What happened
On May 18, 2015, at approximately 13:00 UTC, an AS202 aircraft was performing a takeoff from Runway 05 at Hohenems Airfield in Vorarlberg, Austria. Shortly after liftoff, the aircraft experienced a low airspeed and began to drift to the left. During its initial climb, the underside of the aircraft's left wing collided with the cabin of a tractor that was traveling northeast within the runway safety strip. Following the impact, the aircraft crashed into the grass adjacent to the runway.
The occupants of the aircraft remained uninjured, though the aircraft sustained heavy damage. The driver of the tractor sustained minor injuries, and the tractor's cabin was also slightly damaged.
The investigation
The investigation established that the airfield manager had permitted the tractor to enter the airfield grounds to perform mowing duties. At the time the takeoff clearance was communicated to the pilot, the tractor was not yet within the runway safety strip. However, the tractor subsequently entered the safety area while the aircraft was departing.
Investigators found that the airfield manager was under significant professional stress due to a separate glider collision that had occurred at the same airfield earlier that day. Furthermore, the tractor was not displaying the required 1 x 1 meter yellow flag mandated for ground vehicles operating on movement areas; instead, it was marked only with red and white striped signs, which do not meet regulatory standards for visibility.
Findings
- The pilot initiated the takeoff despite the runway safety strip being obstructed by the tractor.
- The tractor was not properly marked with the required yellow flag.
- The aircraft lifted off prematurely at a low airspeed and failed to maintain the runway centerline.
- The airfield manager allowed the tractor to enter the airfield during active flight operations.
- The pilot only perceived the tractor immediately before the collision.