Two airplanes carrying more than 100 passengers narrowly averted a mid-air collision east of Pittsburgh after an Ohio air traffic control trainee told a Delta Air Lines pilot to turn into the path of an oncoming plane, officials said.

The Delta pilot made a nosedive and missed the plane by about 400 feet, the Federal Aviation Administration said. The other pilot also took evasive action, the FAA said.

A cockpit collision avoidance system alerted the pilots to the danger.

Delta Flight 1654 was en route from Cincinnati to LaGuardia International Airport in New York Tuesday morning and was carrying 57 passengers. The other plane, PSA Flight 2273, was flying from Wilkes-Barre, Pa., to Charlotte, N.C. It had 70 people on board.

PSA is a subsidiary of U.S. Airways.

The controller only had about a year on the job, said Melissa Ott, National Air Traffic Controllers spokeswoman at the Cleveland Air Route Traffic Control Center in Oberlin.

"We watched the recording of the incident three times and each time I said, 'Oh my God,"' Ott said. "It was the closest call I have ever seen in my 18 years of air traffic control."

FAA spokeswoman Elizabeth Isham Cory called the incident an operational error. She said a second controller was working with the trainee at the time.

"This ended with the aircraft taking the appropriate action," Cory said. "The controllers will be retrained."

A Delta spokeswoman said the passengers "were never in danger."

Ott said the air traffic industry has downsized over the past year.

"A year ago that area would have been worked by 12 to 14 controllers," Ott said. "Now it's handled by nine or 10. New controllers are controlling airplanes much sooner than before. They used to train two or three years before doing it."