N59600

HISTORY OF FLIGHTOn November 28, 2021, about 1658 central standard time, a Bell 206B helicopter, N59600, was destroyed when it was involved in an accident near Perry, Oklahoma. The commercial pilot sustained fatal injuries and the passenger, who held a student pilot certificate, sustained serious injuries. The helicopter was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

According to the passenger, who is the pilot’s son, the pilot preflighted the helicopter at 1530. The helicopter was kept on the pilot’s property in a barn. Nothing abnormal was noticed during the preflight. During the preflight, the pilot installed the flight controls for the left seat position.

For the flight, both front doors were installed and neither occupant did any filming during the flight. The pilot, in the left seat, had on a surplus US Army (Gentex) SPH-4 helicopter flight helmet, but the flight helmet did not have a tinted visor and he did not have on sunglasses. The passenger, in the right seat, had on a headset, and he did not have on sunglasses.

The helicopter departed from the pilot’s property about 1600 with about 50 gallons of fuel onboard, and when the accident occurred there was about 25 gallons of fuel onboard.

After departing from the property, the helicopter flew to the Perry Municipal Airport (F22), Perry, Oklahoma. The pilot flew three traffic pattern flights. After the three traffic pattern circuits, the helicopter departed the airport and flew to the west of I-35. According to the passenger, everything appeared normal with the helicopter up to this point.

The pilot flew to the west of I-35 over ranch property to demonstrate how he performed his 14 CFR 137 low-level aerial application flights in the helicopter. The passenger reported that the setting sun was in both of their eyes during this timeframe.

The pilot performed several low-level east to west maneuvers and he was demonstrating the use of the Satloc aerial application navigation system to the passenger. During these maneuvers, the helicopter was about 15 ft above ground level (agl) and was traveling about 60 kts airspeed.

During a pass to the east, the two occupants both observed a coyote in a large field. The coyote was in tall grass, just to the south of a barbed wire fence near where the helicopter came to rest. The pilot performed a right pedal turn to get a better look at the coyote.

The pilot maneuvered the helicopter to an out-of-ground effect hover over the tall grass, facing to the south, about 40 ft agl. Both the pilot and passenger were looking at the coyote when the helicopter began an uncommanded left roll.

The passenger couldn’t tell what the cyclic positions were (such as if they both went to the left or if just one went to the left) during the uncommanded left roll. The passenger reported the accident sequence happened “very fast,” the pilot was on the flight controls for the entire flight, and that the passenger was not operating the flight controls during the accident sequence.

The pilot did not announce anything during this time regarding what he thought was going on with the helicopter. The helicopter did not spin, and the passenger did not recall the main rotor blade striking the ground before the helicopter impacted the terrain. There were no vibrations emitted from the helicopter and no alarms or warning lights came on during this period. The helicopter impacted a grass field just south of a barbed wire fence.

The grass around the helicopter instantly caught on fire after the impact. The passenger was able to extract himself and the deceased pilot away from the wreckage. About 5 minutes later, the wreckage caught on fire and was destroyed. The passenger then contacted first responders from his cellular phone who then arrived shortly after. There were no known witnesses who observed the accident sequence. PERSONNEL INFORMATIONPilot

The pilot, who owned the accident helicopter, worked full time as a helicopter air ambulance pilot. The pilot also worked part time as a 14 CFR Part 137 aerial application pilot (as the sole pilot in the business he owned) and as a rancher.

The pilot’s helicopter air ambulance company records were available for review; however, the pilot’s personal logbook was not available for review.

According to Federal Aviation Administration (FAA) records, the pilot did not hold a mechanic certificate.

Passenger/Student Pilot

The passenger was enrolled in a university aviation program and was learning to fly helicopters. AIRCRAFT INFORMATIONThe helicopter was certificated by the FAA in both the standard and restricted airworthiness categories. According to FAA records, the pilot purchased the helicopter in November 2013.

According to the pilot’s girlfriend, she flew with the pilot in the helicopter about 1.5 weeks prior to the accident. The pilot took her on an aerial application flight in the local area to spray several crop fields and nothing abnormal was noticed with the helicopter. The girlfriend reported that the pilot was the only one who would install and remove the copilot cyclic control in the helicopter. The pilot would install the copilot cyclic if he was going to fly with his son and then the pilot would later remove it.

The helicopter was modified with a Simplex 4900 aerial application spray system per a FAA-approved supplemental type certificate. At the time of the accident, the helicopter did not have the spray booms installed. Per FAA records, the helicopter was equipped with a Satloc unit (unknown model) and a Shadin Fuel Flow Indicator unit (unknown model); however, the Satloc was destroyed and the Shadin Fuel Flow Indicator unit was not identified in the wreckage. The helicopter was not equipped with a crash-resistant fuel system, nor was it required to be. An emergency locator transmitter was not identified in the wreckage and the passenger reported he was unsure if one was installed in the helicopter.

The airframe and engine maintenance records for the helicopter were not available for review. METEOROLOGICAL INFORMATIONThe passenger reported the local weather conditions for the flight were no wind, no turbulence, and clear visibility.

A review of meteorological data indicated a light southerly wind below 2,000 ft agl, no indication of turbulence or low-level wind shear, or any other outflows or wind shifts. A pilot report indicated flight visibility of 10 miles. There were no inflight weather advisories over the region during the flight. Astronomical conditions indicated the accident occurred before sunset with a low sun elevation present.

A review of the meteorological data surrounding the time and location of the accident did not reveal any meteorological areas of concern.

The estimated density altitude for the accident site was 931 ft above msl. AIRPORT INFORMATIONThe helicopter was certificated by the FAA in both the standard and restricted airworthiness categories. According to FAA records, the pilot purchased the helicopter in November 2013.

According to the pilot’s girlfriend, she flew with the pilot in the helicopter about 1.5 weeks prior to the accident. The pilot took her on an aerial application flight in the local area to spray several crop fields and nothing abnormal was noticed with the helicopter. The girlfriend reported that the pilot was the only one who would install and remove the copilot cyclic control in the helicopter. The pilot would install the copilot cyclic if he was going to fly with his son and then the pilot would later remove it.

The helicopter was modified with a Simplex 4900 aerial application spray system per a FAA-approved supplemental type certificate. At the time of the accident, the helicopter did not have the spray booms installed. Per FAA records, the helicopter was equipped with a Satloc unit (unknown model) and a Shadin Fuel Flow Indicator unit (unknown model); however, the Satloc was destroyed and the Shadin Fuel Flow Indicator unit was not identified in the wreckage. The helicopter was not equipped with a crash-resistant fuel system, nor was it required to be. An emergency locator transmitter was not identified in the wreckage and the passenger reported he was unsure if one was installed in the helicopter.

The airframe and engine maintenance records for the helicopter were not available for review. WRECKAGE AND IMPACT INFORMATIONThe accident site, at an elevation of 1,056 ft above msl, consisted of private property that is used as a cattle pasture. The barbed wire fence that the helicopter came to rest just prior to, was found intact with no sign of impact. The barbed wire fence was later cut by the investigative team to facilitate access to the wreckage. All major structural parts of the helicopter were accounted for at the accident site.

Most of the forward and intermediate fuselage was consumed in the fire. The tailboom detached from the intermediate fuselage and was found near the main wreckage.

The main rotor hub and blade assembly remained attached to the mast which fractured just below the hub. Both main rotor blades suffered various degrees of fracturing and bending. All remnants of the main rotor blades were accounted for. The transmission case was partially consumed in the post-crash fire. Due to the thermal and impact damage, main rotor drive continuity could not be established. The tail rotor drive system was continuous within the tail boom section found adjacent to the wreckage.

During the impact sequence, the tail rotor gearbox separated from the tail boom. The complete tail rotor assembly separated from the tail rotor gearbox output shaft. The tail rotor gearbox was able to be rotated by hand in both directions with no binding or abnormal sounds coming from the tail rotor gearbox.

The components of the fuel system, including the fuel bladder, two electric boost pumps, lower and upper tank indicating units, fuel/vent lines, fuel shutoff valve, airframe fuel filter, and an electric sump drain valve wer...