Nine people - three aboard the plane and five Italian tourists and a pilot aboard the helicopter - were killed in the Aug. 8 accident in an area of busy air traffic over the river between New York and New Jersey.
The board now says in a statement released Monday that while the controller at Teterboro Airport in New Jersey failed to warn of several aircraft in the path of the single-engine Piper, the tour helicopter wasn't one of the aircraft on the controller's radar screen until seven seconds after the handoff to nearby Newark Liberty International Airport.
Officials for the National Air Traffic Controllers Union, which represents the controller, said the board's report released Friday, which described the handling of the plane by controllers, unfairly implied the Teterboro controller could have prevented the collision. They had been pressing the board for a correction since then through media conferences Friday night and Monday afternoon, and in conversations with NTSB staff over the weekend.
In response, the board removed the union from its investigation of the crash. NTSB Chairman Debbie Hersman said in the board's statement, released shortly after the union's second news conference, that parties to investigations sign an agreement not to publicly discuss the information gathered by the board while the investigation is ongoing.
"Although we appreciate the technical expertise our parties provide during the course of an investigation," Hersman said, "it is counterproductive when an organization breaches the party agreement and publicly interprets or comments on factual information generated by that investigation. Our rules are set up precisely to avoid the prospect of each party offering their slant on the information."
Union spokesman Doug Church said: "It's important that the NTSB has clarified this key point in the sequence of events. All we want to see is a factual account of the incident and we continue to believe the facts show that our Teterboro controller could not have done anything to prevent this horrible tragedy."
The Teterboro controller made a personal phone call shortly after clearing the Piper for takeoff at 11:48 a.m. EDT and remained on the phone until the collision five minutes later, even while he was directing traffic, according to the board and the Federal Aviation Administration.
The controller and his supervisor, who was out of the building at the time of the collision, have been placed on administrative leave with pay by the FAA. The agency said in a statement last week that while it appears the controller's conduct didn't have any impact on the crash, his behavior was inappropriate and unacceptable.
The NTSB, in a pointed statement in its report, said it would decide what role the controller played in the accident and other opinions at this time are "speculative and premature."
The public spat between the board and the union and FAA is unusual. Typically, the union and FAA avoid any public statements regarding an ongoing investigation so as not to jeopardize their status as parties, which gives them access to information uncovered by the NTSB long before it becomes public.
However, union officials said they were willing to give up their role in the investigation because they felt strongly the controller's part in the tragedy was being misrepresented.
The brouhaha has created a rocky start for Hersman, who took over the chairmanship last month after five years as a board member.
The chairman of the Senate committee with oversight over the NTSB and FAA said in a statement late Monday that "the NTSB must be allowed to complete a full investigation before conclusions are drawn."
"Even if the investigation reveals their (controllers') actions did not contribute to the accident, it represents a serious violation of FAA procedures," said Sen. Jay Rockefeller, D-W.Va.
Hersman is a former aide to the committee.
