Incident”Investigators revealed that a Southwest Airlines Boeing 737 Max sustained structural damage following a “Dutch roll” during a flight from Phoenix to Oakland on May 25. Despite the incident occurring at 34,000 feet, Southwest only informed the National Transportation Safety Board (NTSB) about the event and subsequent damage on June 7.
“After the incident, maintenance on the aircraft by SWA revealed damage to structural components,” the NTSB disclosed. This statement suggests that the situation might be more severe than initially understood, although aviation experts cautioned against drawing conclusions too soon.
Southwest Airlines, headquartered in Dallas, is actively cooperating with the investigation, a spokesperson confirmed, declining further comment.
A Dutch roll involves a combination of yaw, or lateral movement of the tail, and rocking that induces the wings to oscillate up and down. The term originates from a rhythmic ice skating motion popular in the Netherlands.
“It’s a fundamental aspect of aerodynamics,” explained John Cox, a former airline pilot and current aviation-safety consultant. “What passengers typically feel is the aircraft’s gentle swaying.”
Pilots are trained to recover from Dutch rolls, aided by modern aircraft which are equipped with yaw dampers to stabilize the aircraft by adjusting the rudder. A preliminary report from the Federal Aviation Administration noted that upon landing, damage was identified in a unit responsible for providing backup power to the rudder, with the extent of damage described as significant.
Cox speculated that the damage likely occurred in the tail fin of the aircraft, where these power units are typically housed. He expressed surprise at the backup unit being affected, given that it typically remains inactive during a Dutch roll.
Although Dutch rolls were hazardous in earlier Boeing aircraft models like the 707 and 727, Cox reassured that the design of the Boeing 737 Max mitigates such risks naturally, without requiring pilot intervention to dampen oscillations.
The NTSB retrieved data from the Boeing 737 Max 8 involved in the incident to assess its duration and severity. However, due to the cockpit voice recorder being overwritten after two hours, the precise communications between the pilots remain unknown.
The flight safely landed at Oakland, and there were no reported injuries among the 175 passengers and six crew members aboard. The NTSB anticipates issuing a preliminary report on the incident within the next 30 days.
