U.S. District Court Judge Richard L. Williams yesterday sentenced one former airline flight attendant to prison and ordered a second and a Warrenton man to spend time in a half-way house and perform community service for conspiring to distribute drugs with an estimated street value of $250,000.

The three were arrested in September as the result of the attempted sale of three pounds of morphine base to an undercover agent at a Manassas restaurant, the FBI said.

Ralph Ernest Zomora, 37, of Merritt Island, Fla., was sentenced to two years at the minimum security prison facilities at Eglin Air Force Base, Fla.

Donna Claire Edwards, 36, also of Merritt Island, was ordered to serve 90 days in a half-way house, pay a $2,500 fine, perform 300 hours of community service and submit to psychiatric counseling under the direction of her probation officer. Williams set a three-year probationary period for Edwards.

John Charles Loberg, 34, of Warrenton was ordered to spend 120 days in a half-way house and perform 400 hours of community service followed by three years of supervised probation.

Zomora and Edwards were flight attendants for Pan American World Airways at the time of their Sept. 13 arrest by the FBI.

Morphine base is a substance that may be processed into heroin and has a street value of about $80,000 a pound, FBI officials said.

The three pleaded guilty to the charges, which carry a maximum penalty of 15 years in prison and a $25,000 fine.