Distress alert

The DSC transmission of a distress alert indicates that a mobile unit (ship, aircraft or other vehicle) or person is threatened by grave and imminent danger and requests immediate assistance. It is sent using a DSC format in the bands used for terrestrial radiocommunications or a distress message format, in which case it is relayed through space stations. It is normally followed by a distress call on the associated R/T channel. The distress alert shall provide the identification of the station in distress and its position.