Changes to VHF Channel Spacing- more equipment upgrades?
If you have an old VHF radio, which is not uncommon considering almost half of the General Aviation fleet in Australia is more than 31 years old, you may be forced to upgrade very soon.
Airservices Australia is responsible for assigning VHF aeronautical frequencies in Australia. Due to increasing number of frequencies being assigned they are struggling to continue to find interference-free frequencies for use in high traffic areas. To overcome the problem frequency spacing has been reduced from 50khz to 25khz.
We have been warned this was coming. In September 2005 Airservices Australia and CASA told us about the pending changes in AIC H11/05. There was also an article in Flight Safety Magazine (Channel Squeeze) around the same time. At the time, the real effect was too far in the future for most pilots and owners to worry about. The first to be affected was the high-flying IFR traffic in Class A Airspace (Nov 2005), next in line in November 2006 was Class C, D and E airspace users in high density traffic areas. I bet you didn’t even notice. There are relatively few frequencies at 25khz spacing, so you may not have needed to use any yet. Is it something you check during flight planning?
CAO 103.25 (receiving) and CAO 103.24 (transmitting) tell us “The frequency range and number of channels must be adequate for the intended operational purpose of the equipment” which means, if you don’t need to use a 25khz spaced frequency, you don’t need to have a radio capable of transmitting and receiving at 25khz spacing. That’s a relief. So, all you need to do is check your charts before you go, and as long as there are no tricky frequencies (118.02, 134.32 etc) along the way, you can continue to fly with your antique equipment.
This will continue to be the case; however it is going to become more difficult to practice. Bruce Bilton, CTAF frequency assigner at Airservices Australia, has advised that in high density areas 25khz spacing of CTAF frequencies is a year away at the most. Anyone flown at Kyneton and heard aircraft at Geelong and Barwon Heads? It can get busy and confusing at times with these areas sharing a frequency.
So if you fly at CTAF’s around the major east coast cities, it is highly likely you are going to be affected by the new frequency spacing in the next year or so.
Let’s get clear on who has to do what.
If your VHF radio displays 3 decimal places, e.g. 118.025 can be dialed up and displays on your radio, you are not affected; your radio supports 25khz spacing.
If your VHF radio displays 2 decimal places you need to check if you can dial up frequencies like 118.02, 118.17. If you can, that’s great, you are not affected.
If your VHF radio goes straight from 118.00 to 118.05 when you turn the knob, you have a 50 khz antique and this article was written for you, read on.
The next thing to do is consider the area you operate in. Anyone regularly flying in controlled airspace or flying IFR should already have upgraded, but if your home base is Broken Hill, and your biggest cross country is to Menindee to see a mate, you will probably not need to take any action at all. If you operate in the maze of CTAF’s on the outskirts of Melbourne or Sydney, or in South East Queensland, you should plan an upgrade soon.
An upgrade shouldn’t be too heart breaking if you are constantly having problems with your old radio. They are expensive to repair these days, and once they start to have problems it is usually the beginning of the end.
For VFR aircraft, a new Icom A-210 non TSO’d is about $1500. For IFR aircraft a TSO’d radio is needed, and these start at about $5000. In order to install a new radio (or anything new) in a certified aircraft you will need CAR 35 approval. This is where it starts to add up. You need design drawings to show how the radio will be mounted, a wiring diagram, an electrical load analysis and weight and balance change calculation. Once the CAR 35 approval is received, the installation begins. Removal of the old radio, manufacture of mounting brackets, wiring new radio, materials and a possible new antenna all add up. You would need to budget at least another $2000 for the installation and associated approvals and documents. If you are considering upgrading anything else in your panel, this would be the time to have it done as the installation cost will only increase slightly for each new item installed at the same time (of course the purchase of the new gear could easily blow the budget).
If you have one of these antique radios and can’t bear to part with it (it works perfectly- why throw it away?) you could consider having a more modern radio installed as a second radio. Two radios are really quite useful, and it won’t matter if only one of them is capable of the 25khz spacing. You may have to factor in the additional cost of an audio selector panel.
In the information issued in 2005 regarding changes to frequency spacing, there was mention of CASA introducing new frequency stability requirements of 0.003% from November 2009. That would mean that even if you could get by with your old radio with 50khz spacing in your operations, your radio would have to comply with the new requirement (which stops transmissions from ‘spilling’ over and jamming adjacent frequencies). Many of the older radios would be unable to comply, and therefore no longer be approved for use. No NPRM has been issued by CASA on the proposal and current information suggests this won’t be happening now. AIC H03/09 is the latest information on the topic, issued by Airservices Australia. They have confirmed upgrade of equipment is not mandatory, and only required if 25khz spacing is needed for your particular area of operation.
Article by Kim Skyring