According to Skip Stewart who was flying in formation with him,
"Kirby's engine gave out and there was no other place for him to land, so he descended into a rocky ravine and crashed into the side of a steep embankment. The plane collided into the trees and flipped over. I called the rescue helicopter and they arrived immediately.The plane suffered serious damage, but Kirby escaped the aircraft on his feet.”
According to El Salvadorean military, Kirby is doing well, with superficial scratches and bruises.