Two lovers who fled a Federal prison in a stolen helicopter last November were convicted today of charges stemming from their escape.

The two, Ronald McIntosh and Samantha Dorinda Lopez, sat side by side as the verdicts were read in Federal District Court here. Ms. Lopez placed her hands over her mouth but both remained speechless.

Mr. McIntosh, a 42-year-old veteran of the Vietnam War, was found guilty of air piracy and helping Ms. Lopez escape and could be sentenced to 25 years to life in prison. He had been scheduled for release next year.

Ms. Lopez, 37, who would have been eligible for parole in about five years, was convicted of escape. She had been serving a 50-year term for aiding and abetting a Georgia bank robbery. Prison Officials Blamed