Human error was behind the Jan. 9 missile strike that down the UIA flight shortly after it left Tehran airport, killing all 176 aboard. At an air defense unit, an operator foorgot re-adjust the north direction on the radar system after moving to a new position, an error that contributed to misreading the radar’s data, according to a report posted Saturday on the website of Iran’s Civil Aviation Organization. Six people have been arrested. Next Monday, six months after the shootdown, Iran promises to deliver the jet’s black boxes to Paris.