406 in conjunction with Spot

[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.

[photofly]

I don’t want permanent mandatory government tracking. So I shall stay out of US class B and C airspace and more than 30nm from the relevant nominated airports, and so shall continue happily to fly into and across the US with no ADSB. Thanks.

[AirFrame]

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

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.

Actually, it hasn't changed. I had the first-gen SPOT, and even with *no* tracking service, tracking was activated as soon as you hit the emergency button. Basically, all hands on deck if something goes wrong, you can have whatever coverage you need. I have a third-gen SPOT now, and while I only pay for basic tracking (5- or 10-minute, I forget), I know if I call the cavalry it jumps up to 2.5 minute tracking automatically.

If i'm flying up a valley in cloud and run into a mountain without seeing it, I won't get to push the button. But I most likely won't be around to be rescued so I don't care. If i'm flying over top of the mountains on a clear day at 12K and the engine quits, I can hit the button and ride it down, knowing that there will be a detailed track to my landing site.

I wouldn't put a 406MHz ELT in my plane unless i'm (a) mandated by a change to the law, or (b) I can install one and wire it to a GPS that is active full-time while i'm flying. You can turn a 406MHz ELT on in flight pre-emptively, but unless the GPS is *already* locked on, you likely won't get a good position lock for at least 5 minutes... Which could be an eternity. I want one wired into my panel-mounted GPS that i'm already using for navigation anyway. I know it works, I know it knows where I am. It just needs to feed that to the 406MHz ELT.

[photofly]

I wouldn't put a 406MHz ELT in my plane unless i'm ... or (b) I can install one and wire it to a GPS that is active full-time while i'm flying.

You absolutely can do that, if you have a panel mount GPS. It just increases the installation costs, a bit. It’s not much trouble to have the GPS on as you fly.

[Pavese]

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.

But you know the operating premise of SPOT-like systems is that you turn it on before you leave the ground so it has downloaded all the data it needs and knows where you are.

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.

I think you're reading something from my words that I didn't intend. Obviously the ELT couldn't run the GPS from its battery pack, hence my reference to activating the avionics master and my preface about not knowing about the fine details of operation of an embedded GPS in an ELT. My comment was to say that if there was a GPS receiver embedded in your ELT then having it active while the aircraft was in operation would be intelligent. So, anyone out there know if this is the case?

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]

My comment was to say that if there was a GPS receiver embedded in your ELT then having it active while the aircraft was in operation would be intelligent. So, anyone out there know if this is the case

I’m sorry, I thought I answered that: because having any circuit in the ELT active while the aircraft was in ordinary operation would drain the ELT’s battery, it would not be intelligent to have the GPS receiver active during all that time.

I just checked the connection details for my ELT: while it does have an SMA connector for an external GPS antenna, it doesn’t have a data input for GPS data from any other aircraft-powered source.

The GPS test mode instructions state:
“GNSS Self Test will start (can last up to 5 minutes depending on satellite lock time) will be indicated by the following beacon function”

and elsewhere:
“The internal GPS antenna of the ELT MAY work depending on the aircraft fuselage material when mounted inside the aircraft.”

My point is that while I would still activate the ELT at the first sign of trouble in the air, if impact disrupts the transmissions only a short while after it’s activated it’s extremely unlikely to have achieved a GPS lock and have transmitted a position.

[Pavese]

My comment was to say that if there was a GPS receiver embedded in your ELT then having it active while the aircraft was in operation would be intelligent. So, anyone out there know if this is the case

I’m sorry, I thought I answered that: because having any circuit in the ELT active while the aircraft was in ordinary operation would drain the ELT’s battery, it would not be intelligent to have the GPS receiver active during all that time.

You're STILL not getting it so I'll say it 5 X 5.

If the enbedded ELT GPS were powered by A/C power (that would be the avionics bus) when the avionics master is turned on then you would have current GPS support data and thus current position available to the ELT if it is needed. As I said before, obviously the ELT battery pack would NOT be used to run the embedded ELT GPS. CLEAR?!?

While it seems not to be the case for current ELT design the above would be intelligent!

Over and out!

D

[AirFrame]

I wouldn't put a 406MHz ELT in my plane unless i'm ... or (b) I can install one and wire it to a GPS that is active full-time while i'm flying.

You absolutely can do that, if you have a panel mount GPS. It just increases the installation costs, a bit. It’s not much trouble to have the GPS on as you fly.

Let me add to that: As the owner of an amateur-built aircraft, I do my own maintenance and electrical work. My understanding is that the law requires an AME to do the GPS hookup, even on Amateur-built aircraft. I find that requirement to be arbitrary and unnecessary.

[photofly]

If the enbedded ELT GPS were powered by A/C power

Maybe there’s one that is. Or maybe it’s not permitted by the design criteria. I don’t think the absence of such a feature is because of a lack of intelligence on the part of system designers.

[Posthumane]

Actually, it hasn't changed. I had the first-gen SPOT, and even with *no* tracking service, tracking was activated as soon as you hit the emergency button. Basically, all hands on deck if something goes wrong, you can have whatever coverage you need. I have a third-gen SPOT now, and while I only pay for basic tracking (5- or 10-minute, I forget), I know if I call the cavalry it jumps up to 2.5 minute tracking automatically.

If i'm flying up a valley in cloud and run into a mountain without seeing it, I won't get to push the button. But I most likely won't be around to be rescued so I don't care. If i'm flying over top of the mountains on a clear day at 12K and the engine quits, I can hit the button and ride it down, knowing that there will be a detailed track to my landing site.

I wouldn't put a 406MHz ELT in my plane unless i'm (a) mandated by a change to the law, or (b) I can install one and wire it to a GPS that is active full-time while i'm flying. You can turn a 406MHz ELT on in flight pre-emptively, but unless the GPS is *already* locked on, you likely won't get a good position lock for at least 5 minutes... Which could be an eternity. I want one wired into my panel-mounted GPS that i'm already using for navigation anyway. I know it works, I know it knows where I am. It just needs to feed that to the 406MHz ELT.

So then this SPOT service has changed since there is no more "no tracking" service available. If you have time to push the button before the crash then yes, you do get all hands on deck, but if you are not using in flight tracking (if you didn't have it with a Gen 1) then there is no position other than when you push a button, so with a sudden catastrophic problem it does you no good.

The 406 ELT that I have does not have an integral GPS - it has to be wired to an external GPS source and a cable is provided for that. It takes a standard NMEA183 input, I believe. This can come from a panel mount GPS or a handheld which is wired in to ship power. Of course, the drawback of this is, like the spot, you have to remember to turn on the GPS at the start of the flight. Normally this isn't a problem as most of the time the GPS will be on for navigation, but if you're just out for a local flight or over familiar territory you might leave the GPS off. Without that, all that's transmitted is the aircraft ID, so locating it will be based on triangulation and Doppler tracks.

Let me add to that: As the owner of an amateur-built aircraft, I do my own maintenance and electrical work. My understanding is that the law requires an AME to do the GPS hookup, even on Amateur-built aircraft. I find that requirement to be arbitrary and unnecessary.

Interesting. Do you have a reference to that? Definitely something to keep in mind for future installs.

[Pavese]

If the enbedded ELT GPS were powered by A/C power

Maybe there’s one that is. Or maybe it’s not permitted by the design criteria. I don’t think the absence of such a feature is because of a lack of intelligence on the part of system designers.

D

[AirFrame]

So then this SPOT service has changed since there is no more "no tracking" service available. If you have time to push the button before the crash then yes, you do get all hands on deck, but if you are not using in flight tracking (if you didn't have it with a Gen 1) then there is no position other than when you push a button, so with a sudden catastrophic problem it does you no good.

Not quite... Even with the Gen 1, if tracking wasn't turned on (ie. broadcasting up to the satellite), the GPS was still active and "tracking" you, it just wasn't telling anyone where you were. The GPS on the SPOT runs continuously when it's on, it just starts sending the data to the satellite when tracking is activated.

[Posthumane]

Yes, that's true. If the spot is turned on and the GPS locked, then sending out a ping is very quick.

Btw, I'm curious why you wouldn't install a 406 ELT unless mandated? I can understand not spending the money to upgrade if you have a good 121.5, but if putting one in a new aircraft or you have to replace an old one for whatever reason, I don't see how it would be a disadvantage. A dual band unit still has the old signal in addition to the new one, and when I was looking for a replacement a new dual band wasn't any more expensive than a 121.5 only unit.

[charrois]

I don’t want permanent mandatory government tracking. So I shall stay out of US class B and C airspace and more than 30nm from the relevant nominated airports, and so shall continue happily to fly into and across the US with no ADSB. Thanks.

But is it really that easy? Amongst other things, you need to have a discrete transponder code to cross the border with your transponder turned on and broadcasting. Granted that you aren't necessarily crossing into transponder airspace when you get to the other side, but the requirement of a broadcasting transponder may easily cause the people who make up the border crossing rules to apply the same rules - that you need to have ADS-B out to do so... I don't know if they have definitively ruled on that or not. Perhaps the zone following the border is considered transponder airspace, if they require you to have a working transponder to cross the border.

It may well be that you can fly outside of transponder airspace in the US, if you can legally get your Canadian aircraft into the US in the first place.

As for me, I've given up any illusions of flying without tracking of some sort, government or otherwise. And I personally don't think that is necessarily a bad thing.. I always file a flight plan and get VFR flight following when I can (I don't think I've actually ever been refused). I want people to know where I am in case something bad happens.

Dan

[charrois]

Let me add to that: As the owner of an amateur-built aircraft, I do my own maintenance and electrical work. My understanding is that the law requires an AME to do the GPS hookup, even on Amateur-built aircraft. I find that requirement to be arbitrary and unnecessary.

Do you have any reference to this? It's the first I heard of it, and I'd be very surprised if it were actually the case - especially considering that I know of no other requirement for an AME to be involved in any other part of the construction or maintenance of a homebuilt aircraft. I know that amateur-built owners can even do their own pitot/static and transponder checks if they have access to the appropriate equipment and know how to use it, so if an AME is required to do the relatively very simple GPS hookup to a 406 ELT, particularly when 406 ELTs and their encoded position information isn't even mandatory equipment., you are right that it would be a very arbitrary rule.

[AirFrame]

Let me add to that: As the owner of an amateur-built aircraft, I do my own maintenance and electrical work. My understanding is that the law requires an AME to do the GPS hookup, even on Amateur-built aircraft. I find that requirement to be arbitrary and unnecessary.

Do you have any reference to this? It's the first I heard of it, and I'd be very surprised if it were actually the case - especially considering that I know of no other requirement for an AME to be involved in any other part of the construction or maintenance of a homebuilt aircraft. I know that amateur-built owners can even do their own pitot/static and transponder checks if they have access to the appropriate equipment and know how to use it, so if an AME is required to do the relatively very simple GPS hookup to a 406 ELT, particularly when 406 ELTs and their encoded position information isn't even mandatory equipment., you are right that it would be a very arbitrary rule.

I had to go back a ways to figure out where this came from, but I am mistaken... This came up in a discussion regarding replacing a 121.5MHz ELT with a 406 ELT in a certified airplane, not amateur-built. An owner is allowed to replace the 406 himself, but that permission is moot as the owner needs an AME to run the wires to the panel for the remote switch and (if desired) connection to a GPS.