Emergency Procedures resources

Emergency Procedures

Emergency signals

Emergency signals

Transmission of signals CAR 191

The pilot in command of an aircraft transmits or displays the signals specified according to the degree of emergency being experienced.

The signals specified in relation to each successive degree of emergency can be sent separately or together for any one degree of emergency.

Distress signals CAR 192

The distress signal shall be transmitted only when the aircraft occupants are threatened with grave and immediate danger and require immediate assistance.

The distress signal shall take the form of:

  • By radiotelegraphy: the group SOS (··· ––– ···) sent three times, followed by the group DE sent once, followed by the callsign of the aircraft sent three times.The signal specified above may be followed by the automatic alarm signal which consists of a series of 12 dashes sent in one minute, the duration of each dash being four seconds, and the duration of the interval between consecutive dashes being one second.
  • By radiotelephony: the word ‘Mayday’ repeated three times, followed by ‘This is’, followed by the callsign of the aircraft repeated three times.
  • By one or more of the following means:
    • the Morse signal · · · – – – · · · with visual apparatus or with sound apparatus;
    • a succession of pyrotechnic lights, fired at short intervals, each showing a single red light;
    • the two-flag signal corresponding to the letters NC of the International Code of Signals
    • the distant signal, consisting of a square flag having, either above or below it, a ball or anything resembling a ball
    • a parachute flare showing a red light and/or
    • a gun or other explosive signal fired at intervals of approximately one minute
    • squawk transponder code 7700.

Urgency signals CAR 193

The following signals, either together or separately, shall be used by an aircraft for the purpose of giving notice of difficulties which compel it to land without requiring immediate assistance:

  • the repeated switching on and off of the landing lights
  • the repeated switching on and off of the navigation lights, in such a manner as to be distinctive from the flashing lights described below and/or
  • a succession of white pyrotechnic lights.

The following signals, either together or separately shall be used by an aircraft for the purpose of giving notice that the aircraft has a very urgent message to transmit concerning the safety of a ship, aircraft or vehicle, or of some person on board or within sight:

  • By radiotelegraphy: the group XXX(–··– –··– –··–) sent three times, with the letters of each group, and the successive groups, clearly separated from each other, and sent before the transmission of the message.
  • By radiotelephony:
    the words ‘Pan-Pan’ sent three times before the transmission of the message. It is also correct to use Pan-Pan if relaying a Mayday call from another aircraft or station that is out of range.
  • By one or more of the following means:
    • a succession of green pyrotechnic lights and/or
    • a succession of green flashes with signal apparatus.

Safety signals CAR 194

The safety signal shall be transmitted when an aircraft wishes to transmit a message concerning the safety of navigation or to give important meteorological warnings.

The safety signal shall be sent before the call and shall consist of:

  • By radiotelegraphy: the group TTT ( – – – ) sent three times, with the letters of each group and the successive groups clearly separated from each other.
  • By radiotelephony: the word ‘Security’ repeated three times.

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