What happened
On October 6, 1974, a pilot departed Karlsruhe, Germany, for a private VFR flight to Friedrichshafen, accompanied by his wife. After an initial period of thorough weather briefing, the pilot performed a precautionary landing in Freiburg, Germany, due to unstable weather. During this stop, which lasted over 90 minutes, the pilot did not seek a new weather forecast or refuel the aircraft.
Upon departing Freiburg, the pilot observed a localized improvement in weather from the west and decided to redirect the flight toward Friedrichshafen. To avoid the Zurich control zone without contacting air traffic control, the pilot navigated north of the Trasadingen radio beacon. During this phase, the pilot relied primarily on a radio compass for orientation and estimated the altitude visually at approximately 500 meters.
As the aircraft passed north of the Trasadingen beacon, it encountered low-lying cloud banks. While attempting to climb above these clouds, the pilot deactivated the carburetor heat. The aircraft failed to climb as expected, and the engine power appeared to diminish. In an attempt to turn back, the aircraft entered the clouds, struck a wooded hilltop, and crashed near Beggingen, Switzerland.
The investigation
Investigators examined the pilot's background and the technical state of the MS-893A (D-EHRF). The pilot was a licensed private pilot with significant military training and over 160 hours of flight experience. Toxicology reports confirmed the pilot was sober at the time of the accident.
The investigation found the aircraft to be airworthy, with no significant mechanical failures identified. While a minor defect was noted in the right magneto, the engine was determined to be functional up to the moment of impact. The aircraft's weight and center of gravity were within permissible limits.
Meteorological analysis revealed highly unstable conditions across Central Europe that day, characterized by low cloud bases and the risk of icing at altitudes above 1000 meters. The investigation also noted that the pilot had left the altimeter set to QFE (pressure at field elevation) rather than QNH, which prevented a direct reference to the altitudes indicated on navigational charts.