What was found
EN ROUTE, THE CREW RECEIVED A RIGHT HAND ENGINE FIRE CAS MESSAGE. THE CREW FIRED THE FIRE BOTTLES AND DECLARED AN EMERGENCY IN ACCORDANCE WITH PROCEDURES. FLIGHT 4178 THEN DIVERTED TO BOS. OUTSTATION MAINTENANCE INSPECTED AND FOUND THE FIRE DETECTOR CONTROL SUBMERGED IN RAIN WATER UNDER THE FLOORBOARDS. OUTSTATION MAINTENANCE THEN REPLACED THE FIRE DETECTOR CONTROL AND THE EXTINGUISHED FIRE BOTTLES IN ACCORDANCE WITH DORNIER MAINTENANCE MANUAL 26-00-00. OPERATIONAL CHECKS WERE PERFORMED AND THE AIRCRAFT WAS RELEASED FOR SERVICE.