Ukraine’s military intelligence says a Russian Su-57 fighter exploded at Akhtubinsk airfield on October 29 during engine startup.

Ukraine’s military intelligence says a Russian Su-57 fighter exploded at Akhtubinsk airfield on October 29 during engine startup. The aircraft is valued at around $150 million. GUR notes that catastrophic failure of its AL-41F1 engines can have several causes, including poor-quality fuel.