2012 Flight Design CTSW accident at Ingenried

Overview and flight details On 27 July 2012, a Flight Design CTSW ultralight aircraft was involved in an accident near Ingenried. The pilot reported departing from Bad Wörishofen for a long circuit flight. After about one hour, he decided to return to the departure airfield. During the flight, he performed a horizontal figure-eight maneuver. Shortly after completing the maneuver, around 10:19 local time, the front cockpit glazing broke with a loud bang. The aircraft then entered an uncontrolled flight state, which the pilot regained control of. The aircraft remained in a continuous descent, prompting the pilot to make an emergency landing. During the approach to a meadow, he activated the ballistic recovery system after shutting down the engine, at an altitude between 80 and 50 meters above ground. The aircraft was heavily damaged on hard landing, and the pilot sustained spinal injuries. ## Personnel and aircraft The 46-year-old pilot held a valid air sports pilot license for aerodynamically controlled ultralight aircraft with passenger privileges, valid until 3 September 2015. His Class 2 medical certificate was valid until August 2014. He reported approximately 300 total flight hours, with 2 hours 12 minutes and 27 landings on the affected aircraft type. The aircraft was a three-axis controlled, braced high-wing composite ultralight, manufactured by Flight Design GmbH in 2007, with serial number 07-06-15. It had 406 engine hours and was powered by a Rotax 912 ULS engine. The aircraft was equipped with a BRS 5/6 UL 4 SP ballistic recovery system. ## Meteorological and data information Witnesses reported summer weather with 25 degrees Celsius, light wind from the east at 3 knots, no clouds, and a pressure of 1,025 hPa. The aircraft was equipped with a Dynon system and a Garmin GPS 496, and radar recordings were available. The data showed the aircraft was flying at ground speeds between 207 and 275 km/h at the time of the event, and the altitude at the time of the cockpit glazing failure was approximately 1,800 feet. ## Accident site and aircraft findings The aircraft landed on a meadow near Ingenried, and the ballistic recovery system had been deployed. The nose gear was broken and bent forward, the windshield was shattered, and the main gear and pilot seat were also broken. The left horizontal stabilizer was detached and found in a wooded area about 3 kilometers away. The wings had cut-like scratches in the laminate in the torsion box area and on the upper surface. The underside of the fuselage and the right horizontal stabilizer were oil-stained. The landing flaps were in the neutral position. ## Ballistic recovery system and horizontal stabilizer investigation The minimum operating altitude of the ballistic recovery system was 80 meters according to its data plate. The manufacturer's inspection found the system was in the required maintenance cycle and the parachute had no damage. However, the auxiliary parachute was torn from the pack tube over a length of 19 of 34 centimeters, suggesting the base seam may have caught on the outer edge of the exit opening. The damping line stitches were only slightly torn, indicating the rocket impulse was already significantly reduced when the line was stretched. The horizontal stabilizer was investigated by Cranfield University in the United Kingdom. The report concluded that the most likely scenario was that the damage to the horizontal stabilizer was caused by an aerodynamic overload. Both the design of the horizontal stabilizer and suboptimal assembly increased the likelihood of failure. The manufacturer conducted a structural strength test with a comparable horizontal stabilizer from the same production period, which broke at a load of 523.6 kg, corresponding to a safety factor of 4.12.