FSII & certification
Not sure of this, but I believe that some helicopters are certified on the basis that fuel shall contain FSII. My Enstrom 480B is one of these. I have been told by the manufacturer that FSII is not required for technical reasons, but because the certification was done with FSII, it is now called out in the FM as "required." Given this, it would seem that without FSII the acft is not considered airworthy under FAA regs; if so this would have implications for insurance coverage if operated without , as well as other unhappy implications. Any brilliant insights?