Federal officials said Thursday they are investigating an unusual roll motion on a Southwest Airlines Boeing 737 Max 8 that may have been caused by a damaged backup power control unit.
The Federal Aviation Administration said it is working with Boeing and the National Transportation Safety Board to investigate the incident on a May 25 flight from Phoenix to Oakland. Southwest says it is working with the FAA and Boeing.
The FAA said the plane went into a “Dutch roll,” the name given to the combination of a screeching motion as the tail slips and the plane rocks from wingtip to wingtip. It is said to mimic the movement of a Dutch skater. It happened when the jet was at about 32,000 feet.
Pilots were trained to recover from the condition and the plane landed safely in Oakland about an hour later. There were no injuries among the 175 passengers and six crew members on board.
According to a preliminary report from the FAA, a post-landing inspection of the plane showed damage to a unit that provides backup power to the rudder.
CBS News Aviation Safety analyst Robert Sumwalt told CBS News senior transportation and national correspondent Kris Van Cleave via email, “Any uncommanded flight control movement is potentially significant. The fact that this resulted in significant damage makes this a major problem.”
The FAA said other airlines have not reported similar problems and Southwest said it has not had a similar problem with other Max jets in its fleet.
Van Kleave notes that the aircraft in question was delivered in November 2022 and has therefore been in use for just over a year.
The incident was first reported by The Aviation Herald, which said a temporary repair was made in Oakland and the plane was then “transferred” to Boeing’s plant in Everett, Washington for further repairs.
The latest incident comes as the 737 Max comes under heavy scrutiny in the wake of a door plug blowing out of a brand new Alaska Airlines 737 Max 9, which led to a temporary grounding of that Max version.
