Summary
On July 14, 2011, a Robinson R22 Beta helicopter, registration JA007J, rolled over upon landing at Sabaekoizumi temporary helipad (Sabae Helipad) in Sabae City, Fukui Prefecture, Japan. The accident occurred around 18:15 local time after a familiarization flight. The pilot in command (PIC) and a passenger were on board; the PIC sustained major injuries, and the passenger minor injuries. The aircraft sustained substantial damage but no fire occurred.
Flight History
According to statements from the PIC, passenger, and a witness, the PIC arrived at Sabae Helipad around 17:30. After a pre-flight check, the helicopter took off to the north-northeast at about 18:00. The flight headed south over Echizen City for about five minutes, then turned north for the return. The PIC began a final approach from about 600 m south of the helipad at 500 ft and 60 kt airspeed, using a steeper approach angle than normal to clear electric wires. The approach ended in a 2 m hover. The PIC felt the hover became unstable in the wind and struggled to land. Upon touchdown, the helicopter leaned right and began to spin right. The PIC did not recall his control inputs. The passenger observed the helicopter touch down with its left skid forward, then drift right, then pop up 1–2 m while spinning right. A witness saw the helicopter touch down, pop up, spin one or two times to the right, then go out of sight.
Injuries to Persons
The PIC sustained severe injuries including fractured ribs; the passenger sustained minor injuries such as a left shoulder bruise.
Damage to the Aircraft
The aircraft was substantially damaged. The left side canopy and left door were broken; the left skid was fractured, the right skid cracked, and the cross tube deformed; the main rotor and rotor mast were deformed, and the tail rotor was fractured. The flight control system was connected normally, but swashplate operation was partly restricted due to mast deformation.
Personnel Information
The PIC was a 67-year-old male with a private pilot certificate (rotorcraft) issued March 13, 1989, and a single-piston engine rating. He held a Class 2 medical certificate valid to June 12, 2012. His total flight time was 317 hours 1 minute, with 288 hours 56 minutes on type. In the last 30 days, he had flown 1 hour 36 minutes; in the last year, 3 hours 54 minutes with only 9 landings. He had not flown for 125 days between February 17 and June 21, 2011.
Aircraft Information
The Robinson R22 Beta (serial number 2636, manufactured November 1, 1996) had a certificate of airworthiness valid to March 1, 2012. Its total flight time was 1,752 hours 2 minutes, with 5 hours since the last periodic check (100-hour check on February 23, 2011). Estimated weight and balance were within allowable limits.
Meteorological Information
Wind observations from Sabae Nyu Fire Department, about 2 km southeast of the helipad, showed north-northeast winds at 18:00 averaging 6 kt with gusts to 15 kt, and at 19:00 averaging 4 kt with gusts to 13 kt. The windsock at the helipad was hardened and drooped, giving inaccurate wind velocity indication.
Accident Site Information
Sabae Helipad is an elevated concrete surface (11 m by 11 m, elevation 48 ft) located in paddy fields. Its surface is about 3 m higher than surrounding terrain, with a near-vertical concrete wall on the north side. Takeoff direction is north-northeast; landing directions are north and south-southwest. The aircraft came to rest on its left side on the south slope of the helipad, nose oriented east. Scratch marks about 2.3 m long and three dents were found on the helipad surface; the garage roof (about 30 cm lower) showed fracture, depression, and distortion.
Probable Cause
The Japan Transport Safety Board determined that the accident likely occurred because the aircraft lost balance after touchdown and rolled over onto the south slope, injuring occupants and damaging the fuselage. The loss of balance was probably caused by the PIC's unintentional pull-up of the collective pitch and insufficient left pedal input for directional control, which led to a right spin. This situation possibly resulted from the PIC's insufficient skill maintenance.