What was found
DURING DEPARTURE, THE DE-ICE PRESSURE CAUTION ILLUMINATED. COMPLIED WITH EC. DE-ICE PRESSURE =19 PSI PHASE FLIGHT =CLIMB, THE INBD SECTION ON THE LT HORIZONTAL STAB WOULD NOT ILLUMINATE. IT TESTS OK. LIGHT MODE SWITCH=SLOW. RETURNED TO FIELD, LANDING UNEVENTFUL. PERFORMED TACTILE INSPECTION ON ALL L/E WHILE INFLATED WITH NO DEFECTS NOTED. INTERROGATED CDS AND FOUND "LOW PRESSURE 6B FAIL" R & R THE NR 6 DDV IAW AMM TASKS 30-11-16-000&400-801. CLEARED FAULT FROM CDS. PERFORMED OPERATIONAL TEST OF THE DUAL DISTRIBUTING VALVES IAW AMM TASK 30-11-16-710-801. OPS TEST GOOD, CAUTION DID NOT RETURN. NO FAULT CODES. NO FURTHER DEFECTS NOTED. RETURNED TO SERVICE.