Act of God (AOG): also known as a `force majeure'. This encompasses the situations where airlines are not legally responsible for providing lodging, transport, or other expenses that travellers may incur as a result of an AOG. Inclement weather, civil disruptions, and other unanticipated events may be classified as an AOG or Aircraft On Ground (AOG): when an aircraft urgently needs some sort of maintenance on the ground when it is supposed to be in the air.