Accident
On October 28, 2016, at approximately 1240 Pacific daylight time, a Eurocopter S.N.I.A.S. AS350B helicopter, registration N369BD, sustained substantial damage during a forced landing following a loss of engine power near Starbuck, Washington. The commercial pilot, the sole occupant, was not injured. The helicopter was registered to a private individual and operated by Leading Edge Aviation LLC under Title 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which originated from a nearby staging area at 1137.
Pilot Report
According to the pilot, he was making his sixth pass of the fifth application load, traveling upslope from west to east, when the fuel pressure warning light illuminated. He scanned the instruments and observed low fuel pressure and a fuel quantity indication between 40 and 50 percent. About three to four seconds later, the engine began to lose power. The pilot entered an autorotation and set up for a landing in the flattest area he could find in the canyon. He extended the approach to reach a more suitable site, resulting in a hard landing.
Aircraft Damage and Recovery
The helicopter sustained substantial damage to the tailboom and main rotor assembly. During recovery, personnel noted that the fuel tank was intact, undamaged, and void of fuel, but the fuel quantity gauge still indicated 42 percent fuel remaining, which converts to about 60 gallons. The helicopter was recovered from the accident site for further examination.
Examination of Fuel System
Examination of the fuel transmitter revealed that the float guide pin had separated from the float assembly at the tack weld. According to the manufacturer, separation of the float guide pin would allow the float to slide down the center torque shaft and prevent the potentiometer drive plate at the bottom from rotating with changing fuel quantity. Maintenance records for the overhauled fuel transmitter indicated that the float guide was replaced at the time of overhaul on November 23, 2015.