The FAA and NTSB are investigating an unusual rolling motion of a Southwest Airlines Boeing 737 Max
Associated Press Finance
Thu, 13 June 2024
WASHINGTON (AP) — Federal officials said Thursday they are investigating an unusual rolling motion on a Southwest Airlines Boeing 737 Max that might have been caused by a damaged backup power-control unit.
The Federal Aviation Administration said it was working with Boeing and the National Transportation Safety Board to investigate the May 25 incident, which happened on a flight from Phoenix to Oakland, California.
The FAA said the plane went into a “Dutch roll,” the name given to the combination of a yawing motion when the tail slides and the plane rocks from wingtip to wingtip. It is said to mimic the movement of a Dutch ice skater.
Pilots are trained to recover from the condition, and the Southwest plane landed safely in Oakland. There were no injuries reported among the 175 passengers and six crew members.
According to a preliminary report by the FAA, an inspection after the plane landed showed damage to a unit that provides backup power to the rudder.
The FAA said other airlines have not reported similar issue
Southwest Airlines Boeing 737 Max sustains 'substantial' damage from 'Dutch roll' incident
Zach Wichter, USA TODAY
Fri, 14 June 2024
A Southwest Airlines jet was damaged during a flight last month after it experienced an unusual maneuver called a Dutch roll.
Flight 746 was en route from Phoenix to Oakland on May 25 when the incident occurred.
According to the Federal Aviation Administration, the plane sustained “substantial” damage to its tail section as a result of the maneuver, although it was able to complete the flight. The damage was only discovered during a post-flight inspection. The rudder’s standby power control unit (PCU) was damaged. The standby PCU is a backup system in case the main rudder power unit becomes inoperable. No injuries were reported as a result of the maneuver.
Tracking data from FlightAware shows that the aircraft, a Boeing 737 Max 8, registered N8825Q, was sent back to Boeing on June 6.
Boeing referred to Southwest for comment, and Southwest referred to the FAA and National Transportation Safety Board.
The FAA said it is working with the NTSB and Boeing to investigate the incident.
The NTSB did not immediately respond to a request for comment.
What is a Dutch roll?
A Dutch roll is an airplane maneuver that involves simultaneous yaw (side-to-side motion across a flat horizontal plane) and roll (see-saw motion over a horizontal plane).
"Dutch roll is an oscillatory motion characterized by a combination of rolling and yawing of an aircraft. It typically arises when the combination between the lateral (roll) and directional (yaw) dynamics of the aircraft are out of balance," Ken Byrnes, assistant dean and associate professor of aeronautical science, and chairman of the Flight Department at Embry-Riddle Aeronautical University, told USA TODAY in a written statement.
"In Dutch roll, the aircraft experiences a rolling motion primarily driven by the design (dihedral effect) of the wings, while simultaneously yawing due to the adverse yaw effect caused by the sideslip angle. This coupled motion results in a dynamic instability where the aircraft oscillates in both roll and yaw directions," Byrnes said.
Dutch rolls are farely rare in commercial aviation.
“The opportunity for Dutch roll is usually lessened in the design of the aircraft," Byrnes said. "If it occurs, pilots often mitigate Dutch roll using various control inputs, but most large aircraft have a system that is designed to automatically counteract it called a yaw dampener.”
The movement can stress the airplane fuselage and cause damage as it did in the Southwest incident. Dutch roll incidents have previously caused planes to break apart inflight.
Zach Wichter is a travel reporter for USA TODAY based in New York. You can reach him at zwichter@usatoday.com.
This article originally appeared on USA TODAY: FAA, NTSB investigate Southwest Airlines 'Dutch roll' incident
Kelly Rissman
Fri, 14 June 2024 at 7:35 am GMT-6·2-min read
A Boeing 737 Max has been grounded for 20 days after the aircraft experienced a dangerous “Dutch roll” mid-flight, causing it to sway side-to-side in yet another troubling incident for the embattled aviation company.
The Southwest Airlines flight was traveling from Phoenix, Arizona, to Oakland, California, carrying 175 passengers and six crew members, when the aircraft experienced a Dutch Roll, an “unsafe” movement in which the tail wags and the wings oscillate, according to the Federal Aviation Administration (FAA).
The June 12 incident report indicates that pilots regained control of the aircraft, but an inspection upon landing revealed “damage to the standby” power control unit, which provides back-up power to the main rudder.
No passengers were injured, the report says, but the damage to the plane was “substantial.”
It’s unclear when the aircraft will be able to fly again.
“The FAA is working closely with the NTSB and Boeing to investigate this event. We will take appropriate action based on the findings,” the FAA said in a statement to The Independent. The agency noted that other airlines have not reported similar issues.
Boeing deferred comment to Southwest Airlines.
A spokesperson for the airline referred questions to the NTSB and the FAA, adding “Southwest is participating in and supporting the investigation.”
The Independent emailed the NTSB for comment.
This incident is just the latest in a series of problems that have plagued Boeing aircraft in recent months. Perhaps the most well-known accident occurred in January, when a door plug blew out on an Alaska Airlines flight while en route.
The aerospace company is also embroiled in potential legal issues. Not only did passengers on the January Alaska Airlines flight sue, but the company is also up against the Justice Department.
The Justice Department last month claimed that Boeing breached the terms of an agreement that allowed the company to avoid criminal prosecution after two deadly crashes — one in 2018 and one in 2019 — involving its 737 Max aircraft. Boeing argued as recently as this week that it upheld its side of the deal.
It also faces potential problems internally. Despite the deaths of two whistleblowers, around 50 current and old Boeing employees have expressed a desire to speak out about safety concerns, a lawyer previously told The Independent.
Investigation underway into rare, unsafe airliner roll experienced by a Boeing 737 Max
Gregory Wallace, CNN
Fri, 14 June 2024
Federal authorities and Boeing are trying to figure out why a 737 Max 8 experienced a rare, unsafe back-and-forth roll during flight.
The oscillating motion is known as a Dutch roll, and one characteristic described by the Federal Aviation Administration is the nose of an aircraft making a figure-eight.
There were no injuries onboard Southwest Airlines flight 746 on May 25, according to the airline and a preliminary report by the FAA. The report said the crew “regained control,” and the plane safely landed.
But the aircraft suffered “substantial” damage and the FAA classified the incident as an “accident.” The FAA report said an inspection “revealed damage to the standby PCU,” or power control unit, which controls the rudder.
It is unclear if the damaged unit led to or was a result of the roll.
The plane has not flown since landing in Oakland, California after the incident, except to move it to a Boeing facility in Washington state. Boeing did not immediately comment to CNN.
Southwest told CNN it referred the incident to the FAA and National Transportation Safety Board and is participating in and supporting the investigation.
The incident occurred almost three weeks ago and was added to a FAA database this week. There were 175 passengers and six crew onboard, according to the airline.
CNN has reached out to the NTSB. It has not said whether it is investigating the incident.
In February, the FAA required airlines flying some 737 Max 8 and similar aircraft to inspect the rudder assembly for loose or missing nut, washer and bolt. It said the flaw would prevent the pilots from controlling the rudder using foot pedals. Authorities have not said if this condition and the Dutch roll last month are related.
An unusual motion
Most passengers have never felt a plane make this movement — and most airline pilots have never experienced it in actual flight.
“It’s very obscure,” aviation safety analyst and former airline pilot Kathleen Bangs told CNN. “It’s a very uncomfortable movement and you feel the tail swinging around.”
While moving forward in flight, airplanes can pivot along three axis: Nose up and down, known as pitch; wings dipping down or raising up, known as roll; and the tail shifting left or right, known as yaw.
Airliners turn using a typically seamless combination of roll and yaw coordinated by the aircraft’s computers. These large aircraft also have yaw dampers that make small adjustments throughout flight.
In the Dutch roll, the plane both rolls and yaws excessively. Passengers would feel the plane shift to one side, and back to the other — moving back and forth, Bangs said.
She said airline pilots train for scenarios where their yaw dampers fail. They could take an aircraft simulator to a high altitude and turn off the yaw damper.
“Then you stomp on a rudder pedal really hard to try to initiate [the roll] in the simulator,” Bangs said.
To get out of a Dutch roll, pilots can slow the aircraft and descend to thicker air. Modern airliners are designed to be inherently stable in air, she said, so the plane may return to level flight with minimal additional input.
But the forces can be powerful. In 1959, four of the eight occupants on a Boeing 707 test and training flight were killed just outside of Washington, DC, after extremely steep Dutch rolls.
“The aircraft immediately yawed and rolled violently to the right,” reads a report from the Civil Aeronautics Board, which investigated the incident. “Several gyrations followed and after control of the aircraft was regained, it was determined that three of the four engines had separated from the aircraft and it was on fire.”
FAA 'too hands off', chief says, in Boeing oversight before 737 MAX 9 incident
David Shepardson and Allison Lampert
Updated Thu, 13 June 2024
The fuselage plug area of Alaska Airlines Flight 1282 Boeing 737-9 MAX
WASHINGTON (Reuters) -The head of the Federal Aviation Administration (FAA) said Thursday the agency was "too hands off" in oversight of Boeing before a January mid-air emergency in a new Alaska Airlines 737 MAX 9, as it pursued multiple investigations into the planemaker.
FAA Administrator Mike Whitaker's comments at a Senate Commerce Committee hearing mark the first time the U.S. aviation regulator has acknowledged inadequate oversight in the Jan. 5 incident, in which a door panel blew out during the flight.
"The FAA should have had much better visibility into what was happening at Boeing before Jan. 5," Whitaker said.
He said the agency had permanently boosted the use of in-person inspectors and that he would visit a Boeing factory in South Carolina on Friday.
The FAA's approach before the mid-air incident "was too hands off, too focused on paperwork audits and not focused enough on inspections," Whitaker added.
"We will utilize the full extent of our enforcement authority to ensure Boeing is held accountable for any noncompliance. We currently have multiple active investigations into Boeing and are processing a number of reports filed by whistle-blowers."
Asked if the FAA shared responsibility or some blame for the Jan. 5 incident, Whitaker said: "Boeing makes the airplane so Boeing is responsible, but we're also responsible for oversight, so we should have had a better handle on what was going on."
Boeing did not immediately respond to a request for comment.
Whitaker in February barred Boeing from boosting production of its best-selling plane. He said last month he did not expect Boeing to win approval to increase production of the MAX "in the next few months."
Senator Ted Cruz, the top Republican on the Commerce Committee, said he remained concerned about the FAA's failed Boeing oversight.
"The FAA must guarantee that not only are they certifying an aircraft is safely designed but that the manufacturer is building them to that safe design. Clearly, that was not happening at Boeing."
Whitaker also said the agency will continue increased on-site presence at Boeing and its supplier Spirit AeroSystems for the foreseeable future.
He added there must be a fundamental shift in Boeing's safety culture and "has been a shift in tone" on quality.
"We have been too much in reactive mode, waiting for some event to occur and analyzing the event to find out what to do differently," Whitaker said. "So we’re shifting to a much more proactive approach. On the manufacturing side, it’s introducing inspectors and coming up with clear indices to monitor performance."
On May 30, Boeing delivered a comprehensive quality improvement plan to the FAA after Whitaker in late February gave Boeing 90 days to develop a comprehensive plan to address "systemic quality-control issues."
Outgoing Boeing CEO Dave Calhoun will testify on Tuesday before another Senate committee. Senate Commerce Committee chair Maria Cantwell said she could also call Calhoun to appear at a future hearing.
The National Transportation Safety Board said earlier the door panel that flew off a Boeing 737 MAX 9 jet mid-flight was missing four key bolts and no paperwork exists for the removal of those bolts. Whitaker confirmed no paperwork exists.
The Justice Department has opened a criminal probe into the MAX 9 incident.
(Reporting by David Shepardson and Allison Lampert; Editing by Chizu Nomiyama and Rod Nickel)
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