Accidental activation of ELT

Lycosaurus

Lycosaurus

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We invited a small child (2 yrs) and his parents for a familiarization of the aircraft. We pulled the 2-place aircraft out of the hangar, and letting them sit in it. After some time, the couple and the child left, and the aircraft was returned to the hangar. As we were about to leave the airport grounds, we overheard that an ELT was activated on the field, so I thought it best to go back and double check the state of the aircraft. With my portable aviation radio, I detected a 121.5 MHz emission from what seemed to be coming from our hangar. I turned off and removed the ELT and called the air navigation authority letting them know we might be responsible for the alert (121.5 MHz ELT). This was followed up with a Search and Rescue callback to us, double checking there were no more ELT signals on the field (checked with my portable transceiver), as well as confirming the event times. They decided to terminate the alert.

It would seem that the likely scenario is that the child might have pressed the remote ELT activation button and set off the transmission. In retrospect I should have checked for an ELT signal before putting the aircraft away.

I have the ACK-01, but I am now seriously looking at a 406 MHz replacement.
 
The 406 unit won't be immune to this. Our ACK E-04 unit has gone off twice with no cause, once about a year ago, once a few weeks ago. USAF S&R calls were prompt, and they were not worried about the accidental activations. It is a bit concerning to me because the plane does fly to remote locations without much cell service, so at some point I can see this resulting in a bigger issue.
 
I got in a plane to start the pre-flight when I noticed the little red light was blinking. So I turned it off. No calls, no S&R planes flying over. I had no idea how long it had been activated.

It was a 121.5 unit.
 
When speaking with SAR, they recommended I upgrade to a 406 MHz
ELT. Had I had a 406, then they would have been able to contact me and this could have been resolved much sooner.

True, the trigger mechanisms are the same (especially in my case) for both types of ELT. Oh well, additional AMU to upgrade, plus the additional cost of the battery. Presently the batteries cost me $10 per year.

The reason that I carry and ELT in the first place is not for safety, for legislative reasons. Somebody thinks ELT still have value even if I have ADS-B Diversity (ground and satellite tracking), APRS (amateur radio live breadcrumbs), and PLB (manual activation). The ADS-B is tracked by satellite via Aireon which also provides the tracking data to SAR in case of an event (an event can be triggered by software monitoring the ADS-B transmissions).

Maybe one day we can have ELT as an optionally required equipment.
 
The TSO governing the 406 ELTs requires the installation of a beeper and/or flasher to tell the pilot that the ELT is on. If that stuff is not installed, the whole installation isn't legal. The beeper is in the kit, along with the remote, and the remote also flashes at the pilot.

But of course, since I often found 406's installed in the same skin-mounted location as the old 121.5s, I can see the installers ignoring the instructions. The 406 is required to be mounted to primary structure, which requires the design and fabrication and installation of a new bracket. Too much work, I guess. The ELT is supposed to be rigid enough that it doesn't move more than 0.1 inch in any direction under a 100-pound pull. It's to make sure the thing has the best chance of actuating instead of getting flung around and torn off and thrown out.

From the Artex 406 installation manual:

upload_2022-7-12_16-35-5.png
 
Where are you located? We were on a flight from north central Oregon to Dallas and hear an ELT. Was about to mention it to ATC but then it went away. I believe we were over NW Colorado when we heard it at FL410 or later at FL450. Later someone started meowing on 121.5 and we quit monitoring.
 
Plano Pilot said:
Where are you located? We were on a flight from north central Oregon to Dallas and hear an ELT.
Click to expand...

Nah, we're way way north-east of you :)

ELT is mounted on a primary structure... that is not the issue in this case anyway since it was activated by the remote unit. People familiar with the ACK-01 will recognize the remote unit with a button for activation and an LED for indication. The LED did not flash (its battery was fresh as of last year), don't know why. Will need to troubleshoot.

I was considering updating this setup to an ACK-04 which is a 406 MHz unit, however after reading many reviews describing false activations (from 2017 onwards, even as recent as 2022), I am looking for something else. It seems these units may suffer from electro magnetic compatibility and ACK has an inline filter on the for the coax to help with that. The inline filter does not seem to be the final solution... unless someone here has more information on this. My local avionics guys say to stay away from the ACK-04. Too bad, because it would be a much easier upgrade (both installation time/effort and acquisition dollars).
 
I'm surprised anyone knew or cared about a 121.5 beacon being active. I sat in the Alaska RCC while a 121.5 beacon was going off. They had an idea of the area and unless there was some other action taken to substantiate an emergency, like an overdue airplane, they dismissed it and went about their day.
Dan Thomas said:
The TSO governing the 406 ELTs requires the installation of a beeper and/or flasher to tell the pilot that the ELT is on. If that stuff is not installed, the whole installation isn't legal. The beeper is in the kit, along with the remote, and the remote also flashes at the pilot.

But of course, since I often found 406's installed in the same skin-mounted location as the old 121.5s, I can see the installers ignoring the instructions. The 406 is required to be mounted to primary structure, which requires the design and fabrication and installation of a new bracket. Too much work, I guess. The ELT is supposed to be rigid enough that it doesn't move more than 0.1 inch in any direction under a 100-pound pull. It's to make sure the thing has the best chance of actuating instead of getting flung around and torn off and thrown out.

From the Artex 406 installation manual:

View attachment 108592
Click to expand...

E-01s had the same panel monitor. And in the later years 121.5 ELTs used the same installation instructions.
 
Lycosaurus said:
The reason that I carry and ELT in the first place is not for safety, for legislative reasons. Somebody thinks ELT still have value even if I have ADS-B Diversity (ground and satellite tracking), APRS (amateur radio live breadcrumbs), and PLB (manual activation). The ADS-B is tracked by satellite via Aireon which also provides the tracking data to SAR in case of an event (an event can be triggered by software monitoring the ADS-B transmissions).

Maybe one day we can have ELT as an optionally required equipment.
Click to expand...

How long before the ADS-B system realizes you are no longer in the air? And that you did not just land?

Who is watching your APRS track?

You crash, are unconscious, who activates your PLB?
 
Pinecone said:
How long before the ADS-B system realizes you are no longer in the air? And that you did not just land?
1090 MHz ADS-B is captured by Aireon Satellites. They have software that helps determine if you are in a crash situation.
Also, even if you do not have antenna diversity, you have a very good chance of being found with it: https://canadianaviator.com/ads-b-found-crash-site-in-quebec/

Who is watching your APRS track?
In Canada we must file a flight plan or a flight itinerary. Flight plans expire on time and are managed by the government, while the flight itinerary is handled by a family member, friend etc, with routing and destination/time expected. You can give them the APRS info to track you, along with the ADS-B info as well, which will be relayed

You crash, are unconscious, who activates your PLB?
PLB covers other situations such as when you hit water. The aircraft will sink, while (hopefully) you will still be able extricate yourself and your survival equipment and have a mechanism for summoning help to a precise location.
Click to expand...

Replies embedded, in red.
 
EdFred said:
...which accidentally get set off as well. Then you get a call from the USAF. Ask me how I know. :D
Click to expand...

I hear (from an airman on the telephone) that an ACK-04 antenna (with a slight bend at the end so as to allow one to mount it horizontally inside the fiberglass tail surface intersection fairing of an all metal experimental aircraft) can be seen by the satellites inside a metal hangar with the door closed. :rolleyes:
 
They knew I was inside my hangar last time my 406 was set off.

One of the strategies a panel switch provides is activating a beacon ahead of impact if a crash event is probable.
 
Lycosaurus said:
Replies embedded, in red.
Click to expand...

How long before the ADS-B system realizes you are no longer in the air? And that you did not just land?
1090 MHz ADS-B is captured by Aireon Satellites. They have software that helps determine if you are in a crash situation.
Also, even if you do not have antenna diversity, you have a very good chance of being found with it: https://canadianaviator.com/ads-b-found-crash-site-in-quebec/ In the US we are not required to have antenna diversity, yet. But even so, you are relying on the system to realize you crashed.

Who is watching your APRS track?
In Canada we must file a flight plan or a flight itinerary. Flight plans expire on time and are managed by the government, while the flight itinerary is handled by a family member, friend etc, with routing and destination/time expected. You can give them the APRS info to track you, along with the ADS-B info as well, which will be relayed Most posters are not in Canada. But interesting that they track APRS data. How do they get it? And again, you are waiting for them to figure out you crashed.

You crash, are unconscious, who activates your PLB?
PLB covers other situations such as when you hit water. The aircraft will sink, while (hopefully) you will still be able extricate yourself and your survival equipment and have a mechanism for summoning help to a precise location. And yes, it is just another way of letting people know, so why not add an ELT to the mix?
 
I don't know if this has already been mentioned, but if the ELT activation resulted in cumulative time of battery usage to exceed either one hour or 50% of battery life, replacing or recharging the ELT battery is required by 14 CFR 91.207(c).

https://www.law.cornell.edu/cfr/text/14/91.207
 
Palmpilot said:
I don't know if this has already been mentioned, but if the ELT activation resulted in cumulative time of battery usage to exceed either one hour or 50% of battery life, replacing or recharging the ELT battery is required by 14 CFR 91.207(c).

https://www.law.cornell.edu/cfr/text/14/91.207
Click to expand...
Some 406 ELTs have a limit on number of activations. The ELT tracks them and starts annoying you with warnings when you've used up your number. So don't go testing the thing before every flight or something.
 
Dan Thomas said:
Some 406 ELTs have a limit on number of activations. The ELT tracks them and starts annoying you with warnings when you've used up your number. So don't go testing the thing before every flight or something.
Click to expand...

Whaaaaa? which ones are those? I had an artex randomly go off (ahem, multiple times, to the chagrin of NOAA SARSAT) before I RMA'ed it under warranty for a new one. I would be unhappy to learn it turns into a pumpkin after X activations -- what is the rationale there? "We've detected this is your 11th crash. please insert credit card with your undamaged arm to alert search and rescue." ???
 
Self-testing is in the instructions for my 406 ELTs. ACK says to test every three months and Artex says once a month. I've never had either one flash a low battery code.
 
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