Connect 406 MHz ELT to GPS: worth it?

[PT20J]

The previous owner of my '94 M20J had a ACK E-04 installed, but didn't connect it to the GPS. I'm getting a GTX 345 transponder installed soon, and I'm thinking that might be a good time to connect the GPS to the  ELT since the radio shop will have to mess with the GPS connector anyway. I'm sure some of you have thought long and hard about whether the GPS position really increases the likelihood of being rescued. What do you think: is it worth the cost and trouble?

[Hank]

Whatever it costs, you will be happy tomhave paid double if it resukts in a quick rescue after you've gone down somewhere inhospitable. What would Steve Fosset have paid to be found even the day after his accident, instead of hikers finding his remains two years later? Or those folks whose Mooney went down a couple of winters back near Banff, a place I'd really rather not camp in December?

[Oldguy]

28 minutes ago, PT20J said:

What do you think: is it worth the cost and trouble?

Without any extra words, the answer to your question is "Yes". @Hank lays out a couple good reasons. I would add to them the thought of finding anyone else flying with me should I not make it in the crash. If they were fortunate enough to survive, I would want them found ASAP.

We have many redundant systems and various safety items on our planes. With already having the ELT, connecting it to your GPS should be done while you are having the work done.

[PT20J]

Well, I kinda figured that. But, it would help me get a clearer understanding if I knew the details of how it works. Don't the satellites locate a 406 ELT pretty precisely even without the GPS?  

[GDGR]

2 hours ago, Hank said:

Whatever it costs, you will be happy tomhave paid double if it resukts in a quick rescue after you've gone down somewhere inhospitable. What would Steve Fosset have paid to be found even the day after his accident, instead of hikers finding his remains two years later? Or those folks whose Mooney went down a couple of winters back near Banff, a place I'd really rather not camp in December?

Not certain if you’re referring to the C that went down in bad weather in November 2017 or not. Wreckage was found 200 yards from the highway 10 months after. Guess you could draw your own conclusions as to whether or not it would have been better, if they survived impact. 

[Marauder]

Well, I kinda figured that. But, it would help me get a clearer understanding if I knew the details of how it works. Don't the satellites locate a 406 ELT pretty precisely even without the GPS?  

The 406 MHz ELT by itself will bring the accuracy to 1 to 3 miles. In heavily wooded terrain, this could still take a long time to search. When you add GPS signal to it, the search area goes down to 100 yards or less. That could mean some substantial time savings during a search.


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[PT20J]

33 minutes ago, Marauder said:

The 406 MHz ELT by itself will bring the accuracy to 1 to 3 miles. In heavily wooded terrain, this could still take a long time to search. When you add GPS signal to it, the search area goes down to 100 yards or less. That could mean some substantial time savings during a search. 

OK, I get that. They put a new ELT antenna on the top near the baggage door rather than installing it under the dorsal fin. This also runs the cable across the tailcone to cabin junction. So there is a chance that the antenna may become disconnected during a crash. I'm assuming that if you activate the ELT before impact, that it would broadcast the GPS position -- is this right?

[kortopates]

Whether it's worth it or not depends on how you value your life and your pax's. It wasn't a decision that I had to think about

Although the 121.5 signal is active soon as its turned on, it does take a while for the 406 burst to go out. I recall 50 sec on the ACK 406 but a quick review of their doc can confirm. But if you're gliding to the crash site with any altitude you should be able to get at least one 406 burst off before landing.

Antenna cable disconnection during a crash sequence is highly unlikely, there is only a few feet of coax between the ELT and the top of the fuselage where the antenna is installed and the unit which should be directly below the antenna. Its not like you'll have the antenna and unit in separate sections of the fuselage that can separate (that's a requirement in the install manual if I recall). Of course the biggest risk is the antenna snapping off but obviously there are no guarantees and all we can do is stack the odds in our favor of being found quickly. I carry a personal 406 as well in my survival pack. 

As previously discussed, each manufacturer only approves certain antenna's and also have certification requirements of the max angle from vertical allowed; which prevents most from being installed in the dorsal fin. But if that is important to you, I recall Emerging Lifesaving Technologies has a 270 degree antenna option and builtin-GPS that at least one person has said they could install it in Mooney dorsal fin. But that 406 is the only one without 121.5 broadcast which is a requirement for me since its still the technology in use and often relied on for last mile  despite 10m accuracy of WAAS GPS location data.

[RLCarter]

Install a stand alone GPS ($75.00) for the ELT, that way if you have time the ships power can be turned off before going in reducing the chance of electrical fire...... 

[carusoam]

So it seems accuracy is everything...

1) You get the choice to turn on your ELT before... Landing.

2) You are broadcasting your location...

3) Your family will be comforted by knowing where you are...

4) They won’t notice the amount of dough that came out of your savings...

5) Your forensic accountant will check the box next to spent money wisely...  

6) Somebody might question why you bought a new Gill battery every other year. (Don’t do that.)

PP thoughts only,

Best regards,

-a-

Nine months to get the bad news. Maybe the lost Mooney pilot has a lesson to share...

 

[PT20J]

Well, I’ll probably do it. I do appreciate all the opinions. Problem is, being an engineer, I was hoping someone had found some data. Without data, it’s a subjective emotional decision, and I hate making drcisions that way. I did some searching, but there is precious little data about the effectiveness of ELTs at all, let alone adding GPS. The “problem” is that there just aren’t enough crashes (thankfully) to have a large enough data set to anslyze, and ELT effectiveness data is not well captured. Years ago I recall some study concluding that the ELT didn’t even activate about half the time. That’s why I like flight following so much when I’m VFR.

 

 

 

[carusoam]

38 minutes ago, PT20J said:

Problem is, being an engineer...

Sometimes you have to stop cutting bait, and just go fish... 

 

This goes into the pile of what is the best system to have....

It may not be perfect, but it is the best that is available at this time...

Sure...

1) You could fail to remember to turn it on...

2) Something could break its antenna...

Or...

3) You survive, its a nice day, it works as expected...

4) The local law enforcement arrives as your rescue team... 10 minutes later...

Kind of a first world challenge...

Landing in the woods in Revelstoke, next to the highway... nobody finds you for months... take all the help you can get.

5) a back-up Spot device is going to be your other friend... satellite SOS system...

6) This all depends on where you fly... up and down the East Coast it is hard to not be found...

Flying over the deep woods or endless farmlands... at night or in foul weather... who is depending on you?

7) Existentialism For Mooney Pilots.... 

8) Existentialism can be a tough subject...  we have a solution for that too... pay it forwards using amazon.smile set up MooneySummit as your intended charity.   

 

Get outside your Engineering comfort zone... it is hindering your decision making expertise!

Best regards,

-a-

 

 

[Marauder]

Well, I’ll probably do it. I do appreciate all the opinions. Problem is, being an engineer, I was hoping someone had found some data. Without data, it’s a subjective emotional decision, and I hate making drcisions that way. I did some searching, but there is precious little data about the effectiveness of ELTs at all, let alone adding GPS. The “problem” is that there just aren’t enough crashes (thankfully) to have a large enough data set to anslyze, and ELT effectiveness data is not well captured. Years ago I recall some study concluding that the ELT didn’t even activate about half the time. That’s why I like flight following so much when I’m VFR.
 
 
 

When I was based at KILG, I sub-leased my hangar from an aviation crash recovery company. Quite honestly, if you can’t control crash your plane, there isn’t much need for an ELT. The violence of a crash, even if the ELT survives, doesn’t mean you will.

Where the advantage of an ELT (and personal ELT) is when you survive a crash landing in inhospitable terrain and recovery time is critical. And that is one reason you find remote activation switches in the cockpit. It is on your emergency checklist, right?




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[EricJ]

7 hours ago, PT20J said:

Well, I’ll probably do it. I do appreciate all the opinions. Problem is, being an engineer, I was hoping someone had found some data. Without data, it’s a subjective emotional decision, and I hate making drcisions that way. I did some searching, but there is precious little data about the effectiveness of ELTs at all, let alone adding GPS. The “problem” is that there just aren’t enough crashes (thankfully) to have a large enough data set to anslyze, and ELT effectiveness data is not well captured. Years ago I recall some study concluding that the ELT didn’t even activate about half the time. That’s why I like flight following so much when I’m VFR.

 

The 406 system works very differently than 121.5.   There are a number of different satellites, at different orbits (GEO, MEO, LEO) that all listen for 406 MHz signals.    They don't all have sufficient antenna directivity to provide much location information that way, so the GPS info in the data stream can be critical.   What would be the rationale for NOT connecting the gps signal when you have the opportunity?

 

[Hank]

18 minutes ago, EricJ said:

What would be the rationale for NOT connecting the gps signal when you have the opportunity?

Only two come to mind: 

1. Time in the shop
2. Money

[pwnel]

9 hours ago, PT20J said:

Well, I’ll probably do it. I do appreciate all the opinions. Problem is, being an engineer, I was hoping someone had found some data. Without data, it’s a subjective emotional decision, and I hate making drcisions that way. I did some searching, but there is precious little data about the effectiveness of ELTs at all, let alone adding GPS. The “problem” is that there just aren’t enough crashes (thankfully) to have a large enough data set to anslyze, and ELT effectiveness data is not well captured. Years ago I recall some study concluding that the ELT didn’t even activate about half the time. That’s why I like flight following so much when I’m VFR.

 

I was involved with wilderness rescue in Southern Africa for a decade.  Whereas countries like Botswana made 406 ELTs mandatory, South Africa did not - not even 121.5.  It's an absolute nightmare when a plane goes down.  You would be shocked how difficult it is to spot wreckage from the air - the US CAP has substantial material on this and Steve Fossett is only one of many cases that is well known.  In most of the crashes where we had fatalities it was probably on impact - we won't know what a rescue within the golden hour could have achieved though if a 406 led you straight to the scene.  Also the anguish of family and friends over multiple weeks of intensely expensive search efforts is worth the 406 even if you don't make it. 

[1964-M20E]

YES!!

I'm an engineer too.
 

 

[johncuyle]

Since the interior will be out running wiring for your GTX-345R, it doesn't hurt to at least run the wiring while they have your interior out.  I had mine run and hooked up -- for about a month.  Then I installed an engine monitor and needed the GPS port for it.  The ELT was the least important thing plugged into the GPS, so it got unplugged.

[jetdriven]

The ELt will transmit its last known position at the crash with a gps input.  It’s your life. Don’t get cheap. 

[PT20J]

Not really a money issue for me - just want to understand it. Talked with the radio shop today and issue may be that I’m out of ports on 430W. Last owner didn’t get configuration info or wiring diagrams for 430W/Aspen Installation. I’ll find out when we open it up for GTX 345 installation. I get everyone’s gut response. Was hoping someone had researched this and had data, but now believe data is unavailable. 

[RobertGary1]

On 1/27/2019 at 6:28 PM, Marauder said:

 

 

The 406 MHz ELT by itself will bring the accuracy to 1 to 3 miles. In heavily wooded terrain, this could still take a long time to search. When you add GPS signal to it, the search area goes down to 100 yards or less. That could mean some substantial time savings during a search.


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Don’t forget it still puts out a low power 121.5. We track those things to within 100 yards easily. From the air I’ve reported gps coordinates within less than a block. 

-Robert