For the second time in a week, the NAACP aligned itself with big industry against one of President Carter's energy proposals.

At a congressional hearing yesterday, the civil rights group opposed the administration's proposed truck fuel economy standards for 1980-'81, saying that they would probably increase unemployment in the automotive industry.

The move followed by seven days an NAACP position paper taking the oil industry's side against parts of the President's energy bill pending before Congress. The focus of that complaint was also jobs; the NAACP accused Carter of moving to limit growth at a time when minorities need economic expansion to provide jobs.

Yesterday the NAACP termed the truck fuel standards "ill-conceived" and asked the National Highway Traffic Safety Administration to reconsider them.

That position coincides with arguments that have been made by all three major automakers. Officials of the Ford Motor Co. testified yesterday that the standards would force Ford to cut about 30 per cent of its production, with a resulting loss of about 25,000 jobs among company and suppliers.

It was the second time this month that the NAACP has sided with big corporations in opposing Carter administration initiatives that have some support among groups traditionally allied with consumers, minorities, and the poor.

On Jan. 9, the NAACP's Board of Directors went on record in favor of more subsidies to the energy industry, against continued price controls on new oil and gas, against energy price rebates to consumers, and in favor of more nuclear power plants, including the controversial fast breeder reactor.

Yesterday's testimony was given by NAACP Board Chairman Margaret Bush Wilson, a St. Louis attorney who called in November for a "progressive partnership" among "big government, the big minority, and big oil . . ."

"I do not appear today as an expert, or to question the figures used by the National Highway Traffic Safety Administration to justify its proposed fuel economy rules. . .," she said. "I want to talk about the social costs of the proposed regulations."

Wilson said job loss in the auto industry, which overall has a work force about 25% minority, would be "a relative certainty" if the proposed standards go into effect.

"It is our information," she said, "that plans have been suspended for converting Chrysler's Jefferson Avenue plant in Detroit to light truck production. . . The minority population in that plant is over 55 per cent...

"Obviously, if the Chrysler Corp. shuts down that one plant, there will be an increase in general unemployment along with a disproportionate increase in unemployment among minorities."

Safefy Administrator Joan Claybrook disputed Wilson's claims.

In a brief interview, Claybrook said that she believes Chrysler has been trying to close that plant for years, and that Chrysler board chairman John J. Riccardo called her the day the standards were announced, Dec. 12, to tell her he would close it.

"I said to him, "Don't you want to see what the rules will be first?"' Claybrook said. "He said, 'Well, we're just going to close it."

Claybrook also said that the law requires her agency to issue "economically practicable" standards, and that a standard which would require companies to cut production and jobs would not meet that test.

"We did set a very tough, vigorous proposal," Claybrook said. But she said it should make more jobs, not fewer, because "each improvement costs a little more money, and gives a few more jobs."

Ford, which testified most specifically on the standards yesterday, argued that they would require a 33 per cent to 37 per cent jump in fuel economy over 1979. The only way to do that, Ford officials said, would be to cut production of the most gas-hungry vehicles.