Both Russia and China have used airplane crashes to get rid of politicians they had concerns about. Recently, the Wagner group was wiped out in total. Further back in time, a mysterious crash helped Mao consolidate control. It’s convenient, and it has plausible deniability. The suspect list is probably pretty long, but I’d wonder who in Iran’s elite benefits the most.
Of course, it’s entirely possible it’s an accident. But if there’s a few more mysterious deaths and someone new in Iran acquires more control or power...well...just coincidence.
BTW, both Iran and China have been making hay in the remote countries that Russia has considered their back yard. It has caused quite a bit of consternation in the Kremlin. Problem is, other than running propaganda and black ops there’s not a thing Russia can do about it at the moment. And those countries have been hit hard by Russian stealth mobilizations. I forget which regional president just said, “If they have another mobilization here, it will wipe out the future of our country entirely.” He was shown wearing a yellow and blue ribbon on his lapel. (Ukrainian colors.)
Either somebody really wanted to put an end to this copter shuttle backdoor diplomacy or somebody found this to be just too much of a fine opportunity to quickly and quietly reshuffle Iran’s leadership.