Greetings,
Mr. BK. I stole this from another site but it seems plausible and accounts for the initial denial of guilt. One branch of government not talking to another. Not uncommon. Very slight editing on my part to make it easier to read...
"Suppose the Iranian authorities who spoke publicly both told the truth.
Day 1. The head of Iran Civil Aviation (Abedzadeh) said the plane had reached a post take off height, had received permission to climb, then experienced a mechanical problem and was returning to the airport. Then radio contact ended and the plane crashed.
Day 2. American 'sources' said the plane was shot down. Iran head of civil aviation denied this, saying the plane was returning and was in safe air space. He said there were 9 other planes in the air in the safe air space.
Day 3, Iran military, head of ground air defense (Salami) said one of his units had fired on the plane. He described how that happened. The anti aircraft operator thought he had a missile or hostile plane headed to the airport or the city. Looks like Iran has safe air space for civilian craft, and restricted air space because of imminent threats. (They had received threats of missile)
Our plane takes off, gets permission to climb, on climbing has an engine glitch, turns to go back to the airport, inadvertently enters restricted air space, spotted and identified as possible threat, fired on. Civil aviation knows only that the aircraft has reported a mechanical problem and is returning, so they don't know about the missile. So when Abedzadeh goes public, he says what he knows, and in reply to American allegation he denies because he figures mechanical problem. It's only the next day he hears military role in firing on the plane."