U.S. Faults Air Control System in Cerritos Collision Killing 82 : Unlawful Entry of Controlled Space Called a Key Factor

The air traffic control system was the cause of a collision between a private plane with an Aeromexico jetliner last August over suburban Los Angeles, federal aviation investigators concluded today.

The National Transportation Safety Board in its final report on the Aug. 31, 1986, accident in which 82 people were killed, sought not to blame either the controller handling the plane or the pilots involved.

Instead, the board sharply criticized the air traffic control system which it said has limitations in protecting against air collisions.

The board also cited as key factors in the accident the unauthorized entry of a private plane into restricted airspace over Cerritos and the “limitations” of too much reliance on pilots having to scan the skies for other aircraft.

The investigation, nevertheless, concluded that the controller who was handling the Mexican jetliner should have seen the impending collision because the Piper aircraft’s signal was on his radar scope.

NTSB Chairman Jim Burnett said that more emphasis should be placed on the failure of the Piper PA-28 pilot to see and avoid other traffic. But the other four board members disagreed.

Investigators told the board that they could not determine why the pilot of the private plane entered restricted airspace.

“We just don’t know why he did what he did,” Martin Speiser told the NTSB.

For nearly two hours, the board reviewed information gathered in its investigation of the collision.

Worst Crash in Year

In opening remarks, Burnett noted that the collision was “the most catastrophic aviation accident” of 1986.

NTSB staff members, including Speiser, reviewed details of a staff report on the accident, although the report was not made available immediately.

Staff members told the board that an analysis, using studies developed before the accident last August, indicated that the pilot of the Piper PA-28 Cherokee should have had a 50-50 chance of seeing the DC-9 in time to take evasive action.

Those same probabilities indicated the two pilots of the DC-9 had about a 30% chance of observing the much smaller Piper.

At one point, the staff was asked to summarize the qualifications and experience of the Piper pilot.

David Kelley, a board staff member, said the pilot had been described as “very sensitive” to the need for preflight planning and had told associates before taking off about his concern over the restricted Los Angeles terminal control area, in which the collision occurred.

Investigators said the pilot had bought a new airspace chart before departure. “I think the characterization is that he was a very cautious, concerned general-aviation pilot,” said NTSB staff member David Kelley.