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ACK E-04 false alarms

rwthompson67

Active Member
A little over 100 hrs on the airplane but only recently flew through moderate rain. VA to TN and back, rain both ways and the ELT went off about an hour into the flight. It was raining on both legs and the ELT went off at around the same point on both flights. This was my fist time flying in significant rain and also my first false alarm on the ELT.

First time it went off I wasn't aware it was me (the led on the RC panel is pretty dim). The 121.5 signal was so strong though that it bled over to the ATC frequency so that whenever someone used the frequency all I could hear was the beacon. I was unable to stop the beacon from xmiting. Tried the Test/Reset on the remote panel and also pulled the circuit breaker. Finally reached over my left shoulder and disconnected the cable from the ELT antenna. This allowed normal comms until I could get on the ground, take the emp fairing off and turn the ELT off. Of course I had a voicemail from the AFRC.

After talking to ACK, it sounds like the remote alarm is very sensitive to moisture. And after looking at my installation, there was definite evidence of water making its way to the ELT in the empennage. I ended up drying it out, replacing the battery and wrapping the unit in saran wrap. Hopefully that'll eliminate the false alarms.

Anybody else have this issue?

https://postimg.cc/gallery/246r83110/
 
Do a search here - multiple reports of inadvertent activation of the ACK E04 ELT.

Do the world a favor and file a Service Difficulty Report or whatever its FAA equivalent is. It's the only way the regulatory authorities can gather data on in-service failures. It's the only way we ever see products made better. It's also the only way we get rid of unsafe junk from the market, stuff like the Ameri-King ELTs that had a horrendous failure rate.
 
Do a search here - multiple reports of inadvertent activation of the ACK E04 ELT.

Do the world a favor and file a Service Difficulty Report or whatever its FAA equivalent is. It's the only way the regulatory authorities can gather data on in-service failures. It's the only way we ever see products made better. It's also the only way we get rid of unsafe junk from the market, stuff like the Ameri-King ELTs that had a horrendous failure rate.

I've done a lot of searching...here and everywhere else. I've been unable to find anything specifically regarding the susceptibility of the ACK E-04 to false activation caused by water intrusion from rain in the typical RV-14 install position (beneath the vertical stab).
 
I haven't heard of water intrusion setting off the E-04 specifically, but the E-04 has been the subject of several posts here on inadvertent activations.

The ELT should be able to withstand some moisture as part of its TSO environmental testing. Not submersion, but certainly the presence of moisture on its exterior shouldn't set it off.

Also, if the unit has transmitted for any length of time its battery will have been depleted to some extent. The unit keeps track of its run time... once it hits the magic number it will show a low battery failure under self-test. Just be aware that following this inadvertent activation event you may not get the stated life from the battery if the ELT has spent some time squawking before you could get it shut off.
 
After looking at the photos you've posted I'd suggest there was more than a little moisture on the ELT. The paper label on the unit is pretty well puckered from water.

Your idea of wrapping the unit in plastic wrap might help prevent future challenges, unless it should also work against you by trapping moisture inside the plastic wrap.

Your photos give an entirely new meaning to that old phrase, "Wrap that rascal!" :p
 
ACK E-04 False Alarm

Got home from Petit Jean RV Fly-In yesterday around noon. Had to spend the night 1.5-hours away because of weather. Airplane spent three nights on the ramp at KPMJ but spent the night in a hangar at 18A.

With two Apollo comm radios in the airplane, I always monitor 121.5 while flying on Comm 2. Because my hangar door has a remote control, I typically open the door as I taxi toward the hangar stopping before I reach the door.

Monday, as soon as the engine shut off, (radio was off when I pulled the mixture, killed the ignition, and turned off the master) I heard a beeping sound. For the first time since July 2019 installation, my ELT was going off. Had to press and hold the RESET button and it finally quit making noise and the RED led was no longer flashing.

I phoned the NOAA number just to make sure that search and rescue knew I was ok. They have not gotten the signal yet but took down my info to know that if it comes in it is a false alarm.

I remember that others have had ACK E-04 False Alarms so did a search and this is the first thread that I found.

Hope this is my last false alarm. I know it was not my smoothest landing but the G-meter says that it was not a hard landing.

G-Meter.jpg


I see another thread about ELT false alarms and will read that also. IIRC, it was a different manufacturer's ELT.

Late note is Copy/Paste from FAA Service Difficulty report website: "Your submission has been received. The control number of this submission is: 2019FA0000341"
 
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Please, please file a Service Difficulty Report for these false ELT activations. It's the only way the FAA learns there's a problem in the field.

I take my hat off to you for recording your SDR submission here, Gary. Thank you for being part of the reporting chain that can help make aviation safer.
 
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