The union representing air traffic controllers rejected the FAA’s request yesterday for federal mediation to help the agency reach a labor agreement with controllers, labeling it a “publicity stunt.” A 1998 contract expired on September 30, and the FAA suggests that little progress has been made since it and the National Air Traffic Controllers Association began negotiating on July 13. According to a NATCA spokesman, negotiations continue this week where they left off two weeks ago. “We are not even close to an impasse,” he said. “A federal mediator is not needed. We have been making substantial progress,” although, he conceded, not on several major issues, such as pay. The FAA’s contract proposal maintains the average base pay of current controllers ($166,000), which the agency said is a 74-percent increase since the 1998 contract. The agency said the union is proposing to raise average total compensation for all controllers above $200,000. NATCA’s request for a shorter workday is also being rejected by the FAA, which said controller time actually working aircraft is currently 4.5 hours per day at its largest facilities