Is an air carrier required to participate in Air AMS at a port where it will never have an aircraft required to make entry under 19 CFR 122.41?  In other words, is Air AMS participation mandatory for an air carriers at a port where it only handles in-bond destination cargo?

The air carrier is not required to participate in Air AMS at a port where it will not make entry under 19 CFR 122.41.  Participation in Air AMS for the purposes of handling in-bond cargo at the destination port is voluntary.