(CNN)Southwest Airlines missed required inspections on 128 of its Boeing 737 aircraft, leading to the cancellation of dozens of flights this week. The Federal Aviation Administration has said the airline can keep flying the planes for up to five days while the maintenance checks are completed, Southwest said. The airline was overdue for a required maintenance check on the standby hydraulic system for the planes, both the FAA and Southwest said. Southwest notified the FAA of the lapsed inspections on Tuesday, then voluntarily grounded the 128 aircraft while regulators evaluated the airline's plan to complete the overdue checks, the FAA said. Southwest had to cancel approximately 80 flights on Tuesday because of the groundings. On Wednesday, the airline said it was anticipating "very minimal impact" to its operation "as remaining checks are completed." CNN's Aaron Cooper and Tina Burnside contributed to this report .
The FAA gives Southwest five days to complete the missed checks . The planes were overdue for required inspections . Approximately 80 flights were canceled .