At the airport preflighting...elt going off?

Skid

Skid

Pre-takeoff checklist
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Skid
Ugh I just started preflighting a 172 and as soon as I turn on the master and avionics I hear a siren going off thru my headset then goes away.

I thought that was strange as none of the radios were on 121.5 so I tuned to 121.5 to see if my suspicions were real and sure enough it's a loud peew peew peew.

Question is though I can't tell if it's me or another plane and the elt cover isn't really removable it seems.

Wat do
 
Do you have a handheld? Take off the handheld antenna and walk up to your plane's ELT antenna with the handheld set to 121.5, it should go from inaudible to very loud if it's you, if it's loud everywhere then tune to 121.6 and repeat, repeat with other aircraft if you're bored. Otherwise go fly and see if you can still hear it when you're not at the airport, if it's always the same loudness, then it's you :)
 
Nope no handheld unfortunately. Is that going to cause issue flying around with it knowingly on for someone or is it w/e
 
Well, it was partially in jest. Really no one is monitoring except other aircraft and if it is yours you may have it bleed over into your radios and cause comm problems for you. But I'd recommend seeing if you can get to it really, I've never seen a 172 that was a problem to get to the ELT. Is it a training plane that was likely to have a hard landing or did it come out of maintenance or anything. I'm assuming it's not a new enough plane/retrofit to have a switch on the panel.(Red switch, says ELT, usually has a blinking light too)
 
Is there a remote switch on the panel? If so, is it on or armed?

Also the switch on most ELTs normally isn't hard to access and the battery is easy to remove.
 
It just had a cover that I pried off. It's still in auto mode, can't really see anything else that would indicate it going off. The fact I heard it over the ground control freq initially makes me think it's mine.

I assume I can recycle it by going to off and back to auto?
 
Yes. Off, check to see if you hear it, then back to auto.
This way you know if its you and if maybe it's broken and just starts transmitting on auto.
 
No dice on the recycle. Looks like it's a no go
 
Did you hear it on "off"? If so then there's a tiny chance it's you, probably someone else nearby... still possibly you but unlikely, I'd go fly. If it went away then came back on "Auto" then it's busted and you have to remember your FAA rules about if you can turn it Off and fly without it or not.
 
turn it off. Reset it. Still going off? you either have a bad battery or a bad sensor.

Are you sure its you?
 
Going from auto to off made no difference but the fact I hear blips of it on ground control has me hesitant. The flight was just for fun to kill time tonight so it's no biggy.

I'm the only one at the airport so I can't bum a hand held to zone in on it. I could prob start snooping in other planes but in all honesty I'm zapped now from the crazy heat and sitting in here troubleshooting.
 
Yea, not you, very close by though. For future reference if it's an airport big enough to have a tower often(at least during business hours) the airport ops guys will have a handheld or direction finding unit they can use to find it if you let them know.
 
what time was it when you checked?? inst 5 minutes after the hour when people can check to see if their ELT is working? maybe someone in a hanger is checking theirs.
 
mtnflyr said:
what time was it when you checked?? inst 5 minutes after the hour when people can check to see if their ELT is working? maybe someone in a hanger is checking theirs.
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That was the first thing I thought of but it was 615 or so when I first heard it. Just talked to a guy who said it's been going off for 3 days now.. wat
 
Make an aluminum foil tent to shield your ELT antenna and ask Tower (if they have 121.5) to report whether the signal changes with and without the tent. Absent Tower, ask someone else that's 100 yards or more away to do the same check from their airplane.

If there is a local CAP squadron, they will have the DF equipment to check. Or call AFRCC at 800-851-3051 to report the problem. They don't like getting reports of unknown ELTs going off. (Air carriers monitor 121.5 and report) They can probably help you find someone locally to help with the diagnosis, too. Even if you are sure it is not you, AFRCC will appreciate the report.
 
Take the battery out and go fly. Your entire episode illustrates what worthless crap 121.5 ELTs are.
 
Skid said:
Just talked to a guy who said it's been going off for 3 days now.. wat
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Just renewed my faith in batteries and ELTs. If I need mine I hope 3 days is enough!
 
SkyDog58 said:
Add this to the list of things that pilots sometimes aren't taught but should be.
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Well honestly, the best way to learn is for something like this to happen and so now I have some experience with troubleshooting. All I can ever recall from being taught was the first 5 minutes of every hour they are the test period and to monitor 121.5; which are two things I referenced.

I will admit this is the first time I ever heard one going off, and especially going off on the tower/ground freq. That's a new one. It does peak my curiosity though if this is an indication of the response time and urgency of the ELT. As it seems like its akin to a car alarm going off.
 
Stewartb said:
Three days and nobody's done anything about it. What faith?
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Hard to believe for two reasons.
1. The batteries rarely last that long and if they do, the signal is very weak.
2. By now, the CAP ground team would have been swarming that airport like killer bees.
 
Another follow up: I switched from Auto - Off - Auto - Off - Auto - Off and heard no difference in the siren. Right before I gave up to go home I checked one last time, and no more ELT noise. Strange; especially for someone saying its been happening for days, and it takes me to do that?
 
SkyDog58 said:
Hard to believe for two reasons.
1. The batteries rarely last that long and if they do, the signal is very weak.
2. By now, the CAP ground team would have been swarming that airport like killer bees.
Click to expand...

Yea I'm just going off what a random passerby said. But as soon as I mentioned ELT going off he said "haha yea, we've been hearing that" etc. It was no surprise to him.

And on top of THAT, there is a CAP plane on the field haha
 
BrianNC said:
So you going flying now? :)
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Unfortunately no, by the time it was off I was already towards the end of my time block. But as with everything, there's always tomorrow and already have a flight booked for then :D
 
Had a similar experience - landed and heard ELT on 121.5. Went so far as to disconnect battery from mine to assure wasn't me, then the onfield mechanic and I walked around w handheld - couldNOT better localize it. No one else responded, seemed to care.
Some number of months later the mechanic told me he found it was a plane in his maintenance hangar.
Bottom line - if you still hear it w batterydisconnected, it ain't you. Go fly
 
Stewartb said:
Take the battery out and go fly. Your entire episode illustrates what worthless crap 121.5 ELTs are.
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Wouldn't go that far.


But yeah, switch to off and if you still hear it, not you.
 
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If you have a handheld radio, you can do a pretty good job of hunting. I've sleuthed stuck mics and ELTs before. If you're real close you can take the antenna off the radio and use your body as a sort of shield to point yourself in the right direction.
 
If you're close enough to an ELT, it'll sound on most comm frequencies. We heard an airplane's ELT over Unicom on 122.8 as he taxied onto the ramp.

If you touch your headset cord to the ELT antenna when it's transmitting, you'll probably hear it through your headset.
 
Palmpilot said:
I did go on one ELT search where that wouldn't have worked, because the problem was that water had gotten into the switch
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Had a simulator issue with an ELT going off at my home field. When they finally found it they determined it was a faulty/corroded switch.
 
Capt. Geoffrey Thorpe said:
I always disable the ELT before I land to avoid triggering it again.
Just kidding.
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Hmmm. Just hmmm.
You weren't at GBR on Thursday, were you?
Someone landed a Cub hard enough to set the ELT off.
Twice. :)

Oh. I see what you did there.

I just read a statistic that claims fewer than 1/4 of installed ELTs actually activate in a crash.
I think I need to look into that.
 
Shepherd said:
Hmmm. Just hmmm.
You weren't at GBR on Thursday, were you?
Someone landed a Cub hard enough to set the ELT off.
Twice. :)

Oh. I see what you did there.

I just read a statistic that claims fewer than 1/4 of installed ELTs actually activate in a crash.
I think I need to look into that.
Click to expand...
I'll help your investigation by reporting that neither of my ELTs has activated in a crash.
 
When I was flying a 172 in Australia, I found that there was no ELT in the plane. Upon inquiring to the rental shop, they said that the owner had removed it as he kept setting it off on landing. I've had some hard landings over 35+ years of flying, but I have NEVER set off an ELT.
 
About 10 years ago I was departing Albuquerque at about 2am. At about 500 feet I flip on 121.5 and get blasted with the wailing tone of an ELT.

I call the tower back and ask them if they are aware of the ELT. They were not.

The signal got weaker as I flew away from the airport, and since I did not hear anything about it the news, it was probably from a parked plane on the airport.

But no one was monitoring 121.5.
 
chartbundle said:
Do you have a handheld? Take off the handheld antenna and walk up to your plane's ELT antenna with the handheld set to 121.5, it should go from inaudible to very loud if it's you, if it's loud everywhere then tune to 121.6 and repeat, repeat with other aircraft if you're bored. Otherwise go fly and see if you can still hear it when you're not at the airport, if it's always the same loudness, then it's you :)
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Even quicker, tune the airplane radio to somewhere around 123.0. If the source is YOUR plane or another very nearby, you'll still hear it. If it's across the field, you won't.

Detuning is a common isolation technique.

I had exactly the same experience as the OP once. Turned on the standby battery and it started wailing. I grabbed a handheld and body shielded my way across the airport, isolating the signal to an MX hangar. I even got it down to 10 feet or so on the other side of a wall with aggressive detuning. Airport ops entered the hangar and found an ELT on a bench, right there, and silenced it.

At Reid one day, I started an instrument lesson, and heard an ELT on Ground (121.65). As we taxied by one of the FBOs, we heard it get louder, then quieter. We reported the finding to Ground.
 
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