406MHz ELTs

[small penguin]

If you crash and die the new ones wont do you much good either

[just curious]

Kinda makes you wanna re-visit that whole low-flying thing, then huh?

[small penguin]

No, not really. Maybe Im being ignorant, but I doubt very much the new ELT is going to save my hive anymore than the 121 I got already. Low level flying or otherwise.

[Widow]

People do die after accidents, because SAR has not been called out early enough. An ELT signal would have saved my husband.

[small penguin]

A 406 wouldnt have saved him though. Im not completely familiar with the incident though, but as soon as that plane sank, any chance of ELT signals would have been gone. Furthermore, the 406 takes 50 seconds to fire off the first shot.

What did the Beaver have in terms of ELT? Just a typical mounted one or one rated for water ops? (ie: Im thinking can float/detach from the frame/whatever is required)

Granted the 406 does require an instrument panel switch to be installed which can help in some situations, but ... could have a panel switch on a 121 too, and I wouldnt have to wait the 50 seconds.

*shrugs*

[edit] Im not saying I dont believe in the ELT signal, I just dont believe the 406 ELT is any better for my safety than the 121.5 I have already. Least that one will start off right away.

[Widow]

No, it was not a water op ELT - I'll never understand why comm floatplanes aren't required to have special water-safe ones (or something).

I'm not saying a 406 would have saved my husband, but an ELT signal would have ... the point being, planes do crash, people do survive and then die of exposure because rescue does not arrive in time.

[small penguin]

Agreed on that.

[_dwj_]

121.5 ELTs fail to activate in the majority of crashes, and I don't think 406 ELTs are any different in this regard. Either you crash too gently so the g-meter doesn't activate it, or you crash too hard and the thing gets smashed, or it gets submerged, or it fails for another reason entirely.

The bottom line is that 406 ELTs are only marginally more likely to save your bacon than a 121.5 one. Instead of spending 3000 bucks on a new ELT it makes more sense to spend a few hundred on a system that sends your position to a satellite every few mins, with a 121.5 ELT as backup. Then the authorities and your loved ones will have your location prior to the crash no matter what happens to the device itself.

[small penguin]

Yup. Too bad TC cant see it that way.

[Widow]

According to this chart, 121.5's have "no GPS capablility". What does that mean? Surely you can still use a transmitting GPS with the 121.5 as suggested by dwj ...?

But that doesn't solve the problem of the terrible record of the 121.5's for false alerts. Again, according to that chart:

121.5

Only about 1 in 5 alerts come from beacons. Satellites cannot discern beacon signals from many non-beacon sources. Beacons transmit anonymously with no unique identifier. Non-beacon interferers have included ATM machines, pizza ovens, and stadium scoreboards.

Fewer than 2 in 1000 alerts and 2 in 100 composite alerts are actual distress.

Since 121.5 MHz beacons transmit anonymously, the only way to ascertain the situation is to dispatch resources to investigate -- a costly disadvantage that puts SAR crews at risk unnecessarily..

High false alert rate makes first-alert launch unfeasible

406

All alerts come from beacons. Satellite beacon transmissions are digital, coded signals. Satellites process only encoded data, other signals are rejected.

About 1 in 12 alerts are actual distress.

Beacon-unique coding/registration allow rapid incident corroboration. Registration mandatory since 1994. 90% beacons registered. About 70% of false alerts are resolved by a phone or radio call to registration point of contacts prior to launching SAR assets.

406

First location alert warrants launch of SAR assets. Earlier launches puts assets on scene sooner - an average 3 hours saved in maritime, 6 hours saved in inland.

That is a huge difference if you are waiting for rescue.

[just curious]

You have to remember that these are average, and that a lot of these calls are to the local airport manager to the local AMO's or charter operators who go "oops!" and turn them off in the hour following the tone.

The others are the hard landing, chearted death again types that disappear for a while and take an airborne search to resolve.

[_dwj_]

406 ELTs do have a GPS capability (for extra cost). But they still only actually transmit your position when they are activated. If it fails to activate (which happens more often than not) then the GPS doesn't help you. I was talking about units like findmespot.com which leave a breadcrumb trail so people know your rough position in the event of an accident.

The main advantage of 406 is that they cut down on the false alerts. However in my (and COPA's) opinion that is more an issue of SAR saving money than in saving lives. I can't think of any instances of people dying due to false alerts, but I can think of lots of instances of people dying because nobody knew where they were.

[Widow]

Since it took my husbands death for me to know, I doubt the "unsuspecting public" has learned ... that all commercial aircraft are not sending out a constant (or frequent) position signal. It would seem to solve a lot of problems for not a lot of money.

[small penguin]

dwj, you nailed it on the head IMO. Which is why Im really against flipping a tonne of money on a device that wont save my life any more than my current 121... Just so SAR can save a buck or two for Tims coffee

Spot is a neat system. Thought IMO a simple and free alternative is flight following. *shrugs*

I think the only thing going for the 406 from a pilot's (read: my) perspective is the fact that panel mounted activation switches are mandatory.

[_dwj_]

Flight following doesn't work when the controller is too busy, or when you're flying in mountainous terrain or up north outside radar coverage, so some kind of satellite system is best.

[Spokes]

Spoken like a bunch of geniouses who have never flown SAR before. After years of doing this in the maritime environment, I can tell you that life is alot easier if you have a lat/long from a beacon, rather than just the old sar tone to home.

And yes, I have found people using the 121.5 tone with a homer, and yes I know we could have found alot more had we known the lat/long.

If you crash your plane in a big smoking hole, sure the elt won't do you much good. Neither will your seatbelt. I guess we should do away with those too. If you do crash, and manage to survive, I would say that it would really suck to die later from exposure because no one could find you.

I would say that if you can afford uber-thousands to buy and properly maintain an aircraft, 3 large for one of these devices should not be a big problem.

[ettw]

My only experience in 406 ELTs was in the Twin Otter world.

I can't remember the make but it was supposed to be more reliable in its triggering mechanism. As well it did have the capability to store and transmit the last GPS position and they had a small speaker attached to the structure adjacent to the ELT that would sound when the ELT went off. So in that case, you would not have to tune up 121.5 after that hammered on landing you just had. You'd shut down and you would hear the familliar ELT warbling tone from the tail. It allows you to turn it off and call the nearest FSS to advise them of the false alarm rather than wait for the Herc to appear overhead.

Oh, and the last thing was a remote switch that allowed you to turn it on if need be and as importantly turn it off if it went off accidentally without climbing in the tail. Which I had to do in flight because of a wiring failure in that switch circuit. LOL!

These capabilities may have been specific to the model but I can tell you (and JC will confirm) that all of the Borek twins have them. I think they may almost be defacto required for Antarctic ops because of the accuracy of position determined by the satellite.

So in summary I think TC is mandating because of the reduced false alarms triggering SAROPS as well as the accuracy of satellite determined position off the bad. Sounds sensible to me.

Cheers,

ETTW

[small penguin]

ettw, the panel switch is not unique to that model. Its mandatory that ALL 406 installations have a panel switch. Furthermore, its not even a feature or benefit of a 406 as you can just as easily have a panel switch on a 121.5

As far as I know, the 406 wont reduce false alarms. I read somewhere (perhaps even here) that the 406 uses the same type of g-switch as current ELTs. What it WILL reduce.. false callouts. Because of the fact SAR will just be able to phone you while you're at the BBQ asking why your ELT is going off. Then you peak back at your plane tied down in the grass.

spokes, yes having lat/lon when searching for an aircraft is a huge plus. But... a 406 doesnt give you that. A 406 elt + a probably expensive GPS unit will. And as far as I know, that GPS unit becomes solely dedicated to the elt, ie: its not a garmin or whatever mounted in your panel(someone please correct me).

Just because we own a plane, doesnt mean we're made of money. Furthermore, it also doesnt mean we (maybe just me) want to waste 3000 bucks on a 406. Its like paying more for the same life insurance. It'll just cut costs to DND/TC/whoever. Finally.... why do we grumble about the cost? Because its fucking rediculous when you can get a 500 dollar laptop, 50 dollar cellphone, but you have to pay 1500 dollars for a device that goes beep beep beep. 3000 bucks is a hell of a nice vacation ya know.

Besides, you cant have SAR without searching

[Widow]

Again, this is from the chart linked above ...

406
1-3 nm (2-5 km) accuracy on average. Position calculated by Doppler shift analysis. Position information on first satellite pass.
Better than 300 feet accuracy with GPS equipped beacons. GPS position processed with initial alert, near instantaneous via geostationary satellites.

121.5
12-15 nm (15-25 km) accuracy on average. Position calculated by Doppler shift analysis. Requires minimum of two satellite passes.
No GPS capability.

That is a huge difference in position accuracy. Again, it says no GPS capability for the 121.5 (???)

[ettw]

Penguin,

Thanks for making those points.

If registering with the SAR secretariat in Ottawa allows RCC to call you at the BBQ to prevent a SAROPS then I think thats a great thing.

As far as I know about the unit we had, the GPS was not dedicated to the ELT. There was another box to be added to the installation that interfaced the AC GPS to the ELT. I'm not aware of whether or not there were specific GPS units required for the installation.

I am certainly of the opinion that either the frequency of 406 MHZ or the satellite which req'd the 406 freq allowed for a more accurate initial location over the old sat/121-243MHZ system. That certainly has to reduce SAR times if they can start in a smaller grid off the mark.

BTW, I do love the point regarding the cost of computers vs this equip, of course I could say welcom to aviation but you already know that.

Cheers,

ETTW

PS...I'm not an owner but a pilot with a commercial op so I don't have to bear the cost of this mandated change but I understand the resistance to this as an owner.

[small penguin]

Makes sense, as far as I know you cant interface a GPS with a 121 because its an analogue signal rather than digital. ?

I could be wrong.

lol about your comment ettw! I knew that when I got billed 2 hours of AME time to write an amendment to W&B for removal of wheel pants

Im not by any means saying that the 406 saving false callouts is a bad thing, of course its a good thing. It saves the government money, and it means those SAR resources are available for a real emergency.

What I dont agree on, is the end-user (me, us) having to pay for this, when its the government, mostly, that reaps the reward. I'd love to get the ELT, then send the bill to TC hehe.

[ettw]

As far as I know, part of the 406 standard was designed to allow for the transmitting of data piggybacked on the signal vs. the simple AM 121.5.

Any HAMs out there that could shed some light on the differences between these two types of transmissions?

Cheers,

ETTW

[KnownIce]

I think the most important direct advantage to pilots with the new system was mentioned in the fine print of one of Widow's posts. Getting a reasonable position by Doppler shift can be achieved with the new satellite upon first signal. Which means that within 2 minutes the guys in Trenton known you ident, and your location to within a 5 mile radius. If you activate the ELT on the descent, there's a good chance they know about you and your approx. location by the time you exit the aircraft. Compare this to 121.5, which can establish a 15 nm radius only after a MINIMUM of 2 satellite passes (read: hours), which is a lot to ask of a potentially flaming/submerged ELT.

[_dwj_]

As for "another reason entirely", a very common reason for the ineffectiveness of ELTs is that the antenna is sheared off during the crash sequence. The little orange box then diligently sends its signal for 48hrs, and yet nobody can hear it.

If you're conscious and mobile, you can (and should) always remove the ELT from the aircraft and extend the antenna on the box itself, and you should switch it on at the box in case the g-switch didn't activate and leave it switched on 24/7. Also if it's cold, put the ELT under your clothing to keep it warm and extend the battery life.

I agree with you that you shouldn't put all your trust in any ELT. If the 406 ELTs had a breadcrumb feature that sent regular position reports before you crashed it might be worth the $3000, but as it stands at the moment it seems a lot of money for something that is less useful than a $200 SPOT.

Of course if I had unlimited money I'd install a 406 ELT with GPS, buy a SPOT, and install a parachute and airbags for good measure, but that would cost more than my plane is worth.

[Splatm]

Again, this is from the chart linked above ...

406
1-3 nm (2-5 km) accuracy on average. Position calculated by Doppler shift analysis. Position information on first satellite pass.
Better than 300 feet accuracy with GPS equipped beacons. GPS position processed with initial alert, near instantaneous via geostationary satellites.

121.5
12-15 nm (15-25 km) accuracy on average. Position calculated by Doppler shift analysis. Requires minimum of two satellite passes.
No GPS capability.

That is a huge difference in position accuracy. Again, it says no GPS capability for the 121.5 (???)

The 121.5 signal can't encode information. It just warbles and the satellites just look for a carrier on 121.5, they aren't built to decode any information even if it was encoded. The 406 sends a data stream including the ID which matches up to the registration, the same data stream can send position information from a GPS if equipped.

What is important to note is that the difference from 12-15nm to 1-3nm is without a GPS. In SAR terms that is a massive reduction in the area you need to search in order to have a reasonable PoC (Probability of Containment). Required search area is exponential to the circular accuracy of the beacon. In the marine and wilderness environment 406s save a lot of lives and provide a much higher probability or survival. Both because of the increased accuracy and the fact that a 406 signal results in the searchers launching much sooner as they can quickly rule out most false alarms.

The problem is the implementation standards and ridiculous price associated with these devices. Ultra-durable marine wearable EPIRBs (Marine 406 beacons) are $500. Aviation units don't need to survive the same sort of long term abuse that marine units do and can be much larger since they don't need to be wearable. If I wore the average aviation 406 on the deck of a boat it would be junk inside a day and yet costs 6x for an environment which is less risky (for equipment and people) than being on the water.