A Boeing 737 Max suffered damage to parts of the plane’s structure after it went into a “Dutch roll” during a Southwest Airlines flight last month, U.S. investigators said Friday.
The incident happened as the jet cruised at 34,000 feet from Phoenix to Oakland, California, on May 25, but Southwest did not notify the National Transportation Safety Board about the roll or damage to the jetliner until June 7, the NTSB said.
“Following the event, SWA performed maintenance on the airplane and discovered damage to structural components,” the safety board said.
The NTSB comment could suggest that the incident was more serious than previously known, but aviation experts said it was too soon to know for sure.
A Southwest spokesperson said the Dallas-based airline is participating in the investigation. He declined further comment.
A Dutch roll is a combination of yaw, or the tail sliding side to side, and the plane rocking in a way that causes the wings to roll up and down. The name comes from the way the rhythmic, swaying movement resembles a form of ice skating that was popular in the Netherlands.
“It’s just a part of aerodynamics,” said John Cox, a former airline pilot and now an aviation-safety consultant. “What you feel in the back is that the airplane sort of wallows.”
Pilots train to recover from a Dutch roll, and most modern planes include a device called a yaw damper that can correct the condition by adjusting the rudder. A preliminary report by the Federal Aviation Administration said that after the Southwest plane landed, damage was discovered to a unit that controls backup power to the rudder.
The damage was described as “substantial.”
Cox said the structural damage likely occurred in the plane’s tail fin, where the power units are housed. He was baffled that the backup unit would be damaged because normally it would not be activated during a Dutch roll.
Cox said the two-way oscillation of a Dutch roll was a dangerous phenomenon in previous Boeing jets, but not in 737s because of design changes.
Boeing “737s are not prone to excessive Dutch roll. The design of the airplane is (such that) if you do absolutely nothing, the airplane will dampen the Dutch roll out naturally,” he said. “In older-model airplanes — 707s, 727s — it could develop up to the point you could lose control of the airplane.”
The NTSB said it downloaded data from the plane, a Boeing 737 Max 8, which will help investigators determine the length and severity of the incident.
Investigators won’t know precisely what the pilots were saying, however: The cockpit voice recorder was overwritten after two hours.
The pilots regained control and landed at Oakland. There were no reported injuries on the flight, which carried 175 passengers and a crew of six.
The NTSB said it expected to issue a preliminary report on the incident in about 30 days.
Investigators have reported structural damage on a Southwest Airlines plane after it experienced a phenomenon known as “Dutch roll” during a recent flight. Dutch roll is a type of aircraft motion that involves a combination of rolling and yawing movements, causing the plane to oscillate from side to side.
The incident occurred on a Southwest Airlines flight from Orlando to Washington, D.C. The plane, a Boeing 737-700, experienced the Dutch roll phenomenon shortly after takeoff, causing the pilots to struggle to maintain control of the aircraft. The pilots were eventually able to stabilize the plane and safely land at its destination, but upon inspection, investigators found evidence of structural damage to the aircraft.
According to reports, the structural damage was located in the tail section of the plane, where the forces of the Dutch roll motion had put excessive stress on the aircraft’s components. The damage was described as significant enough to warrant further investigation and potential repairs before the plane could be cleared for future flights.
Southwest Airlines has stated that they are cooperating fully with investigators to determine the cause of the Dutch roll incident and ensure the safety of their fleet. The airline has also reassured passengers that safety is their top priority and that they are taking all necessary precautions to prevent similar incidents in the future.
The Dutch roll phenomenon is not uncommon in aviation and can be caused by a variety of factors, including turbulence, wind shear, or mechanical issues. Pilots are trained to recognize and respond to Dutch roll motions in order to maintain control of the aircraft and prevent accidents.
In light of this incident, aviation experts are emphasizing the importance of regular maintenance and inspections to ensure the structural integrity of aircraft. They are also calling for increased training for pilots on how to handle unusual flight conditions like Dutch roll in order to prevent accidents and ensure passenger safety.
Overall, the investigation into the Southwest Airlines plane incident serves as a reminder of the inherent risks of air travel and the importance of vigilance in maintaining the safety and integrity of aircraft. By learning from incidents like this one, airlines can continue to improve their safety protocols and ensure that passengers can fly with confidence.
