The lex situs rule is singularly ill-adapted to mobile equipment
such as aircraft objects, where the validity of the creation of a mortgage may be determined by the temporary presence of the aircraft in one
jurisdiction while en route to another, as was held to be the position in the Blue Sky case,and even where there is a uniform conflict rule such as the lex registri the substantive content of
the applicable law will vary from jurisdiction to
jurisdiction, creating uncertainty and legal risk
and reducing the availability of finance, increasing
its cost and raising the level of premiums
for credit insurance