What happened
On October 21, 1959, a Piper J-3 aircraft, registration HB-OWY, departed from Locarno airfield with the intention of flying to Grenchen. During the flight, the pilot encountered deteriorating weather conditions on the southern side of the Simpl to the Simplon Pass. Initially, the pilot was able to fly between two distinct cloud layers; however, visibility progressively worsened.
While navigating through the fog, the pilot observed a patch of light and attempted to fly toward it, hoping to exit the cloud cover. This maneuver failed as the light disappeared and the aircraft became enveloped in dense fog. In an attempt to avoid what appeared to be an obstacle, the pilot initiated a turn, but the aircraft's right wing struck trees at approximately 1,960 meters altitude near Engiloch. The impact resulted in heavy damage to the aircraft, though the pilot remained uninjured.
The investigation
The investigation examined the pilot's qualifications, the aircraft's mechanical condition, and the prevailing meteorological circumstances. The pilot held a valid private pilot license and had significant experience in both glider and powered flight. The Piper J-3 was found to be in good mechanical condition, with no defects identified.
Meteorological analysis revealed a stagnant weather situation on the southern side of the Alps, characterized by fog covering slopes above 1,100 meters and a secondary cloud layer. The investigation also reviewed the regulatory requirements for flight in conditions that necessitate instrument flight, noting that the pilot and the aircraft did not meet the necessary formal or material requirements for such operations.