Inadvertant ELT transmission

[Richard]

Just got home to receive a call from the county sherriff tonight. I'm talking to then right now. Turns out all that's gonna' happen is I have to get a new batt because it's been sending for a couple hours. The sherf could fine me to recoup the cost of their efforts but because it was a volunteer who responded it's his call and he says he wont send the bill. Nice guy. He's real happy he happened to be in the area at the time he received the call from the CHP helicopter who had already launched. He almost decided to go to bed and make the trip tomorrow. In that case, because he's the self-described "ELT guy" for the area he would have had to get out of bed for my blunder.

This volunteer responds to all transmissions from Hollister in the north to Ventura in the south and east to Tehachapi. He says he responded to 367 ELTs last year, 6-8 were actual emergencies. The rest were caused by hard landings, changing out the batt, or, as in my case, inadvertant transmission after completing an annual inspection. He says he has gone to people's homes to find their old batt is transmitting. In that case he says more often then not it's usually around midnight when he's pounding on someone's door after he gets a good DF on the source. Of course, by then all the agencies have been notified and are looking for a nonexisting accident. Evidently, not everyone has the DF equipment so they could be searching for a long time.

Now I have to figure out a way to keep this from happening again. ELT-OFF is part of the post flight check but today there was no flight involved. Maybe a post inspection check list?

 

[Tom-D]

PLace your radio in 121.5 and check for a transmition before shut down.

 

[Richard]

PLace your radio in 121.5 and check for a transmition before shut down.

Tom, I knew you wouldn't let me down. But we weren't flying today, not even cranking the engine. All we did today was check rigging and required lubrication. I moved the ELT to a new location because someone previously had installed it smack dab in the center of aft baggage area. Ironic that I moved it so it wouldn't be in the way but ended up setting it off. It's an exposed 3 postion switch with no indicator light like the EPIRBs I'm used to.

 

[Ed Guthrie]

Tom, I knew you wouldn't let me down. But we weren't flying today, not even cranking the engine. All we did today was check rigging and required lubrication. I moved the ELT to a new location because someone previously had installed it smack dab in the center of aft baggage area. Ironic that I moved it so it wouldn't be in the way but ended up setting it off. It's an exposed 3 postion switch with no indicator light like the EPIRBs I'm used to.

In that case just check 121.5 on shut-down or any time you've been working/bungling around in the neighborhood of the ELT. Handhelds are great for this. Tune up 121.5 as you leave the hanger/tie-down area just to confirm that you aren't leaving a present for someone.

BTW, the DF steer gear isn't all that exotic. A piece of 1"x1"x~3' pine with an antenna stretched across it.

 

[Jeff Oslick]

Richard,

You may also want to check that the "G" switch on the ELT isn't going bad. We just replaced our ELT with a new one when the IA determined the switch wasn't reliable. I'd imagine they can fail by becoming too sensitive as well as by not be sensitive enough.

Jeff

 

[Bonanza]

The way to tell if it is you that is transmitting is to very briefly switch on your ELT. If you hear a second "whoop whoop" it is not you. If you just hear the original one then you need to investigate if it is yours that is going off.
Stephen.

 

[Flash]

National search and rescue shows that 99% of the 121.5 ELT's are false alarms. Truth is if they were so good at finding people they wouldn't be trying to get rid of them. The new ELT's have an indicator in the cockpit and they don't go off by accident like the old ELT's anyway.

 

[JoeSelch]

The new ELT's have an indicator in the cockpit and they don't go off by accident like the old ELT's anyway.

If I'm in an accident, I sure as heck want my ELT going off. That's why I'm sticking with the old 121.5!

 

[Doggtyred]

If I'm in an accident, I sure as heck want my ELT going off. That's why I'm sticking with the old 121.5!

Thats great.. but the satellites are no longer listening on 121.5.. you have to HOPE someone in range is maintaining a listening watch.

The new 406 elt's do a burst WITH your coordinates, WITH your ID info, WITH much greater power but its not a "trackable" signal in the sense the old 121.5 devices were... but geez.. if its transmitting your last gps coordinates with each burst that cuts down on the search time dramatically..

Hoping to be found nowadays with a 121.5 is akin to wishing on a star, or screaming help in an empty, vacant theater. Sure.. you are making noise.. but nobody is listening.

 

[weilke]

The new 406 elt's do a burst WITH your coordinates, WITH your ID info, WITH much greater power but its not a "trackable" signal in the sense the old 121.5 devices were... but geez.. if its transmitting your last gps coordinates with each burst that cuts down on the search time dramatically.

Few 406 ELTs installed in light aircraft seem to be harnessed to the ships GPS system. At this point, the cost to do so is considerable.

They are predominantly located by satellite, there is a geostationary satellite that picks up every transmission and forwards the ID and if available GPS info. There are a couple of lower orbit sats that use time of flight ranging to get a fix. For a number of technical reasons, those fixes are a lot more precise than the 121.5 fixes (not as good as a fix with GPS coordinates, but the search area is only a fraction of what the 121.5 system used to spit out).

The 406 signal can apparently be tracked with digital DF equipment. Not all SAR aircraft and few ground units have the new DF systems yet. The 121.5 beacon in the new ELTs has very minimal power 150mW or so, it is intended for localization at very short distance.

 

[Clark1961]

Hoping to be found nowadays with a 121.5 is akin to wishing on a star, or screaming help in an empty, vacant theater. Sure.. you are making noise.. but nobody is listening.

Try something: transmit on 121.5 and wait for a resonse...you won't have to wait long...lots of folks are listening, just not the SARSAT folks...

 

[JoeSelch]

Thats great.. but the satellites are no longer listening on 121.5.. you have to HOPE someone in range is maintaining a listening watch.

Yeah, I know that.
I was just messin' with Flash - a play on words. Apparently, a very subtle play.

 

[Steve]

Have they changed the intercept procedure since 9/11?

Just curious.

Hoping to be found nowadays with a 121.5 is akin to wishing on a star, or screaming help in an empty, vacant theater. Sure.. you are making noise.. but nobody is listening.

 

[ScottM]

Hoping to be found nowadays with a 121.5 is akin to wishing on a star, or screaming help in an empty, vacant theater. Sure.. you are making noise.. but nobody is listening.

Lots are listening. While I agree that geographic issues will affect who can hear you, there are still terrestrial and airborne stations on a listening watch. How many of those have DF capability.....well, how many had it to begin with?

 

[weilke]

How many of those have DF capability.....well, how many had it to begin with?

Airports used to have DF equipment, so did flight service stations.

 

[Clark1961]

Yeah, I know that.
I was just messin' with Flash - a play on words. Apparently, a very subtle play.

While you may be in mid-week form others are ready for the week end (or never bothered starting...)

Now the question for the wordsmiths and grammarians, how many possible meanings can be pulled from "they don't go off by accident" ???

 

[sba55]

Lots are listening. While I agree that geographic issues will affect who can hear you, there are still terrestrial and airborne stations on a listening watch. How many of those have DF capability.....well, how many had it to begin with?

Aren't we all supposed to monitor 121.5 whenever possible or has that changed?

 

[poadeleted20]

Aren't we all supposed to monitor 121.5 whenever possible

Yes, we are. And given the number of responses when someone accidently transmits on 121.5, it would appear a lot of us are monitoring.

 

[4CornerFlyer]

Aren't we all supposed to monitor 121.5 whenever possible or has that changed?

NOTAM 4/4386 is still in effect:
ALL AIRCRAFT OPERATING IN UNITED STATES NATIONAL AIRSPACE, IF CAPABLE, SHALL MAINTAIN A LISTENING WATCH ON VHF GUARD 121.5 OR UHF 243.0.

Jon

 

[SCCutler]

Yes, we are. And given the number of responses when someone accidently transmits on 121.5, it would appear a lot of us are monitoring.

I typically do.

 

[Skip Miller]

The new 406 elt's do a burst WITH your coordinates, WITH your ID info, WITH much greater power but its not a "trackable" signal in the sense the old 121.5 devices were... but geez.. if its transmitting your last gps coordinates with each burst that cuts down on the search time dramatically..

Hoping to be found nowadays with a 121.5 is akin to wishing on a star, or screaming help in an empty, vacant theater. Sure.. you are making noise.. but nobody is listening.

Wait a minute! The 406 elt's are no guarantee of being found with 406 technology alone.

I have a 406 PLB. Aside from the issue of turning the thing on before/during/after a crash, the PLB will broadcast your GPS location.... if it has it. Should your plane slide under a dense tree, the odds of your 406 seeing enough sky to get a GPS fix are pretty low. That's why the 406 sat technology can determine an approximate fix using doppler shift magic. That approximate location will guide the rescue troops to an area where they should be able to pick up the 121.5 signal.

What 121.5 signal?

The PLB and presumably the airframe mounted 406 ELTs also broadcast a 121.5 signal to allow CAP to home in on you. So you better continue to hope those with 121.5 ears are listening to you! 406 merely gets them close, unless you are lucky enough to get a good GPS fix to broadcast.

The only thing that has gone down permanently is the satellite reception of the 121.5 signal.

-Skip

 

[ClimbnSink]

I thought that if you moved/replaced an ELT you had to add the remote panel switch/indicator light? I could be wrong on that, but if you are a stickler might want to look into it.

Tom, I knew you wouldn't let me down. But we weren't flying today, not even cranking the engine. All we did today was check rigging and required lubrication. I moved the ELT to a new location because someone previously had installed it smack dab in the center of aft baggage area. Ironic that I moved it so it wouldn't be in the way but ended up setting it off. It's an exposed 3 postion switch with no indicator light like the EPIRBs I'm used to.

 

[Ghery]

Nice thing about Gnd at OLM being on 121.6, and aircraft receivers not being all "that" selective. You'll hear a nearby ELT when monitoring Gnd. I have. And if it was my ELT it would be lifting the headset off my ears.