Chapter 5 of Annex 11 is concerned with the alerting service, which provides for the alerting of rescue coordination centres when
an aircraft is believed or known to be in a state of emergency, when it fails to communicate or to arrive on time or when information
is received that a forced landing has been made or is imminent. Alerting service is automatically provided to all aircraft receiving air
traffic control service and, as far as is practicable, to all other aircraft whose pilots have filed a flight plan or are otherwise known to
air traffic services. It is also provided to aircraft known or believed to be subject to unlawful interference. The effect of the alerting
service is to set in motion all appropriate rescue and emergency organizations which can provide assistance when and where required.