Kaz3g
Making a broadcast is quite different to making a directed call to ATC. I thought this would be clear.
Under the NAS, it is prohibited from making a broadcast on ATC frequencies that are used for separation – just common sense.
Yes, you can call ATC and request a workload permitting radar information service or request weather information. That means that ATC can simply say “stand by” or “radar service not available”. However making announcements on ATC frequencies, such as taxiing calls or inbound calls for a circuit area can block out necessary ATC transmissions.
Creamy
The present system is a complete mess. I have asked lots of pilots similar questions to the one you are now asking – everyone gives a different answer. This is because people with concrete minds who are trying to resist change and have never once, ever, thought of copying the best from wherever it is in the world, insisted on changing back towards the old separate Flightservice / ATC system. This is clearly impossible because we no longer have a separate Flightservice system.
There are absolute dopes who think the present system means that you have everyone on the correct frequency to use “radio arranged separation” as we did pre-1991. Of course, this is not so. The system at present is so incredibly complex that most people either don’t know what frequency to be on or have made an error and are on the wrong frequency, whatever that may be.
Go to the United States and there are simply no frequency boundaries marked on charts. You can call up a local Flightwatch outlet or on the air traffic control charts there are small boxes (you can call them ‘biscuits’) which allow you to call directly to ATC; even then, the ATC will tell you what frequency to change to for a service depending on what area you are in. It works superbly in the USA and it will work superbly here once we have enough sense to copy the best.