What happened
Following takeoff, the pilot observed that the left-main landing gear would not retract fully. In response, the pilot extended the landing gear and executed various emergency procedures to attempt to achieve full extension of the left-main gear. Because the pilot was unable to get the left-main gear to lock in the down position, the decision was made to land the aircraft with only the nosewheel and right-main gear extended.
During the landing roll, the left-main gear collapsed, causing the airplane to slide to a stop.
The investigation
An inspection of the left-main landing gear identified that the needle bearing connecting the outer-body to the inner-body of the upper-main landing gear strut had failed. Additionally, the lower needle bearing was found to be near failure. Investigators noted a lack of lubrication in this area and observed evidence of severe corrosion development. The investigation also determined that the Manufacturer's Inspection Program for this aircraft model does not specify a calendar or time-based inspection interval, nor does it provide a lubrication interval for the upper and lower needle bearings.