What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot was practicing a single engine approach with their student, and delayed extending landing gear as part of the simulated emergency. The landing gear failed to fully deploy, and the pilot/instructor did not notice that the normal gear-down indication did not appear. Unbeknonst to the pilot a plastic connector that holds the power leads to the hydralic pump had come loose due to vibration. The pilot continued the approach and touched down gear-up. The partially deployed landing gear was pushed back into the fuselage and the airplane came to rest on its fuselage on the runway.
As the FAA filed it
PILOT WAS PRACTICING A SINGLE ENGINE APPROACH WITH THEIR STUDENT, AND DELAYED EXTENDING LANDING GEAR AS PART OF THE SIMULATED EMERGENCY. THE LANDING GEAR FAILED TO FULLY DEPLOY, AND THE PILOT/INSTRUCTOR DID NOT NOTICE THAT THE NORMAL GEAR-DOWN INDICATION DID NOT APPEAR. UNBEKNONST TO THE PILOT A PLASTIC CONNECTOR THAT HOLDS THE POWER LEADS TO THE HYDRALIC PUMP HAD COME LOOSE DUE TO VIBRATION. THE PILOT CONTINUED THE APPROACH AND TOUCHED DOWN GEAR-UP. THE PARTIALLY DEPLOYED LANDING GEAR WAS PUSHED BACK INTO THE FUSELAGE AND THE AIRPLANE CAME TO REST ON ITS FUSELAGE ON THE RUNWAY.