As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT MAIN GEAR ACTUATOR HOUSING FAILED, FLIGHT INSTRUCTOR & STUDENT HEARD A CRACK/BANG NOISE WHEN THE GEAR WAS 1ST RETRACTED. UPON LANDING GEAR EXTENSION LEFT MAIN TRAILED, AFTER SOME TIME WAS SPENT ATTEMPING TO BRING THE GEAR LEG FORWARD INTO THE LOCK POSITION A GEAR UP LANDING WAS MADE.