PPRuNe Forums - View Single Post - BASI "Limitations of See & Avoid" ??
View Single Post
Old 6th Aug 2003, 20:57
  #12 (permalink)  
Join Date: Jun 2003
Location: Awstraya
Posts: 194
Dicky Baby

Glad to get an ATC view. Don't worry about not being a qualified pilot - my pax say it's never worried them!

Didn't know that the broadcast on behalf was SOP for info for VFR as well as IFR acft. Is this workload permitting or a required action? What level of discrimination (i.e. 1, 2, 5, 10 NM) do you reliably get from SSR returns in the GAFA? Unless the frequencies are grouped, it could certainly be busy around Mudgee or Inverell or Coonamble for example with at least 3 potential frequencies for rebroadcast - but that just lets people know that there's ACFT about, doesn't allow for mutually arranged separation if they're on different freqencies or overflying... as you said, doesn't cover all contingencies, and still need to look out the window, jet/turboprop or bugsmasher.....

There's no requirement to carry a transponder outside A, C or E airspace (base 8500 at present) and no requirement to have a radio OCTA below 5000 or in CTAFs. Thus OCTA TCAS doesn't provide full advice then from below 8500 and radios don't provide full advice from 5000 down..... this has been the situation for some time now. I won't even mention ACFT without electrical systems! Except (perhaps) for those who fly all the time in only classes A & C, looking out the window is part of your job. Does it actually do much good at higher speeds and descending/climbing through other's level - who really knows?

Just an aside, and correct me if I'm wrong, from what I understand NAS will extend class E to lower levels and would require TXP carriage - wouldn't that potentially be safer and cost non-TXP ACFT owners some dough? Not really a welcome cost (either to install the TXP or for loss of airspace) to a significant number of private fliers.....

Niles, I'm not convinced that NAS has much to offer the private or commercial pilot over the current system - I don't see it as really any safer nor do I understand (if anyone does) where the cost-cuts are coming from.

I'm not sure if the first aiders want to run the whole health system or if the superspecialised surgeons want the first aiders to do everything to operating theatre standards. There's space for both and that's the balance we need to achieve.

As for preventing two aircraft from occupying the same airspace simultaneously, we have a combination of defenses (radio broadcast alerting, ATC alerting, TCAS if we have it, flying more slowly in dense traffic areas, looking out the window, and the big sky itself)- all have differing importance depending on the phase of flight we're in and local density of traffic and none of which are infallible. Does anyone "scientifically" know the relative importance of any/all of these in preventing en-route tangles? I understand such variables are modelled to some extent when designing airspace.

In agreement with Manwell - when it comes down to it, I would still guesstimate that outside immediate aerodrome areas, in a large country with low density traffic, the sheer statistical improbability of two objects travelling on semi-random paths occupying the same lat/long/altitude at the same time has saved more of us OCTA than un/alerted see/avoid, radio and ATC alerts combined........and yes, I do look out the window and listen to the VHF!!

Fly safely

NOtimTAMs is offline