Arm out the window, you bring up a very good point in your statement:
“What’s the problem with having frequency boundaries marked on charts?”
There is clearly a problem because that is what this CASA discussion paper is about. For over three years now, CASA and the RAPACs haven’t been able to agree on the procedures to be used.
CASA reckons that at unmarked aerodromes, taxiing and circuit calls should be given on the ATC frequency which is also used to separate traffic. Most of the RAPACs reckon that the calls should be on the multicom.
No other country in the world of which I know has air traffic control frequency boundaries marked on charts. Now possibly there could be a reason for this. I know the reason why we have them marked in Australia. It is because many years ago, they were flight service frequencies and VFR and IFR aircraft flew at the same levels. It was called the quadrantal rule, and therefore VFR aircraft had to be in the full position system.
This worked well but was incredibly expensive. I was part of the group many years ago – in 1991 – that made the decision to change to the North American system. Rather than having IFR and VFR aircraft flying at the same levels with the quadrantal rule, we decided to move to the ICAO hemispherical rule, which put VFR aircraft 500 feet apart from IFR.
Then, at the most likely location of a collision – that is when flying en route in the approach and departure airspace of an aerodrome – we recommended that the VFR pilots monitored and announced on the aerodrome frequency. What could be simpler?
Many seem to think that the best frequency to be on if you have to give a MAYDAY is the area ATC frequency as marked on the charts. This is ridiculous. There are many areas in Australia where you cannot get through to the frequency of the ground based transmitter, but if you call the frequency of another transmitter that is closer, you will get immediate communication. VHF is line of site . That is why all the leading GPS units have a system showing nearest ARTC. That is for the American, Canadian and European system – where if you did need to call ATC, you can simply go to the nearest outlet which is likely to give you communication. It is what you call common sense and it has been proven all around the world.
We are in a situation where there is a conflict between the experts at RAPAC and the experts at CASA, because we have attempted to half roll back a very proven, safe system.
What was left out of the paper is the American requirement for radio equipped aircraft to monitor 121.5. This is the safest way of being able to communicate with an aircraft that may have inadvertently flown into controlled airspace. All the air traffic controller has to do is call a high flying airline aircraft and get them to call the aircraft at that location.
Around Sydney I often hear ATC calling a VFR aircraft in a certain location – only about 50% of the time does it get a reply. This is very likely because the particular aircraft is on the wrong frequency, or has the volume turned down.
As I have pointed out, I have done multi-day trips around Australia monitoring over 1,000 radio calls in our present system, and not one has been relevant for traffic purposes.
Also, with the continuing introduction of ADS-B, where position reports are not given, there is less likelihood of being able to find the location of another aircraft to start talking in the old 1950s system of radio arranged separation.
The prime reason that we have these problems is that there are those around (less and less these days) who want to return to the systems of the 1950 to 1980s – when they were learning to fly.
Capn Bloggs is a clear example here.
Capn Bloggs, no we don’t have airline aircraft flying around with unalerted see and avoid. If they are approaching or departing an aerodrome, they can communicate to the VFR aircraft – which if following the recommended practices of NAS, will be monitoring that aerodrome’s frequency.
Having a radio on 121.5 gives the distinct advantage that at any point you can call out MAYDAY with your position if you have an engine failure, and that call will most likely (98% in my experience) be monitored by a high flying airline aircraft. I have checked this in the Indian Ocean near Cocos Island, and also half-way across the Atlantic near Ascension Island, and received an immediate answer to a test call.
This also means that VFR pilots can fly in beautiful silence, appreciating the wonderful scenery and communicating with passengers on the intercom. Imagine if we brought in a requirement that anyone driving on the weekends in there cars must have a CB radio compulsorily on the truck channel. It would be ridiculous.
CASA needs to re-do the paper looking at what the problems would be of going to the international, proven, safe, simpler system.