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-   -   False ELT alerts (https://vansairforce.net/community/showthread.php?t=189068)

TShort 11-17-2020 06:20 PM

False ELT alerts
 
I installed an ACK E-04 during the upgrade on the -10 a couple of years ago.

Since then, I have had 2 separate occasions where the thing has gone off and alerted the CAP.

Before all the comments about crummy landings come in, both events happened 2-3 days after I arrived. The first time the plane was on the ramp at KAEJ and had been there tied down overnight before the ELT went off.

The second was last month, I landed at KLMO and was tied down there for 2-3 days before I got the call that the ELT was active.

Has anyone else had similar issues?

Thanks
Thomas

fixnflyguy 11-17-2020 06:42 PM

Been there done that
 
My Ameriking 450 did same thing, but it was in my hangar and friends scanner caught it. I replaced batteries in the unit, and in the remote head. It was fine for a month, then did it again. AVX shop didnt have any good suggestions, so I got a used one to replace it.

jmra72a 11-17-2020 06:42 PM

Yes I had similar problems with mine. I called ACK and they advised it was water in the batteries or RF interference. My batteries were fine. A friend advised me to remove the ELT and wrap it in aluminum foil. Clamp it back in the holder making sure that the wrap was well grounded.

I did this 6 months ago and have not had a false activation since.

Give it a try.

TShort 11-17-2020 07:06 PM

Quote:

Originally Posted by RV8JD (Post 1478427)
I wonder if it has something to do with not having the static suppressor they supplied with later units:
http://www.ackavionics.com/wp-conten...SUPPRESSOR.pdf

Carl-

I'll have to look into that more, but I hope not, as I bought the unit new ~2 years or so ago...

Canadian_JOY 11-17-2020 07:22 PM

If purchased two years ago it should have had the static suppressor included in the installation kit.

smt6 11-17-2020 08:05 PM

I installed the static suppressor after having many false alerts. It did nothing. The ACKs are junk. Buy an Artex

hpmicrowave 11-17-2020 11:57 PM

False ELT Alerts and Cosmic Rays
 
When weird unexplained electronic event's like this happened during the F35 development program I was involved in Lockheed would close out the issue by stating it was caused by Cosmic Rays, while I was pretty skeptical as far as I remember the Program Office never complained with this excuse.

So wrong time software reboots, autopilot misbehavior, random ELT activations, messed up GPS approaches, ADSB tracks straying into Restricted airspace, wrong frequencies, the list of things that Cosmic Rays can mess up gets bigger every year as we move into the age of Cosmic Avionics.

If this excuse works for a $25 billion dollar jet fighter program it can work for you too!

rv8ch 11-18-2020 12:39 AM

Error detection and correction
 
Quote:

Originally Posted by hpmicrowave (Post 1478483)
When weird unexplained electronic event's like this happened during the F35 development program I was involved in Lockheed would close out the issue by stating it was caused by Cosmic Rays, while I was pretty skeptical as far as I remember the Program Office never complained with this excuse.

So wrong time software reboots, autopilot misbehavior, random ELT activations, messed up GPS approaches, ADSB tracks straying into Restricted airspace, wrong frequencies, the list of things that Cosmic Rays can mess up gets bigger every year as we move into the age of Cosmic Avionics.

If this excuse works for a $25 billion dollar jet fighter program it can work for you too!

Error detection and correction would hopefully be an important part of those systems. Perhaps they just decided it's cheaper to reboot. :( Seriously, this needs to be a standard part of every HW and SW developer's toolkit.

Canadian_JOY 11-18-2020 07:46 AM

Quote:

Originally Posted by smt6 (Post 1478446)
I installed the static suppressor after having many false alerts. It did nothing. The ACKs are junk. Buy an Artex

I'll second this recommendation that the ACK's are a substandard device.

My first recommendation remains the Kannad, despite their expensive battery pack replacement. Their in-service record is at the top of the pack.

The Artex comes next in line.

The ACK E-04 is at the top of my list of "do not install" equipment.

fl-mike 11-18-2020 08:05 AM

1 Attachment(s)
It's unfortunate that some equipment providers do not thoroughly test their products.
We buy them assuming that they are well wrung out, but in reality, many test only enough to get the certification, and many TSOs leave environmental test requirements up to the end user to specify or confirm.

It is amusing for me to look at the DO-160 test categories for many certified products that we install on our planes. Many are filled with "X"s indicating that no testing was performed or claimed in those areas. I've see altitude encoders that basically only tested for temperature. Everything else is X's.
Here are the test categories for the ACK E-04.
Notice what I highlighted. No testing for radiated or conducted susceptibility. So, let's say you have a nice high powered ATC surveillance radar on the field that is sweeping your plane every few seconds. You have no evidence that the unit will not respond in a bad way to that. None. (the aluminum foil wrap was not a bad idea!)
Environmental qualification testing is expensive. Figure $100-250k or so for a basic series of tests, if they all pass the first time. (and every time you make a design change, you have to run though an analysis to determine which tests have to be re-run.)

Oh, and I highly doubt these occurrences are due to single-event or multiple-bit upsets (SEU MBU) from cosmic rays. Those affect memory devices (flash mostly) and i doubt the ACK is using a flash based FPGA. Even those typically have mitigation features. (that's another analysis!)

Take a look at the DO-160 environmental qualification test form on the next piece of avionics you are considering. It might be enlightening.


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