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Thread: elt question

  1. #21
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    Default Re: elt question

    There are a number of places offering advice on testing.
    The best advice you should take is from the manufacturer, as the rule states something to the effect that all testing must be performed in accordance with the manufacturers requirements (or instructions) - can't remember which. Check your manual. If unclear, I would get clarification from ACK before listening to anyone else.

    YMMV, Greg

  2. #22
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    Default Re: elt question

    Upon initial installation and then annually we must check the installation, controls and signal strength of the ELT. Without $5000 worth of shields, receivers and antenna dummy loads the only way to test properly (not by initiating a false alarm) is to either apply to NOAA for permission to do a live test or pay a service to watch for your self test at a scheduled time.

    Use of the service prevents the emergency system from being overloaded with false emergencies.

    Just doing a self test and listening on your radio is insufficient to test signal strength properly.

    Look at the NOAA ELT testing policy for this data.

    Dave, I am at Turners Falls. You?

    Jon
    Kitfox IV 1050, C180. Now I have two backcountry planes! WooHoo!

  3. #23
    Senior Member Dorsal's Avatar
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    Default Re: elt question

    I read that policy as how to conduct tests not which tests are required (though I could be quite wrong). I believe the tests outlined in the ACK install manual should be sufficient, self test every three months, complete inspection each year including testing the G-switch.

    I am based out of KORH, love to see your plane sometime.
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  4. #24
    Senior Member PapuaPilot's Avatar
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    Default Re: elt question

    Quote Originally Posted by Dorsal View Post
    I believe the tests outlined in the ACK install manual should be sufficient, self test every three months, complete inspection each year including testing the G-switch.
    From what I understand this is correct. Once the 406 ELT has been installed you need to do what the manufacture says in the "Instructions For Continued Airworthiness" or similar section. For the ACK-04 this is found in section 10. The self test is part of this, an inspection of the ELT, mounting, antenna, plugs/cables and the G switch test.

    Here is a good link on the subject:
    http://www.supercub.org/forum/showth...-a-406-mhz-ELT

    If you want to check the signal strength you can still do the "AM radio" check, which tests the 121.5 signal and gives you an assurance that a decent signal is being transmitted from the antenna.

    Here is a copy/paste from another site about the AM test:
    "There are two ways to test for sufficient antenna signal on a C91a ELT. One is to evaluate the signal strength using a test box like those made by QCAvionix or Whiffletree. The other method is to listen to the signal using an AM-band radio receiver.

    The FAA endorses the AM radio test and has codified this check in the most recent update of Advisory Circular 43.13-1B (CHG 1). The test for sufficient signal radiated from the antenna is as follows (Par 12-22):

    "Active the ELT using the ON or ELT TEST switch. A low-quality AM broadcast radio receiver should be used to determine if energy is being transmitted from the antenna. When the antenna of the AM broadcast receiver (tuning dial on any setting) is held about 6 inches from the activated ELT antenna, the ELT aural tone will be heard."

    "It has to be a cheap AM radio," said Bob Glorioso, president of QCAvionix. "It can't be too well shielded. You're trying to overwhelm the AM detector."

    Many mechanics, perhaps unaware of the FAA's recommendations, listen the ELT signal on the aircraft's VHF radio, set to receive on 121.5 megahertz. But this isn't a good test, because the aircraft radio's receiver is extremely sensitive. The AM radio test, says AC43.13, "is not a measured check; but it does provide confidence that the antenna is radiating with sufficient power to aid search and rescue. The signal may be weak even if it is picked up by an aircraft VHF receiver located at a considerable distance from the radiating ELT. Therefore, this check [VHF radio] does not check the integrity of the ELT system or provide the same level of confidence as does the AM radio check."
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  5. #25
    jonstark's Avatar
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    Default Re: elt question

    The AM radio test is NOT for the 406Mhz transmission. It is only for the 121.5 signal. That can only be done with a test set, actually activating the ELT or having a service monitor a self test transmission.

    Now... We have to decide whether testing only the 121.5 signal is compliant with the FAA mandated signal strength test.

    What say you all?

    By the way, 406test.com is ONLY for ARTEX ELTs.

    Jon

    Edit to add...
    An FAA Avionics Inspector out of Atlanta now says that the FAA knew it would be difficult to nearly impossible to test the 406 Mhz broadcast so the TSO was written so as to require the SELF TEST PROCEDURE to comply with strength test.
    If your manufacturer has a selftest in the Instructions for Continuing Airworthiness that is all that is required.
    Last edited by jonstark; 07-06-2018 at 08:14 AM.
    Kitfox IV 1050, C180. Now I have two backcountry planes! WooHoo!

  6. #26
    Senior Member PapuaPilot's Avatar
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    Unhappy Re: elt question

    There is an answer to this in the supercub.org link I posted. It mentions the Airman's Information Manual (also from the FAA) as the reference. It's always fun to use other FAA's information to show that FAR 91.207 doesn't make sense in regards to 406 ELTs.

    6-2-5. Emergency Locator Transmitter (ELT)
    a. General. . . .
    b. Testing.

    1. ELTs should be tested in accordance with the manufacturer's instructions, preferably in a shielded or screened room or specially designed test container to prevent the broadcast of signals which could trigger a false alert.

    2. When this cannot be done, aircraft operational testing is authorized as follows:

    (a) Analog 121.5/243 MHz ELTs should only be tested during the first 5 minutes after any hour. If operational tests must be made outside of this period, they should be coordinated with the nearest FAA Control Tower or FSS. Tests should be no longer than three audible sweeps. If the antenna is removable, a dummy load should be substituted during test procedures.

    (b) Digital 406 MHz ELTs should only be tested in accordance with the unit's manufacturer's instructions.

    (c) Airborne tests are not authorized.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  7. #27
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    Default Re: elt question

    Dontcha just love this stuff Phil?
    My DAR questioned the validity of self test so... I go round and round trying to find how to be in compliance with the mandate only to end back at the ICA I used in the first place.

    Jon
    Kitfox IV 1050, C180. Now I have two backcountry planes! WooHoo!

  8. #28
    Senior Member PapuaPilot's Avatar
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    Default Re: elt question

    You betcha. This whole 406 ELT inspection issue has been a nightmare since they first came out. I don't think I have ever heard anybody talk about this subject at an IA seminar. IMO the FAA needs to update 91.207 so we don't need to guess or go searching for this info.

    I would show the AIM reference to your DAR if there are any questions. If he has further questions he should take it up the FAA. In all reality DARs are authorized to perform airworthiness certification of aircraft, that's all. He really can't deny you the C of A based on future maintenance and inspection requirements. If you have installed a new, approved ELT in an acceptable manner (including the registration with NOAA) that is all a DAR can ask for. If he wants to do a self test performed that would be OK.
    Phil Nelson
    A&P-IA, Maintenance Instructor
    KF 5 Outback, Cont. IO-240
    Flying since 2016

  9. #29
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    Default Re: elt question

    I agree with Phil - or find another DAR. The requirement is to test within 12 months of installation - most do it at annual so as to simply inspections. Meeting the manufacturers requirements for testing as stated by ACK in the manual is all that is required. ACK says nothing about using a service or doing the test in a shielded room. ACK does however also require a "self test" be performed every 3 months - so don't forget those too and log them!

    These "suggestions" to take it to an avionics service center that keep popping up are all propagated by the service centers to make them money.

    YMMV, Greg

  10. #30
    Senior Member rv9ralph's Avatar
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    Default Re: elt question

    Agreed the 406 testing issue is a conundrum.

    There is a device, advertised in Kitplanes, to run these tests. It is designed to test 406 and 121.5 ELTs, the cost is $648. Pricey, but my last EAA chapter just bought one a few months before I moved. They were in the initial familiarization stage but it appeared that it would run the necessary tests. The website is www.beacon-tester.com.

    It is something to look into. Too pricey for most as a once a year item, but cold be great to pool resources, like an EAA Chapter, for annual testing.

    Ralph

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