PPRNkof raises an interesting comparison which I take the liberty of paraphrasing as "does this incident between two 747s actually matter compared to other types of airprox ?":
I actually think the third incident in the report was far more significant. The one involving the F15 Cowboy. The plane nearly lived up to it's name. The Strike Eagle.
The ARM methodology(?) now in use by UK CAA gives the F15E/J41 airprox an ERC of 502 and the 747/747 an ERC of only 102. I assume there is supposed to be some steady linear progression of measured risk between these two scores and not some logarithmic scale as with decibel measurement
So, as maxred points out, the rate of climb of an unsuspecting F15E is enormous. Not quite as fast as any bullet but far more lethal projectile than any bullet if it hits you.
However, I wonder if the ERC classifications in any way take into account the obviously differing collision profiles presented by larger and smaller types i.e. if we assume in all cases the two conflicting aircraft are targeted to the same "aiming point" what is the likely grouping of the two hotshots when they punch their mark on target? Will the holes in the F15E/J41 target card ever be likely to overlap ? And even if they do, will one sneak through just in time to avoid the other? I think it is quite remote that two 19m long aircraft will be so unlucky as to punch the same mark even if using equally accurate navigational equipment.
However, take two 75m long projectiles and fling those at the target using the same kind of projectile accuracy then I would say there is a much greater likelihood of the punched holes overlapping. There are arguments that might suggest you need to use the relative airspace displacement volumes to calculate something useful, and others which might suggest a calculation based only on the collision area profiles presented by each typewould be more useful.
Either way I venture to suggest that it might be between 300 and 1000 times more likely that if you fire two 76m long 747s at each other from 20 miles or 6 miles or 3 miles that they will in some way hit each other versus a 19m F15 fired at a 19m J41. Anyone know if that kind of factor is included in the calculation of ERCs (which are supposed to provide a useful comparison of which incidents are the most important to learn from first I think!)? Any anti-missile missile scientists care to chip in with something more useful ?
Another factor in the comparative severity of risk might also be measured in terms of likely casualties both in the aircraft and on the ground.
And as we have also seen both in slow motion
"why are they not complying / now what are they doing?" with the 747s and in
"blink and you missed it" terms with the F15, the lack of adequate time for any intervention is surely a major risk assessment factor.
Does the recently introduced ERC system come close to getting the correct balance, do we think? Is there a corruption in the methodology which may mean that it too easily leads us to ignore lower score civilian operational risks because we are measuring them on the same page of an airprox report against what is essentially an enhanced military risk i.e. measuring both risks with a politically incorrect military mindset ?
Would it take five similar 747 on 747 airprox to gain as much of the CAA's attention as is warranted by the F15/J41 incident or is that not what those relative 102:502 ERC scores mean?