What happened
On January 24, 1968, a student pilot was conducting solo training flights at Samedan Airport. Following a successful landing, the pilot attempted a "touch-and-go" maneuver. After touching down on runway 03, the pilot immediately applied full power without allowing the aircraft to roll out or adjusting the flap settings.
While the flaps were initially set at 30 degrees for landing, the pilot attempted to correct the configuration during the takeoff roll but mistakenly extended the flaps to the full 40-degree position. This caused the Cessna 150, registration HB-CBW, to lift off in an exaggerated flight state. The aircraft climbed only a few meters before banking sharply to the left. The left wing eventually struck the snow near a fence post, causing the aircraft to spin and come to rest on its nose and right wing.
The investigation
The investigation was conducted by the Swiss Federal Office of Civil Aviation following a report from the airport manager. Due to heavy snowfall and road closures caused by avalanches, investigators initially relied on photographic evidence and written reports before conducting an on-site inspection.
The inquiry examined the pilot's training records, noting that while the student had recently passed a proficiency test, they had been flying various models of the Cessna 150 with different flap actuation systems (manual and electric). The investigation also reviewed the aircraft's maintenance history and the specific sequence of pilot inputs during the maneuver.
Findings
- The pilot failed to allow the aircraft to roll out after landing before applying full power.
- The pilot did not retract the flaps from the 30-degree landing setting to the required 10-degree takeoff setting.
- The primary cause of the accident was the incorrect extension of the flaps to the full 40-degree position during the takeoff phase.
- The high drag from the full flaps, combined with high engine power, induced an exaggerated flight state and a leftward yaw due to torque.
- The pilot's attempt to correct the heading with aileron input was ineffective; the investigation noted that the pilot should have prioritized nose-down pitch before attempting directional corrections.
Safety action
No specific safety recommendations were recorded in the final report, as the incident was attributed to the pilot's specific error during a single maneuver.