Accident Summary
On October 5, 2015, at approximately 0805 central daylight time, a Bell 47G-3B helicopter, registration N160CS, sustained substantial damage when it impacted terrain during an aerial application pass near Huntsville, Texas. The helicopter was registered to and operated by Custom Air LLC under 14 Code of Federal Regulations Part 137 for agricultural application. Day visual meteorological conditions prevailed, and the flight was not operated on a flight plan. The local flight originated from a temporary landing site near the application field shortly before the accident. The pilot sustained minor injuries.
Pilot Report
According to the pilot, the helicopter felt "awkward" shortly before the event, which he attributed to an uncoordinated turn. During the next spray pass, the helicopter developed a right rolling tendency, which the pilot initially countered with left cyclic control. He entered a "gentle" right turn intending to return to the fuel truck for a precautionary landing. However, full left cyclic control input was ultimately ineffective in countering the right rolling tendency. The right turn continued for about 150 degrees of heading change, and the helicopter began to lose altitude. It subsequently impacted the ground in a slight right bank, traveling about 40 yards before coming to rest. The pilot stated he did not feel any abnormal vibrations or hear any "pops" before the loss of control authority, noting that the flight went from routine to out of control in a matter of "seconds."
Postaccident Examination
The helicopter came to rest in an open field covered with low vegetation. A postaccident examination by Federal Aviation Administration inspectors revealed that the windshield/canopy had separated from the fuselage, with plexiglass fragments observed at the site. The forward fuselage structure exhibited minor deformations and distortions, but the fuselage integrity was intact. The main rotor blades remained attached to the hub but were deformed over their span. The rotor hub remained attached to the mast and transmission. The transmission and supporting structure were dislocated from the aft fuselage/forward tailboom truss structure. The fuel tanks were separated and located with the main wreckage. The tailboom was deformed, and the tail rotor transmission had separated from the tail boom and was found at the accident site. The tail rotor blades remained attached to the hub, exhibiting tip damage but otherwise appeared intact. Flight control system components were deformed and fragmented consistent with overall impact damage. The examination did not reveal any anomalies consistent with a preimpact failure or malfunction; however, the examination was hindered by the extent of the damage.