Distress and urgency procedures and communications failure procedures
Distress and urgency communication procedures are detailed in Annex 10, Volume II.
Distress and urgency conditions are defined as:
- Distress: a condition of being threatened by serious and/or imminent danger and of requiring immediate assistance.
- Urgency: a condition concerning the safety of an aircraft or other vehicle, or of some person on board or within sight, but which does not require immediate assistance.
The word “MAYDAY” spoken at the start identifies a distress message, and the words “PAN PAN” spoken at the start identifies an urgency message. The words “MAYDAY” or “PAN PAN”, as appropriate, should preferably be spoken three times at the start of the initial distress or urgency call.
Distress messages have priority over all other transmissions, and urgency messages have priority over all transmissions except distress messages.
Pilots making distress or urgency calls should attempt to speak slowly and distinctly so as to avoid any unnecessary repetition.
Pilots should adapt the phraseology procedures in this chapter to their specific needs and to the time available.
Pilots should seek assistance whenever there is any doubt as to the safety of a flight. In this way, the risk of a more serious situation developing can often be avoided.
A distress or urgency call should normally be made on the frequency in use at the time. Distress communications should be continued on this frequency until it is considered that better assistance can be provided by changing to another frequency. The frequency 121.5 MHz has been designated the international aeronautical emergency frequency although not all aeronautical stations maintain a continuous watch on that frequency. These provisions are not intended to prevent the use of any other communications frequency if considered necessary or desirable, including the maritime mobile service RTF calling frequencies.
If the ground station called by the aircraft in distress or urgency does not reply, then any other ground station or aircraft shall reply and give whatever assistance possible.
A station replying (or originating a reply) to an aircraft in distress or urgency should provide such advice, information and instructions as is necessary to assist the pilot. Superfluous transmissions may be distracting at a time when the pilot’s hands are already full.
Aeronautical stations shall refrain from further use of a frequency on which distress or urgency traffic is heard, unless directly involved in rendering assistance or until after the emergency traffic has been terminated.
When a distress message has been intercepted which apparently receives no acknowledgement, the aircraft intercepting the distress message should, if time and circumstances seem appropriate, acknowledge the message and then broadcast it.