What was found
DE-ICE PRESSURE CAUTION AFTER TAKEOFF. BOOT SET SECOND FROM RT WING TIP REMAINED INFLATED, ADVISORY LIGHT STAYED ON. BOOTS DEFLATED AFTER APPROX 20 MINUTES. RETURNED TO THE FIELD AND ACCOMPLISHED A UNEVENTFUL LANDING. PERFORMED OP'S CHECK OF DDV SYS IAW AMM TASKS 30-11-16-710-801. ALSO PERFORMED TACTILE INSPECTION OF ALL BOOTS. NO ISSUES OR DESCREPANCIES REGARDING BOOT SET SECOND FROM RT WING TIP, INTERROGATED CDS, FOUND " LOW PRESS 6B". R & R NR 6 DDV, IAW AMM TASKS 30-11-16-000-801, 30-11-16-400-801. OP'S CHECKED GOOD. NO CAUTIONS OR FAULTS RETURNED. NO OTHER DEFECTS NOTED. PERFORMED FUNCTIONAL TEST OF THE AIRFRAME PNEUMATIC DEICING SYS IAW AMM TASK 30-11-00-720-801. COULD NOT DUPLICATE. RETURNED TO SERVICE.