14 CFR Part 91: General Aviation
Tuesday, April 16, 2019
Fort McDowell, AZ
Bell 206, registration:
Injuries: 2 Fatal.
This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed. NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
On April 16, 2019, at 0706 mountain standard time, a Bell 206B experimental helicopter, N61PH, impacted an alfalfa field, about 1 mile south of Fort McDowell, Arizona. The commercial pilot and pilot-rated passenger were fatally injured. The helicopter was destroyed. The helicopter was registered to TRE Aviation Corporation and operated by Van Horn Aviation, LLC for research and development flight testing under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a flight plan was not filed. The second leg of the test flight originated from Falcon Field (FFZ), Mesa, Arizona at 0632.
The purpose of the flight was to evaluate developmental main rotor blades that had been installed on the helicopter. According to the operator, the helicopter was fueled for two test flight legs. The helicopter departed at 0545 for the first event and returned at about 0620, parked on the ramp with the engine at idle, and 100 lbs. of ballast was added to the helicopter. Preliminary radar data showed that the helicopter departed at 0632 to continue the second leg of the test flight. The test flight legs consisted of multiple autorotations at maximum gross weight involving a simulated loss of engine power. The accident flight was the last test flight of the main rotor blades before the certification process.
A witness who was walking to a bus stop, about 1/3 mile northwest of the accident site on Fort McDowell road heard a loud bang southeast of her position. She saw the helicopter falling from the sky and used her phone to video record the helicopter and several other objects descending to the ground before losing site of it behind trees along the road.
Initial examination of the main wreckage revealed postcrash fire and impact damage consistent with a right side-down, nose-level attitude during ground impact. The main rotor hub assembly, vertical tail, tail rotor assembly, tail rotor driveshaft, and forward induction cowl fairing separated from the main wreckage and was found in the debris field. The debris field was about 1 mile long and 1,000 ft wide, covering an area of wooded desert terrain and flood irrigated alfalfa fields. The wreckage was recovered to a secure location for further examination.
The helicopter was manufactured in 1981 and was equipped with a Rolls-Royce 250-C20B engine. The helicopter was registered to the owner in January 2019.
The 0654 automated weather observation at FFZ, located about 12 miles to the south of the accident site, included wind from 130° at 5 knots, visibility 10 miles, and clear skies.