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SWITCH TO 406

By Carole Smith, NSS

A new era begins… On February 1, 2009, search and rescue satellite alerting across the globe entered a new era. After twenty-seven years of monitoring121.5 MHz emergency radio beacon signals, the International Satellite System for Search and Rescue, COSPASSARSAT, completed its transition to the exclusive processing of digital 406 MHz signals. Just after midnight, Universal Coordinated Time on February 1st, codes transmitted to the COSPAS-SARSAT satellites automatically shut down the 121.5 MHz and related 243 MHz instrumentation.

Today, only marine Emergency Position-Indicating Radio Beacons (EPIRBs), Personal Locator Beacons (PLBs), and aircraft Emergency Locator Transmitters (ELTs) that transmit on a primary frequency of 406 MHz continue to benefit from worldwide search and rescue (SAR) satellite surveillance.

COSPAS-SARSAT chose February 1, 2009 as the termination date for 121.5 MHz satellite coverage over eight years ago, in October 2000. By then, the limitations of 121.5 MHz analog beacons had become increasingly apparent relatively to their more advanced, accurate, and capable 406 MHz cousins. As a result, safety-oriented organizations, such as the International Maritime Organization and the International Civil Aviation Organization, recommended that 406 MHz technology be fully embraced. After the February 2009 phase-out date was set, COSPAS-SARSAT program participants concentrated their efforts, and their financial investments, on the long-term support and enhancement of the 406 MHz system.

Canada’s aviation community and the Switch to 406

While users of maritime and land-based emergency beacons in Canada have already adopted 406 MHz technology, the majority of Canadian airplanes and helicopters that are required to carry a distress beacon (approximately 24,100) are still equipped with ELTs that function on 121.5 MHz only. While Transport Canada is currently engaged in a regulatory initiative to mandate the use of 406 MHz ELTs or an acceptable equivalent, the “Switch to 406” is still voluntary for private, state, and commercial aircraft. Although the United States has not yet indicated that it will require 406 MHz ELTs, several other countries, including Australia and New Zealand, have made them mandatory.

As of February 28, 2009, only about 10 percent of Canadian aircraft had registered a 406 MHz ELT with the Canadian Beacon Registry. However, registrations are on the rise, and this number is expected to double by April of this year. In fact, many more 406 MHz ELTs are believed to be in service than what appears in the Registry. Since the old 121.5 MHz ELTs did not require registration – they were analog and could not transmit a unique coded signal – it is presumed that some aircraft owners and operators are simply unaware of the requirement to register their 406 MHz ELTs. Registration is a critical step in enabling an effective SAR response, since the Registry collects emergency contact information for the aircraft owner/operator, as well as details such as the colour and configuration of the aircraft. This information is invaluable to the coordination and time sensitivity of a successful search effort.

Challenges for air SAR

SAR operations for missing and downed aircraft continue to be managed as usual by the Canadian Forces. However, the current lack of satellite detection and position information for incidents involving 121.5 MHz-equipped aircraft is a potential concern with respect to the safety and efficiency of SAR missions. Without the aid of satellite-derived alerting and location data, missions may be prolonged and rely more heavily on visual search techniques. These effects are also anticipated by the volunteers of the Civil Air Search and Rescue Association, who assist the Canadian Forces in carrying out its aeronautical SAR mandate. Since 121.5 MHz is also the international voice distress frequency for aviation, it continues to be monitored by NAV CANADA’s air traffic control towers and flight service stations during their hours of operation. Many overflying aircraft, particularly airliners, also monitor 121.5 MHz as a courtesy to their fellow aviators. Any ELT signals overheard on this frequency (outside of the first five minutes of every hour, which are set aside for ELT testing) are reported to the appropriate Joint Rescue Coordination Centre as a possible distress alert.

This practice provides an important safety net in the absence of satellite monitoring, and all pilots are encouraged to maintain a listening watch on 121.5 MHz. Unfortunately, these pilot reports are typically far less precise than the coordinates formerly generated by COSPAS-SARSAT’s 121.5 system. The maximum theoretical range of a 121.5 MHz beacon heard by an airliner flying at 37,000 feet could be 200 nautical miles or more, putting the ELT somewhere within a 430,000 square kilometre search area. Additionally, unlike a digital 406 MHz ELT, an anonymous 121.5 MHz signal provides no useful information to SAR authorities as to who might be in distress. On March 14, 2009, various high-flying aircraft reported an ELT signal somewhere within 100 nautical miles of Fredericton, New Brunswick. It was only when a local flight plan expired a half-hour later that the signal was confirmed to be an actual distress transmission, and the probable identity of the aircraft known. Notwithstanding, the 121.5 MHz ELT was instrumental in leading a Hercules aircraft and a Cormorant helicopter from 413 Squadron to the denselyforested crash site, located approximately 25 nautical miles north of Fredericton. The three occupants of the aircraft were treated by SAR technicians, and transported to medical aid. This case also underlines the added value of filing a flight plan.

Finally, the SAR system also expects to be challenged by the impending decommissioning and disposal of thousands of 121.5 MHz ELTs, as they are replaced by 406 MHz units. Failure to remove batteries and disable electronics may generate unnecessary searches when these old ELTs are discovered by curious children (or adults with a child-like sense of curiosity), left to corrode on workshop benches, or rattled around in the back of a garbage truck.

Overall, it seems clear that the pilots and passengers served by air SAR in Canada will benefit from a more rapid uptake of 406 MHz technology by the aviation community.

Promoting the Switch to 406

As reported in previous issues of SARSCENE magazine, the National Search and Rescue Secretariat (NSS) has been leading efforts since the fall of 2007 to communicate and promote the “Switch to 406” within the aviation community. Working in partnership with the Canadian Forces and Transport Canada, the NSS has:

• ensured that Canada’s 91,000 licensed pilots and aircraft maintenance engineers received a briefing package on the Switch to 406;
• staffed exhibits and distributed information at major Canadian aviation events;
• made presentations to regional aircraft maintenance conferences and other special forums across Canada;
• provided letters and articles on the Switch to 406 to newspapers and magazines;
• developed fact sheets and communication materials describing the change to the COSPAS-SARSAT system, and practical information on how to adapt;
• briefed SAR responders on the status and implications of the Switch to 406;
• updated key flight publications affected by the change in SAR satellite monitoring;
• liaised with manufacturers and distributors to monitor ELT supply and demand; and
• researched statistics on ELT performance and false alerts.

Continued momentum

Although the COSPAS-SARSAT system has completed its journey to the digital era, the NSS will continue to provide practical information about this remarkable humanitarian system and the 406 MHz emergency beacons it supports.

A special focus on the aviation community is being maintained through 2009–2010, with specific emphasis on the selection, programming, registration, and testing of 406 MHz ELTs. The reduction of false alerts will also be highlighted, including the proper decommissioning procedures for the thousands of 121.5 MHz units that will likely be coming out of service over the next 12 to 24 months.

The broader community of 406 MHz beacon users also figures prominently in the Secretariat’s plans for 2009–2010. New materials on the use and registration of marine and land beacons will be developed and promoted to ensure that the benefits of the COSPASSARSAT system continue to be accessed to the fullest by all Canadians.

Stay tuned to SARSCENE magazine and www.nss-snrs.gc.ca for additional updates on the Switch to 406 communications strategy.

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