Kannad ELT battery replacement

During a German (or Dutch) avionics test ELT code is verified.

During the battery change and 6 year inspection we measure current cunsumption, power output during transmission and idle, programming verification, reading transmission counters (test and actually tranmissions), including reset after reading, visual inspection, testing of G switch.
Further the battery, seals, padding, desiccant and hardware is renewed. Afther this (depending on the version) the water switch and leak test is performed.

Michael wrote:

But how do you KNOW it’s functioning properly ?

Only by performing the correct testing, include code verification and power output and transmitter power AND idle current.

The times are usefull as well, as you can be sure how long the ELT has been activated when you had it active for some time. It could save you an battery change.

Peter wrote:

Can they test a foreign reg ELT (bought in the USA)?

Not sure what you mean? Most avionics shop can read every ELT. Yet the coding differs from country to country. Some people who bought their ELT abroad didn’t know, neither did the seller, resulting in wrong coding. I come across this every now and then during avionics testing. On some ELT’s it can be expensive too have it reprogrammed, so the “cheap” ELT will result in being more expensive than when bought from EU dealer.

Peter wrote:

the satellites disregard the signals.

Satellites no longer listen for 121.5 MHz signals, these are only used for homing, such that most SAR systems don’t need upgrading. The 406 MHz signals are used by the sattelite. An ELT will send one bit different during self test. The satellite ignores the signal when it is send with this bit set to selftest.
You want to listen to emergency beacons only, that is why their is restrictive timing, to prevent an actually warning being unheard.

Why cannot a US-purchased 406+121.50 ELT be left programmed as it is? Mine is registered with the NOAA and they are happy with a non-US postal address.

It should be possible to

• test it (if required – not required for an N-reg AFAIK)
• change the battery

without losing any config or changing anything.

Would that be correct?

If not, how can any N-reg business jet (etc) which just happens to be in Europe when it gets a battery change manage it?

Peter wrote:

It should be possible to

test it (if required – not required for an N-reg AFAIK)

Part 91.207.d :
(d) Each emergency locator transmitter required by paragraph (a) of this section must be inspected within 12 calendar months after the last inspection for—
(1) Proper installation;
(2) Battery corrosion;
(3) Operation of the controls and crash sensor; and
(4) The presence of a sufficient signal radiated from its antenna.

Peter wrote:

Why cannot a US-purchased 406+121.50 ELT be left programmed as it is? Mine is registered with the NOAA and they are happy with a non-US postal address.

We are talking about different issues. For sure you can buy an ELT from the USA. It should be programmed correctly. There are multiple programming configurations. Yours is likely registered correctly in that case.

There are also quite a number of people who bought an ELT for themself, and had the ELT programmed incorrect. Because they didn’t instruct the programmer in the USA on their requirements. Most US programmers seem to program ELT’s for Europeans the American way. Which for example is not allowed in the Netherlands. So when you register it, or have an avionics test it gets rejected.

For example, in the US programming is often done with aircraft tail number. This is not allowed in The Netherlands, here you have use the 24 bit ICAO adress (the same as used in the transponder). So if a US ELT manufacturer does a Dutch ELT your ELT will get rejected when you try to register it AND/OR when you have your avionics test done.

Often people tend to think it is more affordable in the US. Add shipping as hazardous goods, and EU reprogramming and you have got yourself an ELT which is more expensive than those sold by European companies.

ELT registration often goes wrong as well (AND PLB’s). When not correct registered these make them almost useless. Also at registration change, sale of the aircraft, relocating etc, the ELT is often overlooked. As programmer you will also keep a database, just like the manufacturer. These databases are sometimes needed because people don’t register their product. Or register every 2 years from my memory for NOAA (!)

Peter wrote:

It should be possible to

test it (if required – not required for an N-reg AFAIK)
change the battery
without losing any config or changing anything.

You can test is and change the battery without the losing or changing the coding. Testing and inspecting is also an FAA required according FAR 91.207 as far as I am aware.

achimha wrote:

My understanding is that the battery change interval of 6 years is an airworthiness requirement of Kannad ELTs. Is there a way to run the batteries longer?

Correct, I never had the question for extension, couldn’t tell. I doubt you would get permission for on condition battery renewal.

I have just had my KANNAD AF-COMPACT battery changed by Jesse’s shop.

The battery pack itself was dated 2008 (the unit came from the USA – no idea how old stock it was) and the voltage was 6.2V, which is not bad considering the terminal voltage of the cells used

according to wiki and the actual Friwo data sheets is 3.3V max (6.6V for the two cells in series).

FRIWO are rebranded as Saft now.

Do you know the size? C cell?

It’s a D – the biggest common one (the biggest common battery I mean ).

It’s funny… in the 1980s I used Nicads made by SAFT. Friwo just used to make little power supplies…