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Distress signal

March 10, 2023

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A distress signal, also known as a distress call, is an internationally recognized means for obtaining help. Distress signals are communicated by transmitting radio signals, displaying a visually observable item or illumination, or making a sound audible from a distance.

A distress signal indicates that a person or group of people, ship, aircraft, or other vehicle is threatened by a serious or imminent danger and requires immediate assistance.[1]: PCG D−3  Use of distress signals in other circumstances may be against local or international law. An urgency signal is available to request assistance in less critical situations.

For distress signalling to be the most effective, two parameters must be communicated:

  • Alert or notification of an emergency in progress
  • Position or location (or localization or pinpointing) of the party in distress.

For example, a single aerial flare alerts observers to the existence of a vessel in distress somewhere in the general direction of the flare sighting on the horizon but extinguishes within one minute or less. 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. An EPIRB both notifies or alerts authorities and at the same time provides position indication information.

Maritime

Distress signals at sea are defined in the International Regulations for Preventing Collisions at Sea and in the International Code of Signals. Mayday signals must only be used where there is grave and imminent danger to life. Otherwise, urgent signals such as pan-pan can be sent. Most jurisdictions have large penalties for false, unwarranted, or prank distress signals.

Distress can be indicated by any of the following officially sanctioned methods:

 
Distress Signals
 
Smoke signal
  • Transmitting a spoken voice Mayday message by radio over very high frequency channel 16 (156.8 MHz) or medium frequency on 2182 kHz
  • Transmitting a digital distress signal by activating (or pressing) the distress button on a marine radio equipped with Digital Selective Calling (DSC) over VHF channel 70 or over another designated DSC frequency in the maritime MF and HF bands.
  • Transmitting a digital distress signal by activating (or pressing) the distress button (or key) on an Inmarsat-C satellite internet device
  • Sending the Morse code group SOS (  ▄ ▄ ▄ ▄▄▄ ▄▄▄ ▄▄▄ ▄ ▄ ▄ ) by light flashes or sounds
  • Burning a red flare (either hand-held or aerial parachute flare)
  • Launching distress rockets
  • Emitting orange smoke from a canister
  • Showing flames on the vessel (as from a burning tar barrel, oil barrel, etc.)
  • Raising and lowering slowly and repeatedly both arms outstretched to each side
  • Making a continuous sound with any fog-signaling apparatus
  • Firing a gun or other explosive signal at intervals of about a minute
  • Flying the international maritime signal flags NC    
  • Displaying a visual signal consisting of a square flag having above or below it a ball or anything resembling a ball (round or circular in appearance)

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.

In North America, marine search and rescue agencies in Canada and the United States also recognize certain other distress signals:

  • Sea marker dye
  • White high-intensity strobe light flashing at 60 times per minute

Automated radio signals

In addition, distress can be signaled using automated radio signals such as a Search and Rescue Transponder (SART) which response to 9 GHz radar signal, or an Emergency Position-Indicating Radio Beacon (EPIRB) which operates in the 406 MHz radiofrequency. EPIRB signals are received and processed by a constellation of satellites known as Cospas-Sarsat. Older EPIRBs that use 121.5 MHz is obsolete. Many regulators require vessels that proceed offshore to carry an EPIRB.

Many EPIRBs have an in-built Global Positioning System receiver. When activated these EPIRBs rapidly report the latitude and longitude of the emergency accurate to within 120 m (390 ft). 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). Marine safety authorities recommend the use of GPS-equipped EPIRBs.[2]

A miniaturized EPIRB capable of being carried in crew members' clothing is called a Personal Locator Beacon (PLB). Regulators do not view them as a substitute for a vessel's EPIRB. In situations with a high risk of "man overboard", such as open ocean yacht racing, PLBs may be required by the event's organizers. PLBs are also often carried during risky outdoor activities on the land.

EPIRBs and PLBs have a unique identification number (UIN or "HexID"). A purchaser should register their EPIRB or PLB with the national search and rescue authority; this is free in most jurisdictions. 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 DSC radio distress signal can include the position if the lat/long are manually keyed into the radio or if a GPS-derived position is passed electronically directly into the radio.

Mayday

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:

  • Name of the vessel or ship in distress
  • Its position (actual, last known, or estimated expressed in lat/long or in distance/bearing from a specific location)
  • Nature of the vessel distress condition or situation (e.g. on fire, sinking, aground, taking on water, adrift in hazardous waters)
  • Number of persons at risk or to be rescued; grave injuries
  • Type of assistance needed or being sought
  • Any other details to facilitate resolution of the emergency such as actions being taken (e.g. abandoning ship, pumping flood water), estimated available time remaining afloat

Unusual or extraordinary appearance

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.

During daylight hours when the sun is visible, a heliograph mirror can be used to flash bright, intense sunlight. Battery-powered laser lights the size of small flashlights (electric torches) are available for use in emergency signaling.

Inverted flags

For hundreds of years inverted national flags were commonly used as distress signals.[3] 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. Other countries have flags that are inverses of each other; for example, the Polish flag is white on the top half and red on the bottom, while Indonesia's and Monaco's flags are the opposite—i.e., top half red, the bottom half white. A ship flying no flags may also be understood to be in distress.[4] For one country, the Philippines, an inverted flag is a symbol of war rather than distress.[5]

If any flag is available, distress may be indicated by tying a knot in it and then flying it upside-down, making it into a wheft.[6]

Examples of inverted flags as distress signals

Device loss and disposal

To avoid pointless searches some devices must be reported when lost. This particularly applies to EPIRBs, lifebuoys, rafts, and devices marked with the vessel's name and port.

Expired flares should not be set off, as this indicates distress. Rather, most port authorities offer disposal facilities for expired distress pyrotechnics. In some areas special training events are organized, where the flares can be used safely.

EPIRBs must not be disposed of into general waste as discarded EPIRBs often trigger at the waste disposal facility. In 2013, the majority of EPIRB activations investigated by the Australian Maritime Safety Authority were due to the incorrect disposal of obsolete 121.5 MHz EPIRB beacons.[7]

Aviation

 
Radio beacon of distress
Modulation of a radio beacon of distress on 121.5 MHz and 243 MHz. (Radio triangulation)
Problems playing this file? See media help.

The civilian aircraft frequency for voice distress alerting is 121.5 MHz. Military aircraft use 243 MHz (which is a harmonic of 121.5 MHz, and therefore civilian beacons transmit on this frequency as well). Aircraft can also signal an emergency by setting one of several special transponder codes, such as 7700.

The COSPAS/SARSAT signal can be transmitted by an Electronic Locator Transmitter or ELT, which is similar to a marine EPIRB on the 406 MHz radiofrequency. (Marine EPIRBs are constructed to float, while an aviation ELT is constructed to be activated by a sharp deceleration and is sometimes referred to as a Crash Position Indicator or CPI).

A "triangular distress pattern" is a rarely used flight pattern flown by aircraft in distress but without radio communications. The standard pattern is a series of 120° turns.

Schwarzwald

The recognized mountain distress signals are based on groups of three, or six in the UK and the European Schwarzwald. 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. Three blasts or flashes is the appropriate response.

In the Schwarzwald, the recommended way to signal distress is the Schwarzwald distress signal: give six signals within a minute, then pause for a minute, repeating this until rescue arrives. A signal may be anything visual (waving clothes or lights, use of a signal mirror) or audible (shouts, whistles, etc.). The rescuers acknowledge with three signals per minute.

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.

To communicate with a helicopter in sight, raise both arms (forming the letter Y) to indicate "Yes" or "I need help," or stretch one arm up and one down (imitating the letter N) for "No" or "I do not need help". If semaphore flags are available, they can be used to communicate with rescuers.

Ground beacons

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.

See also

References

  1. ^ Aeronautical Information Manual, U.S. Federal Aviation Administration, 2016
  2. ^ "GPS versus Non-GPS: A comparison of GPS vs non-GPS 406 MHz distress beacons". Australian Maritime Safety Authority. Retrieved 21 March 2014.
  3. ^ For example, 36 U.S. Code (a) provides: "The flag should never be displayed with the union down, except as a signal of dire distress in instances of extreme danger to life or property."
  4. ^ "Slave Ship Mutiny Program Transcript" 15 November 2010 at the Wayback Machine. Educational Broadcasting Corporation. 2010. Retrieved 2012-02-15.
  5. ^ "U.S. Apologizes for flying Philippine flag upside down". Reuters. 27 September 2010.
  6. ^ . Allstates-flag.com. Archived from the original on 13 December 2009. Retrieved 27 July 2009.
  7. ^ Gaden, Phil. . Australian Maritime Safety Authority. Archived from the original on 12 December 2013. Retrieved 21 March 2014.

External links

  • What is the meaning of SOS?
  • US Coast Guard: Flares and other Visual Distress Signals

March 10, 2023
distress, signal, need, help, redirects, here, help, wikipedia, help, contents, wikipedia, questions, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, ch. I need help redirects here For help on Wikipedia see Help Contents and Wikipedia Questions This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Distress signal news newspapers books scholar JSTOR October 2022 Learn how and when to remove this template message A distress signal also known as a distress call is an internationally recognized means for obtaining help Distress signals are communicated by transmitting radio signals displaying a visually observable item or illumination or making a sound audible from a distance A distress signal indicates that a person or group of people ship aircraft or other vehicle is threatened by a serious or imminent danger and requires immediate assistance 1 PCG D 3 Use of distress signals in other circumstances may be against local or international law An urgency signal is available to request assistance in less critical situations For distress signalling to be the most effective two parameters must be communicated Alert or notification of an emergency in progress Position or location or localization or pinpointing of the party in distress For example a single aerial flare alerts observers to the existence of a vessel in distress somewhere in the general direction of the flare sighting on the horizon but extinguishes within one minute or less 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 An EPIRB both notifies or alerts authorities and at the same time provides position indication information Contents 1 Maritime 1 1 Automated radio signals 1 2 Mayday 1 3 Unusual or extraordinary appearance 1 4 Inverted flags 1 5 Device loss and disposal 2 Aviation 3 Schwarzwald 4 Ground beacons 5 See also 6 References 7 External linksMaritime EditDistress signals at sea are defined in the International Regulations for Preventing Collisions at Sea and in the International Code of Signals Mayday signals must only be used where there is grave and imminent danger to life Otherwise urgent signals such as pan pan can be sent Most jurisdictions have large penalties for false unwarranted or prank distress signals Distress can be indicated by any of the following officially sanctioned methods Distress Signals Smoke signal Transmitting a spoken voice Mayday message by radio over very high frequency channel 16 156 8 MHz or medium frequency on 2182 kHz Transmitting a digital distress signal by activating or pressing the distress button on a marine radio equipped with Digital Selective Calling DSC over VHF channel 70 or over another designated DSC frequency in the maritime MF and HF bands Transmitting a digital distress signal by activating or pressing the distress button or key on an Inmarsat C satellite internet device Sending the Morse code group SOS by light flashes or sounds Burning a red flare either hand held or aerial parachute flare Launching distress rockets Emitting orange smoke from a canister Showing flames on the vessel as from a burning tar barrel oil barrel etc Raising and lowering slowly and repeatedly both arms outstretched to each side Making a continuous sound with any fog signaling apparatus Firing a gun or other explosive signal at intervals of about a minute Flying the international maritime signal flags NC Displaying a visual signal consisting of a square flag having above or below it a ball or anything resembling a ball round or circular in appearance 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 In North America marine search and rescue agencies in Canada and the United States also recognize certain other distress signals Sea marker dye White high intensity strobe light flashing at 60 times per minuteAutomated radio signals Edit In addition distress can be signaled using automated radio signals such as a Search and Rescue Transponder SART which response to 9 GHz radar signal or an Emergency Position Indicating Radio Beacon EPIRB which operates in the 406 MHz radiofrequency EPIRB signals are received and processed by a constellation of satellites known as Cospas Sarsat Older EPIRBs that use 121 5 MHz is obsolete Many regulators require vessels that proceed offshore to carry an EPIRB Many EPIRBs have an in built Global Positioning System receiver When activated these EPIRBs rapidly report the latitude and longitude of the emergency accurate to within 120 m 390 ft 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 Marine safety authorities recommend the use of GPS equipped EPIRBs 2 A miniaturized EPIRB capable of being carried in crew members clothing is called a Personal Locator Beacon PLB Regulators do not view them as a substitute for a vessel s EPIRB In situations with a high risk of man overboard such as open ocean yacht racing PLBs may be required by the event s organizers PLBs are also often carried during risky outdoor activities on the land EPIRBs and PLBs have a unique identification number UIN or HexID A purchaser should register their EPIRB or PLB with the national search and rescue authority this is free in most jurisdictions 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 DSC radio distress signal can include the position if the lat long are manually keyed into the radio or if a GPS derived position is passed electronically directly into the radio Mayday Edit 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 Name of the vessel or ship in distress Its position actual last known or estimated expressed in lat long or in distance bearing from a specific location Nature of the vessel distress condition or situation e g on fire sinking aground taking on water adrift in hazardous waters Number of persons at risk or to be rescued grave injuries Type of assistance needed or being sought Any other details to facilitate resolution of the emergency such as actions being taken e g abandoning ship pumping flood water estimated available time remaining afloatUnusual or extraordinary appearance Edit 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 During daylight hours when the sun is visible a heliograph mirror can be used to flash bright intense sunlight Battery powered laser lights the size of small flashlights electric torches are available for use in emergency signaling Inverted flags Edit For hundreds of years inverted national flags were commonly used as distress signals 3 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 Other countries have flags that are inverses of each other for example the Polish flag is white on the top half and red on the bottom while Indonesia s and Monaco s flags are the opposite i e top half red the bottom half white A ship flying no flags may also be understood to be in distress 4 For one country the Philippines an inverted flag is a symbol of war rather than distress 5 If any flag is available distress may be indicated by tying a knot in it and then flying it upside down making it into a wheft 6 Examples of inverted flags as distress signals HMS Romney aground off the island Texel in 1804 In Richard Corbould s print Romney s blue ensign at the stern is shown inverted as a sign of distress HMS Pique in a gale flying the white ensign upside down Device loss and disposal Edit To avoid pointless searches some devices must be reported when lost This particularly applies to EPIRBs lifebuoys rafts and devices marked with the vessel s name and port Expired flares should not be set off as this indicates distress Rather most port authorities offer disposal facilities for expired distress pyrotechnics In some areas special training events are organized where the flares can be used safely EPIRBs must not be disposed of into general waste as discarded EPIRBs often trigger at the waste disposal facility In 2013 the majority of EPIRB activations investigated by the Australian Maritime Safety Authority were due to the incorrect disposal of obsolete 121 5 MHz EPIRB beacons 7 Aviation Edit Radio beacon of distress source source Modulation of a radio beacon of distress on 121 5 MHz and 243 MHz Radio triangulation Problems playing this file See media help The civilian aircraft frequency for voice distress alerting is 121 5 MHz Military aircraft use 243 MHz which is a harmonic of 121 5 MHz and therefore civilian beacons transmit on this frequency as well Aircraft can also signal an emergency by setting one of several special transponder codes such as 7700 The COSPAS SARSAT signal can be transmitted by an Electronic Locator Transmitter or ELT which is similar to a marine EPIRB on the 406 MHz radiofrequency Marine EPIRBs are constructed to float while an aviation ELT is constructed to be activated by a sharp deceleration and is sometimes referred to as a Crash Position Indicator or CPI A triangular distress pattern is a rarely used flight pattern flown by aircraft in distress but without radio communications The standard pattern is a series of 120 turns Schwarzwald EditThe recognized mountain distress signals are based on groups of three or six in the UK and the European Schwarzwald 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 Three blasts or flashes is the appropriate response In the Schwarzwald the recommended way to signal distress is the Schwarzwald distress signal give six signals within a minute then pause for a minute repeating this until rescue arrives A signal may be anything visual waving clothes or lights use of a signal mirror or audible shouts whistles etc The rescuers acknowledge with three signals per minute 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 To communicate with a helicopter in sight raise both arms forming the letter Y to indicate Yes or I need help or stretch one arm up and one down imitating the letter N for No or I do not need help If semaphore flags are available they can be used to communicate with rescuers Ground beacons EditThe 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 See also Edit2182 kHz 500 kHz COSPAS SARSAT Search And Rescue Satellite Aided Tracking Digital Selective Calling DSC Emergency Alert System Emergency telephone number Global Maritime Distress Safety System GMDSS International distress frequency Maritime mobile amateur radio Mayday Mountain rescue Search and Rescue Transponder SOLAS Convention SOS Vessel emergency codes Emergency locator beaconReferences Edit Aeronautical Information Manual U S Federal Aviation Administration 2016 GPS versus Non GPS A comparison of GPS vs non GPS 406 MHz distress beacons Australian Maritime Safety Authority Retrieved 21 March 2014 For example 36 U S Code 176 a provides The flag should never be displayed with the union down except as a signal of dire distress in instances of extreme danger to life or property Slave Ship Mutiny Program Transcript Archived 15 November 2010 at the Wayback Machine Educational Broadcasting Corporation 2010 Retrieved 2012 02 15 U S Apologizes for flying Philippine flag upside down Reuters 27 September 2010 Flying flags upside down Allstates flag com Archived from the original on 13 December 2009 Retrieved 27 July 2009 Gaden Phil A 406Mhz beacon is your best chance of being rescued Australian Maritime Safety Authority Archived from the original on 12 December 2013 Retrieved 21 March 2014 External links EditWhat is the meaning of SOS US Coast Guard Visual Distress Signals for Recreational Boaters US Coast Guard Flares and other Visual Distress Signals Transport Canada Radio Distress Procedures Card Retrieved from https en wikipedia org w index php title Distress signal amp oldid 1142103070, wikipedia, wiki, book, books, library,

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