2014 Mantes-Chérence glider tow accident (F-GEIJ)

Overview and flight details On 20 April 2014 at about 15:45 local time, a Robin DR400-180R registered F-GEIJ, operated by a club, was conducting a non-commercial aerial work flight for glider towing at Mantes-Chérence aerodrome (95). The aircraft was carrying its pilot in command. The pilot was slightly injured, and the aircraft was destroyed. ## Sequence of events The pilot was on his fourth tow of the day, towing a Schempp-Hirth Duo Discus glider with two people aboard. The glider pilot reported that the glider lifted off at about 80 km/h and found it abnormal that the tow plane had not yet become airborne at the intersection with runway 04/22, located 700 m from the threshold of runway 12. The glider pilot released the tow cable and landed. The tow plane continued its takeoff roll, overran the runway longitudinally, broke through a fence, and entered a wheat field. It lifted off and bounced several times before colliding with trees 337 m beyond the runway end. The pilot managed to exit the aircraft, which then caught fire. ## Wreck examination and pilot information Because the wreck was completely burned, investigators could not examine the engine or determine the position of the flaps or trim. The 78-year-old pilot held a private pilot licence for aeroplanes and a glider pilot licence, both issued in 1970, and had obtained his glider towing qualification in 1980. At the time of the accident, he had 1,098 hours of flight time in aeroplanes and 3,310 hours in gliders. He had not flown since November 2013 due to low winter gliding activity. The pilot said he had not detected any engine problem; initial acceleration seemed normal, but he thought he had not been able to exceed 80 km/h. He did not explain why he attempted to continue the takeoff after leaving the runway and had not conducted a pre-takeoff briefing. The glider pilot estimated the tow plane’s speed at about 100 km/h. ## Performance and survival To allow the tow plane the full runway length, the glider had been positioned before the threshold of runway 12, as is customary at this aerodrome. The flight manual recommended a rotation speed of 100 km/h and indicated a grass takeoff roll distance of 300 m for a 750 kg tow plane with takeoff flaps, towing a 600 kg glider at 15 °C. The glider’s mass was about 540 kg and the tow plane’s mass 670 kg. Witnesses estimated a headwind of about 10 km/h, and the temperature was 15 °C. The pilot confirmed he had set the flaps to the takeoff position. The glider’s FLARM recorded its position every four seconds during takeoff; despite low precision, the calculated speed from the two last positions before the glider descended was about 120 km/h. The glider pilot’s testimony and FLARM data indicated the tow plane had reached or exceeded rotation speed and the pilot was likely able to take off. The pilot was wearing a harness, which prevented him from being injured or losing consciousness when striking the instrument panel during the tree impact. He was able to unlock and partially open the canopy, but it became stuck halfway. He did not think to jettison the canopy but still managed to exit the aircraft.