Ka 4 Rhönlerche II structural failure near Boltigen results in fatal crash

On August 12, 1967, a Ka 4 Rhönlerche II experienced a structural failure during an aerotow near Boltigen, Belgium. The glider detached from the towline and entered a steep dive, during which flutter was observed on the wingtips. Shortly after, parts of the right aileron detached, leading to a loss of control. The aircraft collided with the terrain, resulting in the destruction of the glider and the fatality of the pilot. The investigation noted that flutter and aileron failure were contributing factors to the accident.