What happened
On April 3, 2016, at approximately 12:12 UTC, a LAK-19 glider crashed into a steep, heavily forested area near the Hörsterkogel in the Osteralm region, roughly 3.3 km north of the Lanzen-Turnau airfield. The pilot sustained fatal injuries, and the aircraft was destroyed upon impact.
The flight began at 10:20 UTC when the glider was towed from Lanzen-Turnau. Witnesses reported that while the initial takeoff conditions involved light southern winds, significant westerly winds were present at higher altitudes. Another pilot flying nearby observed the LAK-19 suddenly drop significantly in altitude while flying at an elevation of approximately 1,700 to 1,8/00 meters. The aircraft was seen banking sharply to the left and entering a spin at an altitude of only 50 to 100 meters above the ground before striking the terrain.
The investigation
The Austrian Federal Safety Investigation Board (SUB) examined the wreckage, analyzed data from the onboard collision warning device, and reviewed witness statements. The investigation also reviewed the aircraft's maintenance records, the pilot's flight experience, and the prevailing meteorological conditions.
Investigators found that the aircraft was properly registered and maintained, with its weight and center of gravity within permissible limits. The pilot possessed a valid license and sufficient flight experience for the mission. However, the investigation noted that the flight manual on board was an outdated revision (Revision 4), whereas the current manufacturer-approved version (Revision 7) listed a higher stall speed due to changes in maximum allowable mass.
Findings
- The primary cause of the accident was a loss of control in flight near the terrain.
- The aircraft was flying at a very low altitude above the ground when the loss of control occurred.
- There was an insufficient speed margin to safely manage the prevailing weather conditions, which included strong westerly winds and turbulence near the ridge.
- The presence of an outdated flight manual meant the pilot was operating with incorrect stall speed information, as the current revision indicated a higher stall speed than the manual on board.