Pan Am Corp. plans to keep its Pan American World Airways subsidiary flying with replacement workers in the event of a strike.

A federally mandated cooling-off period expired at midnight Saturday, freeing the airline's Teamsters employees to strike from 12:01 a.m. Sunday. Labor has been split, with the Transport Workers Union, which represents 5,000 mechanics and baggage handlers, saying it would not support a strike.William Genoese, director of the union's airline division, promised a traditional type of Teamster walkout in announcing strike plans last week, while negotiations continued.

Separately, the airline announced it lost $245.5 million on revenue of $877.1 million during the fourth quarter. That compares with a loss of $197.7 million on revenue of $798.6 million during the comparable 1986 period.

For all of 1987, Pan Am lost $265.3 million on revenue of $3.6 billion. In 1986, losses totaled $462.8 million on revenue of $3 billion.

Mr. Genoese claimed there is enough support for Pan Am Local 732 among other Teamsters locals to cut off the airline's supplies of fuel, laundry and liquor around the world. And he added that there would be violence if the company provokes violence.

The 4,500-member Pan Am Teamsters local represents passenger reservation clerks, customer service employees and workers who fuel planes.

Pan Am spokeswoman Pamela Hanlon said the carrier had recruited replacement employees and trained managers within the company to perform some of the Teamsters' clerical functions, should the strike occur.

The Teamsters said they were prepared to strike even if they didn't receive the support of Pan Am's four other unions.

The 5,000-member Transport Workers Union unit at Pan Am last week voted unanimously against backing the Teamsters. A spokesman for the airline's flight engineers union said members were advised to continue with their work assignments. The pilots and flight attendants unions also were not expected to support the Teamsters.

The pilots, flight attendants and engineers already have granted labor concessions in an effort to aid Pan Am's financial recovery.

Talks, convened by the National Mediation Board in Washington, continued through the weekend.

Pan Am needs labor concessions totaling about $540 million over three years to ensure its survival, analysts and company sources estimate.

The Teamsters say they have offered $75 million in concessions over the next three years. Pan Am has sought an 8 percent annual wage cut, work rule changes and revisions in the union's health care plan.

The Teamsters claim their concessions amount to a 15 percent to 17 percent wage cut for members who make an average $480 a week. They haven't received a pay increase since 1981.