What happened
On June 4, 2015, a Janus C sailplane, registration SE-UOB, was performing a winch launch at Västerås/Johannisberg airport. After reaching an altitude of approximately 600 meters, the pilot began a landing pattern for runway 23. During the turn to the final approach, the pilot observed a significant increase in wind speed and a sharp increase in the rate of descent.
Due to the low altitude, the pilot did not deploy the airbrakes, attempting instead to maintain enough glide to reach the runway while also maneuvering to avoid nearby trees. The aircraft passed beneath a power line before striking the ground, sliding into a roadside ditch, and bouncing onto a road. The impact caused the aircraft to veer 90 degrees, resulting in one wing striking a car and shattering its windshield. While the aircraft sustained substantial damage, including the separation of the fuselage tail section, there were no injuries to the pilot, the passenger, or the driver of the car.
The investigation
The Swedish Accident Investigation Authority (SHK) analyzed GPS log data from the aircraft to reconstruct the flight path. To establish a baseline for wind conditions, investigators compared the data from SE-UOB with a flight from another Janus C, registration SE-UUB, which had landed just five minutes earlier.
Both aircraft exhibited high sink rates during their final approaches. The comparison of groundspeeds between the two flights confirmed that the wind was high and gusty during the period. The investigation also noted that pilots active at the airfield had previously reported significant sinking areas near the shoreline due to the interaction between strong winds and low water temperatures.
Findings
- The aircraft encountered a high rate of descent during the final approach.
- The landing was performed without sufficient consideration for the actual wind conditions.
- Gusty winds and shifting wind directions contributed to a degraded glide performance.
- Local meteorological factors, specifically wind interacting with the shoreline, created areas of high sink rates.