The Civil Aeronautics Board's enforcement division has charged Southwest Airlines with discriminating against passengers who are both blind and deaf by forcing them to travel with a companion.

The Federal Aviation Act and CAB regulations require airlines to provide handicapped passengers air transportation without discrimination. Southwest, a large carrier headquartered in Dallas, said it would face great operational costs as well as practical complications if it carried unescorted passengers who are both blind and deaf.

Rosaleen Y. Perea, a Lubbock, Tex., resident who is blind and deaf, complained to the board. CAB investigators said that although Perea has flown on Southwest unaccompanied since becoming blind and deaf, the airline now refuses to allow her to board without an attendant. Such a blanket rule with no regard for an individual's ability to travel safely is against federal regulations, the investigators said.

Southwest said that permitting Perea to board unescorted would take too long and that establishing communication between blind and deaf passengers and the flight attendants could impose an unreasonable burden. The airline also said its flight crews would have difficulty communicating with blind and deaf passengers in an emergency.

The board investigators said they knew of no emergency evacuation case in the United States in which an unaccompanied blind and deaf passenger was injured or killed because of the passenger's handicap.

Airlines may set their own rules for dealing with the handicapped but must have a "reasonable and specific basis" for doubting such a person's abilities, the investigators said.

The probers asked the full board to order Southwest to stop violating regulations protecting handicapped air travelers and to order the airline to evaluate its practices.

Because it will go out of business at the end of this month, the CAB will not rule on the matter. The issue is expected to be considered by the Transportation Department, which inherited most of the board's functions.