US Airways yesterday entered a request in bankruptcy court to be allowed to default on its labor contracts with 7,200 Communications Workers of America represented reservation and ticket agents, and 12,000 members of the International Association of Machinists (IAM), who have not agreed to concessions sought by the airline. US Airways is so far holding to its promise not to attempt to default on contracts with dispatchers and crew trainers represented by the Transport Workers of America, or members of the pilots? and flight attendants? unions---all of whom have agreed to wage and benefit concessions (see WIT for Aug. 9, 2002). Having made it clear that they do not support management concession demands that their membership will vote on tomorrow, officers of the IAM expected yesterday?s action by management and announced that they are ready to fight for the 12,000 mechanics and baggage handlers whose contract is threatened.