Lead Balloon, I think its premature to determine an answer at this point. However, the path to a solution is not hard to follow.
1. We need an agreed upon risk framework so that risk can be determined for certain operations in to particular locations (note I have not used the term airspace). The risk model is to include, traffic mix, traffic density and CNS capability. (amongst other things).
2. We also need an agreed methodology to determine the problem we are attempting to solve.
3. We need a risk acceptance framework where by risk can be determined, assessed and accepted against the problem. Not all problems need solutions. Some risks may be acceptable provided all parties are informed.
Lets take Ballina. (None of what I am about to type is a proposal. I have used these examples to trigger a discussion. That is all)
What exactly is the problem we are trying to solve? OAR would have you believe that communications masking from Lismore and over transmission is the problem that lead to the A320/Jabiru incident. But it is known fact that the Jabiru made a transmission, and no one else transmitted at the time. The A320 was in line of sight so terrain shielding also was not at play. So what caused the incident? Is it traffic mix? Is it poor training from Jabiru or A320 crew....I genuinely don't know, but shouldn't we try to find out what the root cause was before we introduce another set of complexities and problems? Class E at Ballina, would not have prevented the incident, and neither would the broadcast zones that are being proposed. Here's the final question, do we absolutely want to prevent a Jabiru from taking out an A320? I would argue, most probably, yes. So the solution is going to have make that the priority outcome, and that may mean excluding some types of operations. So we don’t want any probability of that even happening. (stay with me, I'm going somewhere with this)
Now take Mangalore.
We really don't know yet what actually caused this accident? We may end up putting it down to bad luck? But, how do we know there is not a latent error in the airspace system that could have this happen anywhere else? (I’m sure I read a comment along that line by you somewhere, I agree by the way).
But what if this is the 1:10(-9) event. Is that ok? Should we invest time/money in trying to make a system more safe, when everybody seemed happy with the 1:10(-9) risk?
In this way we need to develop tools to determine if a) there is an latent error or, b) this is the 1:10(-9) event. If its b) we also then need the testicular fortitude to stand by the level of risk that we have accepted. I feel terrible for those 4 blokes, its sad and I hope it never happens to me. But flying has a risk, we all accept it. Its not zero. If we establish that the risk at Mangalore is as we thought it was...does it need a solution?
So take the 2 scenarios above. 2 totally different problems, with what I hope would be 2 different set of airspace performance requirements, which would lead to 2 different outcomes with 2 different associated levels of risk. How then can the same solution be applied to both locations, and the same outcome be expected? All you are doing is adding another variable to an existing set of variables that have not been assessed appropriately in the first place.....this makes the risk increase significantly.
The point being if we have a mutually agreed framework with which to assess and determine the risk of operations at a particular location, and then you have an agreed framework with which to mitigate that risk (or not) then the outcome should be valid.
We are not ready for solutions yet.