What happened
On August 10, 1968, a Cessna 150 (registration HB-CBY) was engaged in a low-altitude flight near Lumino and Monticello in Switzerland. The pilot, who had recently passed his private pilot examination earlier that same day, began a flight following permission from his instructor.
During the flight, the pilot encountered turbulence and downdrafts near the valley mouth of Misox, causing him to descend from approximately 2,100 feet to between 900 and 1,000 feet. While flying near his family's residence, the pilot performed a series of low-level maneuvers. During a left-hand turn, the aircraft's left wing struck the top of a tree, and the aircraft simultaneously collided with an electrical power line. Despite significant damage to the wing, engine cowling, propeller, and right wing strut, the pilot managed to navigate the aircraft back to Locarno and perform a safe landing.
The investigation
Investigators examined the pilot's flight history and the circumstances of the maneuver. It was established that the pilot had only recently completed his theoretical examinations and was flying with very limited experience. While the pilot initially claimed that downdrafts forced him to fly at a dangerously low altitude, he later admitted that the low-level flight over his parents' house was intentional, intended to draw their attention.
Witnesses in the area observed the aircraft flying at an altitude barely exceeding the local church tower and performing multiple left turns. The investigation also noted that the electrical lines, which were approximately 12 to 15 meters high, were difficult to distinguish from the surrounding vegetation and trees.
Findings
- The pilot performed an intentional low-level flight over a residential area to attract the attention of family members.
- The pilot lost control of the aircraft's altitude and positioning during a left-hand turn.
- The primary cause was the pilot's loss of control during a low-altitude maneuver, which led to the sequential impact with a tree and power lines.
- The collision with the electrical wires caused a short circuit and a local power outage.