AIM - COM 5. 11 - Emergency Communications

General

An emergency condition is classified in accordance with the degree of danger or
hazard present.

(a)        Distress is a situation when safety is being threatened by grave and imminent
            danger and requires immediate assistance. The spoken word for distress is
            MAYDAY and is pronounced 3 times.

(b)       Urgency is a situation where the safety of an aircraft or other vehicle, or of
            some person on board or within sight is threatened, but does not require
            immediate assistance. The spoken word for urgency is PANPAN and is
            pronounced 3 times.

The first transmission of the distress call and message by an aircraft should be on the
air-to-ground frequency in use at the time. If the aircraft is unable to establish
communication on the frequency in use, the distress call and message should be
repeated on the general calling and distress frequency (3023.5 kHz or 121.5 MHz), or
any other frequency available, such as 2182 kHz and 5680 kHz, in an effort to
establish communications with any ground or other aircraft station.

The distress call shall have absolute priority over all other transmissions. All stations
hearing it shall immediately cease any transmission which may interfere with it and
shall listen on the frequency used for the distress call.

Example of a Distress Message from an Aircraft:

MAYDAY, MAYDAY, MAYDAY, THIS IS CFZXY, CFZXY, CFZXY, FIVE
ZERO MILES SOUTH OF YELLOWKNIFE AT ONE SEVEN TWO FIVE
ZULU, FOUR THOUSAND, NORSEMAN, ICING, WILL ATTEMPT CRASH
LANDING ON ICE, CFZXY, OVER.

Example of An Urgency Message Addressed to All Stations:

PANPAN, PANPAN, PANPAN, ALL STATIONS, ALL STATIONS, ALL
STATIONS, THIS IS TIMMINS RADIO, TIMMINS RADIO, TIMMINS
RADIO, EMERGENCY DESCENT AT TIMMINS AIRPORT, ATC
INSTRUCTS ALL AIRCRAFT BELOW SIX THOUSAND FEET WITHIN
RADIUS OF ONE ZERO MILES OF TIMMINS NDB LEAVE EAST AND
NORTH COURSES IMMEDIATELY, THIS IS TIMMINS RADIO OUT.

Emergency procedures are contained in RAC and SAR sections of A.I.P. Canada.

Satellite Voice

INMARSAT, in conjunction with ICAO, has developed a telephone numbering plan to
facilitate use by Air Traffic Services (ATS) of satellite voice calls from suitably
equipped aircraft as an additional backup to the existing primary air-to-ground
facilities. A unique number is assigned to each Flight Information Region (FIR) which
may be used only by aircraft using the satellite network. When the unique number is
received from an aircraft by a Ground Earth Station, it is converted and the call is
routed to the appropriate ATS unit.

The INMARSAT numbers for Canadian FIRs, which are to be used for non-routine
flight safety calls only, are:
 

AIM - SAR 4. 1 - Declaring an Emergency

An emergency condition is classified in accordance with the degree of danger or
hazard being experienced, as follows:

Distress:     A condition of being threatened by serious and/or imminent danger and
                  requiring immediate assistance.

Urgency:    A condition concerning the safety of an aircraft or other vehicle, or of some
                  person on board or within sight, which does not require immediate assistance.

The radiotelephone distress signal MAYDAY and the radiotelephone urgency signal
PAN PAN must be used at the commencement of the first distress and urgency
communication, respectively, and, if considered necessary, at the commencement of
any subsequent communication.
 
RTORC Pg. 12 Distress Communications

Distress Communications

Emergency Conditions

In the aeronautical service, an emergency condition is classified in accordance with the degree of danger or hazard as follows:
Distress A condition of being threatened by grave and/or imminent danger and of requiring immediate assistance.
Urgency A condition concerning the safety of the aircraft or other vehicle, someone
on board or within sight, but which does not require immediate assistance.

Distress Communications

Distress communications should be conducted in accordance with the procedures outlined in this section. These procedures shall not, however, prevent a station in distress from making use of any means at its disposal to attract attention, to make known its position, and obtain assistance.

Frequencies to Be Used

The first transmission of the distress call and message by an aircraft should be made on the air-ground frequency in use at the time. If the aircraft is unable to establish communications on the frequency in use, the distress call and message should be repeated on the aeronautical emergency frequency (121.5 MHz) or any other frequency available in an effort to establish communications with any ground or other aircraft station.

Distress Signal

In radiotelephony, the spoken word for distress is "MAYDAY".
The distress signal indicates that the station sending the signal is:

1. threatened by grave and imminent danger and requires immediate assistance; or

2. aware that an aircraft, ship or other vehicle is threatened by grave and imminent
danger and requires immediate assistance.

Distress Call

The distress call shall only be sent on the authority of the person in command of the
station. The distress call should comprise:

1. the distress signal "MAYDAY" spoken three times;

2. the words "THIS IS";

3. the call sign of the aircraft in distress spoken three times.

Example:        MAYDAY, MAYDAY, MAYDAY
                        THIS IS
                        PIPER FOXTROT X-RAY CHARLIE CHARLIE

The distress call shall not be addressed to a particular station and acknowledgement of
receipt shall not be given before the distress message is sent.

Priority of Distress

The distress call has absolute priority over all other transmissions. All stations which
hear it shall immediately cease any transmission capable of interfering with distress
traffic and continue to listen on the frequency used for the distress call.

 Control of Distress Traffic

The control of distress traffic is the responsibility of the aircraft in distress, or of the
station which relays the distress message. These stations may, however, delegate the
control of distress traffic to another station such as an aeronautical station which,
normally, has a very efficient interface with air traffic control (ATC) and all search and
rescue (SAR) organizations.

Distress Message

The distress message shall follow the distress call as soon as possible.
The distress message should include as many as possible of the following elements:

1. the distress signal "MAYDAY";

2. the call sign of station in distress (once);

3. the nature of the distress condition and kind of assistance required (i.e., what has

happened);

4. the intentions of the person in command;

5. the particulars of its position (airspeed, altitude, heading);

6. the number of persons on board and injuries (if applicable);

7. any other information which might facilitate rescue;

8. the call sign of the station in distress.

 Example:        MAYDAY

PIPER FOXTROT X-RAY QUEBEC QUEBEC

POSITION: 20 MILES EAST OF WINNIPEG

ALTITUDE: 1500 FEET

AIRSPEED: 125 KNOTS

HEADING: 270 T

STRUCK BY LIGHTNING

DITCHING AIRCRAFT

ONE PERSON ON BOARD

PIPER FOXTROT X-RAY QUEBEC QUEBEC

 Note: If the aircraft can transmit the distress message immediately after the distress
call, then items 1 and 2 may be omitted from the message.

Repetition of a Distress Message

The distress message shall be repeated at intervals by the aircraft in distress until an
answer is received or until it is no longer feasible to continue. The intervals between
repetitions of the distress message shall be sufficiently long to allow time for stations
receiving the message to reply.
            Any station that has heard an unacknowledged distress message and is not in a
position to render assistance, shall take all possible steps to attract attention of other
stations that are in a position to assist.
            In addition, all necessary steps shall be taken to notify the appropriate search and rescue authorities of the situation.

Action by Station in Distress

When an aircraft is threatened by grave and imminent danger, and requires immediate
assistance, the person in command should direct appropriate action as follows:

1. transmit the distress call;

2. transmit the distress message;

3. listen for acknowledgement of receipt;

4. exchange further distress traffic as applicable;

5. turn on automatic emergency equipment (emergency locator transmitter - ELT) if

provided and when appropriate.