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"The Breitling EMERGENCY is unique in the world of horology; it is the first pilot's watch to be equipped with a 121.5 MHz locator homing beacon for communicating with search and rescue (SAR) services. Although another watch, the McMurdo Guardian is now available and also has an integrated 121.5 MHz locator beacon, it is meant for seamen; it activates upon contact with salt water and its beacon is not as powerful as the Breitling.
The EMERGENCY is specifically designed as an important further item of safety equipment for pilots who already use 121.5 MHz for emergency radio (voice) transmissions and for their on-board Emergency Locator Transmitters (ELTs) that are triggered by excessive G-force during a forced landing or crash. Breitling has also supplied a number of EMERGENCY watches to some military pilots that transmit on 243.0 MHz. The company has long been known for designing watches with functions useful to aviators and the EMERGENCY is no exception.
A lot could be said about the use and efficiencies of other emergency beacons, as well as radio and antenna design theory and survival techniques in general but much of that is beyond the scope of this article. The ultimate objective here is to help the owner get the best performance from his EMERGENCY should the need arise to activate its locator beacon. At the same time, it is useful to give the reader some background on the evolution of emergency signaling, and some basic understanding of the underlying variables that can influence the efficiency of the beacon transmitter contained in this watch. I shall discuss some crucial methods, based upon my antenna and transmitter design experience, for using its transmitter which are not covered in the owner's manual. There are simple techniques that can increase its efficiency and range during an aviation emergency and therefore increase the likelihood of a successful rescue.
The Future for 121.5 and 243.0 MHz
While the prior discussion may seem unnecessary when speaking about a wristwatch ELT, it is important to understand the differences, limitations, constraints and capabilities of the ELT built into the Breitling EMERGENCY relative to what it does, how it can perform and how it compares to other types of emergency beacons. It is also important to realize how the way the watch can be used will change in the future.
As of February 1, 2009, Cospas-Sarsat satellites will have their 121.5 MHz receivers turned off and will only receive 406 MHz signals. They will then no longer be able to be part of Doppler shift location computations. GOES satellites already do not monitor for 121.5 or 243.0 MHz emergency signals.
However, SAR will continue to use 121.5 MHz as a homing signal and commercial and private aircraft will continue to monitor what is called the “Guard Frequency” of 121.5 MHz. As a side note, after the tragedy in New York City of September 11, 2001, all civilian private pilots in the United States are required to monitor 121.5 MHz when they are flying. This is so they can be communicated with by military fighter aircraft should they be intercepted while straying into a restricted flight area. Obviously the incentive for pilots to follow this requirement is strong!
The Breitling EMERGENCY will still perform very useful local notification and homing functions from 2009 but its signal will no longer be acquired by satellites - unless that is, Breitling develop a 406 MHz digital model!
The Breitling EMERGENCY Wristwatch
To create the EMERGENCY, Breitling essentially took the Aerospace model and sandwiched it in a new titanium case with a miniaturized 121.5 MHz ELT beacon designed and built by Dassault A.T., the French aerospace company.
The signal from an EMERGENCY is immediately identifiable as it contains the letter B in Morse code. This makes the transmission stand out from the 'clutter' of false alarms and non-aviation related (e.g. marine emergency beacons) signals on 121.5 MHz. A transmission from a Breitling EMERGENCY watch means one thing and one thing only: aviation emergency! It is not a false alarm or an overturned rowing boat or a lost hiker; it is a downed aircraft and immediate assistance is required.
In the U.S., the Federal Communications Commission (FCC) initially decreed that only licensed pilots could own an EMERGENCY. Lobbying by the Aircraft Owners and Pilots Association (AOPA) and the Federal Aviation Administration (FAA) pointed out there could be situations where aircraft passengers needed to raise the alarm, and so later the FCC relaxed their ruling slightly bringing it into line with the rest of the world. Anyone may buy an EMERGENCY but it will be registered to a specific name and address; it may only be serviced by a Breitling Service Center; and most importantly of all, it may ONLY be deployed in a genuine aviation emergency.
As a matter of interest, after an EMERGENCY has been deployed it must go to back to Breitling for servicing; it cannot be used a second time. This puts further pressure on owners to use it only in a genuine emergency. And the service following deployment is free of charge having effectively been paid for when the watch was originally purchased. This policy ensures that owners will be very unlikely to let anyone else attempt to service the watch and so Breitling can continue to keep a tight control over its efficacy and reliability.
The EMERGENCY watch is a wonderful concept in that it puts an ELT right on the wrist of the person who may need it. However, there are drawbacks since it has a low-power VHF transmitter (30 milliwatts - 0.3 of a watt). Its signal on 121.5 MHz can be absorbed by surrounding materials such as wood or metal and it is likely to be virtually ineffective if activated inside an aircraft hull. It is easily refracted by topography, structures or forest canopies and is absorbed and scattered by dense vegetation, rain, mist, or snow. The EMERGENCY has no GPS capability and the transmitter is analog, not digital. It is essentially a transmitter only for a homing signal for direction-finding capable aircraft and ground SAR personnel.
But, do these limitations make it useless? No. It is still a highly capable 121.5 MHz beacon that will have a useful life well past 2009 since 121.5 MHz will continue to be used as an emergency locator homing signal frequency. All 406 MHz beacons transmit two signals - a digital satellite acquisition signal and a lower power 121.5 MHz SAR homing beacon signal. Is it as good as a 406 MHz ELT or PLB? No, it is not since its signal is weaker and subject to scattering, absorption and refraction and its signal is much more difficult to pick up by satellites. But it is far from impossible that the Cospas-Sarsat satellites can pick up a beacon signal from the EMERGENCY as long as it is used properly. And, that is key - to use it properly. The manual that comes with the watch is very general in its discussion and even vague with regard to some aspects of its proper use. Knowing how to use this device properly requires some discussion of the elements that make up its internal beacon - primarily, the transmitter and the antenna.
So You Need to Use Your EMERGENCY? – Some Guidelines for its Use
Before I tell you what to do if you need to use your EMERGENCY watch beacon, it is important to understand some basic ideas about how antennas work and why they are designed the way they are. This is important since it may well be through these examples that you will better recall what you should do with your EMERGENCY should you need to activate it. In my teaching career, I found that students remembered information about how to do something if they were taught how and why a concept or technique worked. That is, what made something do what it does. This underlying knowledge apparently triggers memory of the details of "how to do something".
The EMERGENCY has its main antenna (the radiator) behind the cap marked “ANTENNA” at the bottom of the watch. The watch's transmitter is activated by unscrewing the antenna cap and pulling out the coiled antenna to its full length of 43 cm (17 ins). In use it should always be oriented as vertically as possible.
The "second antenna" as Breitling call it in their documentation (in both the manual and the VHS video tape that come with the watch) is really a “virtual ground” known as a “radial”. This radial and the metal of the watch itself provide the ground image for the "radiator", the main antenna that actually transmits the signal. In fact when you deploy both antennas on the EMERGENCY you have an antenna system that looks a lot like the dipole antenna used for ham radio. In these antenna systems there are two physical sections to the antenna – one connected to electrical ground and one connected to the positive output from the transmitter amplifier.
A discone antenna has one vertical "element" at the top that radiates the signal, and a set of elements (rods), often oriented at an angle of about 45 to 60 degrees, below. Those elements (rods) under the vertical element are “radials” that are usually a fractional multiple of the wavelength of the frequency being radiated by the vertical antenna. The length of these radials is often determined by a mathematical formula to compute the electrical resonant length of the frequency that the antenna is designed to transmit and receive. The closer the length of the radials to a fractional or whole multiple resonant length for a given frequency, the greater the efficiency of the antenna to perform on that frequency. The "second antenna" of the EMERGENCY is a fractional resonant length of wire for the frequency of 121.5 MHz.
I would not use my EMERGENCY watch until I had to do so. If my primary on-board ELT were not working after checking with my aircraft radios (assuming they still worked) or with my backup hand-held aviation radio (by tuning to 121.5 MHz and listening for the ELT beacon sweep) then I would activate my EMERGENCY watch beacon. I would first use it with the main antenna and I would NOT pull out the “second antenna” at this time since this second antenna is just a radial to provide additional ground image. Instead, I would try to set my watch on its edge on top of the aircraft or a large metal part of the airframe or fuselage after scraping away the paint and making sure I had metal to metal contact. The metal of the aircraft will provide a larger surface area and so a much better ground plane for the antenna than the “second antenna" (radial) coiled up in the watch. And, this will give a lower take-off angle for the propagated signal from the watch’s internal ELT beacon.
The EMERGENCY is particularly useful if you need to leave the scene of the accident. One big advantage of the watch (and one reason why I bought one) is that although I can’t take my aircraft ELT with me, I can take my watch. And the purpose is for SAR personnel to find me not the plane, per se. Again, the EMERGENCY is marginal in its output power for satellite reception. If I were in mountainous terrain and capable of moving without danger to myself, then I would get into a position as high as possible since I would be in a more open position and my chances of having the EMERGENCY watch ELT signal picked up by satellites would be improved immensely. If I were not in hilly or mountainous terrain I would move to a clear area since this would minimize the very real problems of signal absorption, reflection and refraction.
As it turns out, the differences are not really that great:
On-board, permanently mounted aircraft ELT: 90 mw for 48 hours
Breitling EMERGENCY watch: 30 mw for 48 hours
McMurdo PLB with GPS: 50 mw for 24 hours
ACR PLB without GPS: 25 mw for 24 hours
Good job, Dassault! Dassault Aviation have obviously done a lot of homework in designing this transmitter, especially with regard to power consumption from such small and low voltage and amperage batteries. To design such a small transmitter with such potentially good efficiency and low power drain is quite a feat.
However, please recall that the 406 MHz PLBs are not using the low power output 121.5 MHz transmitter for the purpose of having satellites acquire this frequency. They use a high power (5 watt) transmitter at 406 MHz for satellite acquisition. Their internal 121.5 MHz transmitters are for homing and direction finding by SAR personnel only. But, if you compare 121.5 MHz transmitters for all of these devices, the EMERGENCY does quite well given its small size. In fact, it does very well. In real terms, it has the potential of being only about 2 units of signal strength (on a ten point scale) weaker at the receiving end than my on-board aircraft ELT and roughly about the same signal strength, at the receiving end, as the 121.5 MHz homing beacons in my PLBs.
The bottom line is that the EMERGENCY is not equal to a 406 MHz beacon with regard to effectiveness but it should hold its own as a decent homing beacon to get you found once someone knows your approximate location. But if you rely on the EMERGENCY alone it is highly likely that it will take SAR longer to be notified due to the low output power and the increased difficulty Cospas-Sarsat satellites will have in acquiring a low power 121.5 or 243.0 MHz signal.
For my needs and requirements, the EMERGENCY watch is not a primary signaling device. Its limited power and the fact that it is really more of a homing beacon limits its usefulness despite it having the theoretical capability of being only about 60% less efficient than the 121.5 MHz ELTs mounted on-board my aircraft. My view is I would rather use the EMERGENCY as "additional insurance". When I am flying I always carry a 406 MHz Personal Locator Beacon with integrated GPS in addition to my aircraft ELT. For bush flying I would carry a satellite phone and, if possible, a small, portable high frequency (HF) radio (radio license required to use such equipment). So my EMERGENCY is really a third or fourth order backup device. But, I would rather have that third or fourth option in any situation that causes me to use those emergency notification or communication devices.
Enjoy your EMERGENCY, if you own one, and use it properly and knowledgably. I wish you all the best of luck and hope you never need to activate the beacon on this very unique timepiece. I hope I have added some additional insight about emergency signaling; the operation of emergency beacons in general; and some specific suggestions to get the most out of the 121.5 MHz beacon in the Breitling EMERGENCY."
by Time Flies and altro (G. Buhyoff and A. Trott)
G. Buhyoff is the technical author of this article which is written in the singular person based upon his experience with the subjects contained herein. He is a licensed pilot in the United States. A. Trott served as the text and technical editor and was also responsible for the detailed illustration of the article and its conversion into HTML and vB code formats. He is a glider pilot in the United Kingdom. The article is the result of an intensive collaboration between the co-authors.
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