Date: 201208
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Challenger 300
Operator: Fractional
Operating under: Part 135
Mission: Passenger
Flight phase: Landing
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Gear Extend/Retract Mechanism
Component problem: Malfunctioning; Improperly Operated
Reporter organization: Fractional
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Executed Go Around / Missed Approach; General Maintenance Action
Contributing factors: Human Factors; Aircraft
Primary problem: Ambiguous

Narrative: We were flying the ILS in visual conditions. Fully configured; stabilized and before landing checklist completed and the gear was confirmed down three green by both myself and pilot not flying. At approximately 200 FT AGL I heard a clicking noise in the cockpit. Either simultaneously with the clicking noise or right after the noise we received the 'gear too low' warning message. I quickly glanced at the CAS messages and noticed gear was in transit up. The pilot not flying called for a go a round which we executed. On the Tower directed missed we climbed to 2;000 FT and were on a heading provided by Tower. On the downwind leg we received the RA. I disconnected the autopilot and was preparing to follow climb commands when I glanced to the right of the plane and visually located the helicopter. As we were clear of any conflict no changes of heading or altitude was deemed necessary. On downwind we again lowered the gear; confirmed it indicated 3 green and proceeded to land visually. On final Tower communicated to us that the gear was in fact down. As this was an uncommanded movement of the landing gear I don't have any suggestions for avoiding a recurrence of this event.


Second narrative: After configuring for landing (flaps 30 and landing gear down and locked indications) and completing the before landing checklist while flying the ILS VMC day; at approximately 200 FT AGL we heard a click followed by the aural warning 'too low gear'. An uncommanded gear retraction was then confirmed by in-transit icons on the MFD and tactile and audible feedback from the gear doors moving and closing. I (pilot not flying) called for the Go Around (GA) and the Captain executed the GA. The gear was confirmed up and locked and flaps retracted to 10. We followed Tower vectors for the downwind and climbed to 2;000 FT. We then received a TCAS RA; confirmed the traffic position and continued the downwind without maneuvering to avoid traffic. As we were certain the gear handle had been caught in between the up and down position detents on the previous approach; we selected the gear down again and confirmed 3 green indications after positioning the flaps to 20. I maneuvered the selector to verify that it was seated in the down detent. Tower confirmed the gear was down. Flaps were selected to 30 and the visual approach and landing was completed without incident. Until the gear selector malfunction is addressed; I suggest crews verify that the selector is locked in the down detent after selecting the gear down.


Synopsis: CL300 flight crew reports an uncommanded landing gear retraction at 200 FT during approach. A go around is initiated and a TCAS RA is annunciated on downwind but evasive action is not required. On the second approach the gear handle is verified in the down detent and an uneventful landing ensues.