The Bush administration wants to trim the Federal Aviation Administration's (search) budget for buying new air traffic control equipment at a time when more planes are in the air.

Air traffic controllers argue that more backup equipment could have mitigated the shutdown of a radio system at Los Angeles International Airport (search) on Tuesday that left controllers unable to talk to pilots and caused a ripple effect of delays across the country.

Controllers have been asking the FAA for another backup radio system for years, said Hamid Ghaffari, president of the local air traffic controllers union in Los Angeles.

"The response was, 'We don't have the funding,"' Ghaffari said.

The loss of voice contact with pilots caused at least five incidents where planes flew dangerously close to each other and delayed or canceled hundreds of flights.

FAA spokesman Greg Martin said the Los Angeles air traffic control center already has two backup systems.

Sept. 2 was the busiest day ever for the U.S. air traffic control system. The FAA forecasts a 24 percent increase in the number of planes in the sky — including passenger and cargo planes, general aviation and military aircraft — between this year and 2015.

But the administration has proposed cutting next year's FAA budget for equipment and facilities by 12.6 percent, from $2.862 billion to $2.5 billion. Both the House and the Senate have gone along with that figure so far in the budget process.

"We're investing the taxpayers' money wisely in systems that will have maximum benefits in minimal time," said Martin. Some programs have been deferred because there isn't a pressing need for them in the next decade, he said. Those programs are in the beginning stages of development.

Air traffic controllers fear if Congress goes along with the cut it will force them to work with outdated equipment longer and prevent new backup systems from being installed.

Tom Brantley, president of the Professional Airways Systems Specialists (search) union, said the systems that keep track of the planes in the centers between airport towers will soon reach their capacity.

"Cutting the budget by almost 14 percent is insane," said Brantley, who represents the people who maintain air traffic control equipment. "Seventy percent of the systems out there are in need of upgrade or replacement."

The FAA's Martin said that number doesn't reflect reality. "There's no major system out there that's older than 9 years old. Systems have either been replaced or are currently in the process of being replaced."

Ruth Marlin, executive vice president of the National Air Traffic Control Association (search), predicted a return to the late 1980s, when outages at air traffic control facilities were more common.

"Air traffic control modernization has got to be constant," she said. "It's a continual process."

Buildings are another problem, Marlin said. One air traffic control center is sinking. Another has mold on the walls. Some leak.

"As we see our buildings degrade, we lose the infrastructure that protects the system," Marlin said.

Oregon Rep. Peter DeFazio, ranking Democrat on the House aviation subcommittee, said the administration is scrimping on equipment needed to meet the growing air traffic demands.

"They're driving the public air traffic control system toward a cliff," said DeFazio.

He said he found it "extraordinary" that the Los Angeles Air Traffic Control Center lacks a redundant backup system. "Tax cuts won't fix the air traffic control system," he said.

Rep. John Mica, chairman of the subcommittee, said the FAA can update the national air traffic control system with fewer dollars if it takes a more businesslike approach to developing technology.

"They spend a great deal of time trying to change the technology. By the time they change it, the private sector comes up with off-the shelf-technology or new technology that does a better job," said Mica, R-Fla.

"I think we can do more with less," he said.