Introduction
On December 30, 2020, at approximately 15:33 Japan Standard Time, a privately owned Robinson R66 helicopter registered as JA77AR crashed into a mountain forest near Ojiro, Shimada City, Shizuoka Prefecture. The helicopter was destroyed, and the sole occupant, the captain, was fatally injured. There was no post-impact fire.
History of the Flight
The helicopter departed from Isewan Heliport in Tsu City, Mie Prefecture, at around 14:59, en route to Hodogaya Imai Temporary Operation Site in Yokohama City, Kanagawa Prefecture. The pilot was alone in the right seat. According to flight plan, GPS records, radar data, and eyewitness accounts, the aircraft established communication with Hamamatsu Aerodrome Terminal Control Facility at 15:16 and received radar advisory. It passed approximately 11 km south of Hamamatsu Aerodrome at 1,500 ft altitude and 130 kt ground speed, then turned northeast. Radar advisory ended at 15:29. About 11 km northwest of Shizuoka Airport, at 1,900 ft and 120 kt, the helicopter's attitude became unstable around 15:31:10. After rolling right and left, it crashed nose-down while turning right at about 15:32:55.
Eyewitness Observations
Four eyewitnesses provided statements. Eyewitness A saw the helicopter about 500 m southwest of the crash point, tilted right while swinging its tail, then tilting left and descending steeply while turning left before disappearing northeast. Eyewitness B, 260 m northwest, heard a loud roaring sound and saw the helicopter flying low from the south with its nose down largely while turning right, then disappearing. Eyewitness C, 100 m northwest, observed the helicopter at low altitude with nose down and tilting right, heading southeast toward the mountains. Eyewitness D, about 100 m east, did not see the helicopter but heard a loud banging and saw fragments of yellow metallic parts fall nearby.
Injuries and Damage
The captain, aged 46, was fatally injured. The helicopter was destroyed: cockpit and cabin destroyed, aft fuselage deformed, main rotor drive shaft deformed, main rotor hub dented, teeter stops deformed, tail cone deformed and broken at the forward horizontal stabilizer, main rotor blades deformed and scattered, tail rotor blades damaged, and landing gear broken. No fire occurred.
Aircraft and Pilot Information
The aircraft was a Robinson R66, serial number 0756, manufactured February 1, 2017, with a valid certificate of airworthiness. Weight and center of gravity were estimated within allowable limits. The pilot held a commercial pilot certificate for rotorcraft, type ratings for single-piston and single-engine turbine, and a valid Class 1 medical certificate. Total flight time was 3,340 hours 54 minutes, with 63 hours 52 minutes on the Robinson R66.
Meteorological Conditions
At 15:00, general weather over the Tokai region was influenced by a developing low-pressure system east of Japan and a high-pressure system over the continent, creating a winter pressure pattern. At Shizuoka Airport, 11 km east-southeast, wind was from 260° at 26 kt, gusts to 39 kt. Visibility was 10 km or more, cloud amount 1/8 cumulus at 2,500 ft, temperature 12°C, dew point 0°C. Sunset at the destination was 16:38.
Accident Site
The site was a small hill with cedar trees about 30 m high, in a mountain forest. An opening space about the length of the main rotor (10 m) and fuselage (12 m) was found, with contact marks on trees. The tail rotor was left on top of trees. The estimated approach angle at impact was about 40°. An Emergency Locator Transmitter was present. The site is about 11 km west-northwest of Shizuoka Airport.