NTSB issues 'urgent' safety alert on Boeing 737 rudder system

The National Transportation Safety Board (NTSB) issued urgent safety recommendations Thursday to Boeing and the Federal Aviation Administration (FAA) in response to a possible jammed or restricted rudder control system on some 737 Next Generation and 737 MAX 8 aircraft.

The rudder controls the side-to-side movement of the aircraft's nose, also known as yaw.

The agency is in the midst of investigating an incident in February in which the rudder pedals on a United Airlines Boeing 737 MAX 8 plane were “stuck” in their neutral position during landing initiation at Newark Liberty International Airport in New Jersey.

At the time, the captain had to rely on the steering lever to control the plane's direction after it landed, the NTSB said.

The pilots reported that the plane was able to reach the gate “without further incident” and all 155 passengers and six crew members were able to deplane. No injuries were reported.

As part of the investigation, NTSB investigators tested a rudder control component from the accident aircraft at the component manufacturer, Collins Aerospace.

After testing was conducted in a cold environment, investigators found that the component's function was “significantly compromised.” Collins Aerospace later discovered that the component had been incorrectly assembled during production.

As part of the Boeing 737 flight manual, pilots with a jammed or restricted rudder are required to “overcome the jammed or restricted rudder [using] Maximum power, including the combined effort of both pilots.

However, NTSB investigators expressed concern that this amount of force applied during either landing or roll “may result in significant input to the rudder pedals and a sudden, significant, and unwanted rudder deflection that may inadvertently cause a loss of control or run off the runway.” . . ”

Among its recommendations, the agency suggested that the aircraft manufacturer determine “the appropriate flight crew responses coupled with the application of maximum throttle force” for such in-flight or landing situations.