WASHINGTON (AP) — Five air traffic controllers have exposed a problem that is putting planes at risk of colliding or causing accidents due to wake turbulence, a federal whistleblower protection office said Tuesday.

The problem occurs when pilots, air traffic control centers or airline dispatchers try to make changes to a flight plan by creating a second plan for the same flight, according to letters sent to the White House and Congress by the Office of Special Counsel, an independent agency.

The computers that controllers use don’t automatically take note when multiple flight plans have been filed and notify controllers, the letters said. This can result in a controller clearing a flight for departure based on an outdated plan, and the pilots flying a route not anticipated or planned for by the controller.

To try to catch the problem, controllers have to review flights plans, call pilots and search through paper printouts that are passed from controller to controller to track a plane’s progress from taxing to takeoff. Then they compare the information on the strips of paper to data displayed on computers.

The Federal Aviation Administration confirmed the problem in December 2014 and revived a working group to address the matter, the counsel’s office said in a statement.

But an audit earlier this year confirms that the group had little impact and problem still remains, the counsel’s office said.

The controllers who blew the whistle on the problem work at the Detroit Metropolitan Airport in Romulus, Mich. But the problem affects air traffic nationwide.

“The whistleblowers in Detroit deserve our deep gratitude,” Special Counsel Carolyn Lerner said. “While more work needs to be done, their actions reignited efforts to address the problems.”

In 2012, the FAA created a working group to address the problem of multiple flight plans. However, the counsel’s office said FAA officials have acknowledged the group “had little impact.” The agency also told the counsel’s office that senior officials either were not aware of, or did not perceive, the significance of the problem.

Vincent Sugent, one of the controllers who reported the problem to the counsel’s office, said controllers have been complaining to FAA officials about the problem for about seven or eight years. The National Air Traffic Controllers Association also raised the problem with the agency, he said.

“They (FAA officials) admitted the problem multiple times,” he said in an interview. “But they were just really slow. They weren’t acting quickly enough.”

Just recently, controllers in Detroit cleared a small airliner for takeoff using a flight plan that said the plane was to head west, Sugent said. It wasn’t until after takeoff that controllers discovered a second flight plan had been filed by the airline’s dispatchers calling for the plane to head east, which is the direction pilots took, he said.

Incidents like that typically happen once or twice a week in Detroit, and there have been similar incidents reported at other airports, he said.

___

Follow Joan Lowy on Twitter at http://www.twitter.com/AP_Joan_Lowy