Introduction
On January 21, 2023, at approximately 14:00 Japan Standard Time, a PZL-Bielsko Model SZD-51-1 Junior glider (registration JA2524) operated by Nagano Gliding Association experienced a serious incident during landing at Naganoshi glider site in Nagano City, Nagano Prefecture. The lower surface of the fuselage forward section contacted the runway, resulting in damage. The sole occupant, a 64-year-old private pilot with 192 hours of total flight time, was not injured.
Factual Information
The glider launched at about 11:40 via winch towing from Runway 04L for a leisure flight. After approximately two hours, the pilot entered the left traffic pattern to land on Runway 04R. The pilot extended the airbrakes slightly more than halfway after flying about halfway through the base leg. After turning final, he set the aiming point near the starting point of the center line marking—shorter than the point recommended by the association. While passing over the grassy area short of the runway, the pilot felt the approach altitude was lower than usual, so he pulled the control stick back and closed the airbrakes to less than half to correct the path angle. When passing over the designation marking (his usual target to begin flare), he felt the height from the runway was higher than usual but initiated the flare for the original aiming point. Subsequently, feeling the glider shake, he suspected a stall and quickly pushed the control stick forward. Immediately after, the main wheel and the lower forward fuselage contacted the runway nearly simultaneously. The glider then rolled without bouncing and stopped around the middle of the runway.
Meteorological conditions were fine with good visibility, no turbulence, wind direction about 40°, and wind speed 4 to 6 m/s. The glider's flight manual specifies that stall is sensed by buffeting, with recovery by releasing the control stick forward. Approach airspeed is 90–100 km/h, and touchdown should be on the main and tail wheels.
Analysis
The Japan Transport Safety Board (JTSB) analyzed that the pilot's actions—pulling the stick and closing airbrakes when feeling low on approach—likely caused excessive nose-up and floating. Starting the flare before the glider began to sink again likely slowed the glider, leading to shaking. The pilot's rapid forward stick movement to avoid a stall failed to recover airspeed, and the glider sank with a nose-down attitude, probably causing the forward fuselage to contact the runway.
Additionally, the pilot and association did not recognize the event as a reportable serious incident at the time. The Civil Aviation Bureau later learned of the incident during a maintenance inquiry and reported it to the JTSB on June 9, 2023.
Probable Causes
The JTSB concluded that the probable cause of this serious incident was that the lower surface of the fuselage forward section more likely contacted with the runway surface because the nose of the glider went down immediately before the touchdown and glider s.