Distress signal
A distress signal indicates that a person or group of people, watercraft, aircraft, or other vehicle is threatened by a serious or imminent danger and requires immediate assistance.
A hand-held flare burns for three minutes and can be used to localize or pinpoint more precisely the exact location or position of the party in trouble.
[3] Distress can be indicated by any of the following officially sanctioned methods: A floating man-overboard pole or dan buoy can be used to indicate that a person is in distress in the water and is ordinarily equipped with a yellow and red flag (international code of signals flag "O") and a flashing lamp or strobe light.
The position of non-GPS EPIRBs is determined by the orbiting satellites, this can take ninety minutes to five hours after activation and is accurate to within 5 km (3.1 mi).
[4] A miniaturized EPIRB capable of being carried in crew members' clothing is called a Personal Locator Beacon (PLB).
In situations with a high risk of "man overboard", such as open ocean yacht racing, PLBs may be required by the event's organizers.
EPIRB registration allows the authority to alert searchers of the vessel's name, label, type, size, and paintwork; to promptly notify next-of-kin, and to quickly resolve inadvertent activations.
A Mayday message consists of the word "mayday" spoken three times in succession, which is the distress signal, followed by the distress message, which should include: When none of the above-described officially sanctioned signals are available, attention for assistance can be attracted by anything that appears unusual or out of the ordinary, such as a jib sail hoisted upside down.
[5] However, for some countries' flags it is difficult (e.g., Spain, South Korea, United Kingdom) or impossible (e.g., Japan, Thailand, and Israel) to determine whether they are inverted.
A distress signal can be three fires or piles of rocks in a triangle, three blasts on a whistle, three shots from a firearm, or three flashes of light, in succession followed by a one-minute pause and repeated until a response is received.
In practice, either signal pattern is likely to be recognized in most popular mountainous areas as nearby climbing teams are likely to include Europeans or North Americans.
The COSPAS-SARSAT 406 MHz radiofrequency distress signal can be transmitted by hikers, backpackers, trekkers, mountaineers and other ground-based remote adventure seekers and personnel working in isolated backcountry areas using a small, portable Personal Locator Beacon or PLB.
