Opening move against the Iran nuclear threat?
This also may be an internal action.
It has been said here on FR that Ahmadinejad wanted to replace Supreme Leader Khamenei with a mullah of his own choice, but that it would be difficult because so many of the leaders in the IRGC were loyal to Khamenei. It appears that all the men who died in the crash were Khamenei loyalists (they reported to the Supreme Leader and not to Ahmadinejad).
This may be a prelude to further consolidation of power by Ahmadinejad.