The NTSB has issued an emergency warning to airlines operating Boeing 737s. Some of the rudder control systems on 737 Next Generation and 737 Max aircraft may fail in cold weather conditions. The NTSB recommended that the FAA “determine whether the actuator:” Bearings that are not assembled correctly should be removed from the airplane. ”
This story has been updated with new information.
The National Transportation Safety Board has issued an emergency warning to airlines operating Boeing 737s, saying a defect first identified on a United Airlines flight in February could cause problems on other planes. .
According to the NTSB, parts of the rudder control systems on the 737 Next-Generation and 737 Max aircraft, the two latest generations of the airline’s best-selling planes, may lose function in cold weather.
On February 6, a United Airlines passenger plane returning from Nassau, Bahamas to Newark, New Jersey, experienced a rudder pedal that became stuck in its neutral position during the landing roll. The NTSB said the captain was able to control the plane using the nosewheel steering system. No injuries were reported.
Still, authorities investigated and found a problem with the plane’s rudder system.
The NTSB said in a statement Thursday:
NTSB investigators tested one of the aircraft’s rudder control components, the rollout guidance actuator, at component manufacturer Collins Aerospace. When the actuator involved in the accident and an identical unit from another aircraft were tested in a cold environment, the function of the actuator was significantly impaired. Investigators found evidence of moisture on both actuators, but the tests failed. Collins Aerospace subsequently discovered that the sealed bearings were incorrectly assembled during the manufacture of the actuator, leaving the unsealed side susceptible to moisture, which could freeze and restrict movement of the rudder system. I decided that there was.
The Federal Aviation Administration said United Airlines was the only U.S. airline that had the part, and that “it is the FAA’s understanding that the part is no longer in use.”
At Boeing, we want you to be safe on our airplanes. We are working to improve factory safety.
According to the NTSB, Collins Aerospace announced that more than 353 actuators assembled since 2017 were affected.
The NTSB advised Boeing to notify airlines of appropriate pilot responses in the event of a similar accident, and warned that “moisture that has accumulated and frozen within the actuator may cause the rudder control system to become inoperable.” ” to warn the pilot.
The agency also asked the FAA to “determine whether actuators with incorrectly assembled bearings need to be removed from aircraft and, if so, instruct U.S. operators to do so until replacements are available.” ”.
The agency announced Thursday that it had accepted the NTSB’s recommendation. “As parties to the investigation, the agency is closely monitoring this situation,” the FAA said in a statement. “Tomorrow, we will convene a Corrective Action Review Committee based on the NTSB’s interim recommendations to determine next steps.”
This is the latest headache for Boeing. Boeing Co. is under pressure from a mechanics strike and increased regulatory pressure from Capitol Hill following a January crash in which an Alaska Airlines 737 Max lost part of its fuselage mid-flight.