What happened
On February 14, 1968, a Cessna 210-5, registration HB-CMH, was performing a commercial taxi flight from Geneva-Cointrin to La Côte. After picking up three passengers, the pilot initiated a takeoff from runway 04. During the initial climb, the aircraft's stall warning activated. Shortly after reaching an altitude of approximately 1 to 1.5 meters, the pilot reduced engine power, causing the aircraft to descend back onto the runway.
As the aircraft continued down the strip, the pilot attempted to brake, but the plane could not be stopped before reaching the end of the runway. The aircraft crossed a road bordering the airfield and entered a vegetated area. During the excursion, the nose wheel dug into the soft ground, causing the aircraft to capsize onto its back. While the four occupants escaped without injury, the aircraft sustained approximately 75% damage.
The investigation
Investigators examined the aircraft and the airfield conditions at La Côte. The investigation confirmed that the aircraft was within its maximum takeoff weight, totaling 1412 kg. The flaps were found set at 15 degrees, and the propeller was in a fine pitch position. No mechanical failures were identified in the braking system or the landing gear, although the right wheel showed signs of intermittent contact with the ground during the overrun.
The airfield conditions were a significant factor; the grass runway was noted to be saturated and soft. Additionally, the investigation reviewed the pilot's recent experience, noting that while the pilot was professionally licensed, they had not flown this specific aircraft type since a transition training session in December 1967.
Findings
- The primary cause of the accident was the pilot's inappropriate decision to interrupt the takeoff after the stall warning sounded.
- The saturated and soft condition of the grass runway significantly reduced the effectiveness of the wheel brakes.
- The pilot's lack of recent experience with the Cessna 210-5 likely contributed to the decision to reduce power in response to the stall warning rather than maintaining airspeed.
- The use of 15-degree flaps, rather than the recommended setting for short-field takeoffs, may have influenced the aircraft's performance.