By Naveen Athrappully
Contributing Writer
The National Transportation Safety Board issued urgent safety recommendations to aircraft manufacturer Boeing and the Federal Aviation Administration regarding a “significantly compromised” critical flight control component on some 737 airplanes.
NTSB is investigating an incident that occurred on Feb. 6, when the rudder pedals on a United Airlines Boeing 737-8 got “stuck” in their neutral position while landing at Newark Liberty International Airport in New Jersey. According to the Thursday report from the U.S. government investigative agency, the captain “used the nosewheel steering tiller to control the airplane’s direction after touching down” to avoid any mishaps to the aircraft or the 155 passengers and six crew members on board.
Upon testing one of the rudder control components — a rollout guidance actuator — from the incident airplane along with an identical unit from another airplane, NTSB investigators found that the components’ functioning was “significantly compromised” when tested in a cold environment.
The component was manufactured by Collins Aerospace, a North Carolina-based company that is one of the world’s largest suppliers of aerospace and defense products.
“Investigators found evidence of moisture in both actuators, which failed testing,” the NTSB report states. “Collins Aerospace subsequently determined that a sealed bearing was incorrectly assembled during [the] production of the actuators, leaving the unsealed side more susceptible to moisture that can freeze and limit rudder system movement.”
Faulty Rudders, FAA Response
Collins Aerospace notified Boeing that more than 353 actuators delivered to the company since 2017 faced the same condition, according to the NTSB report.
Installed in the tail of some B-737NG and 737 MAX airplanes, the rudder controls rotation along an aircraft’s vertical axis and is a primary flight control mechanism. It is not used to steer the direction of flight but rather to control adverse movements.
When jammed, pilots are instructed to use maximum force, “a combined effort of both pilots,” to overpower the restricted rudder, according to the NTSB. The report expressed concern that such an amount of force applied during landing or rollout “could unintentionally cause loss of control or departure from a runway.”
The NTSB recommended that Boeing notify pilots of the potential jamming of rudder control systems due to moisture. The agency asked the FAA to determine whether the affected actuators should be removed and to notify aviation regulators in other countries.
The FAA acknowledged the issue in an emailed statement, saying the agency “accepts this recommendation from the NTSB.”
“As a party to the investigation, the agency has been monitoring this situation closely,” the statement reads.
The FAA said it will soon “convene a corrective action review board based upon the NTSB’s interim recommendations and determine next steps.”
Moreover, the FAA confirmed that United Airlines was the only U.S. operator that had the components and said that “the units are no longer in service.”
Boeing Problems
Boeing has been facing a litany of issues lately. A prolonged strike by 33,000 employees, largely from the Seattle metro area, weighs heavily on the company.
Boeing and its shareholders, suppliers, and workers stand to lose at least $1.4 billion during the second full week of the strike, from Sept. 13 to Sept. 27, according to a recent analysis by the Anderson Economic Group.
“Additional losses were calculated this week for Boeing suppliers, who lose $144 million, and non-Boeing Seattle workers impacted by the strike, who lose an estimated $25 million,” the report said, adding that the disruption has shut down most of the company’s commercial airplane production.
After the Jan. 5 Alaska Airlines incident in which a door panel blew off a Boeing 737 Max 9 jetliner in mid-flight, the airplane manufacturer has been under increasing scrutiny and faces investigations by federal agencies.
The FAA has capped Boeing plane production volumes following the incident.