406 in conjunction with Spot

[geneticistx]

Hi all.
I continue to read these tragic aircraft accidents in the most beautiful and rugged terrain, the BC mountains. Planes go missing for various reasons, mechanical failure or otherwise. The reasons are really not important in order to find someone in a downed aircraft.

The 406 ELT is supposed to be a huge step above the 121.5 technology in assuring SAR.

My question is whether the SPOT tracker would provide more accurate or relevant info to aid SAR than just the ELT. And if so, maybe mountain flyers should be educated more about the SPOT as an additional piece of safety equipment.

I’m just starting my flying passion and have been training in the mountains for my PPL. I always carry a SPOT with me when I’m away from a regularly travelled track. Ensuring the batteries are fresh and power is on for the SPOT is part of my checklist.

[BE20 Driver]

It is my personal belief that SPOT is far superior technology to that of ELT's. An ELT may only go off during an impact event over a certain threshold. SPOT devices are continuously leaving a breadcrumb trail that should in theory assist in finding someone or an aircraft should the worst happen. I would like to see the regulators allow SPOT or other devices like this as an alternate means to installing and certifying general aviation aircraft. TC moves at the speed of government though so I don't see this happening any time soon.

[CpnCrunch]

The recent accident in BC had a 121.5 ELT, and the antenna probably got sheared off by the trees. Apparently 406 ELTs are more likely to be able to transmit a signal without the external antenna, as they use 10x the power of the older ELTs. Still, I've read accident reports of 406 ELTs failing, so a SPOT with 5 min or better tracking is probably the best option.

Also, that Mooney had lap belts. You stand a much better chance of survival with shoulder harnesses.

[ScottS]

A combination of both is a good idea. I also carry a PLB in addition to the SPOT and 406

[Posthumane]

Something to keep in mind with the SPOT is that the tracking service is not standard - it is an option you have to pay extra for. With just the standard SPOT service a message is only sent when a user pushes a button on the device. The tracking service would be a good idea for aviation, but if a person has just the standard service they need to remember to hit the help button before they go down, in case they are unconscious after the crash.

[StudentPilot]

There is no doubt that satellite tracking (Spot, inReach, SpiderTracks, Blue Sky, etc) is extremely helpful, the shorter the period between position reports the more useful, especially in rugged terrain. At the very least a properly functioning unit will reduce the potential search area to a radius around the last point.

I have used both handheld and fixed satellite tracking installations. I do not see a handheld unit being approved at any point - it is not hard to forget about it and either not charge the device or to forget to turn it on. Fixed installations are better, but the ones I have used have not had a battery, which would also be useful after a crash to (try to) send a final position.

Five minutes between positions is better than nothing, but it can still mean a difficult search in rugged terrain and covers a decent sized area. Having been involved one way or another in a few searches or the aftermath of an accident with planes using satellite tracking, I would set my personal unit to two minutes or less when flying in mountainous terrain. Five minutes/10 miles is simply far too big of an area unless in the prairies or other easily searchable area (ie not densely forested).

[JasonE]

I think the SPOT is far better than ELT in some ways, however it doesn't activate to tell anyone you just crashed! So I would say both. I always include the link to tracking in my flight plan as well.

Actually bought a SPOT this year so family could track our east coast trek. Quite enjoyed being able to go review the data afterwards and review it. Best part was my dad was there waiting for me at the airport when we arrived! He had been following us for 2 days, no phone call needed.

[Schooner69A]

SPOT (or equivalent) is an excellent idea. Especially here in the mountains. Many times, the direct flight plan - or even the "follow the VFR route" flight plan - has to be modified because of weather. Unfortunately, given the terrain, it is not always possible to alert FSS of the change of plan.

Yes, there are sometimes "holes" in the breadcrumb track left by SPOT; however, I have used it for trips across Canada and back with good results. I have mine on 2 minutes reports and, should I go missing, I should be within a 5-8 miles radius of the last crumb.

They are "a good piece of kit"!

[Pavese]

Something to keep in mind with the SPOT is that the tracking service is not standard - it is an option you have to pay extra for. With just the standard SPOT service a message is only sent when a user pushes a button on the device

This statement is not correct, the basic service includes tracking. https://www.findmespot.ca/en/index.php?cid=133

Once you start your SPOT and activate the tracking mode (your normal operating mode) it reports your position periodically with the time period dependent on which option you have signed up for, standard is 5 to 60 minutes, extra cost option is 2.5 minutes.

You can also send an SOS message manually.

In the absence of an ELT message SPOT would narrow the search area to much less than somewhere along the intended flight path, personally I carry one to complement the ELT.


To the comment by another poster, if the antenna of your ELT is sheared off or otherwise put out of service (apparently far too common) the fact that the 406 has a higher transmit power is unlikely to be much use. The coax cable leading to the antenna is inherently shielded to keep RF from entering and corrupting the signal and to keep the RF intended for the antenna from being leaked (transmitted) until it reaches the antenna. It needs the antenna and ground plane of the aircraft to properly transmit the RF to the satellite.

D

[ahramin]

We had a crash at our airfield where the aircraft ended up upside down with the ELT antenna broken off. The SAR satellite still got the aircraft registration and I think got the position as well.

[photofly]

It’s not all-or-nothing: You might find the LEO satellites receive a weak signal, if the antenna is damaged, while the geostationary ones do not, since they are about 35 times further away.

That’s about 30dB difference, if my maths is right.

[RatherBeFlying]

There are apps that send your position through your cell phone to a website every minute or so. Friends can monitor your track in real time.

You need a way to keep your phone charged.

Livetrack24 is one example.

http://www.livetrack24.com/services/index#services1

There are others.

You do have to remember to turn the app on in your phone.

[Posthumane]

Something to keep in mind with the SPOT is that the tracking service is not standard - it is an option you have to pay extra for. With just the standard SPOT service a message is only sent when a user pushes a button on the device

This statement is not correct, the basic service includes tracking. https://www.findmespot.ca/en/index.php?cid=133

Once you start your SPOT and activate the tracking mode (your normal operating mode) it reports your position periodically with the time period dependent on which option you have signed up for, standard is 5 to 60 minutes, extra cost option is 2.5 minutes.

You can also send an SOS message manually.

In the absence of an ELT message SPOT would narrow the search area to much less than somewhere along the intended flight path, personally I carry one to complement the ELT.


To the comment by another poster, if the antenna of your ELT is sheared off or otherwise put out of service (apparently far too common) the fact that the 406 has a higher transmit power is unlikely to be much use. The coax cable leading to the antenna is inherently shielded to keep RF from entering and corrupting the signal and to keep the RF intended for the antenna from being leaked (transmitted) until it reaches the antenna. It needs the antenna and ground plane of the aircraft to properly transmit the RF to the satellite.

D

Indeed, you are correct about the SPOT tracking service. This has obviously changed since I signed up with my Gen 1 device. At that time it was 150/year for no tracking service, and an extra 50/year for tracking.

Regarding the antenna - even a broken off antenna still acts as a poor transmitter. An ideal 1/4 wave dipole on 406 MHz would be about 18cm long, but even a short wire antenna that's a couple cm will transmit, just with a weaker signal. See: key fobs operating on 433 MHz.

[ahramin]

There are apps that send your position through your cell phone to a website every minute or so. Friends can monitor your track in real time.

You need a way to keep your phone charged.

Livetrack24 is one example.

http://www.livetrack24.com/services/index#services1

There are others.

You do have to remember to turn the app on in your phone.

You also need an internet connection.

[CpnCrunch]

Regarding the antenna - even a broken off antenna still acts as a poor transmitter. An ideal 1/4 wave dipole on 406 MHz would be about 18cm long, but even a short wire antenna that's a couple cm will transmit, just with a weaker signal. See: key fobs operating on 433 MHz.

The problem is that it's shielded by the aluminum structure of the plane. Handheld GPS generally won't pick up any signal unless it has a clear view through a window.

[CpnCrunch]

You also need an internet connection.

They don't really use much data though, so you just need the most basic data plan. I use greenalp tracker set to transmit once per minute, and it only uses about 0.25MB/hr.

[Broken Slinky]

As JasonE said, the Spot and most PLBs wont activate automatically. You'd have to ensure they're on and functioning before the crash in the event you're incapacitated. I had a Spot but the subscription plans have become very silly over the last 2-3 years. When I first activated it, the plan was $100 CAD with their promo. In 2015 it jumped to $150 US. In 2016 they wanted $200 US. They were willing to drop it down to $150 US to keep my business.
If you're the outdoorsy type and can utilize the Spot during other activities, it's easier to justify the yearly fee. For me it didn't make sense. I ended up buying a ACR ResQLink 406 PLB-375. No yearly fees and just have to send it in every 6 years to replace the battery. At $380, that works out to around $65 a year. For that money, I'll probably just buy a new one. Besides, in 6 more years, who knows what type of tracking/locator tech will be available.

[Pavese]

Regarding the antenna - even a broken off antenna still acts as a poor transmitter. An ideal 1/4 wave dipole on 406 MHz would be about 18cm long, but even a short wire antenna that's a couple cm will transmit, just with a weaker signal. See: key fobs operating on 433 MHz.

The problem is that it's shielded by the aluminum structure of the plane. Handheld GPS generally won't pick up any signal unless it has a clear view through a window.

And an antenna broken off at the base or worse yet, the coax torn out of the BNC? That's why I made the observation of "....unlikely to be much use.....".

I'm not trying to pick on anyone here, this is interesting discussion.

WRT car fobs, the power & range is the point and that's with an intact, purpose Engineered antenna (A track on the printed circuit board). As ahramin & photofly mentioned some signal level can be transmitted and detected, the question is how much and would we would want to depend on that for our safety.

Broken Slinky makes a great observation about the quick pace of electronic tracking technology. While the SAR secretariat is pushing again for mandatory 406 ELT implementation (already obsolescent because of new positioning technology), Canadianized ADSB (Satellite based) is waiting in the wings as the next big thing and before the bureaucracy can get it together on that, tracking suppliers and cell apps will make it obsolete for A/C location reporting.

Let's do the sums, $2 - 3k for a 406 ELT, (installed) then $2-4k for an ADSB capability (Satellite based) that may not be compatible with the rest of our neighbours and what do we as A/C owners have to show for it when the next big thing comes along and makes it obsolete?

Right now I'm inclined to keep my SPOT close by and with fresh batteries thanks.

D

[photofly]

with fresh batteries thanks.

And therein lies the rub. Too easy not to have fresh batteries around, especially those ultra-expensive lithium AAA ones they want you to use at $20/set.

A SPOT system wired to the aircraft power would be nice, and I believe there’s one available, but any kind of certification and we’re talking $2k, minimum, as usual.

[Posthumane]

The signal will definitely be degraded with any kind of antenna damage, the question is always how much is too much. Even from a cut coax inside a metal fuselage there is some signal getting out, but I don't know the sensitivity of the satellite receivers. It may not be enough in many cases. A SPOT as a backup is a great way to go, and is the reason I generally fly with one. I say "generally" because sometimes if I'm just going for a local flight or a short flight to a known location over the flat lands, I get lazy and leave the spot in my flight bag. Still useful if I'm conscious after a crash, but it won't activate automatically.

The 406 I had on my plane (because my old 121.5 died) was an ack-04 which is currently listed at $683 CAD at aircraft spruce. The remote on the panel makes it easy to push the manual activation if you know that you're in danger of crashing. Perhaps this isn't emphasized enough in training. An antenna may brake off after a crash and make the system useful, but in the 30 seconds preceding the crash you can activate the ELT and have a signal go out while it's still good. If you end up landing safely, you can always call and cancel the search.

[photofly]

but in the 30 seconds preceding the crash you can activate the ELT and have a signal go out while it's still good.

One needs to temper one's expectations with how well this will work. Unless your ELT is connected to an approved GPS source it will take at least a few minutes to get a position. A whole bunch of current almanac and ephemeris data has to be downloaded over a very slow data channel. And it can only start to do that if its internal GPS antenna isn't shielded inside an aluminum fuselage, and can see the sky. Without GPS The LEO satellites need up to an hour of signal to get a position.

So in the event that your ELT installation is damaged on impact to the extent of ceasing to transmit, a minute or two of activation time isn't likely to be a great deal of help; SAR will know that your ELT has been activated but will have very little idea of where.

Of course if you have a fabric-covered aircraft so the ELT's internal antenna can receive a signal, and you activate it at 10,000' and glide all the way to sea level then that may be another story.

[Pavese]

but in the 30 seconds preceding the crash you can activate the ELT and have a signal go out while it's still good.

One needs to temper one's expectations with how well this will work. Unless your ELT is connected to an approved GPS source it will take at least a few minutes to get a position. A whole bunch of current almanac and ephemeris data has to be downloaded over a very slow data channel. And it can only start to do that if its internal GPS antenna isn't shielded inside an aluminum fuselage, and can see the sky. Without GPS The LEO satellites need up to an hour of signal to get a position.

So in the event that your ELT installation is damaged on impact to the extent of ceasing to transmit, a minute or two of activation time isn't likely to be a great deal of help; SAR will know that your ELT has been activated but will have very little idea of where.

Of course if you have a fabric-covered aircraft so the ELT's internal antenna can receive a signal, and you activate it at 10,000' and glide all the way to sea level then that may be another story.

Not to be difficult but to nitpick just a little bit, the spec. allows for a minimum of 50 seconds warm-up for the first message to be transmitted. It has to do with the heated crystal oscillator in the transmitter coming up to temp and on frequency so you need to push the button about a minute before your imminent, unplanned landing. It would give you time to hit the button on your PLB and SPOT though.

Of course the PLB would have the same delay for first message but it doesn't depend on the aircraft for function.

I have no idea about an embedded GPS in the ELT but I'd think it would be intelligent for it to be running all the time the avionics master was on so that the data Photofly spoke of would be current.

D

[photofly]

Not to be difficult but to nitpick just a little bit, the spec. allows for a minimum of 50 seconds warm-up for the first message to be transmitted. It has to do with the heated crystal oscillator in the transmitter coming up to temp and on frequency so you need to push the button about a minute before your imminent, unplanned landing. It would give you time to hit the button on your PLB and SPOT though.

Right. The first message will include the digital ID, but will not include a GPS position unless the ELT was installed connected to an aircraft GPS system and that GPS system is already providing position data at the time.

The SPOT system has to be powered on, before you press the emergency button, otherwise it too requires time to get a GPS position. This may be a shorter time because, if it's in roughly the same location as it was last powered down, and it was powered down recently, it already has up to date almanac data. If you want to do a relevant test, leave your SPOT unpowered for two and half years, and switch it on, and see how long it takes to get a GPS lock.

I have no idea about an embedded GPS in the ELT but I'd think it would be intelligent for it to be running all the time the avionics master was on so that the data Photofly spoke of would be current.

That wouldn't be intelligent because keeping the GPS running all the time would drain the battery pack on the ELT.

ELT's are (mostly) not connected to the aircraft systems at all, and are definitely not powered from the avionics bus. They have their own battery packs which need replacing every 5 years, usually. If you do want your ELT plumbed in to your GPS the install has to be done by an avionics shop. But there's a exemption for ELTs that are not connected to any other aircraft systems that allows them to be installed by any AME.

Pop quiz - who here flies in an aircraft where the ELT is connected to an aircraft GPS receiver? I know mine isn't; and nor is it in any of the other six or so aircraft I fly in.

[photofly]

Overall it seems to me that the two systems have different strengths and weaknesses, because they're designed for different tasks:

SPOT is cheap, needs a subscription, eats batteries like crazy, needs to be switched on every flight, needs to be activated to summon assistance, is small and portable, and run by a private enterprise that could go out of business tomorrow. It uses and therefore suffers from all the advantages and disadvantages of GPS.

your 406 ELT is expensive, doesn't need to be switched on each flight and (if you keep up the maintenance) has batteries charged and ready to go at all times, is fixed to the aircraft, has an impact sensor so has at least some chance of summoning help on its own. And the whole system is government funded so it's probably not going to pack up shop just when you need it. It also works independently of GPS (although can use GPS for faster location.)

[charrois]

I think another great contender for the future of SAR is often overlooked - ADS-B out.

By 2020, all aircraft flying in US transponder airspace will have to have ADS-B out. So in a few years, pretty much all of the US aircraft will have that technology, not to mention a lot of other aircraft which fly into the US (my own aircraft included). The great thing of ADS-B is it transmits your position regularly (typically much more frequently than SPOT), and requires no monthly/yearly subscription fees. There are lots of ground stations to pick up signals (look at https://flightaware.com/adsb/coverage for their current map of feeder sites). Many of those are run by amateurs, but anyone can get involved and more and more people are every day). Also, up here NavCanada is in a joint venture called Aireon to ultimately use ADS-B receivers on satellites to pick up position information anywhere on the globe (http://www.navcanada.ca/en/products-and ... ads-b.aspx).

We're not quite there yet with regards to universal coverage - in particular, if you're flying in very remote areas where nobody has set up a ADS-B receiver as a feeder site to something like FlightAware, there is still nobody to receive your position reports - SPOT still wins there. But the advantages otherwise are numerous:

1. If you plan on flying in the US, you're going to need the technology in your aircraft anyway. Not that it's inexpensive, but it's an expense that will have to be spent regardless.
2. There are no monthly or yearly subscription fees
3. Coverage right now is already fairly good, though not perfect or global yet. As time goes on there should be more receiving ground stations, and if the NavCanada venture materializes hopefully sometime soon there really will be worldwide coverage. No word on if they plan on making that information publicly available as is done now with the ground stations, but even if they don't, I presume it would still be available to SAR operations.
4. Position information is transmitted every few seconds at most, so SAR regions can be narrowed down significantly.
5. More aircraft utilizing ADS-B out improves functionality for everyone, not just the individual aircraft. Aircraft with ADS-B In can see where other ADS-B equipped aircraft are to help with traffic avoidance. This is true everywhere, though ADS-B In will only show other ADS-B equipped aircraft.. except in the US where the position of everyone tracked by radar is rebroadcast regardless of the equipment they have (plus, weather info to boot).

A disadvantage over ELTs is that ADS-B doesn't transmit a mayday signal if an airplane goes down. But then, neither does SPOT, and at least if a plane goes overdue, the aircraft should be near its last transmitted position. And it doesn't matter if the ADS-B antenna or transmitter is destroyed on impact.

The problem with ELTs is they don't send a signal unless there is an impact, and in many cases they can't after impact. Though they have the advantage in that they signal that a problem actually occurred, that only happens if they work.

A 406 Mhz ELT is better than a 121.5 Mhz ELT, no question. But though I agree that SPOT is a good thing, depending on the locations a person is flying, ADS-B out can be just as effective for tracking if not more so. And the situation should only improve over time.