Accident Summary
On Sunday, November 22, 2015, a privately owned Robinson R22 Beta helicopter, registration JA7963, departed Tokyo Heliport at 09:55 Japan Standard Time for a familiarization flight to Komoro Temporary Helipad in Nagano Prefecture. At approximately 10:56, the helicopter collided with a slope face of a mountain alongside the Joshin-etsu Expressway near Matsuida Town, Annaka City, Gunma Prefecture. The captain and a passenger were on board; both died in the collision. The rotorcraft was destroyed, but no fire occurred.
Flight History
According to the flight plan, the helicopter was operating under Visual Flight Rules (VFR) at a cruising speed of 80 knots, with a planned route via Kawagoe, Takasaki, and Karuizawa. The estimated flight time was 1 hour 30 minutes, with a fuel endurance of 3 hours 20 minutes. The aircraft had taken off earlier from Nagareyama Helipad at around 09:05, stopped at Tokyo Heliport for refueling, and then departed at 09:55.
Data from a portable GPS receiver carried by the captain, communication records, images from a digital camera, and eyewitness statements provide the following timeline:
- 09:55: Departure from Tokyo Heliport.
- 09:57: End of communication with Flight Service.
- Around 10:20: Overflew Higashi-Matsuyama City, Saitama Prefecture.
- 10:53:20: Crossed the Joshin-etsu Expressway westbound about 460 meters south-southwest of the accident site.
- 10:53:52: Changed heading from a mountain 700 meters west-northwest to the accident site direction.
- Around 10:55: Turned to fly over the expressway near the accident site.
- 10:56:11: GPS records ended near the accident site after crossing the expressway from south to north.
Eyewitnesses reported hearing the helicopter circling for about 10 minutes. One witness observed clouds obscuring the helicopter, then saw it descend, pitch down after crossing the expressway, and heard an impact. Another witness saw the red helicopter cross the expressway from south to north and collide with the slope. At the time, about half of the mountain above the accident site was hidden by cloud.
Injuries and Damage
Both occupants were killed. The rotorcraft was destroyed, with the fuselage broken, bent, and ruptured; the tail cone broken; the engine broken and damaged; the main rotor and tail rotor broken and bent; landing gear broken and bent; and the control system partially ruptured.
Personnel Information
The captain, aged 54, held a private pilot certificate for rotorcraft with a single-piston engine rating, valid until March 24, 1989 (type rating), and a class 2 aviation medical certificate valid until June 8, 2016. His total flight time was 376 hours 33 minutes, with no flight time in the last 30 days. Flight time on the accident type was unknown; also, last 30 days was 0 hours.
The passenger, aged 57, also held a private pilot certificate with a type rating for single-piston engine (land), valid until October 2, 2002, and a class 2 medical certificate valid until November 19, 2016. His total flight time was unknown.
Probable Causes
The Japan Transport Safety Board determined that the accident occurred because the rotorcraft continued flight despite deteriorating weather, resulting in low-altitude flight under conditions where visual meteorological conditions (VMC) could not be maintained. The pilot was likely attempting to find a route to the destination when the helicopter struck the terrain.