Accident Sequence
On December 18, 2023, at about 12:15 JST, a Robinson R44 helicopter (registration JA01CG) crashed during hover training at the JPD Kyoto Operation Site in Kyoto City, Kyoto Prefecture. The helicopter, operated by Takumi Enterprise Helicopter & Airplane Co., Ltd., was conducting flight training for a student pilot (Trainee) obtaining a private pilot license. The flight instructor (Instructor) occupied the left pilot seat, and the Trainee occupied the right pilot seat. At the time of the accident, the wind was from the northwest at approximately 5 knots, and the helicopter was oriented with the nose facing north.
The training had begun around 11:20 JST with hover and vertical takeoff/landing exercises, followed by a flight to a nearby training area for basic maneuvers. After returning and landing at about 12:10, the Instructor decided to conduct additional hover training. During a hover at approximately 4 ft above ground level, the Instructor handed control to the Trainee. The helicopter became unstable, moving rearward. When the Instructor advised, “The helicopter is backing up again,” the Trainee attempted to correct with forward cyclic input, but the helicopter then moved rapidly forward toward the northern boundary. The Instructor took over and applied nose-up cyclic. Immediately, a loud impact was heard from the rear, followed by a sudden right yaw and airframe oscillation. The Instructor applied rudder pedal input but could not regain directional control, suspecting tail rotor (TR) ground contact.
Determining that a normal landing was impossible, the Instructor maneuvered the yawing helicopter toward the center of the touchdown zone marker. After approximately two right yaws, the Instructor executed a landing on the asphalt surface, pulling the collective to mitigate impact. The helicopter made a hard touchdown on the forward part of the skids, continued yawing right, and came to rest with the nose oriented south. About three to four seconds elapsed from aft fuselage contact to final touchdown. The engine shut down due to impact. The Instructor and Trainee escaped without injury.
Damage and Aftermath
The helicopter was destroyed. Damage included deformed outer skin and structural components, damaged main rotor blades (both blades), broken TR blades (both), fractured tail cone and tail drive shaft at two points, broken and deformed TR attachment and stabilizer, buckled left and right skids and attachments, and detached left windshield. No fire occurred.
On the ground, three scratch marks from TR blades were found about 9 m northwest of the center of the touchdown zone marker, with a maximum depth of about 1 cm. The heading at TR contact was about 340°. Contact marks from the helicopter touchdown and scratch marks from right yaw after landing were observed on the paved surface outside the western boundary. The helicopter’s heading upon ground contact was approximately northeast; after coming to rest, the heading was about 170°. Wreckage, including parts of the TR blade, tail cone, TR attachment and stabilizer, and left windshield, was scattered around the site.
The witness, an employee monitoring the training area, observed the helicopter’s movements and sensed danger as the helicopter pitched up, climbed, and yawed right. After the accident, the witness ensured the main rotor had stopped before approaching, disconnected fuel, shut off battery power, and moved the occupants to safety. The company’s pilot turned off the helicopter’s Emergency Locator Transmitter (ELT), which had activated.
The investigation was conducted by the Japan Transport Safety Board (JTSB), with participation from the United States as the state of design and manufacture.