Factual Information
Flight History
On May 3, 2023, a Robinson R22 Beta helicopter, JA7875, operated by a private owner, departed from the Yamafuji Temporary Operation Site (Old Operation Site) in Toyama City for a familiarization flight to Noto Airport and back. The pilot occupied the right seat, and a passenger (holding a helicopter pilot certificate but not a flight instructor certificate) sat in the left seat. The helicopter took off at approximately 12:20 JST, landed at Noto Airport at 13:00, and departed from Noto Airport at 14:54. While approaching the Old Operation Site from the south at about 15:32, the helicopter encountered a strong westerly wind, lost directional control shortly before touchdown, and rolled over, coming to rest against grapevine shelves on the east side.
According to the pilot, the wind at Noto Airport had a maximum velocity of 25 kt and an average of 11 kt at takeoff. The pilot was aware of strong winds near the Old Operation Site due to the wind direction indicator. As the helicopter approached, the nose swung sharply left. The pilot applied right pedal to counteract, but could not control the attitude. The passenger reported that the nose swung left, then the helicopter spun right and moved forward; the passenger operated the cyclic to assist. The steel wires of the grapevine shelves wrapped around the main rotor, causing the helicopter to roll over.
Injuries
None.
Damage to the Aircraft
The helicopter was substantially damaged. The cockpit right front windshield and left door window were broken. The base of the tail cone was broken, with contact marks on the left side. The rear of the tail cone was broken upward, and the vertical and horizontal stabilizers were damaged. More than 20 steel wires from the grapevine shelves coiled around the swashplate, jamming the collective pitch control in the uppermost position. One main rotor blade had contact marks and deformation; the other had none. Tail rotor blade tips were broken off and scattered about 30 m west of the accident site. The tail drive shaft was broken.
Personnel Information
- Pilot: Age 57, private pilot certificate (rotorcraft) since July 6, 1995; total flight time 321 hours 46 minutes, all on type; last 30 days 2 hours 41 minutes. Class 2 medical certificate valid until March 1, 2024.
- Passenger: Age 75, private pilot certificate (rotorcraft) since July 6, 1995; total flight time about 1,300 hours, all on type; last 30 days 24 hours 36 minutes. Class 2 medical certificate valid until August 24, 2023.
Aircraft Information
- Type: Robinson R22 Beta
- Serial number: 1915
- Date of manufacture: August 23, 1991
- Certificate of airworthiness: No. Dai-2022-131, valid until June 23, 2023
- Total flight time: 5,282 hours 24 minutes
- Weight and center of gravity were within allowable limits at the time of the accident.
Meteorological Information
General weather: A moving high-pressure system covered Japan; clear and calm, but with a slightly strong north to northwest wind in the Toyama region in the afternoon. At Toyama Airport (11 km northeast of the accident site), observations at 15:00 showed wind from 010° at 9 kt; at 16:00, wind from 300° at 9 kt with fluctuations between 250° and 320°. At the Old Operation Site, the wind direction indicator showed changes in wind direction and velocity immediately before the accident (Figure 8 in the source).
Accident Site
The Old Operation Site was a concrete paved area with a hangar on the north side. A wind direction indicator was located about 25 m to the southeast. Grapevine shelves approximately 1.3 to 1.4 m high were present on the east and west sides. The site had been used as an operation site until 2018; the approved operation site at the time of the accident was about 150 m east. The helicopter rolled over when steel wires from the eastern grapevine shelves coiled around it.
Additional Information
Surveillance camera video was available and used to analyze the wind indicator. The helicopter had no recording equipment.