What was found
UPON DECENT THE LT PITOT HEAT ANNUNCIATOR ILLUMINATED. THE AIRCRAFT MADE AN UNEVENTFUL LANDING AT DESTINATION. THE HEAT WAS DEFERRED PER MEL BUT DUE TO RESTRICTIONS OF THE MEL THE AIRCRAFT COULD NOT COMPLETE THE REMAINDER OF THE SCHEDULED MISSION AND RETURNED TO BASE. THE AIRCRAFT WAS THEN TURNED OVER TO MAINTENANCE. INVESTIGATION REVEALED THAT THE LT PITOT TUBE WAS DEFECTIVE AND SUBSEQUENTLY REPLACED AND AIRCRAFT RETURNED TO SERVICE AFTER SUCCESSFUL OPERATIONAL AND LEAK CHECKS.