CEN21LA259 · Cessna 560XL

The pilots were on approach to the destination airport. They reported that the approach was stabilized and normal and that the landing gear indications were normal with three green landing gear indicator lights illuminated. During landing and after speed brake deployment, an aural landing gear warning sounded, the right wing gradually dropped and scraped on the runway, and the airplane veered to the right and subsequently came to rest on the right side of the runway, which resulted in substantial damage to the right wing. After the accident, the right main landing gear was found retracted, and the left main landing gear and nose gear were found extended and locked in place. The landing gear handle was found in the UP (retracted) position. The copilot did not recall manipulating the landing gear handle after the initial landing gear extension during flight. Further, cockpit audio captured the crew verifying the gear extension twice, and recorded data showed that the landing gear were extended. Functional testing of the landing gear handle revealed that the unit passed all manufacturer acceptance test procedure requirements except for the test that required the landing gear handle return to either the UP or DOWN position when released from any position. During the testing, the handle exhibited a tendency (multiple times) to stick in place when released. When the landing gear handle was stuck in a position outside of the extend and retract detents, the handle would move if vibration was applied to the case or if the handle was moved manually. After the handle moved out of the retract detent, it sent an “extend” command throughout the remaining travel to the extend position. This allowed the handle to send an “extend command” while the handle was stuck in a mid-travel position and, with some vibration on the case, it would slowly transition towards the retract position and would eventually move into the retract detent position and provide a “retract command.” The results of the testing as well as the postaccident examination of the landing gear handle did not reveal the reason that the handle would stick in a midtravel position. However, the results of the testing showed that a malfunction of the landing gear handle occurred, which likely caused the right main landing gear to collapse during the landing roll. The reason why only the right main landing retracted could not be determined. Postaccident examination and functional testing of the rest of landing gear system revealed no mechanical malfunctions or anomalies that would have precluded normal operation.

Verbatim NTSB analysis and probable cause from the NTSB dataset