The Department of Justice and Equality and An Garda Síochána have primary responsibility for the internal security of the State. Among the roles assigned to the Defence Forces in the White Paper on Defence is the provision of Aid to the Civil Power which, in practice, means to assist An Garda Síochána when requested to do so. On each occasion that the support of the Defence Forces is required, An Garda Síochána issues a form C70 to the Defence Forces to request their assistance.
Since 5 February 2003, the Gardaí have requested support from the Defence Forces at Shannon Airport on occasion. The duration of Defence Forces deployments at Shannon Airport is determined by the length of time an aircraft is on the ground. As a deployment is a 12 hour shift, a single aircraft on the ground for an extended period, perhaps overnight, would involve more than one deployment of troops per request.
The request for assistance from An Garda Síochána to the Defence Forces does not stipulate the reason for landing or the expected duration of the stay.