ELT "G Test"

Arnold

Arnold

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Arnold
The one open item from Lady Luscombe's annual is the ELT which the mechanic said did not "pass the G test."

Could someone please explain what this test is and how to perform it.
 
You did not specify type so it’s possible the aka “Toss Test “ is not being

done correctly.

91.207 allows you to remove the unit and placard when maintenance is needed.

You then have 90 days to address the issue.
 
FastEddieB said:
Never heard it called that, but might it be where you smack it against a hard surface to see if it activates?
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Not so violent. Most just hold it, shove it forward and jerk it back. Striking a hard surface could impart way more force and mask any insensitivity in the switch.
 
Magman said:
You did not specify type so it’s possible the aka “Toss Test “ is not being

done correctly.

91.207 allows you to remove the unit and placard when maintenance is needed.

You then have 90 days to address the issue.
Click to expand...

Been removed and placarded.

ACK E-01
 
Some of the later models will not activate by striking.

Dan’s method provides need time to the equation.
 
Magman said:
Some of the later models will not activate by striking.

Dan’s method provides need time to the equation.
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Here's the g-switch test instructions from Artex, for their ME406. One of the most popular ELTs.

upload_2021-6-28_21-21-52.png

For the ACK-E04:

upload_2021-6-28_21-25-49.png


There is no need, or specification, to strike anything. You go whacking it on the bench and you could inflict more than the unit is designed to handle and bust up the electronics inside it. The 406's have to be mounted so that they can take a 100G load. A hammer striking a nail imparts far, far more than that.

The instructions for the old E-01 say this:

upload_2021-6-28_21-42-2.png

A "quick rap with the palm" doesn't impart much G force.
 

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I stand corrected. I recall that hitting it against the palm of my hand wouldn't activate my old ELT, to the point of almost injuring myself. Next annual I’ll verify that and see if a repair is needed and possible.
 
I just did the G load test and it works just fine. Not sure why they rejected it at annual.
 
Note that the ELT needs to be inspected annually, but that inspection isn't necessarily part of your "annual inspection," though most people do it then.

THe FAA guidance is to test it with a whipping motion.
 
flyingron said:
Note that the ELT needs to be inspected annually, but that inspection isn't necessarily part of your "annual inspection," though most people do it then.

THe FAA guidance is to test it with a whipping motion.
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With the annual makes it easy to keep track of.
 
Arnold said:
Been removed and placarded.

ACK E-01
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They don't monitor for the 121.5 ELT's anymore. IMHO it's almost useless. Get yourself a newer ACK E-04, it is more accurate and gives the rescuers a much smaller area to search. Feet instead of miles
 
AKBill said:
They don't monitor for the 121.5 ELT's anymore. IMHO it's almost useless. Get yourself a newer ACK E-04, it is more accurate and gives the rescuers a much smaller area to search. Feet instead of miles
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Yup. But make sure it gets installed in accordance with the installation manual that comes with it. I have found far too many 406s just fastened to the old ELT mounting plate, which does not meet the specifications for the 406. The new one might not activate because of mount flexing during the crash. The mount must not move more than 0.1 inch when a 100-pound pull is put on the ELT in any direction. The old skin-mounted stuff could never even approach that. The antenna has to be able to withstand a similar 100G load on its base, which means a stiffening plate needs to be made and installed, and if the antenna mount is in a different fuselage section from the ELT (if the cable has to cross a riveted seam, for example) a stout steel cable has to run between the sections to prevent the antenna cable being torn apart if the sections separate.

One would hate to have spent an AMU or two on it, only to have it fail in the crash and you sit there hearing SAR buzzing off into the distance, looking for the signal that ain't there. ELTs fail half the time as it is. Making it 80% isn't helping.
 
Dan Thomas said:
It wouldn't be an Ameri-King, would it?
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Yes, it would be.

I have a feeling I should have been better informed on this. I do my own Annual Condition Inspections on my E-LSA. I always test the ELT and document it via a logbook entry in the airframe logbook.

Questions…

1) Does the AD apply to EXPERIMENTAL aircraft?

2) If so, should the logbook entries going forward include language referring to that particular AD being complied with?

3) What, exactly, beyond a regular annual test is that AD calling for? It’s not immediately clear.

Maybe it’s time to upgrade to a 406mhz ELT at my next annual? On an EXPERIMENTAL can I legally do the install?

Thanks for your patience.
 
FastEddieB said:
Yes, it would be.

I have a feeling I should have been better informed on this. I do my own Annual Condition Inspections on my E-LSA. I always test the ELT and document it via a logbook entry in the airframe logbook.

Questions…

1) Does the AD apply to EXPERIMENTAL aircraft?

2) If so, should the logbook entries going forward include language referring to that particular AD being complied with?

3) What, exactly, beyond a regular annual test is that AD calling for? It’s not immediately clear.

Maybe it’s time to upgrade to a 406mhz ELT at my next annual? On an EXPERIMENTAL can I legally do the install?

Thanks for your patience.
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US law is a bit different than Canada's. Othe members here would know the legalities that apply to you.

The AmeriKings were terrible. Our local avionics shop wouldn't touch them. Too many G switch failures. That was before the AD. The FAA issued an SAIB or something on it some time before the AD.

I intalled a number of the Artex ME406s. Nice units. They also have a less expensive version now.
 
Dan Thomas said:
Here's the g-switch test instructions from Artex, for their ME406. One of the most popular ELTs.

View attachment 97784

For the ACK-E04:

View attachment 97785


There is no need, or specification, to strike anything. You go whacking it on the bench and you could inflict more than the unit is designed to handle and bust up the electronics inside it. The 406's have to be mounted so that they can take a 100G load. A hammer striking a nail imparts far, far more than that.

The instructions for the old E-01 say this:

View attachment 97786

A "quick rap with the palm" doesn't impart much G force.
Click to expand...

The Artex and other instructions for whatever tests may be specified are woefully inconsistent in their specifications. The specs are given in G's (with the wrong units label too) which is not a critical variable. Maybe they mean 4.6 ft/sec which would be a velocity change term? Because 4.6 ft/sec^2 sq is a trivial acceleration - only about 1/8 of the simple acceleration of gravity. Even if the units are ft/sec that is only about walking speed - hardly an airplane accident event. Something is dimensionally crazy in these postings. Gs are not the critical thing to be sensed. The integrals of G's over a short period of time are.

No wonder ELTs are wildly unreliable if they are so specified and tested by those who don't know.

My old IA always just aggressively bounced the ELT into an ordinary pressurized tire and looked for the thing to trip.
 
FastEddieB said:
1) Does the AD apply to EXPERIMENTAL aircraft?
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The registration category of your aircraft makes no difference. An AD is issued against ANY article when an unsafe condition exists. If there's an AD on a particular propeller because the shanks are known to crack and fail causing blade separation, the danger doesn't magically disappear when you bolt it to a Vans RV or whatever. This is why ADs are mandatory.

FastEddieB said:
2) If so, should the logbook entries going forward include language referring to that particular AD being complied with?
Click to expand...

Yes.

I do think it would be worth it for you to upgrade. I'm somewhat partial to the ACK E-04. The Artex ME406 has given me fits before. Not too mention, there's an internal runtime clock. Once it reaches a certain amount of use (which includes testing every twelve months), you've got to send it out to factory to be reset $$$.

Have a look at 91.207 for some legalese on ELTs.
 
Thanks. I’ll make sure to include the “AD ### complied with” language in subsequent logbook entries.

I may budget to upgrade to 406 MHz this fall during my Annual Condition Inspection. It’s not been a priority due to my own risk analysis. In 45+ years of flying I’ve never been in a situation where an ELT would have helped. My calculus is combining the likelihood of a crash, combined with the likelihood that said crash would not be in or near a populated area or near a well traveled road or near an occupied dwelling, combined with the likelihood that I’d be unable to report my location on 121.5 MHz prior to the crash, all taken together making my overall risk of needing an ELT vanishingly small. I know that’s out of character for “Mr. Most Conservative Action”, but we all assess risk differently.
 
Dan Thomas said:
The AmeriKings were terrible. Our local avionics shop wouldn't touch them. Too many G switch failures. That was before the AD. The FAA issued an SAIB or something on it some time before the AD.
Click to expand...

They were terrible no doubt, brand new ones would fail the G switch test especially if it was hit or smacked against something to activate it.

I never hit them, I always just swiftly moved it away from me with both hands with a sharp stop at the end and never had one fail that test.
 
Der Fliegermeister said:
.
I do think it would be worth it for you to upgrade. I'm somewhat partial to the ACK E-04. The Artex ME406 has given me fits before. Not too mention, there's an internal runtime clock. Once it reaches a certain amount of use (which includes testing every twelve months), you've got to send it out to factory to be reset $$$.
Click to expand...

Where do you see that? This is what I get from the manual:
upload_2021-6-30_10-14-37.png

http://www.aeroclubrieti.it/w/wp-content/uploads/2014/01/ELT-Cobham-570-I-CALD.pdf

Page 27 of 60. Frame 35 of the pdf.
 
FastEddieB said:
Yes, it would be.

I have a feeling I should have been better informed on this. I do my own Annual Condition Inspections on my E-LSA.
Click to expand...

The search engines that look for ADs on your airplane don't usually look for appliance ADs. Those are the various bits that are made by people other than the airframe, engine or prop manufacturers. Instruments, radios, wheels and brakes, ignition switches, seat belts, vacuum pumps, alternators, magnetos, and ELTs. Those are just a few examples. I regularly found outstanding ADs on such items. One has to go looking specifically at ADs by manufacturer, and after years of maintenance experience you start to see the suspicious stuff right away. To keep up, you review the biweekly AD releases. At annual you can read back through all those and see if anything showed up in the last year.
 
Dan Thomas said:
Where do you see that? This is what I get from the manual:
View attachment 97827

http://www.aeroclubrieti.it/w/wp-content/uploads/2014/01/ELT-Cobham-570-I-CALD.pdf

Page 27 of 60. Frame 35 of the pdf.
Click to expand...
Fuzzy memory. I knew some error occurred at that point. I suppose a battery replacement isn't bad. But I've had them go off all by themselves. One of my guys came running in like "I can't turn it off!" I was like "what the hell did you do?" He was opening the hangar door. Not even touching the thing and on she came.
 
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