A Southwest jet that did a ‘Dutch roll’ was parked outside during severe storm
What is a "Dutch roll" in aviation terms?
A "Dutch roll" in aviation refers to an oscillating motion of an aircraft involving a combination of yaw and roll movements. It occurs when there is strong lateral stability but weak directional stability, causing the aircraft to sway in a rhythmic, side-to-side motion1. This phenomenon can be dangerous, and modern aircraft are equipped with yaw dampers to counteract the oscillations.
How did the Southwest jet exhibit a Dutch roll?
The Southwest jet experienced a Dutch roll, a swaying, rhythmic combination of yaw (tail sliding sideways) and wingtips rocking up and down, during flight at 34,000 feet and again after descending to 32,000 feet while flying from Phoenix to Oakland, California. The condition occurred after the plane was parked outside during a strong storm and underwent routine maintenance, with pilots noticing odd movements of the rudder pedals1.
What damage was found in the Southwest jet's tail?
Southwest mechanics discovered "substantial" damage in the aircraft's tail after it experienced an unusual "Dutch roll" in flight. The damage was found in the metal bracket and ribs that hold a backup power control unit to the rudder system. The National Transportation Safety Board has not yet determined when the damage occurred.