What is a distress beacon?
Distress beacons (also known as emergency locating devices) come in three types. Mariners use buoyant watertight beacons known as emergency position indicating radio beacons (EPIRBs). Aircraft are fitted with crash-activated emergency locator transmitters (ELTs). Pocket-size personal locator beacons (PLBs) are for personal use by bushwalkers, four-wheel drivers, employees working in remote areas, boatcrew and aircrew.
Distress beacons currently operate at a frequency of 406 MHz. Because of digital technology used in 406 MHz beacons they are far more capable than the old analogue 121.5 MHz beacons.
The digital technology used in 406 MHz beacons enables the beacon to transmit a unique code that identifies the beacon. 406 MHz beacons come in two types: those that provide an encoded (GPS) location and those that do not. The satellite system can calculate an active beacon's location, however the location process is usually much faster if the beacon signal provides a GPS location.
It is important to note that since 1 February 2009, the satellite system will only detect and locate distress beacons operating on 406 MHz. The satellite processing of 121.5 MHz signal has ceased and 121.5MHz analogue distress beacons are no longer detected by satellite.
How does it work?
Distress beacons, when activated, transmit radio signals that are detectable by orbital satellites and overflying aircraft. The satellites report the position of active distress beacons to rescue authorities via stations located in Albany, Western Australia and Bundaberg, Queensland. This information is processed to provide position information and then passed directly to the Rescue Coordination Centre (RCC) in Canberra (RCC Australia). Successive satellite passes are used to refine this information. The satellite system can produce position information with an accuracy of five kilometres for a 406 MHz beacon. Some 406 MHz beacons are capable of transmitting a GPS position with an accuracy of 120 metres. An aircraft hearing an activated beacon will immediately make a report to aviation authorities who will pass this information to the RCC.
It should be noted that detection of the beacon by aircraft or satellites is critically dependent on the beacon placement. Once activated, the beacon should be placed upright in a clear area with the antenna fully extended.
A beacon should not be switched off once activated for a distress situation until directed to do so by the search and rescue agency. EPIRBs are designed to operate continuously for a minimum of 48 hours. PLBs and ELTs are designed to operate for a minimum of 24 hours.
What is considered to be a distress situation?
A distress situation is generally defined as one in which a person or persons face grave and imminent danger and require immediate assistance. On land such situations might include:
- the need for urgent medical evacuation;
- mechanical breakdown where food and water supplies can not be replenished;
- being lost with little hope of reaching outside assistance before food and water supplies are finished; and
- similar life-threatening situations.
Each situation is unique and common sense and good judgement need to be exercised when considering whether to activate a distress beacon.
If time permits and an alternative form of communication to rescue authorities is available, for example, via a HF Royal Flying Doctor Service channel or VHF maritime channel to a coast station, it should be used in preference to a distress beacon.
Authorities may request activation of a distress beacon during a search and rescue (SAR) operation if it is believed that it will assist in location of the station in distress.
What sort of response will RCC Australia provide to an activated beacon?
The RCC will usually know the location of an activated 406 MHz beacon that transmits a GPS location within minutes. Distress beacons that do not have the capability to provide a GPS position will provide an initial alert to the RCC within minutes, however there will be no associated position. In these circumstances the RCC will need to rely on successive passes of the orbiting satellites before the location of the beacon may be determined. Satellites over-fly the Australian region on average every 90 minutes however passes may be anywhere from minutes to 5 hours apart.
Response times will be improved if the 406 MHz beacon has been registered with the Australian Maritime Safety Authority (AMSA) and emergency contacts are aware of trip details. Beacons may be registered online with AMSA at www.beacons.amsa.gov.au/. Trip details may also be submitted to AMSA online.
RCC Australia will organise an initial response using available resources to identify the nature of the distress. Search and rescue for a non-aviation incident over land is the responsibility of state police forces. RCC Australia will normally pass information about such incidents to the police once the nature of the emergency has been established.
Once the position of a station in distress is known, response times will depend on the time for a search and rescue unit, such as a helicopter, aircraft, vessel or ground party to be readied and transit to the search area. The more remote the location of the station in distress, the longer the response time.
What are the procedures if a distress beacon is activated accidentally?
Every year, valuable search and rescue resources are wasted in locating distress beacons that have been activated accidentally or without the owner's knowledge.
To minimise the possibilities of accidental activation owners are urged to pay careful attention to:
- the need for careful and thoughtful stowage of the beacon where the activation switch is not subject to pressure, or to sudden shock due to physical movement;
- the need to educate travelling companions about the consequences of activation;
- the need to prevent interference with the beacon by children; and
- the disposal of unwanted beacons or beacon batteries. Refer to the manufacturer's user or instruction manual for disposal instructions. Beacons should only be disposed of after the batteries have been removed (batteries can remain effective well after the 'replace by' date marked on the beacon). Batteries should be disposed of through a battery recycler.
Once it is known that a distress beacon has been activated inadvertently, it should be switched off immediately. RCC Australia should be notified as soon as possible by calling 1800 641 792 to ensure a SAR operation is not commenced. There is no penalty for inadvertent activations. RCC Australia 24-hour phone contacts:
- 1800 641 792
- 1800 815 257
How can a distress beacon be maintained in good order?
Refer to the owner's manual for recommended servicing and battery replacement. A beacon must not be tested except strictly in accordance with the manufacturer's instructions for self-testing.
The signal from a distress beacon is regarded as a signal of distress and will be given an appropriate response by search and rescue authorities. It is the responsibility of every owner of a distress beacon to ensure that it is not activated unintentionally or in situations that do not justify its use.
The Radiocommunications Act 1992 provides for severe penalties, including imprisonment, for any person found guilty of the activation of a distress beacon with the intention of misleading authorities about an emergency situation.
For more information about distress beacons, contact the ACMA.
The ACMA has fact sheets on a range of topics.
Please note: this document is intended as a guide only and should not be relied on as legal advice or regarded as a substitute for legal advice in individual cases.