The head of the Federal Aviation Administration clashed yesterday with congressional critics who challenged his decision to award a $200,000 contract to a consulting firm without competitive bidding.

"This is not how the public's business is going to be done," Rep. Herbert E. Harris II (D-Va.) told FAA administrator Langhorne M. Bond.

"Let's go back to the facts," Bond shot back during the pointed 45-minute debate. "There isn't a single defect in this [contracting] process and it stands up to scrutiny.'"

Later Sen. David Pryor (D-Ark.) accused Bond of displaying "arrogance" in the way he spent government money.

The confrontation followed the release last month of General Accounting Office study that reported "serious, pervasive" abuses in contracts awarded by federal agencies to private consultants. Such contracts amount to 1 billion to $2 billion a year, according to GAO.

The $200,000 FAA contract with Booz, Allen & Hamilton, Inc., a major consulting firm, was cited in the GAO report as an example of a "questionable" federal practice -- reliance on "unsolicited" contract proposals from consultants.

The contract negotiated between FAA officials and Booz, Allen & Hamilton without competitive bidding was designed to help plan a reorganization of the federal agency. However, the GAO report noted, "This contractor, in our opinion, is not the only contractor who can do organization studies."

The dispute over the FAA contract was the sharpest during a congressional hearing yesterday centering on federal contracting practices. It was conducted by Harris, who heads the House human resources subcommittee, and Pryor, chairman of the Senate subcommittee on civil service and general services.

During the hearing, Bond defended his decision to award the contract to Booz, Allen & Hamilton without seeking other bids. He argued that the consultant's recommendations led to a rapid FAA reorganization that cut personnel costs by $35 million to $50 million in the last three years. "There has been an enormous cost saving to the taxpayers," Bond asserted.

Harris challenged Bond's decision to award the contract by citing a Dec. 9, 1977, letter from John R. Dowdle, a partner in Booz, Allen & Hamilton, to the FAA administrator.

The letter, marked "private and confidential," said the consulting firm had developed an "unsolicited proposal" for Bond's consideration. And it noted that Chester G. Bowers, a former FAA airports services director who left the federal agency in 1972, would assist Dowdle in the proposed study.

No Booz, Allen & Hamilton official testified at the hearing. But C. G. Apleby, a spokesman for the consulting firm, responded later to a question about the letter by saying, "There was nothing sinister about the marking of it 'private and confidential.'"

He said this was "standard" practice in all correspondence about any reorganization proposal "because we believe that the client should determine who should see it."

Bond testified that he considered the letter a public document, despite the consultants notation and included it among public records dealing with the contract. He said he chose to award the contract without competitive bidding, in part, because "time was of the essence."

Other federal officials were also questioned sharply yesterday about contracting practices. At one point, John A. Hewitt Jr., the Energy Department's chief financial officer, testified, "There is no question in my mind that the department has had a problem with far too many noncompetitive contracts."