This article has been updated with additional information.

The National Transportation Safety Board (NTSB) has issued an urgent advisory for airlines operating Boeing 737 aircraft, indicating that a malfunction identified on a United Airlines flight in February might pose risks to other aircraft.

The NTSB mentioned an issue with the rudder control system in Boeing 737 Next-Generation and 737 Max models, which can fail in cold temperatures.

On February 6, a United Airlines flight returning from Nassau, Bahamas, to Newark, New Jersey reported that its rudder pedals became stuck in a neutral position during landing. Fortunately, the airline’s captain managed to guide the aircraft using the nosewheel steering without any injuries reported.

Following the incident, the NTSB launched an investigation and discovered complications within the rudder system.

In a statement released on Thursday, the NTSB said:

NTSB investigators assessed one rudder control component from the affected aircraft, specifically a rollout guidance actuator, at its manufacturer, Collins Aerospace. When tested alongside a similar actuator from a different airplane in a cold environment, the functionality of both actuators was significantly impaired. Investigators also found moisture in both units, leading to failed tests. Collins Aerospace later identified that a sealed bearing was improperly assembled during production, leaving one side unsealed and prone to moisture, which can freeze and restrict rudder movement.

According to the NTSB, Collins Aerospace disclosed that more than 353 actuators produced since 2017 are affected.

The NTSB has instructed Boeing to inform airlines of necessary pilot actions in the event of a similar occurrence and to make pilots aware that the rudder control system may jam due to accumulated moisture inside the actuators that can freeze.

The agency has also recommended that the FAA “assess whether actuators with improperly assembled bearings should be removed from aircraft, and if they should be, to instruct U.S. operators to do so until replacements can be secured.”

The FAA stated on Thursday that it agreed with the NTSB’s recommendation. “As a participant in the investigation, the agency has been keeping a close watch on this situation,” the FAA noted in a statement. “We will be assembling a corrective action review board tomorrow based on the NTSB’s preliminary recommendations to outline the next steps.”

This incident adds to the challenges Boeing faces, which include a machinists strike and heightened regulatory scrutiny from Congress following a January incident in which an Alaska Airlines 737 Max lost part of its fuselage during a flight.