The pilot, accompanied by a passenger seated in the cockpit, took off around 12:15 on an IFR flight plan from Figari on the isle of Corsica to La M“le, France. At 12:30, while the aircraft was descending, the pilot contacted the Nice Approach controller and requested authorization to perform an approach via the EM point. The controller contacted the Nice Info controller by phone to inform him of the aircraft’s arrival. After this contact, he informed the pilot that there was heavy rain, visibility four kilometers at the destination and asked him what his intentions were. The pilot replied that he was reducing speed to minimum and requested a heading to avoid bad weather. The controller agreed and asked him to contact the Nice Info controller. Nice Info told the pilot to continue as previously cleared and to keep him informed of his intentions. The pilot replied that he would wait for the showers to end at La M“le and then make an approach via the EM point. The controller replied to call him back when he was ready to turn to the EM point and asked him to descend to FL60. A few minutes later, the pilot told the controller that he could not contact the AFIS agent at La M“le and asked him to tell him when the showers had passed. The controller agreed and contacted the La M“le AFIS agent by telephone to ask him to keep him informed of the progress of the showers. Three minutes later, although he had not received any information on the weather evolution, the pilot asked to turn towards the EM point. In the following minutes, the pilot requested several course changes for weather avoidance. After reaching the EM point, the controller cleared him for a visual approach to runway 24 and then asked him to contact the La M“le AFIS agent. The latter indicated that he was alone in the aerodrome circuit, asked him to call back on final approach and gave him the wind conditions (030ø, 3 kt). The pilot made a first approach, which he interrupted because he could not see the runway due to clouds. He indicated to the AFIS agent that he was returning to the EM point. The AFIS agent gave him the wind conditions (040ø, 4 kt) and asked him to call back on final approach. While the aircraft was heading towards EM , the AFIS agent reported the cloud cover (scattered clouds at 1800 ft). Two minutes later, the pilot asked for visibility on the final approach. The AFIS agent indicated a visibility of 4 to 5 km, before informing him that he had it in sight and giving him the last wind conditions (070ø, 3 kt). On the approach the true speed of the plane varied between 145 kt and 150 kt. The aircraft touched the runway 200 m after the threshold of runway, at a true airspeed of 136 kt. The pilot set the flaps to “full ground” and the spoilers deployed. The aircraft crossed taxiway B thirteen seconds later, at a true airspeed of 77 kt. It continued onto the paved strip beyond the end of runway 24 and veered left. It left the paved surface at a true airspeed of 41 kts and descended into the river below. The aircraft’s nose struck the opposite bank hard. The pilot was able to evacuate the aircraft through the emergency exit located at the rear and right side of the aircraft. It appeared that the landing distance of the aircraft on a wet runway as defined in the AFM performance tables was not compatible with the runway length available at La M“le Airfield. During the preparation of the flight, the pilot used the flight file provided by the operator to determine the landing performance. The landing distance on a wet runway presented in this file increased the landing distance on a dry runway by 15%. However for commercial operations, 60% must be added. Furthermore, on final approach, the aircraft speed was higher than the reference speed on approach and the approach slope was also higher than the nominal slope, which resulted in an increase in landing distance. Contributing factors: – The operator’s use of the same operations manual for two different types of operations; – The absence in the operations manual of a calculation method, coefficient and safety margin for the calculation of performance in non-commercial transport; – Lack of knowledge by the pilot and the operator of the method of calculation of landing performance in non-commercial transport; – The lack of indication in the operations manual that the landing performances at La M“le aerodrome are limiting in case of a wet or contaminated runway.