406 ELTs

[pmanton]

A bit ago I griped about battery cost for my 406 ELT. There was some disparaging discussion about how useless the ELTs are.

Well I was just installing my ELT under the front seat with my new battery, when somehow I triggered it. It was on for perhaps a minute before I got it back out and turned it off. I had just turned the switch off when my phone rang. Air Sea Rescue in FL calling to check up. I told him what happened and all was well. He had my exact location.

Had I not answered the phone there would have been a helicopter along shortly.

I'm a real believer now.

 

[4CornerFlyer]

The issue isn't that the ELT doesn't work when you accidentally hit the on switch. It is that they do not reliably activate in a crash. Even if they do the signal may be blocked by the position of the crashed plane, or by the surrounding terrain or by being underwater. There are ways to mitigate these problems. The point is you should not rely on any ELT to activate and transmit after a crash without any crew action. While that often does happen, in a substantial number of times it does not.
Jon

 

[brcase]

What I have heard from the people that actually go to the crash sites is that especially with 406ELT's they do generally activate if the crash is survivable. That also has the advantage now with Panel Mounted activation switches that if survivable even if it doesn't go off automatically, it can usually easily be triggered manually.

Having them go off even on un-survivable events may not be of use to the occupants but can be very useful for search crews or family in reducing the time and cost is locate the wreckage and remains.

Brian

 

[Silvaire]

One of the problems is the external antenna getting ripped off in the crash. If you have an old rag and tube aircraft you can mount the antenna within the fuselage structure aft of the baggage area where it will be better protected. In a scenario such as an engine failure in a remote area you're just going to switch the thing on before the crash so they will have at least an initial fix on you even if you were to lose the antenna.

 

[Bell206]

with 406ELT's they do generally activate if the crash is survivable

FYI: thats been the big difference between the old ELTs and the 406 ELTs. Some reports put it at 80%+ on the activation rate vs the sub-25% rate of the old ELTs. Unfortunately when the 406s first came out there was some bad press on their activation rate but it was mainly due to installation issues as the 406 requires a mounting surface deflection check that a number of installers failed to perform. In other words they simply installed the 406 in place of the existing 121.5 ELT. However, when installed correctly the 406 ELT has a very good record of activating when needed. And while there has been an increased level of false alerts with the 406 ELTs they are easily dealt with as noted by the OP. Prior to that each 121.5 ELT alert had to be physically looked for once it was reported vs a simple phone call within minutes of the signal being received at the monitor station.

 

[bflynn]

They are getting better. The 406 ELTs have practically put CAP out of the search and rescue business. Or maybe that was just that the govt quit listening for 121.5 elts.

off field landing, turn it on before you land. Even if the antenna gets ripped off later, your location will already be tagged.

 

[Stewartb]

A few years ago a C-182 crashed into a shallow lake in north central Alaska. The airplane nosed over so the antenna was submerged in water and totally blocked by the fuselage. The occupants survived the crash and were picked up about an hour later after a nearby private operator had been given the coordinates by RCC.

Pmanton, Same experience. Twice. Once outdoors at Lake Hood and once inside my hangar at Wolf Lake. Both times the duty officer knew precisely where I was when he called and was very friendly when I apologized for my inadvertent beacon.

 

[Domenick]

https://iflyamerica.org/elt.asp

Most 406 MHz ELTs are dual 121.5/406 MHz units. I imagine that is to ensure owners/pilots can test the units with current aviation radios.

In regards to testing, the article at the link above states, "If the selection to the 'ON' position is minimized to 30 seconds or less, there is sufficient time protection to prevent crossing the 50-second time threshold for activating the 406 MHz locator signal."

And this on the TEST function, "Activating the 'ON' function, which is part of the remote control panel rather than gaining access to the combined ELT and activating the 'TEST' function, has led to violations..."

Do all 406 MHz ELTs have a TEST function? If the TEST function does not activate the 406 MHz portion of the ELT of what use is it? Or does the TEST function include some sort of "Ignore me, I'm a test" flag in the 406 MHz data?

If true that there is a 50 second 406 MHz activation delay, then you better activate your ELT more than 50 seconds before impact in case it is destroyed or the antenna lost.

 

[Dan Thomas]

As Bell206 says, too many 406s have been just mounted to the existing 121.5 ELT location. There are explicit instructions in the 406 installation manuals prohibiting that. The mount must not move more than 0.1 inch when a 100-pound load is applied to to the ELT in any direction. The antenna has to withstand a large acceleration, too, so just screwing it to the fuselage's .025" skin isn't going to keep it upright unless there's some reinforcement. There is another requirement that the antenna be installed in the same section of fuselage, with no production breaks between it and the ELT, or a steel cable must be installed between the ELT mount and antenna mount to prevent separation ripping the antenna cable apart. I found numerous 406s improperly installed, sometimes unregistered, because doing it right meant more time and money. Or the installer simply didn't read the manual. Why bother installing it at all if it isn't going to have the best chance of bringing help? Might as well save the money and stick with your ancient 121.5.

An ELT with internal GPS can take some time to find the GPS location and blip it off to a satellite. That's why the 30-second test window. Even non-GPS ELTs take time to boot up and fire off the airplanes ident. The 121.5 is for testing and for final homing. There is a regulatory requirement that the ELT be registered with the national SAR authorities, too.

An ELT antenna inside a steel cage is going to emit an attenuated signal. It has a ground plane surrounding it, which is not as per design. Some ELTs will trigger a test fault warning with that sort of stuff. I had problems with a 406 in a Cessna 400, where the ELT and antennal were mounted in a tight spot aft of the baggage area, and the antenna (inside the composite fuselage) was curled over because of the internal radius of the fuselage there. I had to fool with it, moving the antenna whip around a bit, to find a position where it wouldn't do that. Then tape it in place. Factory install, that.

 

[Bell206]

Most 406 MHz ELTs are dual 121.5/406 MHz units. I imagine that is to ensure owners/pilots can test the units with current aviation radios.

A couple FYIs: All TSO126 406 ELTs are dual 121.5/406. The 121.5 was retained to allow local airborne assets to find the aircraft once the satellite data was received. And actually in most ELT OEM procedures they recommend to use an AM radio vs the aircraft radio to check the 121.5 signal.

Do all 406 MHz ELTs have a TEST function? If the TEST function does not activate the 406 MHz portion of the ELT of what use is it? Or does the TEST function include some sort of "Ignore me, I'm a test" flag in the 406 MHz data?

Yes, all 406s have a self-test function which is recommended to be done monthly. Once it is performed there will be a visual and/or aural reply of the self-test results. If any other method is used to test the 406 ELT it will start transmitting in real time. The self-test software tests all the critical items without transmitting (edit: no sat xmit but a 2 sweep 121.5 xmit as part of self-test) but those test instructions must be followed. There are separate annual performance tests that do check transmit signal strength and are required by a few countries like Canada. Regardless even with limited data received by the satellite it is enough to narrow down a search area dramatically. Egypt 804 accident was a prime example.

 

[Clip4]

A bit ago I griped about battery cost for my 406 ELT. There was some disparaging discussion about how useless the ELTs are.

Well I was just installing my ELT under the front seat with my new battery, when somehow I triggered it. It was on for perhaps a minute before I got it back out and turned it off. I had just turned the switch off when my phone rang. Air Sea Rescue in FL calling to check up. I told him what happened and all was well. He had my exact location.

Had I not answered the phone there would have been a helicopter along shortly.

I'm a real believer now.

You have some very unrealistic expectations. You are not accounting for the ELT failure rate, the real response times for SAR and EMS, the trauma experienced in an aircraft crash and the time to get you to a trauma center.

That’s assuming you aren’t DRT (dead right there).

Don’t get me wrong, for many regions I have flown I would want at least a PLB, but for many operations a mounted ELT is not needed.

 

[Dan Thomas]

You have some very unrealistic expectations. You are not accounting for the ELT failure rate, the real response times for SAR and EMS, the trauma experienced in an aircraft crash and the time to get you to a trauma center.

That’s assuming you aren’t DRT (dead right there).

Don’t get me wrong, for many regions I have flown I would want at least a PLB, but for many operations a mounted ELT is not needed.

Transport Canada once told us that in so many crashes, the occupants survived, perhaps with some injuries, but they succumbed to the injuries or just hypothermia before they could be located and rescued because their ELT wasn't maintained or didn't work (the old ELTs). It must be sad for some of those people to sit there and see the search planes fly by, sometimes for days, and they can't get their attention. They start wishing they'd been better prepared and hadn't cheaped out on equipment.

A PLB is no good if you're too busy to trigger it while going down. Or if you get into IMC and run into the trees or mountainside. Stuff happens quickly, and it's why the PLB has never been approved as a replacement for the ELT.

I foresee a day when we won't have ELTs, but a SPOT-like device that is tracked by satellites. It would need a location signal every five seconds or so instead of the SPOT's long intervals. It would also need to be automatically activated when the airplane starts or takes off, not by the pilot, who will surely forget it. And it would need a dedicated power source. It would eliminate the ELT failure scenario. It wouldn't be affected by post-crash sinking or fire or being violently spread across a rocky mountainside.

 

[asicer]

I foresee a day when we won't have ELTs, but a SPOT-like device that is tracked by satellites. It would need a location signal every five seconds or so instead of the SPOT's long intervals. It would also need to be automatically activated when the airplane starts or takes off, not by the pilot, who will surely forget it. And it would need a dedicated power source. It would eliminate the ELT failure scenario. It wouldn't be affected by post-crash sinking or fire or being violently spread across a rocky mountainside.

That doesn't sound too far from from the Canadian flavor of ADS-B (Aireon).

 

[Clip4]

Transport Canada once told us that in so many crashes, the occupants survived, perhaps with some injuries, but they succumbed to the injuries or just hypothermia before they could be located and rescued because their ELT wasn't maintained or didn't work (the old ELTs). It must be sad for some of those people to sit there and see the search planes fly by, sometimes for days, and they can't get their attention. They start wishing they'd been better prepared and hadn't cheaped out on equipment.

A PLB is no good if you're too busy to trigger it while going down. Or if you get into IMC and run into the trees or mountainside. Stuff happens quickly, and it's why the PLB has never been approved as a replacement for the ELT.

I foresee a day when we won't have ELTs, but a SPOT-like device that is tracked by satellites. It would need a location signal every five seconds or so instead of the SPOT's long intervals. It would also need to be automatically activated when the airplane starts or takes off, not by the pilot, who will surely forget it. And it would need a dedicated power source. It would eliminate the ELT failure scenario. It wouldn't be affected by post-crash sinking or fire or being violently spread across a rocky mountainside.

I have both flown in rural Canada and been treated in a rural hospitals in Canada. A claim of we could have saved them if we could have found them is a bit over a bit over the top.

Many years ago on Lake St Clair, I saved a Canadian citizen in a boating accident in October. Ontario PP did even have a boat on the water and used my boat search for a drowned victim. The immediate aerial search for possible survivor well in Canadian waters was perform by the US Coast Guard helicopters.

I have also seen the volunteer EMS and hospital facilities in Alberta, Saskatchewan, and Manitoba.
Neither is equipped for rescue and treatment of trauma injuries of people in GA aircraft accidents.

Also of the top 9 cause of GA crashes in the US, they all have fatality rates of more than 60% and some them are occurring within 1/2 of the airport.

 

[Dan Thomas]

I have also seen the volunteer EMS and hospital facilities in Alberta, Saskatchewan, and Manitoba.
Neither is equipped for rescue and treatment of trauma injuries of people in GA aircraft accidents.

Of course they're not equipped for that. The military SAR guys are the ones that rappel into a crash site and see what they can do, stabilizing victims and lifting them out. What hospital in New York is equipped to go get crash victims out of upstate NY's remote areas?

Also of the top 9 cause of GA crashes in the US, they all have fatality rates of more than 60% and some them are occurring within 1/2 of the airport.

That leaves nearly 40% survivable crashes. You want to just let them die? And in Canada, even 1/2 mile from the airport can take some time to find. I remember an R-22 crash a few years ago not far from a rural airport that took days to find. No one saw it take off, no one saw it go down. ELT didn't work. Heavy bush around that area.

Once again, I have to post this population density map to make the point that Canada is NOT the US:



Something like 80% of the population lives within 150 miles of the border with the US. That leaves a terrific amount of lonely space to crash in and it's usually fatal no matter what if you don't have an operable ELT. Even if you land the airplane with little or no damage. They just aren't likely to find you, especially if you're not exactly on a filed flight plan track. In BC alone there are something like 100 airplanes that have gone missing and never found. Once in a while someone stumbles on one of them.

I often told people to get on Google Earth and see what's out there in the way of roads or settlements, and see if you want to trust your ancient 121.5 ELT when flying across those areas. In fact, a Mooney, flying from the Okanagan in BC to Edmonton, didn't arrive. Searches turned up nothing at all. The pilot was following the highway, and presumably lost control in cloud in the Rogers Pass and spun in. The wreck was finally discovered ten months later by a medevac helicopter transiting the Pass, with the crew alerted to watch for that airplane. A sharp-eyed EMT spotted something and they went back and found it. It was about 160 yards off the highway. It's 121.5 ELT had broken loose and lost its battery. It worked when the battery was inserted. That's one of the sort of things the 406 was meant to fix. https://copanational.org/tsb-cites-elt-issues-in-2017-mooney-crash/

And it's not just saving lives. It's providing closure for the families. It's minimizing the expense of the search, which can cost a million taxpayer dollars per day.

 

[Clip4]

Of course they're not equipped for that. The military SAR guys are the ones that rappel into a crash site and see what they can do, stabilizing victims and lifting them out. What hospital in New York is equipped to go get crash victims out of upstate NY's remote areas?



That leaves nearly 40% survivable crashes. You want to just let them die? And in Canada, even 1/2 mile from the airport can take some time to find. I remember an R-22 crash a few years ago not far from a rural airport that took days to find. No one saw it take off, no one saw it go down. ELT didn't work. Heavy bush around that area.

Once again, I have to post this population density map to make the point that Canada is NOT the US:

View attachment 105049

Something like 80% of the population lives within 150 miles of the border with the US. That leaves a terrific amount of lonely space to crash in and it's usually fatal no matter what if you don't have an operable ELT. Even if you land the airplane with little or no damage. They just aren't likely to find you, especially if you're not exactly on a filed flight plan track. In BC alone there are something like 100 airplanes that have gone missing and never found. Once in a while someone stumbles on one of them.

I often told people to get on Google Earth and see what's out there in the way of roads or settlements, and see if you want to trust your ancient 121.5 ELT when flying across those areas. In fact, a Mooney, flying from the Okanagan in BC to Edmonton, didn't arrive. Searches turned up nothing at all. The pilot was following the highway, and presumably lost control in cloud in the Rogers Pass and spun in. The wreck was finally discovered ten months later by a medevac helicopter transiting the Pass, with the crew alerted to watch for that airplane. A sharp-eyed EMT spotted something and they went back and found it. It was about 160 yards off the highway. It's 121.5 ELT had broken loose and lost its battery. It worked when the battery was inserted. That's one of the sort of things the 406 was meant to fix. https://copanational.org/tsb-cites-elt-issues-in-2017-mooney-crash/

And it's not just saving lives. It's providing closure for the families. It's minimizing the expense of the search, which can cost a million taxpayer dollars per day.

About 70% of the aircraft crashes in the US are reported by witnesses of the crash and located without a search utilizing an ELT signal. In really isolated areas there are few planes flying in the lower 48 states and a high rate of ELT failures.


In 2019 in the US, there were 987 non fatal crashes and 233 fatal crashes.

The same year the Civil Air Patrol (who does aircraft SAR in the US) reported they saved 117 people. Other missing persons searches are 10-15% of CAP missions. CAP also does hurricane missions. 4 hurricanes landed in the US in 2019 (Barry, Dorian, Imelda and Nestor.)

Also keep in mind the majority of SEL aircraft in the US are still not equipped with 406 ELTs pinging a satellites. AOPA in the US has and continues to argue 406 ELTs not be mandated.

 

[Dan Thomas]

Also keep in mind the majority of SEL aircraft in the US are still not equipped with 406 ELTs pinging a satellites. AOPA in the US has and continues to argue 406 ELTs not be mandated.

COPA in Canada also continues to argue that. It's expensive to get it installed, especially if it's installed properly, which usually requires the fabrication of a mount that is attached to primary structure as per instructions, and not just the skin. I've done a bunch of them. It's actually easier in a tube-and-rag airplane.

Way back in about 2006 Canada came out with a proposed mandate for them. The transport minister at the time shot it back to committee because the law wasn't worded properly or something, and it has never been re-mandated. There was some concern, also, that a mandate would result in a flood of requests for installation that the avionics shops couldn't handle; such work is Specialized Maintenance here. So they came up with a "temporary" exemption that permitted AMEs to do them. If the unit was to be interfaced with onboard GPS for constant position updating, it had to be installed by the avionics folks.

Maybe the mandates will hold off long enough for something truly effective like I mentioned. One cannot rely on witnesses saving your bacon. That's a good way to expire waiting for someone to find you.

Back in the 1970s, as ELTs were just being introduced, a Twin Comanche went down in icing weather between two towns in BC. No ELT of any sort. It skimmed the treetops and then fell nose-first into the forest and the trees closed back over it. The three occupants survived, but with injuries. There was at least three feet of snow in the bush, and none of them could move much. They could hear chainsaws and logging equipment in the distance, so they pounded on the airplane and yelled when there were quiet periods. The loggers reported the sounds to SAR, who could find nothing. One of the occupants wrote their story in the airplane's journey log. They all perished after a few days. Several years later an RCMP pilot, flying that same route, saw something glint as he passed over it, so he turned back and orbited some time before he got another indication. He marked the spot on his map and alerted SAR.

A friend went down in the same area in a blizzard. A rancher, rounding up cattle from the bush, found the airplane several years later. 121.5 ELT failed. The differences between those old ELTs and the new ones is stark. They carry the same designation and that's about it.

Those Twin Comanche guys would have survived had they had a 406. Even if it didn't trigger, they could have switched it on. Stories like this are too common. This is Canada where, in plenty of places, you can get lost on a hike not far from town. This isn't California. Even in CA airplanes go missing in the mountains. It took a year for someone to stumble onto Steve Fossett's crash site.