Untangling the Airspace Alphabet

The development ofthe new system has not been without its critics, notably the immediate past Chairman of the CAA, Dick Smith who has vigorously attacked the CAA board through the national media statingthat the proposedsystem is “fundamentally flawed and potentially dangerous”.

It was against this background that I accepted the offer by Buck Brooksbank,CAA General ManagerAir Traffic Services, of an extensive face to face briefing on the new arrangements. Although I was reasonably familiar with the new structure, having previously studied the proposed model which was detailed in the October 1992 edition of the CAA’s Aviation Bulletin (a new Bulletin will provide the latest information), my aim was to discuss in depth, Dick Smith’s concerns.

Outline of new airspace arrangements

Beforedetailingthe results of our discussions on the particular matters raised by Dick Smith, it might be helpful to review the new arrangements for those who may not be totally familiar with them.

As outlined in the October edition of theAviation Bulletin, in March 1990, the International Civil Aviation Organisation (IACO) formally adopted seven international classes of airspace, designated A to G.

After due consultation and deliberation, the CAA decided to adopt the ICAO A, C, D, E and G classes as best suited to Australia’s needs.

Only the United States and Canada have adopted B airspace in which IFR and VFR flights are permitted, all flights being provided with anair traffic control service, and separatedfrom each other.

No major country has adopted F airspace in which IFR and VFR flights are permitted, and in which all participating IFR flights receive an air traffic advisory service and all flights receive flight information service if requested. It follows, depending on the extent of coverage, that class B and F airspace would be costly to implement.

The five categories of airspace adopted for Australia’s needs each provide a level of air traffic services appropriate to type, numbers and traffic complexity of aircraft using that airspace. In summary they are as follows:

Class A – airspace between Flight Level 200 and 600 over continental Australia. IFR aircraft only – separation provided – no change from present arrangements.

Class C – terminal areas up to 20,000ft surrounding major airports such as Sydney and military airfields such as Richmond – procedures little changed from present.

Class D -designated controlledairspace around airfields with a control tower such as Bankstown, from ground level to base of E airspace. IFR traffic separated from IFR traffic and traffic information provided to IFR aircraft on VFR aircraft, with a traffic avoidance service on request. All aircraft require a clearance.

Class E – airspace below Class A airspace down to 10,000ft in non radar airspace and to 5000ft in airspace within low level radar coverage. (latter known as Radar E airspace). IFR aircraft will be separated from IFR aircraft and given a radar advisory service on radar observed VFR aircraft.

Class G- all other airspace. No direct control but, within radar coverage, a traffic information service will be available on request subject to controller workload.

An important point to note is that all categories of airspace will be supported by a Flight Information Service (not Flight Service) which will provide pre and in flight operational and weather information on request. SAR will also be provided.

The existing Flight Service aerials and radio equipment, supplemented by a further 20 transmitters, is expected to be able to provide this service over most of the continent to VHF equipped aircraft operating above 5000ft. A pictorial presentation of the airspace categories is set out in the accompanying diagram.

Differences between ICAO and the Australian model

As pointed out by Buck Brooksbank, apart from not adopting Class B and F airspace categories, there are only three differences between the ICAO recommendations and those adopted for Australia, these are: retention of GeneralAviation Airport Procedures (GAAP); less stringent cloud separation heights; the establishment of Mandatory Traffic Advisory Frequency (MTAF) procedures at certain aerodromes in G airspace.

Although the ICAO model does not have GAAP, these procedures have worked well at our secondary capital city airports for many years and as they are more flexible than the ICAO procedures, they are being retained.

The ICAO vertical separation from cloud is 1000ft; the CAA has reduced this to 500ft in certain circumstances.

Returning to the MTAF; this is the airspace around a designated non-controlled aerodrome in which certain procedures apply. It extends from ground level to the lower level of Class E airspace, expanding with altitude like an inverted wedding cake, and has been designed to cater for the descent profile of RPT aircraft such as the Boeing 737. The final shape and form of MTAF procedures is not yet set, and iscurrentlythesubject of an Aviation RegulatoryProposal (ARP) which has been sent to all pilots, operators, and Air Traffic Controllers for comment. The CAA has stated that in addition to the input of the airspace users, it will seek independent expert advice on the final proposals.

As it appears that the MTAF arrangements are the focus of Dick Smith’s concern, this aspect ofthe new arrangements will now be addressed in greater detail.

Previous procedures at non-controlled aerodromes

Prior to the introduction of the first stage of AMATS on December 12 1991, certain non controlled aerodromes (ie, no tower) had established around them an Aerodrome Flight Information Zone (AFIZ). Generally a Flight Service (FS) unit was co-located and traffic information was provided to all aircraft on other pertinent traffic operating in the AFIZ. The AFIZ extended to 5000ft with a radius of 15nm. Although procedures were in place for information to be broadcast by the FS unit when traffic density reached a level beyond the capacity of the FS unit to advise individual aircraft, it is understoodthat there was seldom a need for these procedures to be employed.

In addition to the AFIZ, to assist in the provision of a flight information service, certain nominated aerodromes had a Mandatory Broadcast Zone (MBZ) established around them; however these became remote AFIZ (FS unit not colocated) with the passage of time. Yulara in the NT was one such aerodrome. Both the AFIZ and the MBZ were essentially establishedto provideforIFRtrafficintothedesignated non controlled aerodromes.

Following the introduction of the first stage of AMATS, traffic information on VFR aircraft was no longer provided to IFR aircraft in the interim MTAF which had replaced the AFIZ.

Now, with the planned introduction of the new airspace arrangements on November 11 1993, there will no be a traffic information service in Class G airspace and that includes MTAFs located in that airspace. This means that traffic information IFR to IFR will not be provided. (However, within radar coverage, a traffic information service will be available to all aircraft on request, controller workload permitting. ) Aircraft will now be required to talk to one another direct rather than through Flight Service and to cater for this will be a number of mandatory radio calls as follows:

• Inbound before reaching the MTAF boundary taxying;

• Lined up or rolling;

• Circuit area or commencing an instrument approach;

• Prior to transitting the MTAF;

• En route calls (in G airspace).

The principle underlying the new procedures is commonsense self help, and takes into account our generally favourable weather conditions and relatively low level of IFR traffic density at thedesignated aerodromes. Pilots will be required to indicate their location by giving it in compass point terms eg “north east Cooma 15 miles”.

Dick Smith’s objections to new structure

Dick Smith, in a widely distributed briefing paper to the national media, has called the new procedures “a second rate airspace system”, maintaining that the CAA should return to theoriginalplanmootedwhenhewasChairmanofthe CAA, for an ATC service to be provided to allIFRaircraft to ground level where traffic levels were high but would not justify a tower. In other words, Class E airspace would be extended down to ground level.

In his paper he states that this is the system operating in the United States and Canada and would not be costly as the existing high level controllers would provide the service.

He maintains quote “that the proposed system is potentially dangerous as airline traffic will be largely on their own below 5000ft in radar airspace and below 10,000ft in other airspace. This means that large aircraft like 737s going into Yulara and F28s going into Cooma (the latter often subject to bad winter conditions) will not be provided with a traffic separation on all other IFR traffic”.

It is understood from the CAA that a conservative estimate for theprovision of the type of servicedemanded byDick Smith would amount to some $30m annually in terms of training and extra equipment. This raises the question of the often quoted statement about affordable safety? Someone would have to pay, the question is who? On the basis of user pays, logically it should be passengers into such destinations as Yulara. I can hear the screams from the tourism industry even as I write!

Whilst concerned about insufficient safety in MTAFs, Dick Smith, inwhat appears to bea contraview on safety,isopposed to mandatory transponder or radio requirement for aircraft above 5000ft in en route radar airspace. He states: “This is not an ICAO recommendation and no other country in the world has shown it can afford such a restrictive and expensive requirement (USA is 10,000ft and Canada is 12,500ft). This unique Australian requirement will cost up to $6m and only affects GA aircraft as airline aircraft already have transponders”.

Buck Brooksbank, in a recent press release has stated that:

“The CAA strongly recommendsthat all aircraft flying in areas covered by radar carry atransponder-a radar alerting device. However, radio alerting procedures are specified for aircraft not equipped with a transponder. Transponders enable Air Traffic Controllers to “see”, and therefore separate, aircraft in busy airspace. F1ying in E airspace where radar coverage exists will also be safer”.

There has been some agreement with Dick Smith from industry over the cost of transponders, but as they materially assist the safe and orderly flow of air traffic in radar airspace it is believed that the requirement for transponders is a sound one. It should be noted that TCAS ( an article on TCAS will shortly appear in AA) is not capable of providing collision avoidance to aircraft which are not fitted with a mode C (height) transponder.

Australian Aviation Industry Association (AAIA) viewpoint

The CAA management, mindful of the need to have all users of airspace in agreement on the proposed new airspace arrangements, established, through the Australian Aviation IndustryAssociation, aworking grouptoexaminethe proposals.

This group representing the entire spectrum of airspace users from the airlines through to sport associations (down to hang gliders), reported earlier this year that subject to minor amendments, and appropriate audit procedures, the new arrangements were agreed.

Other aspects of the new airspace changes

In a significant move, agreement has also been reached that military airspace will be treated the same as other controlled airspace andbothIFRandVFRtrafficwill be abletocallupand ask for a clearance through it. This means that Richmond and Tindal for example, will be on the same basis as Sydney.

In another very user friendly move, a “help desk” will be established to assist any pilot who is uncertain of his position or has been caught out by weather. All that will be necessary is for the pilot concerned to call up and state his problem and the assistance that he thinks he needs. There will be no recriminations, no suspensions, but obviously if it is apparent thatthepilothas acted foolishly,counsellingwillbenecessary.

Because the new arrangements will do away with the need forretransmitting,a singlefrequency of126. 7 will beused in all G airspace. Should experience show that overloading is occurring, an alternate frequency in the 126 slot will be provided. MTAFs will normally be on 126. 7 unless they are a control tower shut down at night in which case they will be on the normal tower frequency.

Finally, for the high flyers, VFR traffic will be able to fly up to 19,500ft!

Training and education

To cater for the necessarytraining and education, the newly formed CAA Industry Support Branch will conduct an education programme which will include safety seminars and workshops to be held across the country. A total of some $3m will be spent on the programme.

For the professionals operating in our·airspace, the new procedures will present little problem. However, there is no doubt that there remains a continuing need to educate some sections of the aviation community in the proper and sensible use of radio following the introduction ofAMATS. The balance has yet tobe achieved between those who indulge in garrulous chatter, and those who maintain a stony silence.

Summary

Considerable effort has been expended over the last three years to determine just what type of airspace model best suits Australia’s needs in terms of safety and cost.

The CAA believes that the model chosen will be safe and efficient, and with the cooperation of all users, should be capable of implementation with the minimum of problems. However, the Authority is mindful of the need to monitor the newprocedures following their introduction and has an active programme planned to achieve this.

I look forward to flying under the new arrangements