The NTSB has started the investigation into what was likely to be the worst U.S. aviation disaster in almost a quarter century, officials said Thursday. CBS 8 spoke with a commercial pilot with more than 40 years of experience who said he suspects the pilot of the Blackhawk helicopter that collided with an American Airlines jet Wednesday may have been distracted. "Everything that transpired on the radio appears routine, including the performance of the helicopter, but the helicopter pilot failed to follow through. The pilot said, 'I have the aircraft in sight,' but then he didn't maintain separation," said Robert Katz. "So now we're left to try to figure out why. Well, we know there's a training mission going on and that there's three people onboard that helicopter. So there had to be conversation going on between the three of them when somebody's attention was distracted away from keeping eyes on the American Airlines jet landing on Runway 33," he added. MORE: https://www.cbs8.com/article/news/commercial-airline-pilot-analyzes-final-moments-before-american-airlines-jet-and-blackhawk-helicopter-crash/509-7e226ef0-9052-4931-b136-fa311c5992ff