Dick,
As you are so fond of trotting out VOR's thoughts on Class E airspace ... which they do in fact support ... in principle, I thought I might extract a few more of their thoughts. I know some are dated, but they do bear some reflection, less we fall into similar traps:
On implementation:
That said, it has been evident through the last two years, that there is an aggressive campaign to “crash or crash through” the airspace reform agenda, with no regard for established safety and change management systems and practices.
Indeed over this period we have been supplied with large quantities of information that would indicate, if not a deliberate attempt to circumvent those processes, then at the very least a level of naïveté of the processes.
Once more we have to say that the proposed changes under NAS were not necessarily unsafe – but the manner in which they were being introduced, and the total lack of transparent process, made the transition risk unacceptable. If further reform is to be achieved, not only must the risk associated with the changes be examined, but those associated with implementing the changes must be examined and carefully managed.
Relative risk in different Airspace classes:
It is absolutely correct to say that in any given volume the level of risk associated with Class C airspace is less than that associated with Class E.
Yes, it is absolutely true to say that for a given volume of airspace, with a set volume of traffic, the risk associated with Class G is higher than Class F, which is higher than Class E, which is higher than Class C etc.
On radar requirements:
Perhaps you would like to find a reference in ANY global documentation that identifies a requirement for radar in Class E airspace. It is not a pre-requisite, and Class E - in fact Class A, B, C, D E, F and G can - and are - be operated satisfactorily with or without radar coverage.
On risk to the fare paying passengers:
Good and effective airspace management is about ensuring that the fare paying passenger is not exposed to inappropriate risk levels – and just as important – inequitable risk levels. So, the risk to a passenger flying to Sydney should be no higher than that for a passenger flying to Broome, Alice Springs, Launceston or Mildura, and vice versa.
On differening risk appetites:
We said “appropriate levels of risk”. Here is where it can get exceptionally difficult, even for a clean sheet approach. What one section of the aviation community will accept as appropriate may differ by one or two orders of magnitude to another section of the community. So a glider pilot might well be prepared to accept risk levels one hundred times higher than an airline pilot, or ten times higher than a VFR general aviation pilot. A VFR general aviation pilot might accept risk at a level ten times higher than an airline pilot. Is this wrong – basically no. The point of most contention comes where the high risk acceptor and the low risk acceptor come together. Here the airspace designer may need to impose an airspace classification that accommodates the lower risk threshold, or establish mitigating procedures.
On transplanting airspace systems:
What we have repeatedly stated is that you cannot simply pick up a set of procedures from one country – be it the United States or Mongolia – and apply them in another State, without addressing the potential safety issues [and by the way we have already stated that we don’t believe there is a significant safety issue associated with the proposed changes] – AND implementing the changes safely.
The United States has grown up with a culture of free access to airspace. You only have to spend time with US AOPA management to realize that the culture is GA focused, with air transport having to fight for access to – or retention of – controlled airspace. Type “Class E airspace” into your internet search engine, and you will find hundreds of references to legislative processes around simple matters such as establishing Class E surface areas. Being based in North America, you will also be aware that it is the States of the United States that request Class E airspace in excess of corridors associated with IFR routes – and that is why some States have blanket E, and some simply have corridors. Changing terminal area routing at major airports in the United States requires at least two years notice, and legislative change.
On using TCAS as a mitigator:
You CANNOT [yet], however, design a system that relies on aircraft-to-aircraft surveillance or separation based on the use of transponders – that is, the use of airborne collision avoidance systems, like TCAS and Mode A/C transponders, as an airspace design tool, is prohibited.
..... Effectively, ICAO – and the ANC specifically – has determined that ACAS MAY NOT be used as a risk mitigator under any circumstances in the design of airspace management procedures. ALL ICAO Technical Panels have been directed that they may not factor such systems in the development of separation standards, the design of procedures, or the development of future systems. ACAS is a “last line of defence” for pilots – NOT a system design tool.
ICAO ANNEX 11:
SECTION 2.4: DETERMINATION OF THE NEED FOR AIR TRAFFIC SERVICES
2.4.1 The need for the provision of air traffic services shall be determined by consideration of the following:
a. the types of air traffic involved;
b. the density of air traffic;
c. the meteorological conditions;
d. such other factors as may be relevant.
Note:- due to the number of elements involved, it has not been possible to develop specific data to determine the need for air traffic services in a given area or at a given location. For example:
a. a mixture of types of aircraft of varying speed (conventional jet, etc) might necessitate the provision of air traffic services, whereas a relatively greater density of traffic where only one type of operation is involved would not;
b. meteorological conditions might have considerable effect in areas where there is a constant flow of air traffic (e.g., scheduled traffic), whereas similar or worse meteorological conditions might be relatively unimportant in an area where air traffic would be discontinued is such conditions (e.g., local VFR flights);
c. open stretches of water, mountainous, uninhabited or desert areas might necessitate the provision of air traffic services even though the frequency of operations is extremely low.
2.4.2 The carriage of airborne collision avoidance systems (ACAS) by aircraft in a given area shall not be a factor in determining the need for air traffic services in that area.
On airspace upgrading:
So if you determine that you should have Class C in one area, Class D adjacent to that airspace, and then Class E adjacent to that airspace – AND it would cost you no more to make it all Class C – then that should be your decision.If there is no cost impact – and no demonstrable negative impact on amenity for a VFR flight – nothing in the “rule book” says you can’t exceed the “minimum requirement”.
On Class E workload differences:
Where the differences occur, of course, is the interaction between IFR and VFR flights. By that, we mean that an IFR aircraft may require services more urgently [i.e., tactically rather than in a planned fashion] in Class E airspace because of the proximity of VFR flights, or may not be able to comply with a planned ATC instruction. This adds a level of complexity to the model – for both pilots and providers of services – something that needs to be factored in the holistic airspace design. That is not to say Class E should not be used – far from it – but it must be appreciated that Class E operates in a fundamentally different way than Classes A through D.
On risk increases:
In any given volume of airspace, with the same number of IFR and VFR flights, the level of risk must increase when Class C airspace is changed to Class E [or Class D, or Class F or Class G for that matter]. Equally, a change upwards in classification, from Class C to Class B or Class A, for a given volume of airspace, with the same number of IFR and VFR flights, the level of risk is decreased.
On transponders in non-surveillance Class E:
As we have pointed out previously, the operation of transponders within Class E airspace is only of use as a design tool where there is secondary radar coverage – to allow enhanced provision of traffic information by a third party.Transponder carriage and operation outside of radar coverage cannot possibly be used as a tool to enhance airspace design.