Two aircraft that were part of the Indian Air Force’s (IAF) acrobatic demonstration team, Surya Kiran, collided in mid-air on Tuesday while practicing for an upcoming air show. The jets, Hawk 132 trainers made by BAE, were attempting a “mirror” maneuver when the accident occurred. According to Flight Global, at least two pilots were able to eject, but another was pronounced dead. The surviving pilots sustained significant injuries, and according to the IAF, one pilot suffered two broken legs and was taken into surgery.

“Today at around 11:50 a.m., two Hawk aircraft of Surya Kiran aerobatic team of IAF crashed while practicing for the Aero India Air Show,” the IAF said in a statement, according to the Times of India. “Three pilots occupants. Two pilots ejected and have been evacuated to the Command Hospital. The third pilot sustained fatal injuries. Damage to life and property in the vicinity of the crash site is being ascertained.”

Surya Kiran is the IAF’s version of the U.S. Air Force’s Thunderbirds and typically flies in a formation of nine. Although the Hawk has two seats, under normal conditions, only one pilot is on-board. The remaining seven Surya Kiran aircraft are grounded, and the IAF stated that an investigation into the cause of the crash is being launched.

The mirror maneuver the two aircraft were attempting involves one aircraft flying above and inverted over another. According to Flight Global, the nose of the inverted plane impacted the wing of the other, which resulted in the crash. The two Hawks impacted the ground in a residential area near several houses. The extent of the damage to the aircraft made it difficult for rescue crews to extricate the body of the third pilot. Reports say two civilians on the ground were also hurt.

The Aero India Air Show began in 1996 and has continued on a biennial basis since. According to the air show’s organizers, more than a million people attended the event in 2017. Although major business is done during Aero India, the five-day show also offers aerobatic displays from various aircraft, a “Drone Olympics,” and several seminars.

“Aero India 2019 will provide a significant platform in bolstering business opportunities in the international aviation sector,” wrote organizers on the air show’s website. “A rapidly growing economy and opening up of defense production to the private sector have given a major fillip to the defense industry in India. It has also become a hub for defense businesses in Asia.”