The National Transportation Safety Board yesterday blamed the collision last August of a small, private plane and an Aeromexico jetliner on an outdated air traffic control system that pays inadequate attention to light planes.

"We've got to change the priorities," said board member John Lauber. "If we don't, we're going to continue to have these accidents."

The planes collided over the Los Angeles suburb of Cerritos and killed 82 people, including 15 on the ground. Five houses were destroyed by fire and seven others were badly damaged by the fire and wreckage from the two planes.

The board cited the unauthorized intrusion by the private plane into restricted air space and the "limitations" of relying on pilots to avoid collisions by watching the skies for other planes.

NTSB Chairman Jim Burnett dissented from his four colleagues and added a separate statement to the final report emphasizing that the pilot of the private plane had time -- 90 seconds -- to see the larger jetliner in his path and could have avoided the collision. Board investigators said the Aeromexico crew had only 15 seconds to avoid the crash after sighting the small plane.

The crash occurred last Aug. 31 as Aeromexico Flight 498, a DC9 carrying 58 passengers and six crew, was preparing to land at Los Angeles International Airport. The jetliner was under direction of air traffic controllers, but the private plane was not. The Piper was not equipped with an altitude-reporting device, which is required of planes entering restricted airspace around major airports.

The full board opted to emphasize the broader, philosophical reasons of the accident rather than cite error by the air traffic controller or either of the two pilots. The NTSB also is investigating three other collisions, which killed 17 people, that have occurred this year. One of the other accidents, in which a private plane and a commuter airliner collided over a suburb of Salt Lake City, also occurred in restricted airspace.

Lauber described the controller in the Cerritos crash -- "the most tragic character in the accident" -- as conscientious and well-trained. He described the pilot of the private plane, a Piper PA28, as well-trained and meticulous, "not known to take risks, not known as a scofflaw."

Board member Joseph Nall said that the message of the hearing had to portray the limitations of the air traffic control system, and Burnett added after the meeting: "Periodically, the board has to quit trying to patch up the system and address its basic design."

Board members criticized the Federal Aviation Administration's policy, which does not require that controllers advise pilots about the location of other planes that are not under the direction of an air traffic controller. FAA rules now require controllers to make such advisories if their workload allows it.

The controller told investigators the private plane did not appear on his radarscope. The NTSB said yesterday that the plane probably appeared on the scope as a small triangle, but without any indication of altitude. The controller had no reason to believe that the small plane was in the jetliner's path, because, under flight rules, the Piper was not supposed to be in the restricted airspace. The small triangle could have been either below or above the restricted area.

"All three parties -- the controller and the two pilots -- relied on that system to work," Nall said.

After the meeting, Lauber explained that the air traffic control system was developed in the days before radar. It was designed to provide separation for airplanes flying under instrument flight rules, as opposed to visual flight rules.

"Everything else becomes secondary," he said. He added that, with radar, the information about planes flying under visual flight rules is available to controllers. "What is missing is a set of procedures that mandates the use of that information."

FAA spokesman Bob Buckhorn said the agency took a number of steps immediately after the accident, including a 60-day license suspension for pilots who stray into restricted air space. More recently, the agency has proposed a rule requiring all private planes flying within 30 miles of restricted airspace to install altitude-reporting devices by Dec. 1. The FAA also is involved in development of a collision-avoidance system for jetliners.