What was found
(PIREP) AFTER TAKEOFF, L MAIN GEAR DOOR AMBER ADVISORY LIGHT REMAINED ILLUMINATED AFTER GEAR UP SELECTION. VISUALLY CONFIRMED DOOR OPEN. RECYCLED GEAR PER CHECKLIST, DOOR RETRACTED NORMALLY. (MX) ADJUSTED L MAIN LANDING GEAR DOOR (FWD) ACTUATOR IAW DHC -8 MM 32-10-21 PG 224. ADJUSTED PROX SENSOR APR IAW DHC -8 MM 32-10-21 PG 237. C/W FUNCTIONAL TEST OF LANDING GEAR EXTENSION AND RETRACTION IAW DHC -8 MM 32-30-00 PG 205-206. C/W ALTERNATE EXTENSION CHECK IAW DHC -8 MM 32-35-00 PG 201-203. NO DEFECTS NOTED.