PITTSBURGH — A pilot for US Airways Express pleaded guilty to selling a powdered drink mix over the Internet to help drug users pass federal drug tests for truck drivers, pilots, train engineers and other safety-sensitive positions.

Stephen Sharp, 41, of Port Orange, Fla., was a pilot for PSA Airlines when he also ran the website www.yourintheclear.com from November 2006 through May 2008.

U.S. District Judge David Cercone granted Sharp permission Thursday to continue flying out of his base of Charlotte, N.C., until he returns to be sentenced Sept. 3, when he faces a maximum of 5 years in prison.

PSA Airlines removed the employee from duty and placed him on unpaid administrative leave as soon as it became aware of the court hearing, US Airways spokesman Andrew J. Christie Jr. said.

PSA flies under the US Airways Express banner and is wholly owned by US Airways, Assistant U.S. Attorney Mary McKeen Houghton said.

Sharp didn't comment at his guilty plea.

Prosecutors did not say whether Sharp had used drugs or his own product, which was advertised as "100 percent" effective in defeating drug testing standards developed by the federal Substance Abuse and Mental Health Services Administration. SAMSHA tests are used to screen pilots and others by the U.S. Department of Transportation, as well as employees of other federal agencies, including the FBI.

"You simply mix the powder with a large glass of cranberry juice 1-5 hours before your test and then just relax!" Sharp's website said. Federal prosecutors said the product worked.

Sharp pleaded guilty to conspiring to defraud the United States because his product was specifically designed and marketed to defeat U.S. Department of Transportation drug tests.