NTSB · Safety Recommendation
Safety Recommendation A-24-027
Recommendation
TO THE BOEING COMPANY: Instruct operators of Boeing 737NG and 737MAX airplanes with Collins Aerospace SVO-730 rudder rollout guidance actuators with incorrectly assembled bearings to notify flight crews that the rudder control system might become jammed or restricted in flight or during landing due to moisture that could accumulate and freeze in the actuators. (Urgent)
Safety Issue and Context
The National Transportation Safety Board (NTSB) is providing the following information to urge The Boeing Company and the Federal Aviation Administration (FAA) to take immediate action on the safety recommendations in this report concerning the potential for a jammed or restricted rudder control system on certain Boeing 737 airplanes. We identified these issues during our ongoing investigation of the rudder pedal anomaly involving a Boeing 737-8, N47280, while landing at Newark Liberty International Airport (EWR), Newark, New Jersey, on February 6, 2024.
On the basis of the results of postincident testing conducted in July 2024 and information from Boeing and Collins Aerospace, the NTSB is concerned that Boeing’s mitigation to overcome a jammed or restricted rudder control system during landing could also result in a large input to the rudder pedals and a sudden, large and undesired rudder deflection sufficient to cause loss of control or departure from the runway.
A jammed or restricted rudder scenario could become even more concerning if a high crosswind or an engine-out condition were simultaneously occurring with a jammed or restricted rudder, not only because the amount of rudder available to respond to these conditions might be insufficient to maintain control of the airplane if the jam is not cleared—but also because excessive rudder input may result if the jam is cleared by responding with Boeing’s mitigation. As a result, the NTSB is issuing two urgent safety recommendations to The Boeing Company and two urgent safety recommendations to the FAA.
Response History
June 17, 2025 · NTSB Correspondence · Boeing Company
On October 4, 2024, Boeing distributed the following multi-operator messages (MOMs) to operators of affected Boeing 737NG and 737MAX airplanes:
• MOM-MOM-24-0142 informed operators about these recommendations and encouraged flight crews to follow the Jammed or Restricted Flight Controls Non-Normal Checklist (NNC) if a rudder restriction condition is encountered in flight. If encountered on the ground, the MOM encouraged flight crews to use differential braking and/or tiller to maintain runway centerline. • MOM-MOM-24-0442 informed operators about Collins Aerospace RRGA, part number SVO-730, Notice of Escapement concerning clutch bearing installation errors on a portion of the 737NG and 737 MAX fleet.
On October 9 and 10, 2024, Boeing distributed Flight Crew Operations Manual Bulletins (OMBs) TBC-125 (737NG) and TBC-38 R1 (737MAX), respectively. The OMBs inform flight crews that, because rudder application is typically unnecessary throughout most of the flight, a frozen RRGA and associated jammed or restricted rudder may not be evident until the approach and landing phases.
The OMBs recommend that flight crews perform the Jammed or Restricted Flight Controls NNC if a jammed or restricted rudder condition is experienced during flight; however, if encountered prior to touchdown, flight crews should perform the Go-Around and Missed Approach Procedure and climb to a safe altitude before performing the Jammed or Restricted Flight Controls NNC. Finally, if restricted flight controls are encountered after touchdown and rollout is continued, the OMBs recommend that flight crews apply differential braking to maintain runway centerline and avoid using nosewheel steering above 100 knots unless necessary to prevent overcontrol.
During our March 17, 2025, meeting, representatives from Boeing answered questions my staff had about the guidance contained in Boeing’s MOMs and OMBs. However, we remain concerned about this safety issue, which is also the subject of one of our open investigations. Because we are still reviewing information to determine if Boeing has sufficiently addressed these recommendations, we will reevaluate Boeing’s actions and classify these recommendations in our final report. In the meantime, the Board has voted to keep Safety Recommendations A-24-27 and -28 classified OPEN-- INITIAL RESPONSE RECEIVED.