i propose the following plans to counter normal cockpit crc denial problem: plan "a", simpliest one: a1.we create storage of legitime cockpits a2.you get message of wrong crc a3.you download it from legitime list plan "b", complex one: b1.you get message of wrong crc b2.you send zipped cockpit to address stated b3.we check the cockpit b4.if cockpit is ok, we calculate crc and add it into legitime list b5.if cockpit is transparent, we do nothing.