N922SHRobinson Helicopter R22 BETA · 2005

On March 6, 2010, about 1120 central standard time, a Robinson R22 Beta II, N922SH, was substantially damaged during impact with terrain while maneuvering at low altitude at the Agave Ranch near Cotulla, Texas. The commercial pilot and passenger were fatally injured. The helicopter was registered to and operated by a private individual. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 local flight. The aerial hog hunting flight was the sixth flight of the morning and had departed around 1110.

According to individuals at the Agave Ranch, they were contacted about providing an Axis deer hunt for the accident weekend. During the initial arrangements, the hunters were offered an aerial hog hunt in addition to the deer hunt, to which they agreed. To facilitate the aerial hog hunt, the ranch manager contacted the helicopter owner and arranged for the owner to furnish the helicopter, pilot, shotgun, and ammunition. Following the hunt the helicopter owner would provide an invoice for payment.

On the morning of the accident, the pilot arrived at the ranch around 0900 towing the two-seat helicopter on a trailer. The pilot provided a safety briefing to the four hunters to include proper use of the shotgun. The pilot also mentioned that each flight would be approximately 20 minutes in length, and that he would be operating the helicopter "light" on fuel so the helicopter would be more maneuverable.

An initial flight of 5 to 10 minutes was conducted with the ranch manager so he could point out the ranch perimeters to the pilot. The pilot then proceeded to fly the next three hunters, one at a time, for approximately 20 minutes each. The forth hunter requested the pilot return and land after approximate 10 minutes in order to give the first hunter more time to hunt. Approximately 10 minutes after the last flight departed, several of the waiting hunters heard what they described as a "whoosh whoosh whoosh," or a sound that resembled "a lawn mower bogging down in tall grass.” The helicopter wreckage was located a short time later.

According to the hunters, during each flight the pilot would fly about the height of a telephone pole and in a speed range of 0 to 25 mph. The pilot would notify the hunter when it was safe to shoot. While offloading and boarding the next hunter, the pilot would exit the running helicopter and add fuel from a tank located in the back of his truck. Those interviewed were unsure how many times the pilot added fuel to the helicopter. Two of the hunters reported that it was at least twice and the ranch manager recalled the pilot refueling between each hunter; however, he did not recall if the pilot had refueled before the last flight.

An examination of the truck-mounted fuel tank revealed that there was no gauge or means to determine how much fuel was being pumped into the helicopter.

The pilot, age 40, held a commercial pilot certificate for rotorcraft helicopter and a rating for instrument helicopter. His last Federal Aviation Administration (FAA) second-class medical was issued on June 24, 2008, with no limitations.

A partial record of the pilot's flight time was submitted to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC). As of the last entry dated July 26, 2008, the pilot had accumulated a total flight time of 498 hours; of which 303.3 hours were in this make and model of helicopter. No flight records for the time between July 26, 2008 and the date of the accident were submitted to the IIC. The pilot’s last noted flight review was completed July 2, 2009.

The owner of the helicopter estimated the pilot’s total flight time, at the time of the accident, to be approximately 1,000 hours, with 700 hours in make and model.

The two-seat helicopter, serial number 3863 was manufactured in 2005. It was powered by a Lycoming O-360-J2A, 145-hp engine. Review of maintenance records revealed the last annual inspection was completed April 16, 2008, at an airframe and engine total time of 1273.3 hours. The helicopter had accumulated a total airframe and engine time of 1,935 hours at the time of the accident and 27.2 hours since the last 100-hour inspection.

At 1053, the automated weather observing system at the Cotulla Airport (COT), Cotulla, Texas, located 12 nautical miles southeast from the site of the accident, reported wind from 130 degrees at 13 knots, 10 miles visibility, clear of clouds, broken ceiling at 1,700 feet, temperature 64 degrees Fahrenheit (F), dew point 57 degrees F, and a barometric pressure setting of 30.18 inches of Mercury.

On site documentation of the wreckage was conducted by investigators from the NTSB, FAA, and Robinson Helicopter Company.

The helicopter impacted in an open field on a heading of 190 degrees and came to rest on a heading of 335 degrees. Control continuity was established to all flight controls and all major components were accounted for at the site.

The fuselage came to rest in an upright position and exhibited downward crushing. The tail boom was bent downward and the aft end had been separated in a manner consistent with a main rotor blade strike. The aft section of the tail boom, with the attached tail rotor gearbox, was located 127 feet from the main wreckage. Both main rotor blades remained attached to the rotor head. One blade exhibited a gradual curve upward along its entire length. The other blade contained less upward curvature then the first blade and exhibited several areas of buckling.

Main rotor driveshaft continuity was established from the upper drive sheave through the main rotor head. The sprag clutch operated normally when manually rotated. Impact signatures on the swash plate were consistent with the collective being in the full up position during impact. The automatic carburetor heat control was found locked in the cold position. Both fuel tanks contained residual fuel and did not exhibited hydraulic deformation.

The engine’s valve covers and lower spark plugs were removed. Investigators manually rotated the engine and valve train continuity was established to each cylinder and to the accessory gears. Thumb compression was developed in each cylinder. Both magnetos were removed and produced a blue spark at each terminal when rotated by hand. The oil filter was removed and cut open. An examination of the oil filter element revealed no visible abnormal contaminants.

The carburetor exhibited impact damaged and the bowl was found separated from the engine. The carburetor fuel inlet screen was removed and found to be clean and unobstructed. The fuel gascolator bowl was found separated from the gascolator upper housing and mount. The grass directly underneath the helicopter, with the attached upper fuel gascolator housing, contained a discolored area, approximately 5 inches in diameter, which was consistent with fuel blight. The IIC removed the topsoil and found a live earthworm approximately one half inch below the discolored grass. No other blight was observed on the surrounding vegetation.

The Webb County Medical examiner’s office, Laredo, Texas, performed an autopsy on the pilot on March 7, 2010. The cause of death was reported as "multiple blunt force injuries.”

The FAA Civil Aerospace Medical Institute (CAMI), Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. The toxicology report stated no carbon monoxide or cyanide was detected in the blood, and no ethanol was detected in the vitreous. Chlorpheniramine and Ibuprofen were detected in the urine.

According to the FAA’s Rotorcraft Flying Handbook, chapter 11, page 4, “A height/velocity (H/V) diagram, published by the manufacturer for each model of helicopter, depicts the critical combinations of airspeed and altitude should an engine failure occur. Operating at the altitudes and airspeeds shown within the crosshatched or shaded areas of the H/V diagram may not allow enough time for the critical transition from powered flight to autorotation.”

A Robinson R22 Pilot Operating Handbook was located in the wreckage. According to the H/V Diagram, chapter 5, page 11, the helicopter was being operated in the crosshatched area.