Collision between a Robin DR 400/180 R and a model aircraft in Reinheim

Overview and Damage Assessment On 25 September 2021, a collision occurred between a Robin DR 400/180 R and a model aircraft in the vicinity of Reinheim. The incident resulted in no injuries. The Robin DR 400/180 R sustained heavy damage, while the model aircraft was destroyed. No third-party damage was reported. ## Aircraft and Personnel The involved aircraft was a Robin DR 400/180 R, a single-engine low-wing aircraft with a fixed tricycle landing gear. It was operated by an air sports club and had a maximum takeoff mass of 1,000 kg. The aircraft was built in 1977 and had a total operating time of 6,425 hours and 47 minutes. The pilot was a 56-year-old holder of a Part-FCL Private Pilot Licence (PPL(A)) with a valid glider towing endorsement. The model aircraft was a custom-built single unit with a wingspan of approximately 1.6 meters and a maximum takeoff mass of approximately 3.5 kg, powered by a 10 cc two-stroke engine. The remote pilot was a 55-year-old with 42 years of model flying experience. ## Sequence of Events The Robin DR 400/180 R took off from runway 19 at the Reinheim glider airfield at 15:25:02 local time, towing a DG-1000S glider. Approximately two to three minutes before the collision, the model aircraft took off from a model airfield located about 2 kilometers southeast of the glider airfield. The towed glider's pilot radioed the Robin pilot less than a minute after takeoff, reporting a model aircraft ahead at the 11 o'clock position at approximately the same altitude. The Robin pilot subsequently observed the model aircraft at the 1 o'clock position, initially below his altitude. The model aircraft moved from left to right, turned right, and descended out of the pilot's field of view. The towed glider's pilot also lost sight of the model aircraft. A few seconds later, the model aircraft reappeared and collided with the left horizontal stabilizer of the Robin DR 400/180 R at approximately 15:26:05 local time. The collision occurred at the southwestern boundary of the model airfield at an altitude of approximately 300 meters above mean sea level (AMSL) or 100 meters above ground level (AGL). ## Post-Collision Actions The collision nearly completely severed the left horizontal stabilizer of the Robin DR 400/180 R. The glider pilot informed the Robin pilot via radio of the collision and the missing stabilizer. The Robin pilot noted a vibration and a slight nose-down pitch, which was corrected by retrimming. A slight sideslip was corrected with rudder input. The pilots agreed via radio for the glider to release the tow. Both aircraft landed at the departure airfield a few minutes later. ## Site and Regulatory Context The model airfield is located approximately 2,200 meters southeast and 50 meters above the glider airfield. It falls within the protected areas defined for glider airfields and within the standard circuit for runway 19. The model airfield's operating permit, first issued in 1987 and amended in 1992 and 2002, restricted combustion-engine model aircraft to a maximum altitude of 100 meters above ground. The permit also required that model aircraft be continuously observed by the operator and must always yield to other manned aircraft. A 300-meter radius flight sector west of the airfield was established in a 2002 amendment. The Robin pilot stated he had occasionally seen model aircraft near the accident location but was unaware of the model airfield's existence until after the incident.