Incident Description
The pilot reported that the landing gear indicators showed three green lights. During touchdown and the subsequent landing roll, the landing gear collapsed.
Investigation Findings
Examination revealed that the landing gear control switch collar was defective. If the pilot did not manually hold the gear selector in the down position, it may have returned to the off position before the gear was locked down. This scenario could account for the gear collapsing under the weight of the aircraft during landing.
It was not determined how long this defective condition had existed. Additionally, the switch may have been installed upside down, requiring the handle to be pulled out to place the gear in the down position.