Southwest Airlines
Southwest commercial airliners taxied at McCarran International Airport in Las Vegas, November 19, 2014. Reuters/Mike Blake

Update as of 5:53 a.m. EST: The Federal Aviation Administration (FAA) said that Southwest Airlines Co. can continue to operate the planes it grounded Tuesday -- for missing a scheduled maintenance system -- provided the jets are inspected within the next five days, ABC News reported Wednesday.

Original Story:

Southwest Airlines Co. grounded 128 jets, or almost 20 percent of its fleet, after the company failed to perform mandatory inspections, a spokeswoman for the low-cost carrier reportedly said, late Tuesday. The move affects the carrier’s Boeing 737 planes and 90 of its flights have so far been cancelled.

The Dallas-based carrier is the world’s largest operator of Boeing 737 jets. The system at issue -- known as the “standby hydraulic system” -- is used to control the rudder if the main system to steer the aircraft fails.

“Once identified, we immediately grounded the affected aircraft, initiated maintenance checks, disclosed the matter to the FAA, and developed an action plan to complete all overdue checks. Approximately 90 cancellations have occurred,” airline spokeswoman Brandy King reportedly said, The Dallas Morning News reported.

Authorities from Southwest and the Federal Aviation Administration (FAA) reportedly discussed plans to complete the overdue maintenance checks and were evaluating a proposal that would allow the airline to continue operations until the inspections are completed.

“The airline voluntarily removed these aircraft from service while the FAA works with Boeing and Southwest to evaluate a proposal that would allow the airline to continue flying the planes until the inspections are completed over the next few days," the FAA said, according to Bloomberg.

Previously, there have been several clashes between Southwest Airlines and the FAA over maintenance issues. Last July, the FAA announced a $12 million fine against the airline, primarily for violations related to repairs performed on its Boeing 737 jets by a contractor. The lawsuit was filed in U.S. District Court in Seattle, according to The Dallas Morning News.