Helicopter Was Spinning In A Counterclockwise Motion For Several Full Rotations

Location: Kingston, NJ Accident Number: ERA23FA357
Date & Time: August 31, 2023, 15:25 Local Registration: N2356M
Aircraft: Robinson Helicopter R22 Beta Injuries: 1 Fatal
Flight Conducted Under: Part 91: General aviation - Instructional

On August 31, 2023, about 1525 eastern daylight time, a Robinson Helicopter R22 Beta, N2356M, was substantially damaged when it was involved in an accident near Kingston, New Jersey. The private pilot was fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 solo instructional flight.

The pilot was an Israeli citizen and fixed-wing airline pilot. He held a private pilot certificate with a rotorcraft rating and had come to the United States to obtain a commercial pilot certificate with a rotorcraft rating. He departed Princeton Airport (39N), Princeton/Rocky Hill, New Jersey, about 1520. According to preliminary Automatic Dependent Surveillance-Broadcast (ADS-B) data provided by the Federal Aviation Administration, shortly after departing the airport traffic pattern to the east, the helicopter climbed to 1,375 mean sea level (msl) then subsequently turned south toward the Millstone River.

A witness, who was photographing wildlife, was standing on the river’s dam when she observed the helicopter approach the river. She said the helicopter was in a steep nose down attitude about 800 ft above ground level. She held her finger down on the shutter release of her camera and took about 20 sequential photographs of the helicopter until it descended out of view.

A review of the photographs revealed the helicopter was spinning in a counterclockwise motion for several full rotations. The helicopter then rolled onto its right side, and pitched to a steep nose up attitude before the main rotor blades impacted the tailboom. The impact severed the tail rotor blade assembly into three distinct pieces; the tail rotor blades and gearbox, the stabilizer, and the tail rotor drive shaft. The helicopter then entered an uncontrolled descent and impacted trees before coming to rest in a tributary in 3 ft of water.

The helicopter fuselage containing the cockpit, engine, transmission, and main rotor blade assembly came to rest inverted at an elevation of about 15 ft msl and was oriented on a heading of about 243°. Miscellaneous pieces of plexiglass, placards, a fire extinguisher, a partial tail rotor blade and tailboom fragments were discovered within 200 ft of the main wreckage. The section of the tailboom containing the tail rotor, drive shaft, and tail rotor blade assembly was not located.

Both main rotor blades remained attached to the main rotor head. Both blades had impact marks and gouges consistent with tailboom contact. The main rotor drive system gear box remained attached to the airframe with both left and right longitudinal pitch restraints separated from their respective stops. One pitch control link (PCL) was separated and had features consistent with overload; the opposing PCL remained attached. The pitch was manually actuated, and it was free of any binding.

The cyclic and collective push-pull tubes were traced to their respective control inputs and actuators. Fractures in the system were consistent with overload. Control continuity was confirmed for both collective and cyclic controls. The tail rotor pedals were impact fractured but manually traced through breaks in the control tubes to where the tailboom was  separated.

The engine drivetrain and crankshaft control continuity were confirmed through 720° of manual engine rotation through the accessory section. 

Both magnetos remained attached to the accessory housing. The right magneto was undamaged and sparked at all four leads. The left magneto capacitor was impacted damaged and did not produce spark when rotated. The spark plugs displayed coloration consistent with normal engine operation, except for the No. 2 cylinder, when compared to the Champion Aviation AV-27 Check-A-Plug chart. The top and bottom spark plugs contained blue staining. 

The carburetor bowl was impact separated from the upper portion of the unit and remained with the engine via the mixture cable. The floats were separated and fragmented. The fuel inlet screen was unobstructed. The induction pipes were removed, and blue staining was observed in all four induction pipes.

The wreckage was retained for further examination and the induction pipes were sent to the NTSB Materials Laboratory, Washington, DC for additional examination.

FMI: www.ntsb.gov