What was found
RT ENGINE TAI VALVE DID NOT CLOSE AFTER LANDING. ACFT GROUNDED. VERFIED BOTH LIGHT ON P5-11 AND ON UPPER DU. T/S IAW FIM 30-21, TASK 801. VERIFIED OVERPRESSURE SWITCH S806 GOOD, VERIFIED WIRING FROM P5-11 TO OVER PRESSURE SWITCH GOOD. TRIED NEW P5-11, PANEL IAW AMM 30-11-40-000-801/-400-801. NO HELP. REINSTALLED ORIGINAL IAW SAME REF FOUND INLET COWL TAI VALVE BAD. R & R RT COWL THERMAL ANTI-ICE VALVE IAW AMM 30-21-11-000-801/-400-801. OPS AND LEAK GOOD. VERIFIED RT COWL CORRECTLY EXTINGUISHED AFTER ENG RUN.