By David Shepardson

WASHINGTON (Reuters) -The Federal Aviation Administration said on Friday it is planning additional helicopter route changes near Ronald Reagan Washington National Airport after the January 29 mid-air collision of an American Airlines regional jet and an Army helicopter that killed 67 people.

FAA official Nick Fuller said at a National Transportation Safety Board investigative hearing that an agency work group is planning changes on a key helicopter route near Reagan after imposing permanent restrictions on non-essential helicopter operations in March and further restricting where they could operate in June.

NTSB officials at the hearing expressed concerns about a “disconnect” between front-line air traffic controllers and agency leaders and raised other questions about FAA actions before the fatal collision, including why earlier reports of close call incidents did not prompt safety improvements.

Board members have also raised concerns about the failure of the FAA to turn over documents in a timely fashion during the investigation of the January collision.

The NTSB received details on staffing levels at the time of the January 29 crash “after considerable confusion and a series of corrections and updates from the FAA,” a board report said.

The hearing has run more than 30 hours over three days and raised a series of troubling questions, including about the failure of the primary controller on duty to issue an alert to the American regional jet and the actions of an assistant controller who was supposed to assist the primary controller.

“That did not occur and we’re trying to understand why. And no one has been able to tell us what the individual was doing during that time,” NTSB Chair Jennifer Homendy said.

Homendy said earlier this week the FAA had ignored warnings about serious safety issues.

“Every sign was there that there was a safety risk, and the tower was telling you,” Homendy said.

“You transferred people out instead of taking ownership over the fact that everybody in FAA in the tower was saying there was a problem … Fix it. Do better.”

FAA officials at the hearing vowed to work more collaboratively and address concerns.

Senator Tim Kaine on Friday also cited concerns raised by an FAA manager about the volume of flights at the airport before the collision and the decision by Congress last year to add five additional daily flights to Reagan.

“Congress must act to reduce dangerous congestion by removing flights into and out of (Reagan National),” Kaine said.

(Reporting by David Shepardson; Editing by Sandra Maler and Tom Hogue)