Sierra 24
Flight Crew Private
Flight Crew Last 90 Days 22; Flight Crew Total 50; Flight Crew Type 1.0
Aircraft Equipment Problem Less Severe; Ground Event / Encounter Loss Of Aircraft Control
Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
Private pilot; instrument student flying ZZZ direct to ZZZ1. Flew the RNAV Runway XX; circling approach to Runway XY for circling practice as well as winds were favorable to Runway XY. Before the Final approach Fix we performed our pre-landing checklist which included gear selector down. Gear selector switch came down at the Final approach fix; and showed 3 green lights indicating gear is down and locked. Student and instructor confirmed 3 green lights indicating gear down.  Landing was very smooth; lightly touched down and began sliding.  We were unaware that the gear was not down and locked.  There was no impact or sparks.  The plane remained on the runway; veered slightly to the left due to the left gear collapsing more than the right.
I was with my instrument student who was flying ZZZ direct to ZZZ1. Upon completion of the descent checklist; we confirmed we would fly the RNAV XX approach and circle to land Runway XY as winds were favoring XY. Prior to the Final Approach Fix; we performed the pre-landing checklist. Upon arrival at the Final Approach Fix; the landing gear selector was set to the down position. Shortly after putting the gear down; both my student and I confirmed 3 green lights indicating the gear was down and locked. We later started our circle to Runway XY and performed the landing checklist and confirmed landing gear indicated down and locked. Shortly after flaring; the airplane touched down then we began sliding to the left of the runway. Once realizing the propeller stopped spinning and was bent; we promptly performed shutdown procedures and exited the aircraft. Upon exiting the aircraft; the right main was partially extended while the nose gear and left main appeared mostly collapsed. Neither myself nor my student experienced any injury.
Flight Instructor and student flying a Sierra 24 reported loss of directional control on landing during training flight due to a landing gear failure.