As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GRAVITY XFLOW WILL NOT TURN OFF WHEN COMMANDED. OPS CHECK OF GRAVITY XFLOW GOOD IAW AMM 28-13-16. SEE NON-ROUTINE CARDS N23501, N23513, N23517, AND N23515 FOR R&R OF GRAVITY XFLOW VALVE. REMOVED AND REPLACED GRAVITY XFLOW VALVE IAW 28-13-16 REFERENCE NON-ROUTINE CARD N23513.