The sleek hummingbird of a plane was unveiled in February 1985 like a precious jewel, basking in flashing red lights and clouds of vapor. There were clanging gongs, the whooshing of jet engines and the host's promise of "a very great day in the history of aviation for all of us."

It was a crowning moment for Fairchild Republic Co. (FRC), the baptism of its new T46A jet trainer long sought by the Air Force to hone the flying skills of a new generation of combat pilots.

But within a year, the T46A crash-landed in a thicket of corporate bungling, bureaucratic infighting, budgetary pressures and congressional jousting. The Air Force killed it in August and, despite the government's $600 million investment and the plane's impressive showing in recent test flights, President Reagan signed the T46A's death notice in the "hard choices" budget he sent to Congress last month.

In another age less awash in red ink, the T46A probably would have survived. It may yet, since it still has powerful patrons on Capitol Hill.

But the trainer illustrates two colliding themes in the U.S. war machine of 1986. It is perhaps the Pentagon's first victim of the Gramm-Rudman-Hollings deficit-reduction law. And it shows, even amid self-imposed austerity, how difficult it is to sustain the simple decision to end one uncomplicated military program.

These countervailing pressures are likely to clash repeatedly as the government tries to whittle down big weapons projects traditionally nourished by constituencies in the military, industry and Congress.

The Air Force officially cites "contractor cost and schedule difficulties" and fewer pilots to explain its possibly first-ever cancellation of a plane in production.

But this public rationale masks the tortuous demise of a plane that was:

*Prematurely presented to the public as virtually ready to fly at the February 1985 gala despite the absence of critical engineering and structural components that made it far from flyable.

*Jilted by one-time Air Force supporters who were disappointed by the premature rollout and dismayed at inefficiencies in the T46A plant on Long Island.

*Caught in a power strugle between influential lawmakers from New York, where the plane was built, and Senate Majority Leader Robert J. Dole (R-Kan.), who favors an alternative manufacturer in his home state.

*Finally voted down in Air Force budget meetings by generals who outmaneuvered the trainer's advocates to protect funding for weapons.

The official rationale also does not reveal the rear-guard fight that breathed life into the T46A until final budget decisions were made. The fight was joined by Air Force training officials marshaling documents and FRC orchestrating a major lobbying campaign involving political benefactors and subcontractors in 31 states.

A behind-the-scenes look at the T46A provides a snapshot of military procurement in a new fiscal era. It is a story that revolves around three key players from different worlds.

For the Air Force, Gen. Lawrence A. Skantze, 57, commander of the Systems Command, was an early champion of the T46A who turned against FRC.

For the manufacturer, Robert J. Sanator, 55, was FRC's president during the controversial rollout. The factory under his stewardship was later determined to be riddled with "management and production deficiencies."

And there was Rep. Joseph P. Addabbo (D-N.Y.), 60, political patron saint of the T46A and chairman of the the House Appropriations defense subcommittee, whose serious kidney ailment from August to December cost the company an important ally at a crucial time.

The three men worked in concert in the early days of the T46A -- Sanator, the talented aeronautical engineer who helped design the plane; Skantze, the procurement specialist who helped sell it to Congress, and Addabbo, the savvy politician who helped assure its funding.

Air Force generals began pressing Congress in 1980 for a new primary trainer for young pilots. The venerable T37, designed in the early 1950s, was described as "operationally deficient" -- limited in range, endurance, altitude and instrumentation. The old trainer was expected to reach the end of its service life in the late 1980s. Then, in the words of one general, it would be "relegated to the boneyard."

FRC won a contract in July 1982 to develop the T46A, a fuel-efficient, twin-engine jet with side-by-side seating and pressurized cockpit. Plans called for 650 T46As by 1992 for $4 billion.

By late 1984, Sanator began planning the T46A's "rollout," a ritual of aerospace companies to mark a plane's readiness except for fine-tuning. He sent about 1,500 invitations for the Feb. 11, 1985, event.

A month earlier, Skantze visited the FRC plant in Farmingdale, N.Y., and said later, "I was very shocked with the state it was in and convinced myself that they would be hard-pressed to roll it out as a flyable plane."

Sanator pledged to "absolutely do whatever it takes to get that airplane in shape," Skantze recalled.

The rollout went ahead as scheduled at FRC's terminal. It was an estimated $250,000 show drawing Washington's political and military elite, including Air Force Secretary Verne Orr and Sen. Alfonse M. D'Amato (R-N.Y.).

A few speeches set the tone -- Sanator calling the rollout a "milestone event" and Orr praising the T46A as "an outstanding trainer for years to come."

An FRC official then took the stage. "This is it," he declared. "Mr. Secretary, Senator D'Amato, will you please press the switch on the left-hand side to ceremoniously start and initiate the unveiling of the T46A."

The cavernous room darkened and filled with the sound of Aaron Copland's "Fanfare for the Common Man." Suddenly, stage lights illuminated a platform covered by white canvas. The tarpaulin lifted, revealing the T46A enveloped in vapor as if flying through clouds. As colored lights flashed, a choir belted out the "Air Force Hymn."

Orr and D'Amato were invited to "please come forward and personally inspect the aircraft. You get to fly it if you like."

It was only a few days later that Air Force officials examining the plane in the FRC hangar discovered that critical components, including small engine parts and pieces of the airframe, were missing.

"I was very upset they didn't meet the commitment," said Skantze.

In an interview, Sanator said he too was misled into believing the plane was "essentially complete." He said he received "totally inaccurate and inadequate" reports about the plane's readiness only to discover a few days after the rollout that it would not be able to make its April 15 first-flight deadline.

Sanator fired two plant officials and was demoted himself in April. He had a heart attack in September, part of what he terms the "personal toll" of the T46A imbroglio.

Skantze, meanwhile, became sharply critical of FRC to Orr and top Air Force officials, said informed sources, who said they believe the four-star general lost face by advising Orr that the rollout would be legitimate. Skantze says his criticism was motivated solely by concern for efficiency and cost savings.

His concern led him to move up a full-scale Air Force management review of FRC. The 10-day survey, circulated internally in July, was damaging. The inch-thick report cited "numerous management and production deficiencies" and rated the FRC plant "unsatisfactory" in eight major areas. More than 40 percent of parts inspected were "defective." Valuable tools and materials were being sold to scrap dealers for "practically nothing." Metal debris littering the plant was imbedded in electrical cables, posing "extreme danger" of fire.

The Air Force penalized FRC by cutting its $8 million-a-month contract payments in half.

FRC's cascading troubles came at a bad time. The Air Force, then in the early stages of budget-crafting for fiscal 1987, was already expecting a lean year because of deficit-busting sentiment in Congress.

On Aug. 8, Deputy Defense Secretary William H. Taft IV sent budget targets, known in Pentagon jargon as "bogeys," to his three service secretaries. The bogey, which arrived on a Thursday, required deep cuts in Air Force spending.

Orr set in motion a flurry of weekend meetings at the Pentagon to meet Taft's Monday deadline for preliminary breakdowns. The secretary suggested that budget-cutters consider cancellation of the T46A.

In meetings with the brass, budget officials proposed to scrap the trainer. On Sunday, the Air Force Council -- the service's top corporate review body chaired by the vice chief of staff -- concurred.

Although those critical deliberations were conducted in secret, their basic content has been revealed by sources close to the Air Force. At each briefing level, sources said, the issue pitted advocates of a new trainer against "warlord" generals responsible for offensive weapons, such as B1 bombers and F16 jet fighters, who argued that cutting their budgets would weaken the nation's military muscle.

Its Air Force constituency eroded by Skantze's criticism and the July report, the troubled T46A seemed expendable, sources said.

Conspicuously absent from the crucial briefings was Gen. Andrew Iosue, head of the Air Training Command responsible for primary instruction of all Air Force pilots. As the eventual user of the T46A, Iosue has long been its biggest booster, and it remains unclear why he failed to attend the weekend meetings -- or whether he was invited.

Iosue, who works at Randolph Air Force Base in San Antonio, Tex., declined to be interviewed, as did Orr and other top Air Force generals.

By late August, the Air Force plan was tentatively approved by the Defense Resources Board, a panel of senior officials who make final budget decisions. But it was still early in the budget-drafting process for fiscal 1987.

At its low point, the T46A was set back again when Addabbo was taken to Walter Reed Hospital Aug. 26 for an extended bout of kidney illness. Many of Addabbo's constituents in Queens work at the nearby FRC plant, and he has long been considered a pivotal ally of the T46A, which sometimes is known as "the chairman's program."

As Addabbo entered the hospital, FRC was embarking on a major lobbying offensive. The contractor, a subsidiary of Fairchild Industries, had already sunk $100 million into the project to cover cost overruns exceeding its firm fixed-price contract. It was determined to reap as much as $6 billion expected in eventual U.S. and foreign sales.

Command of the lobbying foray fell to Tom Turner, 61, an FRC and Fairchild Industries vice president familiar with Washington's inner workings after more than 30 years in the aerospace business.

Turner opened two battlefronts. At the Pentagon, he said, he was guided to "the right doors" by a former Air Force colonel now working for Fairchild Industries, visiting nearly every general and senior Pentagon official involved in the T46A decision.

The second front was political -- to shore up the T46A in Congress.

FRC has a natural following among members of the New York delegation, especially Long Island legislators. The Farmingdale plant employs 3,600 persons and is a major source of income in the area. In addition, the parent company's political action committee contributed $11,200 to the recent election efforts of Addabbo, New York's two senators and five of Long Island's six House members.

Like a good campaign manager, Turner crafted a strategy to broaden the trainer's political support by tapping the pool of T46A subcontractors -- 280 firms in 31 states from New Hampshire to California -- which were urged to pressure the Pentagon and Congress.

Addabbo's staff kept him informed during his hospital stay. Well enough to use the telephone, his first official call was to Orr to discuss the trainer, an aide said.

Dole entered the picture Sept. 11 after a meeting in his Senate office with Taft and Russell A. Rourke, then the Pentagon's chief congressional liaison and Orr's successor as Air Force secretary in December. Declaring that the T46A contract could soon be "up for grabs," Dole said that Cessna Airplane Manufacturing Co. in Kansas, which produced the old T37, is "ready now to step in and do the job" of upgrading the T37.

The emergence of so influential a figure as Dole on the issue is widely thought to have neutralized the pressure from Addabbo and his New York colleagues.

At the Pentagon, meanwhile, T46A advocates counterattacked. Iosue's Air Training Command, assigned to consider a Brazilian trainer and Cessna's proposal to upgrade the T37, reported in December that neither was an attractive alternative, informed sources said. Even Skantze began speaking more favorably of the T46A after flying it and visiting the FRC plant, where he noted "progress" in correcting problems.

Iosue also was privately criticizing the T37, sources said. His concerns were highlighted in an internal memo Sept. 19 by the Air Force inspector general, citing the T37's accident history and concluding that it is "limited" both in ejection capability and performance when one of its two engines fails.

Gen. Charles A. Gabriel, Air Force chief of staff, was "shocked" by the memo, an aide said in a reply to the inspector general four days later, "and he wants to lean forward to fix it if at all possible."

On Dec. 2, Taft forced an abrupt end to the Air Force debate. Noting the service's plans to cancel the trainer in fiscal 1987, he said the Pentagon would ask Congress to rescind $200 million budgeted for the plane in fiscal 1986. He gave the service 48 hours to demur or lose the program.

The Air Force never responded and by mid-December affirmed its decision to scrap the trainer. The generals resolved to "keep the T37 viable for several more years, not infinitely, and revisit the issue later," Skantze said.

Congress, meanwhile, had other ideas. On Dec. 16, it appropriated $200 million for the trainer, including $63.3 million for procurement in fiscal 1987. A House-Senate conference committee report said the lawmakers "expect the Air Force to budget for and procure T46A aircraft in fiscal year 1987 . . . and in subsequent years to meet this critical and well justified requirement."

The language was drafted by Addabbo's staff. For the first time in months, the Queens congressman was back on Capitol Hill to do battle with Dole, still pushing for the Cessna alternative.

On Jan. 24, Addabbo wrote to Rourke, saying the Appropriations Committee expects "no delay" in buying T46As this year. He threatened to take money from other Air Force programs, if necessary, to buy "an appropriate quantity" of T46As in fiscal 1987.

Supporters of the T46A kept pressing until the budget was sent to the White House in late January. But Pentagon elders, facing the effects of Gramm-Rudman-Hollings, did not budge.

Rourke, however, agreed to review the program again in mid-March. CAPTION: Picture 1, T46A jet trainer was unveiled at plant with great fanfare in February 1985. Fairchild Republic Co. photo; Picture 2, Fairchild Republic Co. officials had hoped to attain as much as $6 billion worth of domestic and foreign sales of its fuel-efficient, twin-engine T46A trainer; Pictures 3 and 4, Robert J. Senator; Gen. Lawrence A. Skantze