DALLAS – Southwest Airlines says it expects to meet a federal deadline this weekend and finish examining 128 planes that were grounded because of missed inspections.

Southwest Airlines Co. spokeswoman Brandy King said Friday that the airline had inspected 115 of the planes and would check the others by the Sunday night deadline.

The Federal Aviation Administration is letting Southwest keep flying the planes while inspections of a backup hydraulic system for the rudders are done during overnight hours. An FAA spokesman says an investigation is continuing.

Southwest grounded the planes – about one-fifth of its fleet – on Tuesday and cancelled about 100 flights. King says the airline doesn’t expect any more cancellations while it inspects the last 13 planes.