A pilot and co-pilot were killed Thursday afternoon when a small jet broke in half after it went off a runway, through a fence and into a road at the Greenville Downtown Airport, according to the coroner.Coroner Jeff Fowler said one pilot died at the scene of the crash and the other died at the hospital. The coroner identified the co-pilot as Stephen George Fox, 66, of Indian Rocks, Florida. He died at the hospital. Police said the crash was reported at about 1:40 p.m. The plane went off a runway, through the fence and down about a 200-foot safety area that includes a fairly steep embankment. It then crashed onto Airport Road and broke apart.Airport Director Joe Frasher said the jet's landing appeared "very normal," but something kept it from stopping.He said there were also two passengers on board. The passengers and the pilot who died were taken to the hospital, Coroner Parks Evans said. He said all four people on board were trapped in the wreckage after the crash. Frasher said early Thursday evening that one survivor was in surgery and the other was conscious and speaking.Frasher said the plane slammed into the ground nose first, and the fatalities and injuries were caused by blunt force trauma from the impact.Frasher said one of the pilots was unconscious, lying on the throttle after the jet crashed. He said a window had to be broken to throttle back the jet.Police said motorists should avoid the south side of the airport and the roads will remain shutdown for some time. Police Chief Ken Miller said fuel leaked from one of the engines, and at about 3 p.m. they were still trying to shut it down. He said jet fuel flowed downstream, so people should avoid any of the streams in the vicinity that flow toward Haywood Road. Miller said a hazmat crew contained the jet fuel to prevent any further contamination of the watershed. He said the crash investigation has been turned over to the Federal Aviation Administration who will secure the scene until a National Transportation Safety Board team arrives Friday morning.According to its registration, the jet is a Falcon 50 owned by a Delaware company. Frasher said that in the past 20 years, there have only been three or four similar incidents, and this crash is the most serious. He said the fatalities are the first at the airport in 35 years.Frasher said that much larger planes land at the airport and "nothing is wrong with the runway and there is no issue with the airport.""It may have been something beyond the pilot's control," Frasher said. "It may have been a medical issue."