SonexBuilders.net

Hello All,

As I look forward to potentially having a completed airframe in the next 9 months, I am starting to research avionics in-detail. One area that I'm having to decide on is the ELT solution... From reading FAR 91.207 it seems like an E-AB Sonex doesn't need an automatic ELT, but can instead use a "personal type" device.

This leads me to a quandary:
For $300 I can get a decent PLB with a built-in GPS.
For ~$600 I can get an ELT (like the ACK E-04) with no GPS.
Or for $1200 - $2000 I can get an ELT with GPS.

The ELT+GPS seems prohibitively expensive for what it is... So let's concentrate on the two lower-cost options: Obviously an automatic-activation system has some safety benefits; but so does GPS! Do I want the peace-of-mind of knowing the system activated automatically in a crash, or do I want the peace-of-mind of knowing that when I punch the "Help" button, people are going to find me and get to me soon?

Would love to hear people's thoughts/opinions...

--Noel
Sonex #1339
Center-stick, TD, Acro-ailerons, all-flush rivets, AeroVee Turbo

If you have a bad crash then your survival may depend on people knowing you are hurt and coming to get you. Time may be critical. If your bad crash happens while at the airport with your buddies watching then no problem. They call 911 and run to the crash. If you are out somewhere and have a crash, will you be able to activate a PLB? Or will you be disabled and your life clock ticking away?

ELT's are another form of insurance. Insurance is an absolute waste of money, unless you happen to need it. Then it is a bargain.

I want a 406 with GPS all properly registered with NOAA.

Noel,
I think you have the regulations confused. If you intend on carrying a passenger you need an ELT.
Jake

You definitely will need to install an ELT in your Sonex. So far you can still get by with a 121.5 MHz unit (TSO C91a), which are quite a bit less expensive (although less effective as well) than a 406 MHz unit (TSO C126). And while FAR 91.207 would suggest that you don't need the ELT installed during flight testing, every FAA inspector and DAR I have talked to will not issue the airworthiness certificate without seeing the ELT installation. So you might as well go ahead and install the unit right off the bat.

For ~$600 you should be able to get an ELT with GPS if you already have a GPS source in the airplane.

My ACK E-04 406MHZ ELT cost ~$600. It includes a wire that you can connect to a serial GPS source. My Stratomaster Enigma outputs serial GPS data and I believe it should work. It's on my list of possible improvements, but haven't done it yet.

I have also considered getting an amateur radio APRS transceiver like this one: http://www.byonics.com/mtt4b. This also needs a GPS source that could possibly be shared with the ELT. I also might consider a SPOT tracker for its simplicity.

Bryan Cotton wrote:If you have a bad crash then your survival may depend on people knowing you are hurt and coming to get you. Time may be critical

See, this is interesting. The logic you're using to suggest an automatic ELT is exactly the same logic I am using to suggest that a GPS system is more-important. Even the 406mhz ELT units still give an initial search area of something like 5 square miles, AFAIK... That's potentially several hours of searching at least - and I say this as someone who was lost near Donner Pass for a couple of days as a teenager, and watched search helicopters fly by and not see me!

A signal with GPS coordinates means people don't waste time searching for you, they know where you are.

As a glider pilot, I'm often flying in mountains and over unpopulated areas - I carry a SPOT tracker and love that people can see exactly where I've been and my last position (to within about 10 minutes)... Having had to punch the button a couple of times (to let people know I landed in a remote field), I am convinced of the value of folks being able to see exactly where I am on a map, and come get me. :D

BTW, one thing to note is that I'm not envisioning waiting for an accident and _then_ punching the PLB after the crash. With a GPS-based unit I would punch the button at the first sign of serious trouble and then trust that the unit was running while I flew the airplane "as far into the crash as possible" (to quote Bob Hoover). I look at a lot of fatal accident reports and note that they are often situations that developed over time. Rarely does it seem like the pilot is suddenly incapacitated or rendered unable to manipulate a control.

The real bottom line is that it appears the ELTs with built-in GPS are either expensive because of the limited market and no competition pressure; OR because of the regulatory hurdles and requirements... I wish there was more emphasis on making safety gear less-expensive and more-available! Perfect functionality is a nice goal; but erecting unnecessary barriers to the adoption of safety systems runs contrary to the goal of increased safety! This is why in the glider world we have voluntarily adopted "FLARM" (PowerFLARM here in the USA, thanks to FCC curmudgeons) as a standard for traffic awareness & anti-collision warnings - its way cheaper and easier to implement than TIS or ADS-B, has a lower power-draw, and can be iterated and improved without the shackles that something like a TSO (with strict specs and fully-defined functionality) imposes - but I digress... :roll:

--Noel

gammaxy wrote:My ACK E-04 406MHZ ELT cost ~$600. It includes a wire that you can connect to a serial GPS source. My Stratomaster Enigma outputs serial GPS data and I believe it should work. It's on my list of possible improvements, but haven't done it yet.

Thanks for the tip! Its true, the E-04 appears to be one of the better values in the ELT realm; I was not aware it could accept an external GPS signal. There's still one problem with this, though:

If the ELT goes off automatically (i.e. a crash), it is likely that my avionics are dead or malfunctioning... so the external GPS signal is likely to be useless at exactly the moment it is needed! :-P

--Noel

Noel,
I think you will find that the ELT will broadcast the last good GPS coordinate it had. That should get you pretty close to the accident.

Noel, I'm with you. I fly the Pacific Northwest also in my Waiex and we know how little time it takes to fly off into almost "no where".
I have a basic 121.5 ELT and hope to upgrade in the future. My main source of self preservation is my PLB. I have had a Kannad for the last 3 yrs. Whenever flying over hostile territory, I clip it onto my person. Over flat land its hanging near my map pocket with the Icom radio. Another back up.
My rational for going with the PLB was the miserable statistics for ELT success. The rate of finding an aircraft accident based solely on the ELT response, is in the neighborhood of 12% of accidents. You have a better chance of an eye-witness seeing your last approximate position or some other combination of events(radar track, etc) than being found solely by ELT. Its alarming how poor the success rate is. Fire, damage to antennas, a hundred other things contribute to this stat.
For my piece of mind I find the PLB and extra insurance measure worth the cost.
In event you crater it straight in or don't survive the initial impact, its rather a moot point. Just an added burden to rescue, first responders looking for a downed aircraft. I'm hoping my PLB will save that time and frustration in the event its actually needed.

Larry

Bryan Cotton wrote:Noel,
I think you will find that the ELT will broadcast the last good GPS coordinate it had. That should get you pretty close to the accident.

Bryan - I would hope so, but the ACK website doesn't actually state this in the documentation I could find.

If I get a chance, I'll email the manufacturer this weekend and let everyone know what they say...

--Noel