The jet is the world's most expensive weapons system and costs have rocketed One went down over Beaufort, South Carolina at 11.45am local time today The pilot ejected before the crash and is now being treated by medical personnel The F-35B jet went down near a military base in South Carolina, US as photographs from the scene show a thick cloud of smoke enveloping the area. The Ministry of Defence has said it will not be grounding any planes for the time being - but that could change following the investigation. A US F-35 pilot was forced to eject midair after the $100million fighter jet crashed in South Carolina (pictured; the smoking aftermath of the crash) A thick cloud of smoke enveloped the area around the crash site close to a military base in South Carolina Today the Marine Corps are busy investigating what caused one of the planes to go down during a training exercise at 11.45am local time today. A spokesman said: 'Marines from MCAS ...