FAA investigates Southwest Airlines plane that performed a mid-flight Dutch roll

Aviation authorities are investigating an unusual phenomenon that occurred on a Southwest flight last month in which the plane performed a movement known as a “Dutch roll.”

According to a report from the Federal Aviation Administration (FAA), Southwest Flight 746 was en route from Phoenix to Oakland on May 25 when the tail of the Boeing 737 began to move left and right, causing the plane to rock from wingtip to wingtip in what is known as a “Dutch roll.”

The FAA’s initial report stated that there were 175 passengers on board at the time of the incident, as well as six crew members. The plane landed safely in Oakland and there were no injuries, but the report notes that the standby PCU (power control unit), which controls an aircraft’s rudder, had “significant” damage.

Boeing states that the name “Dutch Roll” refers to the movement of figure skaters when they rock side to side.

“Airplanes can perform similar lateral and directional movements in flight, rolling and yawing much like a traditional Dutch ice skater rocking rhythmically along one of Amsterdam’s frozen canals,” Boeing wrote in a report. “…Just as ice skaters avoid rocking too far and losing their balance, airplanes are designed to roll and yaw within regulatory requirements to ensure safety — and potentially reduce the risk of airsickness.”

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Southwest declined to comment on the incident and referred PEOPLE to the FAA and National Transportation Safety Board (NTSB) for comment.

In a statement to PEOPLE, the NTSB confirmed that it has data from the plane’s digital flight data recorder, but noted, “The cockpit voice recorder, currently limited to two hours of audio, has been overwritten and is not available to investigators.”

A preliminary report is expected within 30 days of the event date.

According to the Associated Press, the FAA points out that no similar problems have been reported by other airlines.

This report comes at a turbulent time for Boeing: earlier this year, the company’s CEO, Dave Calhoun, announced that he would step down from his post at the end of the year following a series of incidents involving Boeing aircraft.

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In January, an Alaska Airlines Boeing 737-9 en route to California had to make an emergency landing in Portland after part of the cabin panel burst during the flight. Just a few weeks later, the nose wheel of a Delta Airlines Boeing 757 broke off in Atlanta shortly before takeoff.

Also in March, a United Airlines Boeing jet skied off the runway and tipped over on its side. That same week, another United flight en route to Osaka, Japan, was diverted to Los Angeles after a tire fell off the plane.

Calhoun had previously described the Alaska Airlines incident as a “turning point” in a message to employees.

“We must continue to respond to this accident with humility and full transparency,” he wrote to employees at the time. “We must also embed an absolute commitment to safety and quality at all levels of our company.”