Accident Narrative
On May 27, 2015, about 0815 Pacific daylight time, a Hiller UH-12E helicopter, registration N138HA, impacted an onion field during agricultural application operations near Wasco, California. The pilot was fatally injured, and the helicopter was destroyed by impact and postcrash fire. The helicopter was registered to and operated by Slikker Flying Service, Inc., under 14 Code of Federal Regulations Part 137 as an agricultural flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from a refueling truck about 0813.
The truck operator reported that the pilot had just finished spraying a small field. The helicopter was filled with fuel and about 30-40 gallons of water to clean out the spray system. The pilot took off and departed the immediate area about 15 ft above the field. The truck operator observed a plume of black smoke about ¼ mile away over a field crest and drove toward the fire, finding the helicopter engulfed in flames.
Pilot Information
The pilot held a commercial pilot certificate with ratings for rotorcraft-helicopter and instrument helicopter, and a Federal Aviation Administration second-class medical certificate dated February 18, 2015, with no limitations. The pilot's logbook was not recovered. During his last medical examination, he reported 1,136.2 total hours of flight experience, 277 of which were accrued in the previous 6 months. The pilot was hired by the operator in February 2014. He initially survived the accident but succumbed to his injuries about one week later. No autopsy or toxicology testing was performed.
Meteorological Conditions
The 0754 automated weather observation at Bakersfield Kern County Airport (BFL), about 25 nautical miles southeast of the accident site, included wind from 290° at 3 knots, visibility 10 statute miles, clear skies, temperature 18°C, dew point 8°C, and an altimeter setting of 29.97 inches of mercury.
Wreckage and Impact Examination
The helicopter impacted the onion field in a right-skid-low attitude. The field was disturbed between the first point of impact and the main wreckage, with bearings and portions of the tail boom and windscreen found throughout. The helicopter came to rest on its right side. The cabin area was destroyed and sustained heavy thermal damage. The tail boom was fracture-separated about mid-span and found partially underneath the main wreckage.
The main cabin was mostly consumed by the postcrash fire, but the majority of the airframe remained intact. The cyclic, collective, and pedals were loose within the main wreckage, all exhibiting signs of heat distress. The left side of the spray boom was fracture-separated in an aft direction. The tail boom fracture-separation was consistent with main rotor blade contact.
Control continuity from the cabin controls to the main rotor system was established. There was no evidence of binding or restrictions on intact portions of control linkages. Linkages underneath the seats and behind the cabin firewall exhibited breaks and heat distress; fracture surfaces not consumed by fire showed overload signatures.
Both main rotor blades remained attached to the hub, deformed opposite the direction of rotation. Blade tips were fracture-separated and not located.
The angled tail rotor drive shaft remained connected to the main transmission tail output flange but separated at the aft end. The shaft and housing were deformed about 90° to the left. Separated, deformed, and heavily fragmented pieces of the shaft exhibited overload signatures. The aft portion remained attached to the severed tail boom structure and connected to the tail rotor gearbox; when rotated, the tail rotor blades rotated normally.
The tail rotor blades remained installed at the hub. The first blade exhibited a leading-edge fracture near the root and deformation opposite normal rotation. The second blade showed downward, chordwise bending near its inboard end.
The main transmission and engine remained mounted to the airframe. The main rotor mast exhibited contact evidence with the rotor hub.
Engine spark plugs showed normal operating signatures and sooting. Rocker covers had no heat distress. The dual carburetor was disassembled with no blockage; the right carburetor interior was dry with cracked floats, and the left interior was wet with possible corrosion byproducts. Both magnetos rotated freely. The fuel tank was ruptured and empty; the fuel screen showed no blockage or contamination.