The ground cover was described as dry, knee-high tussock grass. The engine was running and rotors were turning. Within 30 seconds to one minute after landing, flames were observed under the rear of the helicopter. The ground personnel indicated that the pilot attempted to regain full power to lift off, but the engine quit. The pilot exited the helicopter and attempted to put the fire out. The pilot reentered the helicopter and tried to restart the engine, but was unsuccessful. All three persons removed their packs from the helicopter and moved away from the spreading fire.

The Robinson R-44 helicopter's carbureted engine is positioned aft of the main cabin and is partially enclosed by cowling and structure. The engine's exhaust system consists of exhaust tubing from the engine cylinders, routed into a laterally mounted muffler, out of which is an exhaust pipe. The exhaust system is positioned at the rear and bottom portion of the aft fuselage. The underside of the engine area is open, allowing cooling-fan air to exit aft and downward, around the muffler and exhaust. The bottom of the muffler, at the rear area of the engine compartment is about 19.5 inches above the ground. The exhaust pipe, routed through the rear bulkhead of the engine compartment, exits the aft end of the fuselage about 27 inches above the ground.

The pilot/operator manual for the helicopter contains a safety advisory that states, in part: "Never land in tall dry grass. The exhaust is low to the ground and very hot; a grass fire may be ignited."

NTSB Probable Cause

The pilot's selection of unsuitable terrain for landing which precipitated a grass fire. Factors contributing to the accident were the manufacturer's inadequate design of the helicopter's exhaust system, placing it low to the ground, and terrain conditions consisting of dry tussock grass.