In the heat of a labor confrontation, Northwest Airlines Corp. last month took the unusual step of asking that President Bush not intervene to avert a strike by its mechanics.

The airline said it was well prepared to ensure normal operations even if the 4,400 union workers stopped working in protest of proposed job and pay cuts. The nation's fourth-largest carrier worked 14 months to have replacement workers ready to move into place.

The airline's request of the president sent another message: Northwest was prepared to endure a strike, even risk bankruptcy, to guarantee that it would be able to pay its workers less in the future than it does today. The airline's survival depended on it, executives reckoned.

With or without a strike, Northwest's strategy in its battle with its mechanics sends a message that financially strapped airlines are willing to resort to increasingly dire measures to cut costs in a highly competitive industry, labor analysts and union officials said. It also underscores the weakening of the airlines' unions, once a powerful and dominant force in the industry.

"If a corporation can eliminate an entire workforce and bring in replacement workers, it has ramifications for every other unionized company. That's what's at stake," said Steve MacFarlane, the mechanics union spokesman.

The mechanics could strike at 12:01 Saturday morning if the airline and union fail to agree on a contract. Northwest's chief executive, Douglas M. Steenland, is known as a tough negotiator. He took over the leadership of the airline in October after serving as its general counsel and head of labor negotiations.

Northwest is seeking $176 million in concessions from the mechanics as part of $1.1 billion in annual labor savings. The union said the airline wants to slice the mechanic workforce in half by using more outside contractors, and to cut the pay of remaining workers by 25 percent.

Northwest would not say what its targets are in cutting jobs and reducing pay, adding that it is willing to negotiate how it achieves its $176 million cost-cutting goal. The number of Northwest mechanics has dwindled from 10,000 in 2001 to 4,400, according to MacFarlane.

The airline said it received a counterproposal yesterday, which it valued around $100 million but said "falls far short."

Both sides are to continue negotiations today in Washington and are expected to talk through midnight, barring an agreement. "I'm confident that if we don't have a deal at the end of the countdown, we will go on strike. We don't have a choice," MacFarlane said.

Northwest said it has 1,300 replacement mechanics lined up who are willing to work at lower wages. Most have been laid off from other carriers. The rest of the work would be outsourced, the airline said. Northwest said it was legally allowed to resort to "self help" by replacing workers who strike.

It was unclear whether striking workers would permanently lose their jobs to replacement employees. Northwest said it would not speculate on the future job status of strikers.

The airline also said it has about 1,500 former flight attendants ready to report to work in the event current flight attendants refuse to cross the picket lines.

"We started recruiting a long time ago because we wanted the right people. There were a lot of people, and we were able to choose from the very best," said Andrea Newman, Northwest's lobbyist. "These are people who want to work for an airline."

By replacing workers, Northwest is signaling its determination to reduce costs and beat back demands of the mechanics, who are represented by the Aircraft Mechanics Fraternal Association.

"Unions right now are on the ropes," said Charles B. Craver, a labor law professor at George Washington University. "This could be a terrible blow to organized labor."

If Northwest replaces its workers, it would follow a similar move by Alaska Airlines in May. In that case, the jobs were ultimately lost. Alaska Airlines eliminated 472 of its baggage-handler jobs to save about $13 million a year after failing to reach a cost-cutting agreement with its union.

Staring down strikers would come with risks for the airline. Labor observers say it is uncertain how travelers would react, particularly in the Midwest, where union sentiment is still strong. Northwest is based just outside Minneapolis and operates its largest hub at the Minneapolis-St. Paul International Airport. It also has a major hub in Detroit.

Northwest said it has not seen any evidence of travelers changing bookings to other airlines. But if a strike begins, "people get nervous" when they hear about mechanics walking off the jobs, George Washington University's Craver said.

If travelers flee and send Northwest into a Chapter 11 filing, court protection could provide an opportunity for the airline to demand further cost cuts from workers. United Airlines parent UAL Corp. and US Airways Group Inc. both sought court protection after failing to secure desired savings from workers, and have wrested deeper concessions from workers while in Chapter 11 proceedings.

Merrill Lynch & Co. analyst Michael J. Linenberg said he thought it was unlikely that Northwest would back off its cost goal. "We are of the view that the likelihood of a strike is high," Linenberg said in a report.

A Northwest strike would be the first major labor action against a large U.S. airline since 1998, when Northwest's pilots went on strike for nearly three weeks.

The airline has 40,000 workers and is one of the nation's leading international carriers, with a large presence in Amsterdam and Tokyo.

Locally, Northwest has a small presence, with only about 4.8 percent of the flights at Reagan National Airport, 1 percent at Washington Dulles International Airport and 4.25 percent at Baltimore-Washington International Airport.

Steenland has said the airline has lost more than $3.6 billion since 2001. It has spent nearly $7 billion on new aircraft in the past four years.

Northwest has about 4,400 mechanics, and it wants $176 million in concessions from them.