Here is the latest implementing reg from EASA.
Article 5 Obligations of operators
1. An operator shall not operate an aircraft above FL 195 unless the aircraft radio equipment has the 8,33 kHz channel spacing capability.
2. From 1 January 2014 an operator shall not operate an aircraft flying under instrument flight rules in airspace class A, B or C of the Member States listed in Annex I unless the aircraft radio equipment has the 8,33 kHz channel spacing capability.
3. With regard to the carriage requirements of 8,33 kHz channel spacing radio equipment identified in paragraph 2, an operator shall not operate an aircraft flying under visual flight rules in areas operating in 8,33 kHz channel spacing unless the aircraft radio equipment has the 8,33 kHz channel spacing capability.
4. Without prejudice to Article 2(5), from 1 January 2018 an operator shall not operate an aircraft in airspace where carriage of radio is required unless the aircraft radio equipment has the 8,33 kHz channel spacing capability
The number of 8.33 radios required is not clear but appears to be the number of VHF COM radios required by the applicable law in each country which, for private flights in the UK, is 1.
This will be bad news for many people - not least because there is no point in 8.33. The whole requirement comes from different countries in Europe not co-operating on frequency allocation, for job creation / empire building reasons.
A Garmin GNS or GTN box gives you 8.33 (but only one) but most owners of non-Garmin stuff do not have an easy way to get 8.33.
One can replace a KX155A with a KX165A/8.33, which is a straight swap (potentially with a config change in the radio, for the NAV side if driving e.g. an HSI). One can get a KX165A/8.33 from the US for about $3k-4k (example example example - refurbished price) and they give you about $1k for the old 155A.
Replacing a KX155 (i.e. non-A) with a KX165A is a lot more work because the connections on the back are different and have to be required.
There is a possible slight benefit for King HSI (KI525) owners in installing a KX165A because they probably have a KN72 NAV receiver stashed away somewhere, which is not the most reliable box, and the KX165A contains this functionality internally, so with a bit of rewiring you can dump the KN72.
Not every KX165A does 8.33 so the P/N has to be right. I think it is 069-01033-0201.
There are probably other options, but the above are basically high quality radios; not the junk one sees so much of.
The best thing is you can get mad on turning knobs now. 3 times more make a difference.
If one suffers from Repetitive Strain Injury (RSI), turning the Garmin knob 3x more than today is not good for health. Maybe I should seek an exemption from 8.33kHz for medical reasons? A friend of mine has a medical exemption from wearing a seatbelt in the car (due to some injection implant)...
I always used the dual knob entry method (same as on the 430s) in the GTN650 until we arrived over Iceland and had to dial in 8.33 frequencies. The touch screen paid for itself immediately and is much faster for the 8.33 frequencies.
We figured out how to turn off the 8.33 spacing on the Garmin 430 last weekend. One of the software config options. Saves the extra knob turning which is irrelevant for normal VFR purposes. But we are still legal because the unit could use that spacing if needed.
Another wasted and unnecessary expense but with a workaround
That is a way to cope with regulations. ....unless the aircraft radio equipment has the 8,33 kHz channel spacing capability. It has the capability, but it is disabled by software, so we are legal.
Yes but that allows you not to use it for convenience. Doesn't help those who don't have it installed. And it sounds like eventually they are going to require it by using 8.33 frequencies low down.
The key to whether this is a real issue in practice will be whether 8.33 frequencies start to be used below FL200.
If you are given one but can't set it, it will be obvious.
Looks like 8.33 will become more or less mandatory for anyone flying IFR on airways from the beginning of next year - see http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=detail&id=5395
The relevant deadlines are:
The first two sound like they will just happen - the community of IFR flyers in that airspace is pretty small. Good business for the avionics firms over the next few months though! The UK low level IFR fleet will at least have a little while to switch over (very little class C and no class B in the UK, AFAIK), but the 2018 deadline will be very expensive for a lot of people.
What's the chance of that last requirement being cancelled? And which radios will people be installing?
Most IFR pilots I've seen use a Garmin 430 or newer. They are 8.33 ready. I believe it's some kind of firmware upgrade for the 430.