The downing occurred at a time of high tension between longtime foes Iran and the United States. Iran was on alert for attacks after it fired missiles at Iraqi bases housing U.S. forces in retaliation for the killing on Jan. 3 of its most powerful military commander, Qassem Soleimani, in a U.S. missile strike at Baghdad airport.
“A failure occurred after the relocation of one of the air defense units of Tehran … It occurred because of a human error,” the CAO report said, adding that the plane was detected by the system as a target approaching Tehran.
The operator of the air defense system “lacked awareness of the relocation of the air defense unit,” and fired the two missiles without authorisation from the command center, the report said.
“When the first missile was fired, the passenger plane was flying at a normal altitude and trajectory,” the report added.
Last month, Iran said the black boxes of the Boeing 737-800 airliner will be sent to France, to be analyzed starting July 20. (Writing by Parisa Hafezi Editing by Frances Kerry)