What was found
AFTER TAKEOFF AND GEAR RETRACTION, THE GEAR UNSAFE AND DOORS WARNING LIGHTS REMAINED ILLUMINATED AND WOULD NOT EXTINGUISH AFTER CYCLING. FLIGHT CONTINUED TO TOL FOR AN UNEVENTFUL LANDING. GROUND INSPECTION FOUND THE LEFT MAIN LANDING GEAR RETRACT PIN BROKEN. MAINTENANCE REPLACED THE LEFT MAIN LANDING GEAR RETRACT PIN AND ACCOMPLISHED THE GEAR SWING IN ACCORDANCE WITH THE DOUGLAS OVERHAUL AND MAINTENANCE MANUALS 32-1-1 AND 32-60-0.