The National Transportation Safety Board is issuing “urgent safety recommendations” for some Boeing 737s—including the embattled 737 MAX line— warning that critical flight controls could jam.

The National Transportation Safety Board on Thursday issued urgent safety recommendations about the potential for a jammed rudder control system on some Boeing 737 airplanes after a February incident involving a United Airlines flight.

A U.S. transportation safety agency urged the Federal Aviation Administration and Boeing to address a potential hazard on about 350 of Boeing’s 737 models currently flying.Accident investigators with the National Transportation Safety Board said a flaw led to cockpit pedals that control the jet’s rudder getting stuck after a United Airlines 737 MAX landed at Newark Liberty International Airport in February.

The National Transportation Safety Board has issued safety recommendations following a United Airlines incident with a jammed rudder control on a Boeing 737 MAX 8. The issue arose during a landing at Newark when the rudder pedals got stuck in the neutral position,

The National Transportation Safety Board is issuing “urgent safety recommendations” for some Boeing 737s—including the embattled 737 MAX line— warning that critical flight controls could jam.

The US National Transportation Safety Board warned that a faulty component in some Boeing Co. 737 aircraft could cause the plane’s rudder control system to jam.