The Labor Department yesterday accused three firms of failing to give handicapped persons a fair chance for jobs and directed the companies to show why they should not be barred from doing business with the federal government.

The complaints against United Airlines, Trans World Airlines and E. E. Black Ltd., a Honolulu construction firm, were the first ever issued by the department under the Rehabilitation Act.

Under the law, companies that hold government contracts cannot discriminate against handicapped persons and must take steps to hire and promote such persons.

The companies were given 20 days to respond to the administrative complaints issued by Labor Secretary Ray Marshall.

United Airlines was accused of turning down a man for a job repairing ticketing and reservation equipment in Honolulu, because, the company, said noise would damage his already impaired hearing and moving equipment would injure a previously broken ankle.

The department said, however, that the job did not involve working in high noise areas and the man's ankle was completely healed.

A spokesman for United Airlines said that firm is proud of its record of hiring qualified handicapped persons and does not believe it has failed to provide equal employment opportunities for them. It declined comment on the specific case until it has had a chance to review the allegations.

TWA was accused of discriminating against a former pilot in Kansas City who, after recovering from a heart attack was denied any other job with the airline.

By refusing to hire him in a different position, TWA discriminated against a qualified handicapped worker, Labor said.

A TWA spokesman said the company has been unable to find a suitable position for the man, given his medical history and qualifications. However, the company is continuing to make an effort and will review the matter, the spokesman said.

Black, officials, said, refused to hire a man with a spine deformity on grounds that he would be a poor risk for construction work.

However, the Labor Department said the man had already worked in the construction industry for three years and physical examinations showed him to be a good risk for heavy labors.

There was no immediate comment from Black company officials.

Department officials said that in all three cases "the companies were unable to substantiate their refusals for employment, and administrative complaints were issued only after attempts to reach conciliation agreements were unsuccessful."

If, after a hearing, the firms are found in violation of the law, their contracts with the government may be terminated or they may be barred from future government contract work.