U.S. Agents Raid Defense Contractor : Investigation: The veracity of laboratory tests for aircraft fasteners conducted by Air Industries Corp. in Garden Grove is being questioned.

Federal agents raided a defense contractor here Friday in search of evidence in a criminal fraud investigation into suspected false testing of fasteners used in military and commercial aircraft, officials said.

Several dozen agents--armed with search warrants--raided the headquarters of Air Industries Corp., said James M. Donckels, who heads the FBI’s office in Orange County.

No arrests were made, he said.

Donckels declined to discuss details of the investigation. He said no other companies were searched or are under investigation in connection with the case.

The allegations focus on the veracity of laboratory stress tests for fasteners made for Northrop Corp., Boeing Co., Lockheed Corp. and Douglas Aircraft Co., sources said.

Donckels said the company remains open for business.

Robert Coviello, a lawyer representing Air Industries, said the company is cooperating with the investigation.

“It’s too early to know what they are investigating,” Coviello said. “But Air Industries is one of the cleanest, most reputable businesses in the aerospace industry. . . . We feel there will be no finding of any impropriety.”

He confirmed that laboratory test results were included in the search warrant, but declined further comment.

The investigation is being carried out by Northwest Defense Contractor, a Seattle-based federal task force that includes the FBI, Air Force, Navy, departments of Defense and Transportation, the IRS, NASA and the Federal Aviation Administration, Donckels said.

Air Industries Corp. manufactures fasteners, such as rivets and nuts, for a wide variety of aerospace companies. Sales are estimated at $70 million.

It hasn’t been a good year for Air Industries. In March, company President Sam Higgins said in an interview that the company expected to lay off 50% of its 550 employees during the next year because of shrinking orders for military and commercial aircraft parts.

He said the company had eliminated overtime pay for its employees and had scaled back workweeks from five to four days for many of them. Higgins could not be reached for comment on Friday.

Times staff writer Ralph Vartabedian contributed to this report.