What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Wing separated from aircraft in flight. (.4)the pilot was conducting a practice aerobatic flight, with two aerobatic pilots critiquing him from the ground. About ten minutes into the flight, the pilot initiated a pull toward the vertical with about 360 km/hr and 7 gs, according to witnesses. This would have been well within the maximum airspeed and load specifications of 450 km/hr and 10 gs, respectively. The right wing of the airplane separated during the pull up. The airplane entered a right roll and an uncontrolled descent, then it collided with the ground about 1 mile north of the airport. According to witnesses, the engine was developing power until impact, and the pilot did not announce any malfunctions or problems, prior to the wing failure. A postcrash ground fire consumed the fuselage. The unburned right wing was found about 3/4 mile east of the main wreckage. Testing of the wing spar was performed by the NTSB and mak (russian investigative authorities). Both agencies found numerous voids in the composite spar caps. The investigation revealed evidence that the curing process for the wing spar did not provide adequate vacuum pressure. Ther e was evidence that during the curing process, the fibers separated from each other, which resulted in voids in the final composite material.
As the FAA filed it
WING SEPARATED FROM AIRCRAFT IN FLIGHT. (.4)THE PILOT WAS CONDUCTING A PRACTICE AEROBATIC FLIGHT, WITH TWO AEROBATIC PILOTS CRITIQUING HIM FROM THE GROUND. ABOUT TEN MINUTES INTO THE FLIGHT, THE PILOT INITIATED A PULL TOWARD THE VERTICAL WITH ABOUT 360 KM/HR AND 7 GS, ACCORDING TO WITNESSES. THIS WOULD HAVE BEEN WELL WITHIN THE MAXIMUM AIRSPEED AND LOAD SPECIFICATIONS OF 450 KM/HR AND 10 GS, RESPECTIVELY. THE RIGHT WING OF THE AIRPLANE SEPARATED DURING THE PULL UP. THE AIRPLANE ENTERED A RIGHT ROLL AND AN UNCONTROLLED DESCENT, THEN IT COLLIDED WITH THE GROUND ABOUT 1 MILE NORTH OF THE AIRPORT. ACCORDING TO WITNESSES, THE ENGINE WAS DEVELOPING POWER UNTIL IMPACT, AND THE PILOT DID NOT ANNOUNCE ANY MALFUNCTIONS OR PROBLEMS, PRIOR TO THE WING FAILURE. A POSTCRASH GROUND FIRE CONSUMED THE FUSELAGE. THE UNBURNED RIGHT WING WAS FOUND ABOUT 3/4 MILE EAST OF THE MAIN WRECKAGE. TESTING OF THE WING SPAR WAS PERFORMED BY THE NTSB AND MAK (RUSSIAN INVESTIGATIVE AUTHORITIES). BOTH AGENCIES FOUND NUMEROUS VOIDS IN THE COMPOSITE SPAR CAPS. THE INVESTIGATION REVEALED EVIDENCE THAT THE CURING PROCESS FOR THE WING SPAR DID NOT PROVIDE ADEQUATE VACUUM PRESSURE. THER E WAS EVIDENCE THAT DURING THE CURING PROCESS, THE FIBERS SEPARATED FROM EACH OTHER, WHICH RESULTED IN VOIDS IN THE FINAL COMPOSITE MATERIAL.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.