As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF ATTEMPTED TO RETRACT GEAR, RIGHT MAIN AND NOSE UPLOCKED CORRECTLY BUT LEFT MAIN A & B RED LIGHTS REMAINED ILLUMINATED. CYCLED GEAR DOWN THEN BACK UP WITH SAME RESULT, RED A & B LIGHTS ILLUMINATED ON LEFT MAIN. ALL OTHER LIGHTS AND INDICATIONS WERE NORMAL. RETURNED TO FAT. ADJUSTED LEFT MAIN UPLOCK TARGET ADJUSTMENT IAW MM 32-61-01 AND PERFORMED GEAR SWING IAW MM 32-30-00.