As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO RETRACT LEFT MAIN GEAR AFTER DEPARTURE. LT GEAR LOCKED DOWN. RETURN TO DEPARTURE. ALT GEAR EXT PROCEDURE. REPLACED ONE MAIN GEAR DOOR ACTUATOR PER 757 AMM 32-32-12. PAGE BLOCK 401. OPERATIONAL CHECK GOOD MAIN LANDING GEAR EXTENSION RETRACTION IAW AMM 32-32-00-705-003. THE AIRCRAFT WAS GROUNDED.