Malibuflyer wrote:
The current practice of flying semi circular altitudes is extremely safe
Isn’t that a bit fallacious? I would state it more as “it does not matter if or if not you comply with the semi-circular rule” since there are hardly any mid-airs. So of course flying semi-circularly is safe as there are no accidents, but so is equally flying at random altitudes. The correlation between accidents and semi-circular or not is as good as the correlation between accidents and colour of underwear :)
Sebastian_H wrote:
Isn’t that a bit fallacious? … So of course flying semi-circularly is safe as there are no accidents, but so is equally flying at random altitudes.
The difference is: the first half of your statement is based on facts while the second half is based on theory.
I do not want to argue that flying random altitudes can’t be as safe as semi circular altitudes (as explained: can not be better as semi circular is already perfectly safe). I rather argue that we should not try to fix something that is obviously not broken.
Malibuflyer wrote:
The difference is: the first half of your statement is based on facts while the second half is based on theory.
I see your point, but would hold up the AAIB statistics for the UK (where random altitudes are encouraged), and these statistics show no increased risk either, so not completely theoretical.
Malibuflyer wrote:
I rather argue that we should not try to fix something that is obviously not broken.
In the end it seems it does not really matter, doesn’t it. From the discussion I gather that a lot of traffic seems to fly below the required semi-circular altitude anyway, IFR tends to fly higher than the usual VFR cruising altitudes, so yes, nothing needs to be changed.
Alpha_Floor wrote:
Lack of data does NOT mean that both approaches are equally safe in principle
Hmm. Lots of implicit factors here. What is “safe” anyway, except a calculated risk based on data? What is data, except the number of accident events vs the number of non accident events? What I mean is that logic is no measure for safety, only data is. Thus, the semi circular rule works just fine. There is no lack of data, only “lack” of accidental events, which again is the basis if the fact that the rule is safe, based on data. The data shows that mid airs en route is extremely rare. The data also shows that all other rules are safe (flying below 3000 AGL where the rule doesn’t apply is also safe)
