The pilot was landing after a local flight of about 20 minutes duration. Everything was normal until, on touchdown, he sensed that the aircraft adopted a greater than normal nose-high attitude. The aircraft came to a halt on its retracted mainwheels, with the propeller broken.
The Yak-52 uses a pneumatic system for the mainwheels, flaps and brakes. The tricycle landing gear is selected using a lever in each cockpit. It requires the lever to be fully in the UP or DOWN detent to achieve the desired selection and another knob must be actuated to withdraw the detents each time the lever is moved. Three green lights to the left of the levers indicate when the landing gear legs are down and locked and three mechanical indicators, one in each wing and one in the nose, provide additional indications of gear position. The pilot reported that, when he selected DOWN, he did not move the lever fully into the DOWN detent and did not check the indicators. This resulted in the nosewheel only partially extending, whilst the mainwheels remained retracted (the aircraft was designed to land on its retracted mainwheels, with minimal damage, in an emergency).