The U.S. Air Force is trying to say bye-bye to its "Blackbird" spy plane - the high-altitude, high-speed and stealthy SR-71. But Sen. Orrin Hatch, R-Utah, plans to lead a fight to save it.

Contractors in Utah are among those who provide "black box" - or classified and high-tech - equipment for the jet, which Hatch said is important to Utah's economy. But he said that is not why he is fighting to save the plane."I would never fight for a piece of equipment only because it is important to my state. The SR-71 is still vital for reconnaissance and the defense of the nation," Hatch told the Deseret News.

"It has many capabilities that no other systems have and helps provide information that we can get no other way. I wish I could detail them for you but I can't" because they are classified, Hatch said.

He is privy to them, however, because he is a member of the Senate Select Committee on Intelligence. He said he has even visited SR-71 bases and has flown in the plane - which can travel up to four times the speed of sound.

A Senate source told the Deseret News that one way the planes are vital is in providing pictures of areas that satellites cannot cover well from their stationary orbits or at times of day that satellites are not passing overhead.

"That was especially important in Libya," the source said. "The SR-71 lets you take pictures any time of the day you need them. For example, a satellite may pass over only at daytime but maybe you need pictures of night-time operations."

The source also said the SR-71 is considered an important back-up to spy satellites if they fail or are somehow knocked out by anti-satellite weapons that the Defense Department claims the Soviets are developing.

Sources also said the SR-71 became especially important when spy satellites could not be launched after the Space Shuttle Challenger disaster, and it was considered a life-saver a few times.

Despite such arguments, the Air Force in its budget proposed phasing out the Blackbird next year. Suzanne Randle, spokeswoman for the Strategic Air Command in Omaha, said the reason is simply funding, and "we have other reconnaissance platforms that operate less expensively," namely satellites.

Similar Air Force efforts to kill the Blackbird last year were blocked in Congress. Hatch said, "It's no secret that I led the fight" and that he plans to again this year.

As an example of how expensive the SR-71 is to operate, the trade newspaper "Defense News" quoted anonymous Air Force sources earlier this week saying an SR-71 mission to monitor the U.S. escort of Kuwaiti tankers in the Persian Gulf last May cost the Air Force nearly $18 million.

As a result, the Air Force wants to deactivate the SR-71 squadrons beginning this year to save $118 million the first year and $709 million over the long term in operation and maintenance.

Hatch said, "There's no question that the SR-71 is very expensive to operate. . . . I think the Air Force is trying to cut this expensive program so it can operate some of its other expensive programs."

But, he said, "Intelligence is a `force multiplier.' It allows us to maximize our forces. That means if we cancel the SR-71, maybe we would have to buy a lot of other hardware to cover for the holes the SR-71 would leave."

Hatch said the fight to save the Blackbird may be tough because of the current defense-cutting mood in Congress. But he said other leaders on the intelligence committee have said they share his views.

The SR-71 has been used since about 1964, taking over for the old U-2 spy planes. "Defense News" said it has been used in Vietnam, Central America, Libya and the Persian Gulf.

Although the plane was originally designed for only about a 20-year life span, Senate sources said a study in 1984 concluded that the planes could be safely used for many more years because of their advanced design and construction materials.