What happened
On September 28, 1965, a Cessna 182-H, registration D-EFHY, was conducting a private flight from Grenoble to Hannover with three occupants on board. Due to deteriorating weather conditions, the pilot performed a precautionary landing at Grenchen Airport. Upon landing on the northern runway, the pilot noted that the surface was extremely slippery due to recent rainfall.
After receiving updated weather information and clearance to continue toward Zurich, the pilot was assigned the middle grass runway (07). This runway, measuring 680 meters, was significantly longer than the northern parallel runway but was notably saturated and covered with large puddles. At approximately 16:20 CEST, the pilot initiated the takeoff roll with 20 degrees of flaps extended.
During the acceleration, the aircraft failed to reach the necessary rotation speed, reaching only about 40-50 mph when the required speed was approximately 65 mph. The pilot attempted to abort the takeoff, but shortly after reducing power, the engine power was increased again. This secondary acceleration attempt, combined with the slippery surface, prevented the aircraft from stopping. The plane overran the end of the runway, struck a field path, and the nose gear was torn away. The aircraft then slid into a ditch containing a stream, where it overturned and came to rest on its back.
The investigation
The investigation examined the aircraft, the runway conditions, and the sequence of pilot actions. Technical inspections of the Cessna 182-H revealed no mechanical defects; the engine, propeller, and fuel mixture settings were all found to be in normal operating condition. The investigation also noted that the aircraft's weight was approximately 1200 kg, well within its maximum takeoff weight of 1270 kg.
Investigators analyzed the runway state, noting that the grass was heavily soaked and the surface was highly slippery. The investigation also reviewed the pilot's decision-making process regarding the takeoff attempt and the subsequent decision to re-apply power during the abort sequence.