WPR24FA309 · Nanchang China CJ-6A

The pilots departed in separate airplanes (a Nanchang CJ-6A and a Yak 52) as a formation flight from the same airport, with the Yak as the lead airplane and the CJ-6A as the dash 2 (wingman) off the Yak’s right wing. According to the Yak pilot, during the flight the pilots briefed their detachment procedure over the radio because they were bound for separate destinations. The briefed procedure was for them to accelerate from 210 kilometers per hour (kph) to 250 kph, at which time the CJ-6A would pitch up and bank left toward the east while the Yak would continue straight. However, during the detachment, and while the Yak pilot looked away briefly to scan his instruments, the CJ-6A entered a slightly inverted and nose-low position above the Yak and the airplanes collided. The Yak’s propeller blades separated and the pilot subsequently made a forced landing on a nearby road, while the CJ-6A rolled right several times and then impacted the ground. Postaccident examination of the CJ-6A and Yak did not reveal any preimpact mechanical anomalies or malfunctions that would have precluded normal operation. The CJ-6A accident site signatures indicated that the airplane impacted the ground in a wings-level and slightly nose-low attitude as most of the energy was absorbed by the lower engine bay. Paint transfer markings and damage signatures from both airplanes indicated that the airplanes collided when the CJ-6A was inverted and canted slightly right of the Yak’s longitudinal axis. The Yak’s propeller impacted the CJ-6A’s left wing and the Yak’s left wing impacted the CJ-6A’s vertical stabilizer, which resulted in a partial separation of the airfoil. There was insufficient evidence to determine either airplane’s final movements prior to the midair collision. The CJ-6A was not equipped with an ejection seat; however, the pilot had a parachute and may have decided to jump from the airplane since the wreckage indicates that the pilot’s canopy was fully open at impact. However, a witness reported that the airplane was in a roll prior to its collision with terrain, so the pilot may not have been able to initiate a jump. Toxicological testing detected the presence of ethanol in the CJ-6A pilot’s cavity blood and gastric contents. Ethanol was not detected in the pilot’s vitreous fluid, which is the preferred specimen type. The other two tested specimen types also contained npropanol. In the presence of extensive injury, this indicates that the detected ethanol likely was from postmortem sources rather than alcohol consumption. It is unlikely that the CJ-6A pilot was impaired by the effects of ethanol at the time of the accident. The pilots were both part of an association that teaches pilots the fundamentals of formation flight through various clinics. The detachment procedure they used was not in the association’s formation flight manual. In addition, while the Yak pilot reported that they briefed the procedure, there were no recordings to show how the detachment procedure was communicated and whether there were any interpretation errors. The pilot of the CJ-6A did not exhibit any abnormal behavior over the radio or on the ground prior to departure and the flight was not in an area of adverse weather conditions, so it is unknown why the CJ-6A pilot rolled into a nearly inverted position during the detachment. While the accident was initiated by the CJ-6A pilot’s improper roll during the detachment procedure, the Yak pilot failed to continue monitoring the CJ-6A during a critical time as he turned his attention away from the airplane during the detachment.

Verbatim NTSB analysis and probable cause from the NTSB dataset