What was found
WATER DISCOVERED POOLING IN LOW AREAS UNDER FLOOR LEADING TO WETTING OF INSULATION, CLOGGING OF EVAPORATOR DRAINS, AND PREMATURE FAILURE OF LOWER ANTI-COLLISION BEACON LIGHT DUE TO MOISTURE EXPOSURE AND CORROSION. CONDITION DISCOVERED ON FOUR DIFFERENT FLEET AIRCRAFT TO DATE. WATER SOURCE TRACED BACK TO FORWARD EVAPORATOR. IN B200GT AMM, THERE ARE NO REQUIRED OR OPTIONAL MAINTENANCE PROCEDURES TO ENSURE DRAINS FUNCTION OR ARE CLEAR. REPAIR INVOLVES REMOVAL OF SEATS AND MOST FLOOR BOARDS TO INSPECT, REPAIR, AND CLEAN AFFECTED AREAS. ESTIMATE APPROXIMATELY 15 LBS OF WATER ACCUMULATION BEFORE DISCOVERY OF FAILED BEACON.