Six people were killed Wednesday evening when a helicopter crashed in Logan County, West Virginia, authorities said. The Bell UH-1B helicopter nicknamed “Huey” was giving tourists a tour as part of the “Huey Reunion,” an annual convention that celebrates the Vietnam War-era machines. The cause of the crash was not yet clear. The county had been under a thunderstorm warning Wednesday evening but one local official said she believed “the weather was clear” at the time of the crash. Victims’ names have not yet been released; a local official said that they were not from the area. The 1962 aircraft was used during the Vietnam War, the Federal Aviation Administration said. It was still ablaze when authorities arrived at the scene.