A person employed as an officer or member of the flight crew of an aircraft, who would
otherwise have dual coverage under the social security taxation and coverage laws
of both the United States and Belgium, will only have coverage in the country where
the employer is headquartered. This rule is applicable whether the person is in the
other country on a temporary or permanent basis. Non-travelling personnel (e.g., ground
crews or administrative staffs) will be subject to the laws of the country where they
work unless they qualify as a detached worker (see RS 02001.267).