Mayday
Mayday is the international distress signal in radio. It is used worldwide in the maritime mobile service and the aeronautical mobile service and has the highest priority in radio traffic.
Origin
The term Mayday 1923 by Frederick Stanley Mockford ( 1897-1962 ), senior radio officer at London - Croydon Airport, which was then in close contact with the airport of Paris, determined as an emergency. The letters which the interpretation as ' May Day ' suggests, in English, is regarded as phonetic reproduction of a French call for help * [ mede ].
The first international standards body for telecommunications was the CCITT ( Consultative Committee International Telegraph and Téléphonique ), based in Geneva, whose origins go back to 1865. The lingua franca of the CCITT was French, so many keywords of Funk French origin. The other two levels of urgency Pan - Pan and Sécurité derived from the French.
Seafaring
The radiotelephony distress signal MAYDAY - indicates a distress situation, and initiates the distress message. Distress case means that a vessel at sea in distress or a person is in danger and immediate assistance is required.
Examples of distress cases
Flooding with acute threat of sinking; Attack by pirates; Collision with the threat of sinking; Beaching with impending fall; Flip side with threatened sinking; Fire on board; Man overboard; manövrierunfähiges bustle with imminent dangerous stranding or collision or broaching and capsizing by crusher.
Alerting
In the maritime radio distress traffic through the following channels:
- VHF DSC channel 70 ( 156.525 MHz ) (only digital selective calling )
- VHF channel 16 ( 156.80 MHz ) ( message spoken )
- MF / HF DSC
- 2182 kHz ( SSB )
- 4125, 6215, 8291, 12290, 16420 kHz ( shortwave ), possibly on the working channel of a coast station
- 49-421-53687-0 Phone (mobile or satellite)
- Speed dial 124124 from a German mobile networks ( only in coastal areas )
DSC
Today, the emergency call is usually a DSC apparatus and according to the rules of the Radio Regulations Radio Regulations ( Radio Regulations ). In addition to the equipment requiring ships ( SOLAS) now have all the modern charter boats over a VHF radio with DSC controller.
The emergency button is usually labeled red with " distress " and protected under the slot against false triggering. As further insurance, they must be pressed continuously for several seconds on some devices.
The radio system sends a digital distress alert containing the following:
- MMSI of the vessel
- Position of the vessel (via NMEA GPS receiver or by hand)
- Nature of the emergency (English: Man overboard, Pirates attack, ship sinking, fire, etc.)
Distress
The DSC distress alert is then followed by the emergency call followed by the actual distress message by radio:
Emergency call
Distress
Radio without DSC
In the non- GMDSS radio communications take place the emergency call and the distress in the same way, except that the MMSI is omitted because it was not previously sent by DSC. This applies in the same way for urgency and safety messages.
Receiving an emergency call
The receipt of an emergency call is confirmed via GMDSS usually of coastal radio stations and / or MRCC distress control centers with the digitally transmitted message
In the non- DSC radiotelephone of receiving an emergency call with RECEIVED MAYDAY is confirmed. Confirmation is usually done also by a distress control center. A confirmation by another radio station may only be made if assistance can be provided.
The routing of an emergency call is initiated with MAYDAY RELAY.
Radio silence
An emergency call has priority over any other radio traffic. A disabled vessel or the managing authority of the Notverkehrs may require during an ongoing Notverkehrs radio silence with the cry SILENCE MAYDAY. How many keywords of the radio is also the origin of SILENCE French and should be pronounced accordingly. ( The French, " Silence! " Means " peace ". )
End of Notverkehrs
If the emergency is over and held no distress traffic, the ship that has sent the emergency message, or the rescue coordination center must end the emergency call. Terminating the Notverkehrs effected by:
Mayday All Stations All Stations All Stations This is ........................
____ UTC ( time of completion ) ........................
Silence Fini
Legal consequences
An emergency call can be made only on the orders of the captain. Each ship within is thereby obliged to provide assistance. Successful assistance can trigger a payment obligation in individual cases. The very simple trigger a panic alarm via DSC controllers often leads to costly false alarms. Distress messages - own and received - and activities undertaken are always noted in the logbook.
Legal framework
The settlement of the Notverkehrs regulate the international Radio Regulations ( Radio Regulations ). The regulations contained therein are implemented at the national level in the local regulations.
North and Baltic Seas
In the German area of the North Sea and Baltic Sea rescue of the federal sovereign task is transferred to the GMRS and is coordinated radio for the North and Baltic Sea via the RCC or MRCC Bremen Rescue. The rescue from the air is also carried out under the leadership of GMRS via the command headquarters of the Navy in Glücksburg.
Aviation
Emergency call in flight radio transmitted on the frequency currently used or an emergency frequency. For example, the International distress frequency ( 121.5 MHz FM ) monitored at all controlled aerodromes.
The distress call should include the following:
- Introduction to the (preferably three times ) distress signal MAYDAY
- Called ground station
- Own aircraft identifier (mandatory), such as " D- EFSR "
The subsequent distress message shall contain the following information:
- Type of emergency, such as " motor failure "; " VFR pilot in IMC "; " Lost "; " Loss of pressure in the cabin "
- Intentions of the pilot, eg emergency landing
- Kind of desired help, eg "Request radar vectors "; "Request QDM "; " The airspace to the south keep clear "
- Information about position, heading and altitude
In practice, however, to note that the pilot must make an emergency call individually and can transmit it as it sees rapid problem resolution as appropriate.
An emergency call should not be discontinued too late, even if it has its origin in a mistake or error of the pilot. It can also be withdrawn.
The air traffic control will initiate SAR action if necessary.
If a discrete transponder code is connected, additionally should be connected to the emergency transponder to the emergency code 7700. At this the pilot can be reminded of the ground station ( "Squawk 7700 "). This marks the aircraft on the radar screen of the air traffic control with an additional symbol (eg a star).
If the radio has failed ( or is suspected of ), an emergency call can also be placed through the sole Power of the transponder code 7700.
The in distress and controlling the distress radio station can use the arrangement KEEP RADIO SILENCE MAYDAY / STOP TRANSMITTING MAYDAY all or certain other radio stations radio silence imposed. After completion of air emergency air traffic control will release the frequency again for the general radio.
BOS radio, respirator use
Make the fire service with respiratory protective equipment in need guessed forces by giving a Maydays attention.
The in distress squad logs according to fire brigade service provision FwDV 7 according to the following scheme over 2m BOS radio:
" MAYDAY, MAYDAY, MAYDAY
Here
Once the MAYDAY signal is by radio, the entire radio communication is to be set to allow a complete discontinuation of the emergency call. With the given information knows the hurrying to the aid of backup squad where the squad is in distress and what has happened to him.