A jumbo jet-sized mystery has landed in the lap of Argentine officials, who are trying to determine what to do with a Venezuelan-owned Boeing 747 cargo plane with a load of automotive parts and an unusually large crew of 17, including at least five Iranians. The plane operated by Venezuela's state-owned Emtrasur cargo line has been stuck since June 6 at Buenos Aires' main international airport, unable to depart because of U.S. sanctions against Iran and suspicions about its crew.