A Southwest Airlines flight traveling from Phoenix, Arizona, to Oakland, California, experienced a rare “Dutch roll” at 32,000 feet, causing “significant damage” to the Boeing aircraft.

Southwest Flight 746 was in the air on May 25 “when its tail began to wag left and right, causing the plane’s wings to rock from side to side,” the New York Post reported

As the Boeing 737 experienced side-to-side and see-sawing motions simultaneously, it sustained “substantial” damage but was able to complete the flight, according to the Federal Aviation Administration (FAA).

The damage was not discovered until a “post-flight inspection,” USA Today reported

No injuries were reported by any flight crew or passengers.

Rare Dutch roll incidents have previously caused planes to “break apart inflight,” according to the outlet.

“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 said.

“The FAA is working closely with the [National Transportation Safety Board] and Boeing to investigate this event,” the agency said in a statement obtained by the New York Post

“We will take appropriate action based on the findings.”

The incident comes as Boeing finds itself in hot water after several whistleblowers stepped forward about apparent unsafe and negligent manufacturing practices, including one former quality control employee who blamed the company for his March suicide