ELT Recommendation

[WDD]

Time for fun with ELTs. My ELT is so old that two years ago finding a replacement battery was difficult and expensive, and it only has a two year shelf life. Did I mention battery was expensive? And.... yep, it's going to age out in a short bit.

Planning on replacing this ELT with a satellite 406 capable one, and I see you can connect to your GPS (GTN?) to give more precise location. I see that batteries have a much longer shelf life than 2 years on the new units. I could even do this myself when I get the Airframe mechanic certification in January - could be a fun first official project.

Suggestions on what manufacturer? Reading up on this, but always good to check for things you don't know you don't know about.

Going into a Cessna 182 P.

(And no, not planning on using the new ELT for a YouTube video anytime soon LOL).

 

[Ryan Klems]

Unless you are looking for a simplified upgrade for an older Ack E-01, I don't recommend the E-04. You'll have 3 batteries to deal with (one in the remote switch, one in the sounder and one in the ELT itself). My preferred 406 ELT is the Artex 345. I just throw away the included connector (solder cup d-sub connector) and use a crimp pin d-sub. It doesn't require any additional batteries for the remote switch or sounder, and can interface with your GPS (So can the E-04, but you have to solder up a pain in the butt DIN connector to do so).

 

[Bell206]

Suggestions on what manufacturer?

While most of my 406 ELT installs are in helicopters, I prefer the ACK brand as a number were an upgrade from the E01 to the E04. However, Artex ain't bad either. As to the extra batteries on the ACK, if you use lithium in the remote switch and audio alert its a 10 year replacement vs 5 year with Alkaline. On the GPS interface, I found its more a personal choice and for one, the aircraft electrical power must remain ON during the ELT broadcast to get the GPS to data. But as it was explained to me, when a 406 ELT is activated, the initial satellite signal will give a 10 mile search target, however, if the ELT can get 3 "sweeps" to the satellite it drops that target accuracy down to about 2 miles without any GPS data. So it gives you an option to go with no GPS interface. Or you can also carry a PLB with you.

 

[WDD]

On the GPS interface, I found its more a personal choice and for one, the aircraft electrical power must remain ON during the ELT broadcast to get the GPS to data.

Ah - I thought it was continuously getting GPS data, and would simply send out what it got right before the ELT activated. Perhaps the GPS connection isn't the feature that is worth it, as if something bad enough happens to trigger the ELT more than likely the plane isn't working anymore.

 

[M20K]

the aircraft electrical power must remain ON during the ELT broadcast to get the GPS to data.

No, not exactly. The ELT will store the last position it was given. So if you shut the power down in the aircraft 10 miles away from where you set down, then the ELT will continue to send that location from 10 miles away. But I believe it has a time stamp, so it is used as the "last known position" not the actual position.

So yes, it is much better to leave the power on until the last moment (if you can), but the ELT does not stop transmitting a location. And a GPS location is not mandatory. You can have a 406 ELT with no GPS, the satellites will narrow down your general location by triangulation.

 

[Dan Thomas]

Make sure that the new ELT isn't just attached to the old mount for the 121.5 ELT. It's not nearly rigid enough. The ELT installation manual will have details on mounting the thing, and you'll need to create that bit for it. From the Artex manual:



I had to re-do a whole bunch of 406 installations that were simply screwed to the old mounts.

 

[Bell206]

No, not exactly. The ELT will store the last position it was given.

I can’t speak for the other brands, but per ACK the 406 ELT GPS data will only be stored if there is 12 volts applied to the ELT. If that 12v input is lost prior to activation, that GPS data will not be transmitted. We were troubleshooting a battery parasitic drain and found the ELT at fault, which led to that conversation with ACK support. This info is dated, but maybe they fixed that that issue???

 

[TiltOn22]

Artex 345 is what we always recommend.

 

[Stewartb]

I have an ACK and an older Artex ME. The ACK is my preference. As for GPS enabling? The location is transmitted in the first 406 burst, so what happens after is irrelevant. I didn’t connect GPS because my RCC friends told me a standard 406 signal gets them within 50 meters every time, and 20 meters is more common.

 

[MRC01]

Time for fun with ELTs. My ELT is so old that two years ago finding a replacement battery was difficult and expensive, and it only has a two year shelf life. Did I mention battery was expensive? And.... yep, it's going to age out in a short bit.

I resemble this, having just replaced the battery in my ancient D&M ELT. The battery pack is simple: 6 D-cell alkaline batteries with soldered tabs connected in series (9 V nominal) wrapped in thin cardboard with a connector. Yet it costs $150 to $200. I could easily build my own with new parts costing less than $50. This has me thinking about owner produced parts. Mike Busch recently covered this topic and it looks promising for this application. I'll review with my local A&P-IA.

Also, I'm OK with the old fashioned one to check the regulatory box because I already carry a GPS-enabled 406 MHz PLB when flying, so I don't feel the need to have another one hard-wired into my airplane.

 

[brcase]

I have an ACK and an older Artex ME. The ACK is my preference. As for GPS enabling? The location is transmitted in the first 406 burst, so what happens after is irrelevant. I didn’t connect GPS because my RCC friends told me a standard 406 signal gets them within 50 meters every time, and 20 meters is more common.

My understanding which might be total fiction is that without the GPS single yes they can pinpoint you location within a small area, but it requires time for the satellites to move by enough to triangulate the position which might take a few hours. The more time they have to triangulate the more accurate it gets. Good Accuracy assumes the ELT keeps transmitting, which might not be the case, in the case of a fire.
If it can transmit the GPS coordinates then they know your location immediately vs having just an area.

I would like to know some more details about how it stores and transmits external GPS data when connected. From previous posts it sounds like the ELT is connected to aircraft power and the Aircraft signal is sent to the ELT. If I were designing it I would have a capacitor storing enough power to store the GPS data long enough to send a few packets with GPS data after the aircraft power is removed and the ELT is activated within a short amount of time of each other. Or perhaps better yet once the ELT is activated store the GPS data with the ELT battery power after the ELT is activated.

 

[Bell206]

This has me thinking about owner produced parts.

You'll still need approved data to owner produce the battery pack. And the lack of "free" data or the cost to make your data approved tends to negate the cost savings of this route for this type of part. Unfortunately, there was a time where you could use a 337 and get a field approval for the data on owner parts but I think that is merely wishful thinking in this day and age.

 

[M20K]

My understanding which might be total fiction is that without the GPS single yes they can pinpoint you location within a small area, but it requires time for the satellites to move by enough to triangulate the position which might take a few hours.

I believe the the "official" time is 60-90 minutes. But pending the location of the satellites when your ELT goes off, it supposedly can be as little as 30 minutes. If connected to GPS, it can be within a couple of minutes.

BUT... There's some data that shows an ELT, either 121.5 or 406, may not help you at all. Though I still have one, and it falls into Bertorelli's comment in his video on this about living out west and flying over mountains. He discussed a lot about how ELTs may not survive the crash. So not a bad ideal that once you're done transmitting on Guard, go ahead and turn ON the unit while in flight. This way if the ELT is destroyed or the antenna get's sheared off, it will still have set out your approx. location (and with the last GPS location, that will be pretty close).

And on another front, now with Satellite SOS on most newer phones, that can actually be an even more accurate locator. There was a plane crash just a few days ago where the cell phone gave SAR a more accurate location than the 406 ELT.
https://avweb.com/flight-safety/accidents-ntsb/satellite-device-cessna-accident-rescue/

Personally I'm more of a belts and suspenders since I do fly over mountains now.
1) Years ago when I upgraded my panel I also upgraded to a 406 ELT with a GPS feed.
2) I do a lot of hiking, and sometimes alone, so I have an inReach that I have registered with Flight Service and the data is also in my Flight Plan. (I assume you can do this with other devices.)
3) And now my phone has SOS, so if I can move and have access to my phone, I can also use it as a way to notify SAR. (Same with the inReach, I have to manually turn it on, so hopefully before I "land" the plane.)
And with the inReach and the phone, you need to give some thought about where you put them so they don't go flying and you can still reach them. Phone is in the side pick, inReach is clipped to the door handle.

 

[WDD]

If the “landing” destroys the ELT, I don’t think I’ll be in a position to care how long it takes to find the remains.

 

[Dan Thomas]

The Artex manual warns that the ME406 will take up to 50 seconds after activation to begin transmitting on 406 MHz. All these ELTs also transmit on 121.5 for final homing, and that activates immediately.

I once installed a 406 that also had a built-in GPS. The GPS required ship's power so was connected to the bus. I think the ELT's battery took over for the GPS when the G-switch activated. I can't remember the make, but two years later when the battery was due for replacement, the company was dead and batteries were unavailable. An $1100 ELT was now worthless.

Some 406s had a jack to plug your mike into so you could talk to the SAR guys on 121.5 but they couldn't talk to you. Might be handy for guiding them in if you can hear or see them.

 

[Dan Thomas]

If the “landing” destroys the ELT, I don’t think I’ll be in a position to care how long it takes to find the remains.

It's worthwhile for closure for your family. They need to know that you're not crawling around with a broken back, in great pain, trying to flag down a SAR aircraft that can't see you.

 

[WDD]

If the ELT is destroyed, what do you suggest?

 

[Stewartb]

My understanding which might be total fiction is that without the GPS single yes they can pinpoint you location within a small area, but it requires time for the satellites to move by enough to triangulate the position which might take a few hours. The more time they have to triangulate the more accurate it gets. Good Accuracy assumes the ELT keeps transmitting, which might not be the case, in the case of a fire.
If it can transmit the GPS coordinates then they know your location immediately vs having just an area.

I would like to know some more details about how it stores and transmits external GPS data when connected. From previous posts it sounds like the ELT is connected to aircraft power and the Aircraft signal is sent to the ELT. If I were designing it I would have a capacitor storing enough power to store the GPS data long enough to send a few packets with GPS data after the aircraft power is removed and the ELT is activated within a short amount of time of each other. Or perhaps better yet once the ELT is activated store the GPS data with the ELT battery power after the ELT is activated.

A rescue begins with authenticating an event. That’s usually phone calls to your registration’s contacts, flight plan review, etc. A rescue crew isn’t dispatched for 30-45 minutes, and by that time they know exactly where you are. GPS enabling transmits last position on the first transmission, and the only time that really helps is if your ELT is destroyed by fire or sinks in water. In any case the authentication process remains the same.

The really interesting tool for S&R is forensic radar. That’s solved a few accidents in Alaska that I’m familiar with.

 

[Stewartb]

If the ELT is destroyed, what do you suggest?

There’s an advantage to having an ELT switch in the panel. When you’re concerned something bad will happen? Set off the ELT. If you land unscathed? Apologize.

 

[Dan Thomas]

If the ELT is destroyed, what do you suggest?

The point is to install it according to the manufacturer's instructions so that it has the best possible chance of working when it has to. If it is mounted properly, it is much less likely to get destroyed or disabled or even simply fail to activate. The manual also warns that flimsy mounting can result in "crash-hiding vibrations" that inhibit G-switch operation.

There is little point in buying an expensive ELT if one is going to cheap out on the mounting. The installer needs to know that manual thoroughly.

Here's an accident where the ELT failed to operate because the G-switch loop wire had not been installed at the aircraft factory. Five cents' worth of wire missing, maybe because the technician figured he didn't need to read no stinkin' manual. And subsequent mechanics didn't either, because they missed the warning codes when the ELT was reinstalled after annual inspections. https://www.tsb.gc.ca/eng/rapports-reports/aviation/2023/a23w0096/a23w0096.html

 

[FORANE]

Eh, if they weren't required I wouldn't have one in the plane.

 

[WDD]

The point is to install it according to the manufacturer's instructions so that it has the best possible chance of working when it has to.

Yep, will be doing that.

 

[Stewartb]

Max 1/10” of movement with 100# of pull in any direction. Factory mounts didn’t comply in many cases.