Dallas ? American Airlines said it was canceling up to 500 flights Tuesday, potentially more than one-fifth of its schedule, to check the bundling of wires in some planes, the same issue that caused the airline to scrap more than 400 flights last month.

American, the nation’s largest carrier, said the cancellations could spill into today and beyond.

The airline said the Federal Aviation Administration raised more concerns about the recent inspections of the wiring in its approximately 300 MD-80 aircraft.

The inspections will focus on issues including the spacing and direction of cords used to secure bundles of wires in the planes’ auxiliary hydraulic systems. The company said they were not safety-of-flight issues.

Tim Wagner, a spokesman for the airline, said an FAA inspector checked several planes Monday and found that some of the work performed last month didn’t meet the agency’s standards.