Boeing warns United, American about potential loose bolts in 737 Max jets

Boeing is warning Southwest Airlines, American Airlines and other major carriers about “a possible loose bolt in the rudder control system” in its 737 Max jets.

American, Southwest, United Airlines and Alaska Airlines confirmed inspections will be done on the 737 Max jets that they fly. Boeing’s alert comes after an international operator discovered a bolt with a missing nut while performing routine maintenance on a mechanism in a jet’s rudder-control linkage. The company also found an undelivered jet with a nut that wasn’t tightened.

“The issue identified on the particular airplane has been remedied,” Boeing said in a statement. “Out of an abundance of caution, we are recommending operators inspect their 737 Max airplanes and inform us of any findings.”

Boeing also alerted the Federal Aviation Administration, the nation’s air safety regulatory agency.

Southwest is one of the biggest users of the 737 Max. According to its latest quarterly report, the carrier had 206 Max jets among its 817 aircraft. It recently ordered an additional 108 Max jets from Boeing.

The FAA will monitor inspections of the planes, a roughly two-hour process that involves the removal of an access panel to validate the installation. It could take additional actions if additional loose or missing hardware is discovered.

Boeing’s message to air carriers included instructions to inspect specific tie rods that control rudder movement for the potential loose hardware.

It’s the latest safety issue for Boeing’s bestselling 737 Max, which gained notoriety in 2019 when U.S. aviation regulators grounded the jets following two crashes that killed 346 people. The planes weren’t permitted to fly for 20 months.

In recent months, deliveries of 737 Max jets were slowed after the discovery of production flaws in fuselages produced by Spirit AeroSystems. Boeing and Spirit AeroSystems said they discovered improperly drilled fastener holes on the fuselages of some models.