As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR DOOR OPEN LIGHT DID NOT ILLUMINATE BEFORE EXTENSION OF LANDING GEAR. NORMAL OPERATION OF LANDING GEAR SYSTEM OCCURRED (3 GREEN, GOOD HYDRAULICS). EMERGENCY CALLED, CREW DID FLY BY TOWER TO VERIFY GEAR DOWN AND DOORS UP. INSPECTED GEAR DOOR SWITCHES AND LAMP ASSEMBLIES. FOUND LAMP FILAMENT BROKEN POST INSIDE BULB. REPLACED BULB ON GEAR DOOR OPEN INDICATOR. SYSTEM OPS CHECKED GOOD IAW DC-9 MM 32-60.