In this AVweb video, Paul Bertorelli takes a hard look at 406 MHz emergency locator transmitters for aircraft. While an ELT of some kind is required for most aircraft, historically, these devices haven’t performed very well. They still aren’t an impressive value for the money.


  1. You bring up excellent salient points about the two different ELT types but forgot one other important point.

    In your video, you show yourself R&Ring the EBC battery pack and testing the unit with your handheld. You can’t do that with a 406ELT. You MUST have the proper testing equipment and ensure that you don’t “pump out” an erroneous squit that a satellite might see. So you MUST take the thing someplace where they do have the proper test equipment. To me, that’s the largest single reason I haven’t upgraded to a 406ELT.

    And now … why did a female pop out of the lower left corner of your video ??? What was that about ??

  2. Thanks for this video Paul. I have to explain this message to many owners each year while walking them through an ELT inspection/test as required by regulation 91.207(d). They tell me they never did the inspection/test before. I know of three situations that mechanics received a violation for signing-off an Annual with expired ELT batteries. The ELT was not a factor at all in the incident/accidents accept for the fact they had expired batteries.

    It’s very rare for an ADS-b Out equipped aircraft to be missing. My opinion is that ADS-b Out equipped aircraft should be permitted to remove the ELT. The idea of an electronic transmitting device to work ‘AFTER’ an accident doesn’t make any sense to me. There’s many tracking devices available that are transmitting all the time and may be destroyed in an accident. The transmitter still gives a last location transmission to some computer server somewhere. If the pilot gives a ‘may day’ the surrounding aircraft can converge on the distressed aircraft ADS-b location.

    Placing a simple flight plan call to a friend/family will give the most prompt rescue then any minimally funded agency can provide. Tell someone the projected arrival time and how to follow the ADS-b track then, inform them they are the beneficiary of a sizable life insurance and the insurance company needs a body before the pay out.

  3. “So you MUST take the thing someplace where they do have the proper test equipment. To me, that’s the largest single reason I haven’t upgraded to a 406ELT”

    I don’t believe that’s true for 406 ELT’s registered in the US. Check the ICA in the manual. In Canada I believe they do require testing an an avionics facility on a regular basis but not in the US. Still if you want a full function test of your ELT you can go on the Artex site, pay $100, and do a complete test of your ELT all the way through the entire system including the satellites and the reporting network. I did that a couple times before they raised the price.

  4. Dynamic – you clearly haven’t fallen off a bone breaking wave in a yacht in real rough weather. The dynamics of that are WAY worse than a botched landing. I’ll go with mis-handling argument.

    IMO AOPA did pilots a huge disservice in fighting to keep 121.5 – because as you point out – no one is listening. If there had been an implementation date – the market would have responded and a uAvionix would have come along with a budget solution.

    Failed to activate – folks who slapped the 406 in place of their 121.5 – yep – they don’t activate. 406 install instructions are very specific about bolting to real structure to hold it rigidly and strain relievers in the cabling. You have to do some real work to meet the G requirements of the mount platform. Floating around in the empennage – it ain’t gonna work.

    PLB – “turn it on” – assuming you can.

    You actually make the argument FOR 406. The ability to pinpoint FAST.

    1 in 3 – I’ll take it. Better than 0 in 3

    • Every airline flight I take out there is a constant 121.5 watch in the lower 48, Alaska, ocean crossings, etc. Where you general aviation types get your sweeping generalizations from is somewhat short on information regarding actual operations.

  5. As was stated earlier, some 406 ELTs require special equipment for the yearly tests, you have to read the continued airworthiness instructions to find out. All require to be registered with a Bi-annual re-register, so there is something else to keep track of, 406 ELT require a GPS input for location and there are planes that do not have a panel mounted GPS. The initial costs are way out of line for something that rarely works, then there is the replacement battery packs that can cost several hundred of dollars. Someone else stated that ADSB will do as good a job as an ELT, if not better. I will stick to my 121.5 ELT that uses Duracell batteries. I have been in aviation over 30 years and I don’t know of any time a ELT actually worked as it was supposed to, They are USELESS weight and complexity that we do not need.

  6. When I recently cleaned out my hanger, yep, a stack of 4 old EBC 102 epoxied batterie sleeves just looking at me. I just couldn’t throw them away every 2 years knowing they were still good. But how in the hell to get them apart. I see now many ways that don’t work. I’m ashamed to say this, but I’ve even once or twice considered printing a new expire date and sticking it on the battery pack. No, I didn’t and am ashamed for thinking it. But damn, $45 bucks for new double As…and having to throw away good as new ones. It just causes me to think evil.

  7. As couple of years ago while flying over east Texas on an IFR flight plan, I was monitoring 121.5MHz and picked up an ELT signal. I reported it to Ft. Worth center and the response was, “Yeah, we’ve been getting reports of that for a few days now. Thanks.” So even if someone hears an ELT on 121.5, not sure anyone is going to come looking, or if they do, that it will be found.

  8. I had to replace my old Narco 121.5 ELT several years ago after I managed to drop it on the hangar floor during a check of the battery expiration date. Not only did it not activate, it never worked again, and I had to spring for a new 406 unit. The 406 did come with a remote activation switch mounted on the panel, so I guess I could press the “panic” button before hitting the ground and hope it sent out a signal before it got smashed in the wreck. I also bought a PLB for “just in case”. It even floats in case I ended up in the water.
    But, I have a problem with those too. The battery is nearing expiration, so I contacted the manufacturer to see about getting a new battery. They basically said that in order to replace it, I would have to send it in and have them do the replacement. The cost was just about the same as buying a whole new PLB, which is what they suggested I do. If you think spending $40 bucks for a new pack of Duracells is aggravating, try having to fork out $300 plus dollars for a new unit every few years, knowing the battery is probably still okay.

  9. I too am a CPB…Cheap Pilot Bastard. As a CPB, I have the least expensive ADS-B OUT solution. My last CC flight over the Quachita and Ozark mountains showed that while over the Quachita Mountains, no Flight Aware data, plus I was not getting any traffic/weather data from my ADS-B IN. But when I got north of them, Voila! I appeared on Flight Aware via my ADS-B OUT. SO, my CPB 121.5 ELT might have been better than nothing had I gone down in the first 26 minutes of flight with maybe a 1 in 3 chance I might be located. In this same area of Quachita Mountain ADS-B dead zone is also the same area where there is no, zero, nadda, cell phone coverage as well making the 121.5 ELT at least a one in three wreck possibility of working. Since it came with the airplane, still works, and requires new C batteries purchased at Walmart every two years, IAW my current CPB status, I will continue to use the 121.5 ELT along side my cell phone, ADS-B OUT, my 295 handheld, 250XL panel mount, and the iFly740 tablet which does a great job recording the history of my flight. I will make every effort to avoid crashing in the Quachita Mountains “deadzone”. Comforting to see there are at least 35% of all pilots that are CPB’s too.

  10. Paul,
    Thank you. Invariably your dry, deadpan sense of humor has me laughing.
    Being of Scotch descent I’ll do my best to make copper wire from a penny.
    I have a single seat, no ELT required, and a 2 seater that I will, like you, continue to support the old 121.5 system until such time as it won’t work. And then…. who knows!
    Still arguing with myself about ADS-B. They are getting more cost effective, time will tell.

  11. Thank you Paul for another entertaining and informative piece. I’m a CPB with an old 121.5 ELT which I keep to satisfy the regulatory requirement only as I have zero confidence that it will be any use in an accident. If I go down it’s much more likely they will find me from my ADS-B out track and I agree that having it should make the ELT requirement optional.

    A couple of years ago a 121.5 ELT went off on our airport which we heard on the radio. We contacted the nearby USCG station and they said yeah they hard it but they don’t follow up on those any more. Doesn’t that inspire confidence in the system!

  12. Paul, thank you for another in a continuing series of excellent fact-based, data-mined policy briefs. This is the kind of work that ought to support all policy-making in DC; unfortunately it almost never happens there. When reporters and, dare I say it, scholars like you bring out these data and make them public, informed public opinion can drive policy. I strongly hope that happens in this instance; the ELT requirement has to go so small plane pilots can afford to adopt the better, faster, cheaper technology that is now readily available.

  13. Here in Australia, I paid US$186 last year for a PLB. The warranty and the battery are good for 10 years, and the PLB has a 20 year life. It transmits both 121.5 MHz homing signal, and the 406 MHz to satellites, with 66 channel GPS location signal. Unit is buoyant, and water resistant to 3 meters.
    Includes visual strobe light, whistle and signal mirror, velcro armband, and aviation release certificate.
    I have it registered to Australian Safety Authority. It has a self test function.
    The brand is Kti GPS PLB “safety alert”……manufactured in Australia.
    The look on Paul’s face when he lit up the gas torch….priceless!

  14. FAA should change rules so that ELT is NOT required for aircraft equipped with 1090ES ADS-B. 1090ES ADS-B is tracked globally by satellites, by official ground stations, and by enormous number of private receivers (maybe as many as 100,000 of them). ADS-B track is 99.9999% reliable, ELTs fail most of the time.

    For added safety, carry a PLB GPS with you. ADS-B track + PLB GPS = super high chance you are found, WAY higher than 406 ELT.

    UAT ADS-B is not good enough. Lacks satellite coverage, most private receivers don’t pick it up, doesn’t work in much of the country (as described already in this comment thread). Yet another area where UAT should not have existed.

    Current rule being satisfied by 121.5 ELT is just plain dumb. No sat monitoring, hard to find, no ID in message, hugely unreliable, hard to find.

    Change the rule so that ADS-B 1090ES is enough, and I am even okay if you are required to have a PLB on board as a backup, which is far less cost and far more useful IMO.

    Mike C.