These flush mounted drain valves are suitable for all MTO and MTO Sport models for testing fuel-samples and approved by FAA, TSO-C76 and ASRA.
Recommended replacement interval is every 200h or when necessary. The most common reason that fuel drain valves drip is due to dirt build-up in the fuel. The dirt collects in the lowest part of the fuel tank where the fuel valve is located. This dirt can cut the o-ring, or keep the valve from fully sealing.