What happened
On March 10, 1979, at approximately 18:35 local time, a flight instructor and a student pilot departed from Altenrhein in a Piper J3C, registration HB-OEM, intending to fly to Sitterdorf under Visual Flight Rules (VFR). During the flight, the pilot became distracted while testing a newly installed cabin heater. In this interval, the aircraft's heading drifted southward.
As darkness fell prematurely due to heavy snowfall and deteriorating weather, the pilot lost situational awareness. The instructor, perceiving the blurred lights of nearby towns through the snow, mistakenly believed he was experiencing a sudden medical impairment or dizziness. Realizing he could no longer navigate to the intended destination, the instructor attempted an emergency landing in a field near Ruezenwil, near Bernhardzell. During the maneuver, the aircraft descended at a steep angle and struck the ground at approximately 18:50. The impact resulted in two serious injuries and the destruction of the aircraft.
The investigation
The investigation examined the flight path, the meteorological conditions, and the mechanical state of the Piper J3C. Investigators found that while the aircraft was airworthy and the crew held valid licenses, the visibility had dropped to approximately 100 meters due to active snowfall. The investigation also noted that the aircraft was approximately 25 kg over its maximum takeoff weight, though this was not considered a contributing factor to the crash.
Findings
- The pilot lost orientation because the onset of darkness and heavy snow occurred earlier than anticipated due to weather conditions.
- The instructor failed to plan for an adequate daylight reserve when departing.
- The pilot's brief distraction with the cockpit heater allowed the aircraft to deviate from its intended course.
- The emergency landing attempt failed as the aircraft's airspeed fell below the minimum required level during the final approach.