According to Qassem, the cause of the plane crash was because "fire struck one of the plane's engines…"
Don't you just hate it when fire strikes the plane you are on?
https://www.foxnews.com/world/ukrainian-plane-crash-tehran-iran-180-passengers
"Qassem Biniaz, a spokesman for Iran's Road and Transportation Ministry, said a fire struck one of the plane's engines, causing the pilot to lose control of the aircraft, sending it crashing to the ground. Ukrainian officials meanwhile said they are still working to confirm the circumstances surrounding the incident."