The FAA is investigating a new incident involving a Boeing 737 Max 8 jet in midair

WASHINGTON — A Boeing 737 Max 8 jet experienced a rare but potentially serious problem recently known as a Dutch roll before landing safely.

The Federal Aviation Administration is investigating the cause of the incident during a Southwest Airlines flight last month.

Less than an hour after taking off from Phoenix on May 25th, the plane experienced an uncontrolled side-to-side yawing motion known as a Dutch roll while cruising at 32,000 feet. The pilots of Southwest flight 746 were able to regain control and the plane landed safely in Oakland, according to a preliminary report from the FAA.

“A Dutch roll is definitely not something that we like to see,” said Shem Malmquist, a commercial pilot who flies the Boeing 777 and an instructor at Florida Tech.

“It's pretty rare on modern airplanes,” Malmquist said, because the aircraft and their systems are designed to prevent a Dutch roll from occurring. Still, it’s important for pilots to know how to respond when it happens, he said.

“Obviously in this case they were,” Malmquist said. “That training is really, really critical.”

The Boeing 737 Max 8 jet involved in the Dutch roll incident is less than two years old. According to the FAA, a post-flight inspection revealed damage to a backup power control unit, known as a PCU. That system controls rudder movements on the plane's tail.

The plane remained in Oakland until June 6th, when it flew to Everett, Wash., where one of Southwest’s maintenance vendors is based.

Boeing has been working to rebuild the trust of federal regulators and the flying public since a pair of Boeing 737 Max 8 jets crashed in 2018 and 2019, killing 346 people.

Earlier versions of the 737 were involved in several accidents and crashes during the 1990s that were ultimately blamed on problems with the tail rudder.

It was not immediately clear what caused the loss of control during the Southwest flight. No other airlines have reported similar problems.

Boeing referred questions about the incident to Southwest Airlines, which declined to comment.

The FAA says it is working closely with Boeing and the National Transportation Safety Board to investigate.

“We will take appropriate action based on the findings,” the FAA said in a statement.