A member of the U.S. Air Force was killed Tuesday while riding in the back seat of a Ukrainian fighter jet that crashed while taking part in an exercise, the military announced on Wednesday. The Ukrainian pilot was also killed.

The U.S. airman, who has not yet been identified while family members are notified, was taking part in a “familiarization flight” during the multinational exercise in Ukraine, according to a statement from U.S. Air Forces in Europe.