What happened
On August 5, 2020, a Zlin Aviation Savage ultralight aircraft was conducting a low-altitude flight over the Iserlohn-Rheinermark airfield. The mission was intended to locate a tow rope that had broken during a glider winch launch earlier that day. The pilot, accompanied by a passenger, took off from runway 25 at 10:25 AM to search for the cable, which was believed to have landed south of the airfield.
Witnesses on the ground observed the aircraft flying at an altitude between 40 and 70 meters AGL. The aircraft was flying with its first stage of flaps extended and the cockpit door open. During the flight, the aircraft performed a left turn parallel to the airfield. Witnesses noted that the engine sound remained normal throughout the maneuver. However, as the aircraft transitioned from a left turn into a right turn, it suddenly pitched over the right wing. The passenger reported attempting to alert the pilot to the dangerously low airspeed, but the pilot did not respond.
The aircraft entered a spiral dive, rotating approximately 270 degrees around its longitudinal axis, before impacting the runway. The impact was severe enough to trigger the aircraft's emergency parachute system. The crash resulted in one fatality and one serious injury.
The investigation
The BFU examined the wreckage and the flight conditions. The investigation confirmed that the aircraft's center of gravity was within permissible limits. Technical inspections of the wreckage showed no evidence of mechanical failure or control system malfunction. All bolts, struts, and fasteners were intact. The investigation also noted that the aircraft's flight manual specifies that airspeed indications may be inaccurate when flying with an open door.
Findings
- The aircraft entered an uncontrolled flight state characterized by a wing drop and a subsequent spiral dive.
- The pilot failed to respond to warnings regarding critically low airspeed during the maneuver.
- The aircraft struck the ground nearly vertically, leading to the destruction of the airframe.