Distress, Urgency and Safety Communications
What the exam tests here
Priority, correct phrasing and correct procedure. Distress has absolute priority over all other traffic; urgency and safety rank below it but above routine. Examiners look for the exact call format, the correct relay/acknowledgement behaviour, and control of distress traffic.
The three priorities
- MAYDAY - grave and imminent danger, immediate assistance required.
- PAN PAN - urgent message concerning the safety of a ship, aircraft or person (including many medical cases).
- SECURITE - safety of navigation or important meteorological warning.
Distress call on VHF Ch16 (voice)
"MAYDAY MAYDAY MAYDAY, THIS IS <name, call sign, MMSI> (three times), MAYDAY, , position, nature of distress, assistance required, number of persons on board, any other information, OVER." Where time allows, send the DSC distress alert first on Ch70 (or 2187.5 kHz, or the HF DSC band in use), then follow with the voice message on the associated radiotelephony frequency.
Control of distress traffic
- The station in distress, or the station controlling the SAR operation, imposes silence with SEELONCE MAYDAY.
- When distress traffic ends, the controlling station transmits SEELONCE FEENEE.
- A ship that hears a distress alert not acknowledged by a coast station waits about five minutes, then acknowledges by radiotelephony and informs an RCC.
- MAYDAY RELAY is used by a station transmitting a distress message on behalf of another station.
Worked example
A crew member is critically injured 40 nm offshore; the vessel has steering and no immediate danger. The correct priority is PAN PAN (urgent, medical), addressed to a coast station or MRCC, with the nature of the medical problem, the patient's condition, and the assistance requested.
Traps
- Sending MAYDAY on Ch16 first when the DSC alert was possible.
- Using "MAYDAY" for a medical evacuation where the ship is in no grave danger.
- Saying "OVER AND OUT"; OVER invites a reply, OUT ends the contact, and the two are not used together.