Federal Aviation Administrator Langhorne Bond took the unprecedented action yesterday of, in effect, assigning some of the blame for the San Diego air disaster to his agency.

Bond announced changes in air traffic control procedures and equipment the FAA will be making in the San Diego Sept. 25 between a small private plane and a Pacific Southwest Airlines Boieng 727 killed 144 persons.

Furthermore, Bond said, some of those deficiencies have nationwide application. New national rules that could dramatically change air traffic control and improve safety around major airports are to be announced by Bond nex t weeks.

"In the weeks after the accident we were explaining and becoming too defensive, when we should have been investigating and correcting." Bond said. He ordered an unprecedented FAA investigation into the accident and released a 39-page report on the outcome of that investigation yesterday .

At the same time, Bond was careful not to assign "probable cause" of the accident to the FAA or to anyone else. That Responsibility belongs to the National Transportation Safety Board, which is conducting its own inquiry.

The most important change Bond outlined yesterday will be extended to many other airports nationally, he said. He declined to identify the airports.

"It is clear that our criteria" for the degree of air traffic control required for all airplanes around airports "are not correct," Bond said. "We're going to change that " to emphasize higher control at airports with commercial service.

San Diego's Lindbergh Field is to be upgraded in two phases to the level of "terminal control area," the FAA's highest, Bond said. That designation is reserved for only 21 major U.S. airports, including Washington Nationa.

"Such a policy keeps the strays out and gives us much better sequencing and control," a knowledgeable FAA sources said. "It is definitely safer."

"If there is a proliferation of terminal control areas we will violently oppose them" said Charles Spence of the Aircraft Owners and Pilots Association, a loud private-plane voice. Spence contended that such policies would restrict freedom of access to many airports.

Bond has also said he would push for funds to build more reliever airports, long a goal of the private-plane community. There are about 185,000 private and business planes registeted in the United States, and 2,500 commercial airliners.

Bond said a new navigational aid will be installed near San Diego to increase the capacity of the airspace in that complex area, and that a small field runway will be equipped with an instrument landing system that can be used for practice landings.

The small plane was practicing in strument landing at Lindbergh Field When the collision occurred. That practice will be permitted to continue, Bond said, because that was not a factor in the accident. Nonetheless, had there been another runway in the area equipped with the instrument landing system, the plane might have been elsewhere.

Air traffic control equipment in the Lindbergh Field tower will be improved, Bond said.

The procedural problems the FAA discovered at San Diego included a division of control between the two airplanes that collided and a lack of communication among controllers.

An altitude restriction that should have been assigned to the PSA plane was not assigned. An automatic alert that warned of a possible collision was known to one set of controllers, but not to another, and the other set was never informed. Neither were the pilots.

The PSA jet was under thecontrol of the tower at Lindbergh Field. The private plane was in radio contact with a regional air traffic facility at nearby Miramar Naval Air Station. No one had the full picture. The chief of the Miramar facility has been reassigned, Bond said.