Tehran, Iran (AP) Iranian investigators say the crew of the Ukrainian jetliner that crashed outside Tehran the previous day never made a radio call for help and were trying to turn back to the airport when the plane went down. Iran’s civil aviation authority made the comments in a preliminary crash report released on Thursday. Wednesday’s crash killed all 176 people on board the Ukrainian jetliner, many of them from Iran and also Canada, but also of other nationalities. The plane crashed just hours after Iran launched a barrage of missiles at U.S. forces but while the timing of the disaster led to questions by some aviation experts, Iranian officials blamed mechanical trouble.