A picture taken on October 12, 2018 shows the Ukrainian Su-27 UB fighter (Combat Trainer) flights during an air force exercises on Starokostyantyniv military airbase. - Ukraine's general staff said on October 16, 2018 that two pilots died when a Sukhoi fighter jet crashed during military exercises with the United States and other NATO countries. "A Sukhoi-27 plane crashed at around 5:00 pm local time (1400 GMT) during a training flight," the general staff said on its Facebook page, adding that "the bodies of the two pilots have been found." (Photo by Genya SAVILOV / AFP)

A picture taken on October 12, 2018, shows the Ukrainian Su-27 UB fighter (Combat Trainer) flights during an air force exercises on Starokostyantyniv military airbase. - Ukraine's general staff said on October 16, 2018 that two pilots died when a Sukhoi fighter jet crashed during military exercises with the United States and other NATO countries. "A Sukhoi-27 plane crashed at around 5:00 pm local time (1400 GMT) during a training flight," the general staff said on its Facebook page, adding that "the bodies of the two pilots have been found." (Photo by Genya SAVILOV / AFP)

A picture taken on October 12, 2018 shows the Ukrainian Su-27 UB fighter (Combat Trainer) at the Starokostyantyniv military airbase. - Ukraine's general staff said on October 16, 2018 that two pilots died when a Sukhoi fighter jet crashed during military exercises with the United States and other NATO countries. "A Sukhoi-27 plane crashed at around 5:00 pm local time (1400 GMT) during a training flight," the general staff said on its Facebook page, adding that "the bodies of the two pilots have been found." (Photo by Genya SAVILOV / AFP)

A picture taken on October 12, 2018 shows the Ukrainian Su-27 UB fighter (Combat Trainer) at the Starokostyantyniv military airbase. - Ukraine's general staff said on October 16, 2018 that two pilots died when a Sukhoi fighter jet crashed during military exercises with the United States and other NATO countries. "A Sukhoi-27 plane crashed at around 5:00 pm local time (1400 GMT) during a training flight," the general staff said on its Facebook page, adding that "the bodies of the two pilots have been found." (Photo by Genya SAVILOV / AFP)

A picture taken on October 12, 2018 shows the Ukrainian Su-27 UB fighter (Combat Trainer) flights during an air force exercises on Starokostyantyniv military airbase. - Ukraine's general staff said on October 16, 2018 that two pilots died when a Sukhoi fighter jet crashed during military exercises with the United States and other NATO countries. "A Sukhoi-27 plane crashed at around 5:00 pm local time (1400 GMT) during a training flight," the general staff said on its Facebook page, adding that "the bodies of the two pilots have been found." (Photo by Genya SAVILOV / AFP)