RENO, Nev. (AP) — Authorities have released the names of two California pilots who died over the weekend in a collision during an air racing event in Reno.

Officials identified the victims as Chris Rushing of Thousand Oaks and Nick Macy of Tulelake.

The two planes collided at the end of the T-6 Gold race Sunday afternoon on the final day of the National Championship Air Races at Reno-Stead Airport, authorities said.

Race officials said they are cooperating with the National Transportation Safety Board, the Federal Aviation Administration and local authorities to determine the cause of the fatal crash.

“It wasn’t a racing accident. It was indeed a post-race landing accident,” Reno Air Racing Association CEO Fred Telling said. “We all are curious of how this came to pass.”

Telling described Rushing and Macy as skilled, expert pilots who had just finished in the top two spots in the T-6 Gold race.

Rushing was the defending champion in the race. He was dedicated to promoting the history of the World War II-era AT-6 Texan trainer plane as head of a non-profit organization in Van Nuys, California, The Orange County Register reported.

The crash marred the final year of the National Championship Air Races at the Reno-Stead Airport after nearly six decades.

The event has to find a new location because of increased development around the airport and other concerns, organizers said.