American Airlines CEO Robert Isom said the National Transportation Safety Board, which is investigating the deadly midair collision between an American passenger jet and a military helicopter, will be the lone authority on the cause and details of the crash.

Robert Isom, the CEO of American Airlines, has pledged the airline’s cooperation with investigations into Wednesday night’s tragic crash near Ronald Reagan Washington National Airport. Officials had already confirmed that the PSA Airlines plane (PSA Airlines being a wholly owned subsidiary of AA) was carrying 60 passengers and four crew members when it collided with a military helicopter with three people on board.