Accident Overview
On Thursday, March 17, 2016, at about 12:20 Japan Standard Time, a privately owned PZL-Bielsko SZD-50-3 Puchacz glider, registered JA50KM, crashed onto two houses in a residential area of Sakae-town, Inba-gun, Chiba Prefecture. The glider was destroyed, and both occupants—an instructor and a trainee—died. No residents were injured.
Flight History
The glider launched from the Otone airfield at about 12:05 for a flight training mission by aero-tow, with the trainee in the front seat and the instructor in the rear. It was the second flight of the day for both; the first flight was the trainee's initial experience in this glider type. The glider released from the tow plane at an altitude of about 3,000 ft west of the airfield.
A pilot who took off from the airfield at 12:06 observed the glider at about 1,500 ft between Wakakusa-Ohashi bridge and the airfield, then later saw it flying toward Ajikidai to the south. A club member noted that the sky over the residential area was a common flight route to enter the south side of the airfield's traffic pattern and was known for generating thermals.
Witnesses reported seeing the glider with its nose low, rotating, or diving while showing its wing surfaces, but trees obscured the final moments.
Injuries and Damage
The instructor, aged 69, held a commercial pilot certificate, flight instructor certificate, and class 1 medical certificate. His total flight time was 229 hours 30 minutes (626 launches), with 36 hours 34 minutes (92 launches) on the glider type.
The trainee, aged 66, held a private pilot certificate for airplanes and a class 2 medical certificate. His total glider flight time was 1 hour 54 minutes (4 launches), with 0 hours 23 minutes (1 launch) on the type.
Both were killed by the impact, according to the Chiba Prefectural Police Headquarters. The glider was destroyed: the aft fuselage ruptured, the forward fuselage was seriously damaged, and both wings ruptured. The roofs and other parts of two houses were damaged.
The left main wing broke about 5.8 m from the wingtip; the right main wing bent upward near the outside of the airbrake. Both airbrakes were extended. The cockpit's front seat lower part was seriously damaged; the canopy opened and was damaged. The recovered front-seat airspeed indicator indicated zero; the front-seat altimeter indicated an altitude close to the accident site elevation. Rear-seat instruments showed different readings, but the airspeed indicator was positioned at zero, and the altimeter's interior was shock-damaged forward.
Meteorological and Other Information
Weather at the airfield was sunny and good. Wind at nearby Ryugasaki AMeDAS station was from the east at 2.4 m/s at 12:20. The accident site is in a residential area south of the airfield, across the Tone River. Due to the Narita Positive Control Area to the east, glider training flights are mostly conducted west and southwest of the airfield, using the residential area sky as a route.
The glider's weight and center of gravity were within allowable limits at the time of the accident. The glider had been submerged in a flood from the Tone River in September 2015, then repaired according to the manufacturer's manual and passed an airworthiness inspection in January 2016. No abnormalities were reported before the accident, and no emergency radio calls were made. No GPS or other flight data were recorded.
Emergency Call
A neighboring resident made an emergency call at 12:23, as recorded by the Chiba Prefectural Police.
The investigation did not identify a probable cause for the accident.