Investigators found substantial damage in the tail of a Southwest Airlines Boeing 737 Max after experiencing a Dutch roll mid-flight. The plane had been parked outside during a severe storm and underwent routine maintenance, with pilots later noticing unusual movements in the rudder pedals. The Dutch roll, characterized by swaying yaw and rocking wingtips, occurred at 34,000 and 32,000 feet during a flight from Phoenix to California. The damage involved fractures in the metal bracket holding a backup power control unit to the rudder system. Experts suggest the storm likely caused the damage, ruling out maintenance or aircraft design issues. Southwest has inspected its fleet with no further incidents, but the root cause may take over a year to determine. This incident highlights the importance of proper aircraft maintenance and monitoring for potential safety risks.