A new takeoff pattern aimed at easing congestion at Newark Liberty International Airport has confused some pilots and led to several incidents in which planes turned in the wrong direction, according to the union that represents air traffic controllers.

Three of the incidents occurred in the last nine days, said Ray Adams, vice president of the National Air Traffic Controllers Association union at Newark.

Many pilots aren't notified of the specifics of the new pattern until they are on the runway preparing to take off, Adams said.

"It's throwing a wrench into the works, basically," he said.

Jim Peters, a spokesman for the Federal Aviation Administration, confirmed an incident on May 1 involving a United Airlines flight that turned the wrong way on departure. But he said FAA logs had no record of two separate incidents on Thursday involving planes operated by Virgin Atlantic and Continental.

Adams and Newark union president Ed Kragh contend, however, that a controller noted the incidents, which occurred within about an hour of each other, and notified a supervisor in writing. None of the incidents placed planes in imminent danger, Adams said.

On a recording from the Newark air traffic control tower last month obtained by the Associated Press, pilots of several planes that are minutes from takeoff are heard expressing unfamiliarity with the new pattern.