US Airways yesterday announced it will discontinue operations at Orange County, Calif., on Sept. 6. The current schedule includes two daily nonstop flights from Philadelphia, operated with A319 aircraft. "While load factors have been above 80 percent, our yield was low, which translated to unprofitability," said Andrew Nocella, vice president Planning and Scheduling. "Although Orange County tends to have a higher mix of business traffic than most California airports, we were unable to capture enough higher yielding passengers." The decision affects 24 Customer Service employees at the station. Slot constraints at the Orange County airport also would have restricted US Airways' significant schedule growth in the market for the future.