ELT Thought

[109JB]

So first of all, this is for my newly acquired project with fabric on and access a bit limited due to that. The airplane has an old but working 121.5 MHz ACK ELT where the builder put the antenna through the skylight. I have to replace the windshield and I would rather not do that if possible. On my other project I installed a mount and have the antenna internal to the fuselage based on reports of others. That said I was hooking up the handheld radio that i am going to use in this airplane and thought about the rubber ducky antenna that came with the handheld. I have an external antenna for the handheld and won't be using it. Being an antenna for a handheld aviation radio it is appropriate for 121.5 MHz although not perfectly tuned, and I was thinking I could just put it on the BNC connector on the ELT and internal antenna done. Any thoughts?

[efwd]

Hopefully your giving consideration to the fact this is a LIFE SAVING device. Under the circumstance, I would contact the ELT manufacturer or maybe you already know what they would recommend.

[PapuaPilot]

I will put on my A&P-IA hat for this one. :)

For an ELT you need to use the antenna that came with that ELT or one that is approved by the manufacturer. Mounting it inside the fuselage is okay.

[109JB]

Not strictly true. Although that is the guaranteed way to meet the TSO requirements, even the installation manual for the ACK E-01 ELT in question states that other antennas can be used other than theirs:


"Other antennas may be used provided they meet the VSWR requirements as noted in the specifications section of this manual..."


I will get out the antenna analyzer and see how good/bad the ducky is.

[PapuaPilot]

Hmm, I will meet you halfway on that.


For an ELT you need to use the antenna that came with that ELT or one that is approved by the manufacturer. Mounting it inside the fuselage is okay.

[109JB]

As far as a TSO-C91a ELT being a life saving device even with the manufacturer's antenna, personal experience as an NSTB investigator tells me that they aren't very good at saving lives. As a matter of fact, the frequencies used by C91 and C91a ELTS are no longer monitored by satellite and only 406MHz ELTs are monitored by satellite today. So if your legal C91 ELT activates it will have to be picked up by ground based pretty much line of site antennas to do any good.

Now a TSO-C126 ELT is a different story. The 406 MHz signal is monitored by satellite and if you have one that either has an internal GPS or hooked to a GPS, then not only does the satellite hear it but knows where you are at almost instantly.

Personally, I would trust a SPOT device more to save my life than a TSO-C91a ELT

In this case the airplane is in flat corn country of northern Illinois, so rough terrain isn't an issue here anyway. The ELT is still legal, so it will stay at least until the airplane flies again. I may then think about getting a 406 ELT.

[PapuaPilot]

I totally agree with you on that. Most of the saves these days are from ADSB-Out, not the 406 ELTS. There are still way to many false activations of the 406 ELTs.

installing a 406 ELT was a given when I was starting building my KF 8 years ago, especially since I live in Idaho and often go in the backcountry.

[efwd]

"Personally, I would trust a SPOT device more to save my life than a TSO-C91a ELT"

Kind of how I justified the cost of my Garmin InReach I bought for my Oshkosh trip. In spite of having a dual channel ELT with GPS.

[Eric Page]

There are at least two problems with relying on a portable satellite communication device (SPOT, InReach, etc.) to work as an emergency beacon. The first is that you may not be capable of activating it after a crash, and the second is that it may not be within reach once the aircraft comes to rest.

[alexM]

There are at least two problems with relying on a portable satellite communication device (SPOT, InReach, etc.) to work as an emergency beacon. The first is that you may not be capable of activating it after a crash, and the second is that it may not be within reach once the aircraft comes to rest.

That's not how you typically use them. I fire it up and leave it running. It leaves bread crumbs every 10 seconds which show lat/long, altitude and velocity. Mine is an older DeLorme Inreach from before they were consumed by Garmin and will still run for about 72 hours on a charge.

The thing it does which no ELT will do is allow you to send and receive text messages. There are canned messages but you can say anything.

If I crash somewhere and I'm still alive I can use the SOS feature and summon help and still communicate. That may be what you're thinking about. In my case my significant other stalks me and would notice if my string of dots stops moving (and believe me, on the motorcycle that only takes her about 10 minutes).
29032
Of course I would never be doing 86mph on a public road, so there must be something wrong there.

[109JB]

Also. If you know you are going down, such as from an engine failure over inhospitable terrain, or such you can activate SOS before you reach the ground.

[Eric Page]

Aha -- since I don't own one of them, I guess I should have kept my trap shut about how they're used! Thanks, guys; it makes sense now.

[N213RV]

Another consideration….. we had 2 ELT activations at my airport in the past year (inadvertent ones, thankfully). In both cases it took nearly 3 hours for the first phone call from Flight Service inquiring about it…. My personal belief is the ELT would be one of the last things I rely on to save me in such an instance. I feel like it would have been 4-6 hours before anyone started really looking….