PSA reached an accord with a union on USAir bid.

Pacific Southwest Airlines and the 12-member Southwest Dispatchers Assn. agreed on contract modifications demanded by USAir Group as part of its $400-million bid for PSA. The San Diego-based airline previously negotiated contract modifications with the Air Line Pilots Assn., which represents 600 PSA pilots, and is negotiating with a 45-member crew controllers union.