Paragraph 49 Distress, urgency and safety signals

(1)

The following signals, given either together or separately before the sending of a message, signify that an aircraft is threatened by grave and imminent danger and requests immediate assistance:

(a)

by radiotelephony:

the spoken word “MAYDAY”;

(b)

by visual signalling:

(i)

the signal SOS ( ... – – – ... );

(ii)

a succession of pyrotechnic lights fired at short intervals each showing a single red light;

(iii)

a parachute flare showing a red light;

(c)

by sound signalling other than radiotelephony:

(i)

the signal SOS ( ... – – – ... );

(ii)

a continuous sounding with any sound apparatus.

(2)

The following signals, given either together or separately, before the sending of a message, signify that the commander of the aircraft wishes to give notice of difficulties which compel it to land but that he does not require immediate assistance:

(a)

a succession of white pyrotechnic lights;

(b)

the repeated switching on and off of the aircraft landing lights;

(c)

the repeated switching on and off of its navigation lights, in such a manner as to be clearly distinguishable from the flashing navigation lights described in rule 11.

(3)

The following signals, given either together or separately, indicate that the commander of the aircraft has an urgent message to transmit concerning the safety of a ship, aircraft, vehicle or other property or of a person on board or within sight of the aircraft from which the signal is given:

(a)

by radiotelephony:

the repeated spoken word, “PAN PAN”;

(b)

by visual signalling:

the signal XXX ( – .. – – .. – – .. – );

(c)

by sound signalling other than radiotelephony:

the signal XXX ( – .. – – .. – – .. – ).