What happened
On October 8, 2010, a pilot was conducting winch-launch training at the Pavullo nel Frignano airport in Italy. The session involved a series of successive takeoffs and landings on a grass area adjacent to runway 02. The weather conditions at the time were characterized by low cloud bases, calm winds, and persistent light rain.
Following the second takeoff, the pilot attempted to land on the grass strip. However, the pilot was unable to bring the ASK-13 glider, registration I-SANO, to a halt before it struck the airport's perimeter fence. The impact caused structural damage to the forward fuselage, both wings, the tail surfaces, and the tail boom of the aircraft, as well as damage to the airport fencing. The pilot escaped the accident without injury.
The investigation
The ANSV investigation examined the aircraft's mechanical condition, the meteorological environment, and the operational procedures at the aerodrome. Investigators found that the aircraft's braking systems were functioning correctly and that the glider was airworthy.
While the weather was not critical for winch-launching, the light rain had significantly reduced the braking effectiveness of the grass surface. The investigation also revealed that the grass area being used for takeoffs and landings was not an authorized operational area; official documentation indicated that only the asphalt runway 02/20 was permitted for flight operations. Despite this, the investigation noted that using the adjacent grass strip for winch-launching was a common practice at the aerodrome and was even advertised on the operator's website.
Findings
- The primary cause of the accident was an inadequate landing maneuver performed on an unauthorized area, without sufficient consideration for the available stopping distance or the reduced braking coefficient caused by the rain.
- The presence of puddles and the wet condition of both the main wheel brake and the front skid (wetted by the previous landing) contributed to the loss of braking effectiveness.
- The pilot's touchdown point was too far advanced for the available space.
- A contributing factor was human complacency, stemming from the repetitive and seemingly simple nature of the training maneuvers at a well-known airfield.