The National Transportation Safety Board criticized Boeing for never thoroughly informing airlines about the program that failed and the Federal Aviation Administration for its perfunctory response to the danger in response to its , immediate safety alert next week about a possible Boeing 737 rudder failure.
NTSB Chair Jennifer Homendy criticized the FAA “did not take this issue more really” after an event on a United Airlines 737 Max in February in an exceedingly open way.
Homendy continued, “disappointed” that the FAA did not take “urgent steps to tackle the risk of jammed steering settings” after the NTSB initial report on the incident was made public six months ago.
According to Homendy, it’s “equally concerning” that Boeing did n’t provide in-depth information on the component that failed to meet the requirements when it delivered the nine Maxes to its fleet.
United and its pilots were aware that this part, an opportunity the airline had no ordered, was still installed and physically connected to the neck fin’s steering, which is used to navigate the jet down the runway when it lands on the ground.
Homendy appeared to suggest a similar pattern to how Boeing deliberately concealed the Maneuvering Characteristics Augmentation System, or MCAS, from air and pilots.
It is unethical and intolerable to never make operators conscious of the mounted systems and equipment on the airplanes that are delivered, according to Homendy.
Her notice emphasized that 271 additional probably defective parts “may be installed on plane in company operated by at least 40 unusual heat carriers” despite United having replaced the parts on its nine Maxes so that no aircraft flown by U.S. airlines is now in danger.
In addition, she wrote, a further 75 potentially bad parts were sent directly to airlines as spares and “may currently be on airplanes in service” with foreign airlines.
In a statement, the FAA stated that it was serious about the NTSB recommendations from last week.
According to the federal aviation regulator,” the corrective action review board met, and the FAA is moving quickly to call the affected civil aviation authorities to ensure they have the necessary information from the FAA, including any recommended actions,” adding that it will conduct “additional simulator testing” this month.
Boeing declined to respond to questions about Homendy’s letter, citing the “ongoing investigation” into the , incident on Feb. 6 when United Flight 1539 from the Bahamas landed in Newark, New Jersey, and the pilot found the foot pedals used to move the rudder were stuck.
How United got an optional system it did n’t order
The failed Boeing system, which is intended to assist in the airplane’s failure of the “rollout” phase of the flight operation, which involves accelerating the aircraft straight on the centerline as it decelers down the runway upon landing.
It’s a component of an automated landing system designed to precisely land the jet using instruments in very low visibility.
Pilots can reach as low as 50 feet above the ground before having to decide whether the runway is clear to land because of fog’s ability to obscure the runway. These are referred to as Category IIIB landings in aviation.
With minor adjustments to the rudder, a movable panel on a jet’s vertical tail fin that can deflect to one side so that the air pressure on the panel causes the plane’s nose to turn right or left after touchdown, the system maintains the aircraft straight on the runway.
The “rollout guidance actuator,” which has a servo motor that moves the rudder, was identified as the failure component in NTSB tests following the February incident. It’s made by Collins Aerospace, a unit of aerospace giant RTX, formerly known as Raytheon.
However, United does n’t allow its pilots to do Category IIIB landings, only Category IIA landings where the pilots must see the runway no lower than 100 feet above the ground. Consequently, United did not order this system.
In a footnote to the NTSB report on the February incident, how the system still ended up on United’s planes is explained.
It states that Boeing’s nine Max jets “had originally been configured for another operator” and that when transferred to United the “actuators were electrically disabled,” as Boeing had noted in a 2022 service bulletin to the airline.
Critically though, the actuators were still “mechanically connected” to the rudder, the NTSB noted.
The NTSB ran a test of two of these actuators in Cedar Rapids, Iowa in late February, and it revealed that when used in extremely cold conditions,” the actuators ‘ function was significantly compromised.”
The actuators have evidence of moisture inside them, according to investigators.
After being able to identify the actuators ‘ assembly defect, Collins later discovered that the unsealed side was “vulnerable to moisture that can freeze and restrict rudder system movement.”
The malfunctioning actuator mechanically connected the rudder on a United flight in February, despite the Category IIIB autoland system being disabled. That’s why the rudder would n’t move when the pilot tried the foot pedals.
Boeing, according to the NTSB, allegedly failed to inform United that” the 737 airplanes it had delivered to the airline were equipped with these actuators– and that the actuators were mechanically connected to the rudder control system.”
Three months after the United incident, only on May 6 did Boeing release the instructions that would allow United to permanently remove the rudder rollout guidance actuators from its 737s.
” We are concerned of the possibility that other ( foreign ) airlines are unaware of the presence of these actuators on their 737 airplanes”, Homendy wrote in the letter to Whitaker. In response, their flight crews might not be aware of what to expect if the rollout guidance actuator malfunctions while landing or at low altitude.
All Nippon Airlines of Japan, a major Boeing customer, stated in a statement on Tuesday that it would act right away on the NTSB advice.
” As a precautionary measure, ANA is in the process of removing the identified parts”, the airline said. ” There will be no impact on operations”.
How many planes are at risk?
On the United flight in February, the stuck rudder did not lead to a significant issue. The nose wheel tiller allowed the pilot to keep the aircraft close to the center of the runway, and 30 seconds after touchdown, the rudder pedals started to function normally.
The malfunction was different from the two major, fatal 737 accidents, those that occurred in Colorado Springs in 1991 and Pittsburgh in 1994. On those flights, the rudder control power unit sucked and the rudder completely deflected to the side in midair.
A rudder that’s temporarily frozen in the neutral position, as in the United incident in February, is not so dangerous.
However, a pilot needs a functioning rudder in the event of an engine failure to counteract the asymmetric thrust’s turning effect or a crosswind that causes a jet to go off-course when it is near the ground.
Homendy’s letter details that Boeing informed 737 Airlines in August that Collins had delivered more than 353 actuators with this defect since February 2017. ( Lawyer CEO of Boeing, Kelly Ortberg, was Collins Aerospace’s CEO at the time. )
A further 75 were delivered as spare parts to various airlines and almost 300 were installed on aircraft registered to foreign carriers.
” Some of these may be spares, while others may currently be on airplanes in service”, Homendy wrote.
Boeing declined to say how many airplanes could be affected worldwide, citing the ongoing investigation.
Boeing stated last week that it was working with its supplier to create additional guidance to address the potential condition.
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