Jim Hall, of Signal Mountain, who was chairman of the National Transportation Safety Board at the time of the crash and investigation, said Thursday he had declined an invitation to appear in the documentary.

"We spent four years and had the very best investigators the government had working on this matter, and I think the investigation will speak for itself," Hall said Wednesday by telephone.

At the same time, he said, "we have an open investigative process with NTSB and if people have new evidence or a different opinion it would be considered."

He said he was not aware that the investigators had made a formal proposal to NTSB.

"I think this is an attempt to promote the documentary. We live in the Twitter age and everybody gets his 10 seconds," Hall said.