What was found
POST FLIGHT INSP REVELED ICE BUILD UP ON LT OTBD WING SLAT. PERFORMED ACFT RUN-UP TO TEST THE SLAT ANTI-ICE SYS AND USING A TEMPERATURE GUN FOUND THE SLAT TEMPERATURE ON THE OTBD SECTION TO BE HALF OF THE OTHER 3 SECTIONS. INSPECTION FOUND THAT THE HOT AIR SUPPLY HOSE TO THE OTBD SLAT WAS PARTIALLY BLOCKED BECAUSE OF A SEPARATION OF THE INNER LINER OF THE HOSE WHEN IT GETS WARM. WE REPLACED THE HOSE AND LEAK CHECKED THE SYS AND RETURNED THE ACFT TO SERVICE. NO FURTHER ISSUES.