Cessna 550 Citation II, Salt Lake City, Utah, March 29, 2009–During landing roll at Salt Lake City International Airport at the end of a Part 91 flight, N44FR skidded off the runway when the right main landing gear retracted, causing substantial damage to the aircraft but no injuries to the three people on board. The twinjet’s right wing contacted the ground and then clipped adjacent runway lights as the pilot attempted unsuccessfully to keep the airplane on the runway.
According to the pilot, all three green gear-down lights were illuminated before landing. Examination of the Citation showed that the right main gear hydraulic actuator had retracted into its housing. Cessna removed and examined the part under FAA supervision and found three significant anomalies: the mis-rigging of the actuator downlock switch, worn or over-trimmed back-up rings at the lock piston seals and the lack of required sealant at the downlock switch and the visual indicator. The safety wire on the downlock switch was also missing its tamper-proof indicator seal. None of the anomalies was considered to be a clear independent cause of the gear collapse. Further dimensional, visual and non-destructive testing conducted at GE Aviation Services did not produce any findings that the technicians felt would affect the locking of the actuator.