The Iranian Constitution stipulates that in the event of the president's death, the first vice president is to assume the powers and functions of the president, subject to approval by the Supreme Leader.
If the current president were to pass away, First Vice President Mohammad Mokhber would step into the role, pending the approval of Iran's Supreme Leader Ayatollah Ali Khamenei. Reports indicate that Mokhber was en route to the location where the president's helicopter had crashed.