The FAA has issued a Special Airworthiness Information Bulletin (SAIB) cautioning about the use of aviation fuel biocides such as Kathon FP1.5 and Biobor JF. They are used to eliminate microbiological contamination in aircraft fuel tanks, and in engines and aircraft where they are approved, the OEM’s Aircraft Maintenance Manual will include the correct method of application and dosage.
According to the SAIB, several recent instances showing adverse engine effects after biocide application has been noted. While two of the events were the result of overdosing the aircraft fuel system over the recommended amount of biocide, one event caused a reaction even with the prescribed amount. The FAA told AIN, “Evidence suggests that Kathon FP1.5 biocide may deposit trace amounts of material on fuel system components when blending procedures are not followed, or under certain other conditions.”
At this point the agency is not prohibiting the use of the products, but “additional investigation by the aviation community is continuing regarding the solubility characteristics of this biocide additive.”
As a result, DuPont, which makes the Kathon additive, has recommended immediately discontinuing its use for aviation applications, and GE Aviation has removed it from its list of approved fuel additives while testing continues. The FAA has not had contact with the manufacturer of Biobor regarding any limitations on the use of its aviation fuel biocide.