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ELT requirement / suggestions ?

Larry DeCamp

Well Known Member
I have read the threads and AOPA/FAA stuff. Still questions :
1- Is a PLB acceptable or not ?
2- If not, what is best 406 option ? Artex, Kannan,Other ? Why ?
3-Suggestions for RV4/RV8/Rocket ( ie. tandem) install to optimize :
A- Easily accessible.
B- Antenna location.
C- Antenna cable protection in crash.
D- Antenna location if inverted on ground.
Your thoughts much appreciated !
 
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I have read the threads and AOPA/FAA stuff. Still questions :
1- Is a PLB acceptable or not ?
2- If not, what is best 406 option ? Artex, Kannan,Other ? Why ?
3-Suggestions for RV4/RV8/Rocket ( ie. tandem) install to optimize :
A- Easily accessible.
B- Antenna location.
C- Antenna cable protection in crash.
D- Antenna location if inverted on ground.
Your thoughts much appreciated !

1. NO. It does satisfy the FAA requirement.
2. Depends. ACK is what I have.
3A. Not that important.
3B. Needs to have good VSWR.
3C. Must work so that aircraft will be found.
3D. In the event of a crash, I am more concerned about survival of the individuals and the wreckage being found.
 
So...

So, if you follow the manufacturers instructions, the antenna is to be mounted on the top of the fuselage, at least two feet from anything else.

When the aircraft flips over, the antenna is now sticking in the ground and being shadowed by the fuselage...so I guess if you have a "crash", don't end up inverted?
 
What RV-6 Flyer said.

What brand? Look at Aircraft Spruce. See what is out there and or how much. Follow the installation instructions. I have deviated by putting the ELT and antenna both in the baggage compartment. The antenna can transmit through plexi... it is a compromise. Nothing stopping you from having a PLB on your person in addition as well as an ELT. The ELT has "G" switch and is designed to come on when there is an impact. PLB does not.

Some ELT's have GPS interface so you can send your GPS's LAT LONG position through ELT. Other ELT's have GPS built in, and others don't have GPS (so accuracy will be less but much better than older ELT accuracy). Battery replacement cost? Form factor, size, shape....

https://www.aircraftspruce.com/menus/av/elts.html
 
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I would definitely recommend a 406 ELT that takes a GPS input to provide lat/Lon to the satellite. It gets the rescuers directly to you. Without the GPS input there is a much larger search radius.
I also carry a PLB in case I need to travel from the wreckage. Also a good backup.
 
More government wisdom 😒

Thanks for responding guys.
My summary is you are required to spend $500 to $2,000 on a device requiring periodic battery replacement, that only works if you hit something hard enough to activate it and you don't flip over. I think the probability of escaping death from impact and or fire is low, and landing anywhere but a road without flipping is also low.
So my conclusion is buy the cheapest unit, live with the false activations and manage your aircraft so the big fan keeps turning 😊
 
Years ago, someone on this forum who is a first responder said that in his experience, if the ELT goes off, the mission switches from a Search and Rescue to Search and Recovery.

That just doesn't sound good.

Wherever you mount your ELT, put it somewhere that you can access it and its portable antenna without tools. This is much easier to do when building than retrofitting.
 
Based on everything I've seen and heard, along with some personal experience with faulty ELT's, I switched to Kannad and haven't looked back.
 
Although it is not discussed officially, the general consensus at COSPAS-SARSAT is that if the antenna and cable are intact and connected to the ELT after the crash and the ELT activates, they will pick it up.
When NASA did the gantry crash tests with the old 172s recently, the antenna that was in the dirt after the 172 flipped was picked up by the satellites.
So, design your installation to give the coax and antenna the best chance of survival, i.e. leave slack so the connectors don't rip out, and consider how the structure might deform, shear, or breakup. The new installation guidelines also recommend fire-sleeve for the coax, so there is a better chance of getting out a few messages before fire consumes the cable/antenna.

And carry a PLB....
 
I agree. Back in Feb 1, 2009 when Canada first activated the 406 coverage, a buddy & I were busy installing one and accidentally activated it. Wasn't too long before we got a call asking if everything was OK. We were the very first GA aircraft activation so they were keenly interested with their signal location accuracy (before GPS interconnect) as it was about 600ft radius of our location, they expected 60ft radius accuracy for the 406. When I explained we were inside a full metal hangar with doors shut, they felt much better.
The 406 antenna (thick portion at the base) is much more likely to survive even if the 121.5 (long whip portion) is mangled.
 
I agree. Back in Feb 1, 2009 when Canada first activated the 406 coverage, a buddy & I were busy installing one and accidentally activated it. Wasn't too long before we got a call asking if everything was OK. We were the very first GA aircraft activation so they were keenly interested with their signal location accuracy (before GPS interconnect) as it was about 600ft radius of our location, they expected 60ft radius accuracy for the 406. When I explained we were inside a full metal hangar with doors shut, they felt much better.
The 406 antenna (thick portion at the base) is much more likely to survive even if the 121.5 (long whip portion) is mangled.

406 Mh ELTs have had confirmed (moving) locates while traveling cross country in a UPS or Fedx truck with no antenna connected at all......
 
Lots of comments here that apply to the old 121.5 ELT?s, and not the new 406 ELT?s. The g switch is now much more sensitive to g?s in multiple axis, therefore better at detecting crashes.

The old 121.5 frequencies are no longer monitored by satellite, or anyone other than by coincidence.
 
I would definitely recommend a 406 ELT that takes a GPS input to provide lat/Lon to the satellite. It gets the rescuers directly to you.
This is a bit misleading, as the GPS has to be active when the ELT activates in order to get the GPS location included. So now you have to worry about where your GPS antenna is mounted. On the roof, pointing at the ground after a turnover? No GPS signal. On the belly, where it can't get a signal *without* a turnover? Maybe not ideal. Unless the GPS is powered and locked in before you go down, it won't necessarily help.
 
Not true

Lots of comments here that apply to the old 121.5 ELT’s, and not the new 406 ELT’s. The g switch is now much more sensitive to g’s in multiple axis, therefore better at detecting crashes.

The old 121.5 frequencies are no longer monitored by satellite, or anyone other than by coincidence.

Although not officially monitored there are thousands of airliners and GA aircraft that monitor 121.5 every day...
 
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This is a bit misleading, as the GPS has to be active when the ELT activates in order to get the GPS location included. So now you have to worry about where your GPS antenna is mounted. On the roof, pointing at the ground after a turnover? No GPS signal. On the belly, where it can't get a signal *without* a turnover? Maybe not ideal. Unless the GPS is powered and locked in before you go down, it won't necessarily help.

If the ELT gets activated, it will transmit the last GPS position that it was issued.
If I understand correctly, the +12V connection that some ELT's have is part of that system (buffering the GPS position), and that once activation occurs the last issued position becomes what is encoded on the ELT transmission (the 12V is no longer needed).
So even if the GPS is no longer functioning there will still be an encoded position that would provide a much higher level of position detail than without.
 
MEOSAR compatible?

At OSH last year I went to a talk from a NASA guy that leads the Search and Rescue stuff. He talked basically the whole time about their new satellite constellation MEOSAR which is in medium earth orbit.

At that time I recall he said there was 1 PLB manufacturer that was producing a compatible transmitter. Have the ELT companies caught up yet?

NASA MEOSAR info
 
If the ELT gets activated, it will transmit the last GPS position that it was issued.
If I understand correctly, the +12V connection that some ELT's have is part of that system (buffering the GPS position), and that once activation occurs the last issued position becomes what is encoded on the ELT transmission (the 12V is no longer needed).
So even if the GPS is no longer functioning there will still be an encoded position that would provide a much higher level of position detail than without.
So the GPS is powered full-time during flight, even when not needed? Interesting. That's news to me.
 
So the GPS is powered full-time during flight, even when not needed? Interesting. That's news to me.

Some ELT?s use internal GPS and others use data from your GPS navigator. The answer to your question is yes, in both cases.
 
At OSH last year I went to a talk from a NASA guy that leads the Search and Rescue stuff. He talked basically the whole time about their new satellite constellation MEOSAR which is in medium earth orbit.

At that time I recall he said there was 1 PLB manufacturer that was producing a compatible transmitter. Have the ELT companies caught up yet?

NASA MEOSAR info
The MEOSARs monitor 406, so not sure what he was talking about, unless it was 2nd gen ELTs (ED-62B / DO-204B). Those would be rare, because (TTBOMK) there are no labs currently certified to test to C/S T.018. 2nd gen ELTs have more sophisticated g-sensor requirements and transmission parameters. (the NASA crash tests I mentioned earlier supported the ED-62B working group activities related to g-sensor specifications and installation guidance.)

The MEOSARS provide a much faster ELT activation detection due to the number of satellites. That is a very good thing, especially if the plane is burning.
 
Scott is correct. Ok, here are the details. All 406mhz ELT?s are qualified to TSO-C126, and by reference to RTCA DO-204. DO-204 says that the manufacturer of the ELT MAY provide aircraft power to the ELT and allows for the insertion of location data (lat/Lon) in the 406 transmission. The ELT manufacturer may obtain the GPS data from an internal GPS or an external GPS.

From a practical standpoint if the ELT uses GPS data, it has to either actively monitor the GPS data input or operate the internal GPS, both of which require power. The GPS data is captured live for transmission of the last known location after the crash event. If the ELT doesn?t capture and retain the GPS data live, it may not have GPS data to transmit after the crash due to crash damage to the GPS antenna, or external GPS source and connections.

Therefore, if you have an ELT with GPS it does receive power from the aircraft. If there is no GPS, power from the aircraft may not be required.
Otherwise, the ELT transmit functions are powered strictly from the battery.
 
One needs to be somewhat careful in interpreting the "powered by the aircraft" statement. The GPS input typically is not powered by the aircraft in ELTs designed for our non-air-carrier aircraft. Most of them use the little bit of power in the RS232 data signal to write the last GPS position into a non-volatile memory device inside the ELT; the contents of that memory device are accessed once the ELT powers up via its G-switch, remote control panel or the "on" position of the switch on the unit itself.

Some ELT's use aircraft power or dedicated batteries in the remote control panel to power the LED indicator on the remote control panel.

Having GPS data encoded on the first 406 transmission is great but it's not the be-all and end-all - it's an enhancement. We should remember the area of position uncertainty using Doppler location on the raw 406MHz signal is considerably smaller than what it was when 121.5MHz was being monitored by satellites.
 
I have read the threads and AOPA/FAA stuff. Still questions :
1- Is a PLB acceptable or not ?
From an Australian point of view, a PLB is acceptable, if
  • It is portable (funny that) and
  • It is an EPIRB that meets AS/NZS 4280.1:2003, or:
  • It is a PLB that meets AS/NZS 4280.2:2003, or:
  • It is approved by the FAA IAW TSO-C91a and operates on 121.5 and 406, or,
  • CAsA determines it performs to one of the above standards...
  • And (irrespective of type), it must be registered with AMSA

For our ops down here, CAR 252A is the approving regulation (With CAO 20.11 mandating the AMSA registration) and to that end I use a GME MT410G in a pouch in my survival vest, not a fixed ELT.
 
So the other day I heard that the new Apple watches if involved in a hard crash will alert authorities just like a ETL will. So it begs the question can an Apple Watch be used as an ELT?
 
Although not officially monitored there are thousands of airliners and GA aircraft that monitor 121.5 every day...

True, monitored, but without satellites to aid in locating the signal source no one really knows where to search.
NOAA says initial search area would be in excess of 500 sq miles. The primary search capabilities are from CAP flying with DF equipment triangulating from multiple aircraft, if the ELT last long enough.
 
So the other day I heard that the new Apple watches if involved in a hard crash will alert authorities just like a ETL will. So it begs the question can an Apple Watch be used as an ELT?

In the US, there is an FAA requirement for aircraft with two or more seats to have an attached ELT that meets TSO-C91A or TSO-C126. If I were not tired and ready for bed, I would look up and link the reference.

Start reading the requirements of 91.207 to see part of the requirement.
 
In the US, there is an FAA requirement for aircraft with two or more seats to have an attached ELT that meets TSO-C91A or TSO-C126. If I were not tired and ready for bed, I would look up and link the reference.

Start reading the requirements of 91.207 to see part of the requirement.

Totally understand that but there?s been a lot of talk of plbs being substituted and the subsequent interpretation of that rule (by many) allowing plb to be used. Some say yes some say no. The reason many say no to PLB use under the rule is because it doesn?t self trigger in a crash. An Apple Watch will self trigger in a crash. So could it get certified as a
ELT ? Should it be certified as a ELT? It?s a question and it?s a topic for discussion as to wether options like this SHOULD be available.
 
Totally understand that but there?s been a lot of talk of plbs being substituted and the subsequent interpretation of that rule (by many) allowing plb to be used. Some say yes some say no. The reason many say no to PLB use under the rule is because it doesn?t self trigger in a crash. An Apple Watch will self trigger in a crash. So could it get certified as a
ELT ? Should it be certified as a ELT? It?s a question and it?s a topic for discussion as to wether options like this SHOULD be available.

"If wishes was fishes"....
 
ELT Required

Totally understand that but there’s been a lot of talk of plbs being substituted and the subsequent interpretation of that rule (by many) allowing plb to be used. Some say yes some say no. The reason many say no to PLB use under the rule is because it doesn’t self trigger in a crash. An Apple Watch will self trigger in a crash. So could it get certified as a
ELT ? Should it be certified as a ELT? It’s a question and it’s a topic for discussion as to wether options like this SHOULD be available.

An Apple Watch only communicates via Cellular and WiFi. This does not meet the requirements for an ELT to broadcast on the 121.5 or 406 MHz SAR frequencies.

Note that per FAR 14 CFR 91.207, "approved" ELT's are required by all U.S. Civil Registered Airplanes with more than 1 seat. Approved means manufactured to TSO-C91A requirements.

AOPA's ELT discussion: https://www.aopa.org/advocacy/aircraft/aircraft-operations/emergency-locator-transmitters

Skylor
 
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Definition of 2 or more seats ?

RV6 flyer offered that a ? g switch activated ELT? is required for 2 or more seats. Can any of you DAR/FAA folks tell me if a tandem aircraft (-4, Rocket,-8) with ONLY a PILOT SEAT avoid this requirement. Ie, what is the definition of a seat ?
 
RV6 flyer offered that a ? g switch activated ELT? is required for 2 or more seats. Can any of you DAR/FAA folks tell me if a tandem aircraft (-4, Rocket,-8) with ONLY a PILOT SEAT avoid this requirement. Ie, what is the definition of a seat ?

I believe the standard way of removing a seat is to remove the seat belt. No seat belt, no seat, in the eyes of the FAA. I suppose you could also placard it, ?no passengers?.
 
Thanks BOB

Great news! I will install an ELT after Phase 1 if PAX line up for rides. I fly alone and will have a 200 lb capacity baggage area behind my seat LOL .
 
Great news! I will install an ELT after Phase 1 if PAX line up for rides. I fly alone and will have a 200 lb capacity baggage area behind my seat LOL .

I like the way you think. However, if you certify your plane as a single seater, I am curious what you have to do later on to add the second seat with both the FAA and your insurance company.

When I was flying my -9 as a three seater (very young son in the baggage compartment) my insurance company would not have covered him in the event of an accident because they were only covering a two seat airplane, not a three seater.
 
I have an ACK 406. About two week ago my wife was cleaning the cockpit and pushed the on button while cleaning the panel buttons. We were in the hanger.
In less than 15 minutes she got a call from a Lt. Col. from the Air Force Rescue Coordination Center, she handed me the phone and I explained to situation the situation. My phone was in my truck with a message to call him back. She was my emergency contact. He said that they saw the location of the signal was in a hanger area. I thanked them for the attention. I was impressed!
 
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