When procuring commercial turbine fuel, what must be ensured regarding FSII?

• A. FSII Must Be Present In Any Commercial Turbine Fuel Procured
• B. FSII Must Be Absent
• C. FSII Must Be Present Only In Military Fuels
• D. FSII Is Optional

Answer: (A)

FSII stands for Fuel System Icing Inhibitor. It’s added to aviation turbine fuels to prevent ice from forming in the fuel system when the fuel contains small amounts of water and the temperature is low. Ice in pumps, filters, and lines can restrict or block fuel flow, risking engine fuel starvation or other power problems. Therefore, when you procure commercial turbine fuel, you must verify that FSII is included in the fuel at the proper concentration to provide protection throughout the fuel system in the operating conditions you’ll encounter. FSII presence is a standard safety requirement, not optional, and it applies to commercial fuels just as it does to military fuels.