Pilot’s Alcoholism Cited by His Defense : Trial: Three Northwest Airlines pilots face charges over flying their plane after drinking.

One of three former Northwest Airlines pilots accused of flying while intoxicated had a higher tolerance for alcohol because he is an alcoholic, his lawyer said today.

In an opening statement at the pilots’ trial, attorney Peter Wold said Capt. Norman Prouse has been an alcoholic for many years, but he said Prouse performed flawlessly during a March 8 flight from Fargo, N.D., to Minneapolis.

“Being an alcoholic does not mean you are under the influence of alcohol all the time,” Wold said. “A person who consumes alcohol builds up a tolerance.”

Wold and William Mauzy, the attorney for 1st Officer Robert Kirchner, said they will prove that their clients were not impaired during the early-morning flight by the alcohol they consumed the previous night.

Mauzy told the federal court jury to concentrate on the smooth operation of the 91-passenger flight instead of on the pilots’ drinking the night before and the results of blood-alcohol tests taken after the flight.

Kirchner, of Highland Ranch, Colo., piloted the Boeing 727. The plane, carrying 91 passengers, left as scheduled at 6:25 a.m., less than seven hours after Kirchner, Prouse of Conyers, Ga., and flight engineer Joseph Balzer of Antioch, Tenn., were seen drinking at a lounge in Moorhead.

In her opening prosecution statement, Assistant U.S. Atty. Elizabeth de la Vega said blood-alcohol tests taken after the flight showed that Prouse still had an equivalent of eight drinks in his system while the plane was in the air and that Kirchner and Balzer had the equivalent of three beers each still in their systems.

U.S. District Judge James Rosenbaum has said the trial is expected to last about two weeks.