Charles Bryan, a West Virginian, joined Eastern Airlines 30 years ago and became one of its premier engine mechanics.

Frank Borman, a former astronaut, joined Eastern in 1968, and has been its chairman for a decade, leading its struggle to survive the growing pressures of a deregulated airline industry.

The long-standing conflict between the two men produced a standoff at a climactic meeting of Eastern's board of directors in Miami yesterday, leading to Eastern's decision to accept a purchase offer from Frank Lorenzo, president of Texas Air Corp., the holding company that also includes Continental Airlines and New York Air. The Borman-Bryan conflict ran so deep that Bryan was willing to deal with Lorenzo, a nemesis to organized labor after he broke Continental Airlines' union contracts in 1983 in the course of a bankruptcy proceeding.

Bryan, a member of Eastern's board, demanded at the 11th hour yesterday that Borman's removal be a condition of any further labor costs concessions by his union, the International Association of Machinists and Aerospace Workers. To Bryan, Borman was responsible for a long series of poor management decisions and financial blunders that had forced Eastern to repeatedly seek wage cuts and other concessions from its employes.

The union leaders "make the point that they've gone to the well many, many times, and that's true," said one Eastern source close to the negotiations. "But the world is changing." Despite the wage concessions it had obtained, Eastern continued to exceed many competitors in labor costs.

Borman blamed the airline's plight on continued union resistance to more wage cuts. In a recent television interview, he described his union adversaries as "Loony Tunes . . . like that guy from Jonestown," a reference to the Rev. Jim Jones, whose led his followers in a mass suicide in Guyana in 1979.

At the board meeting yesterday, Eastern's other directors were loyal to Borman. They rejected Bryan's proposal and suggested instead that a new vice chairman be appointed at Eastern, with the unstated implication that this newcomer would be Borman's replacement, sources said.

But Bryan would have none of that, not trusting Eastern to make good on the promise, sources said.

"Borman's head has to be part of the deal," machinists union President William W. Winpisinger said in a recent interview.

When the board backed Borman, losing the hope of new concessions from the machinists, it had no choice but to accept Lorenzo's offer, sources close to the board said.

The animosity between the two men symbolized the breakdown in Eastern's 1983 experiment in cooperative labor-management relations -- an experiment designed to solve the deep financial problems of the nation's third-largest airline. The unions accepted 18 percent to 22 percent pay cuts then, but received in return more than 20 percent of Eastern's stock, four seats on the board of directors, access to confidential financial data, and a much stronger union role in workplace decision-making.

Those cooperative measures enabled Eastern to improve productivity and reduce costs because workers assumed a greater role in recommending cost savings. "But clearly that was not enough to save the airline in the face of larger factors," said William F. Whyte, a Cornell University professor of industrial relations.

Heading those factors was the turmoil brought on by airline deregulation, which exposed Eastern to low-cost competition on many of its routes. And the factors also included the animosity between Borman and Eastern's management and the airline's unions.

In the showdown at the Eastern directors' meeting yesterday, Bryan made it clear he preferred Lorenzo, with his reputation for "union-busting," to Borman, according to union sources.

"No one wants this company to be taken over or bought out," Bryan said before the board meeting began on Sunday. But Lorenzo did not represent a threat, he said. "At least he's a businessman who puts a high priority on making a profit . . . It may be an opportunity for us."

Lorenzo earned an antiunion reputation in 1983 when he declared bankruptcy at Continental Airlines and unilaterally canceled union contracts, imposing deep cuts in wages and benefits.