Washington ? Federal officials are working on a navigation system that will let planes fly closer together, prevent crashes into mountains and, perhaps, become part of a system to prevent hijackers from flying planes into buildings or other structures.

The Federal Aviation Administration will establish the automated system at San Francisco International Airport next month and plans to eventually deploy it at other airports. Many commercial aircraft already have the equipment required to use the system.

The satellite-based system was developed by Alaska Airlines, which began using it in 1996 to fly in and out of Juneau in cloudy, wet and cold weather that would otherwise keep the planes grounded or prevent them from landing.

The FAA currently views the system, called “required navigation procedures,” as an important new element of airspace management that will reduce congestion and enhance safety. On Wednesday, the agency announced another modernization step: instant messaging between air traffic controllers and pilots flying into Miami International Airport.

Hal Andersen, a pilot involved in developing the required navigation procedures, describes them as a means of allocating airspace to airplanes. Others have said that it creates “highways in the sky.”

“It’s a system on the airplane that uses autonomous navigational capabilities to define its position very tightly,” Andersen said.

Because of its accuracy and reliability, the system can allow airplanes to safely navigate to any spot on earth, he said. The system could eventually be part of a higher-level system that would prevent the flight path from being diverted or reprogrammed.

“We’re talking about data and about systems already in existence,” Andersen said.

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On some airplanes, he explained, pilots can’t move the controls beyond the plane’s capabilities because the controls send information to a computer that actually flies the plane.

Hypothetically, Andersen said, such a plane could be equipped with a database integrated with the required navigation procedures and programmed to prevent it from flying into the White House or other buildings.

“I’m sure it’s a massive undertaking,” he said.

FAA administrator Marion Blakey said the required navigation procedures would allow more planes to fly more closely together safely.

In San Francisco, the system will allow another runway to be used at the airport in bad weather, she said.

“It’s a big step,” Blakey said.

The FAA is moving aggressively to expand the system, she said.

In a related development, John Thornton, director of the FAA’s Free Flight program, said that a new instant messaging system being used by about a dozen American Airlines planes allows air traffic controllers to exchange routine text messages with the cockpit, which could alleviate the pressure on an overburdened voice communication system.

It is also expected to reduce miscommunication between pilots and air traffic controllers because of language and dialect differences, stuck microphones or simple misunderstandings.

The first instant message was sent Monday morning between an American Airlines pilot and the Miami flight control center near Miami International Airport.

Once federal regulators get comfortable with the system, they will likely find more and better uses for it, Thornton said.