Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 17; Flight Crew Total 7397; Flight Crew Type 3123
Ground Event / Encounter Ground Strike - Aircraft
Aircraft Aircraft Damaged; General Evacuated
Aircraft
Flight was under VFR conditions in accordance with FAR Part 91. There was one passenger on the Plane who was also a Pilot.We landed with gear extended and three green lights. The Passenger/Pilot can attest to this. So can the Tower operator who said during my report that 'we saw you lower the landing Gear on Down Wind'. The Approach; Landing; and Touchdown were uneventful. As we were rolling down the runway the nose dropped and shortly thereafter the main landing gear collapsed. Somehow; the Landing Gear Switch ended up in the Retract Position.We were clearly rolling down the runway with weight on all three gears. The Squat switch should have prevented retraction. There are two squat switches either one of which should have prevented retraction. But the Shop Manual only calls for the adjustment of one. If that switch failed; the other may not have been adjusted and would do no good.
Landing gear retracted during landing rollout. Landing gear switch was reported as up by pilot.