CASA Response:

CASA has proposed a hierarchy of risk mitigators applicable to terminal airspace i.e. CTAF, AFRU, MBZ, CA/GRS, Class D and Class C control towers.

CASA has not included UNICOM in that hierarchy for the following reasons:

a) UNICOMs originated in the USA, however, CASA understands that the FAA does not include them in any risk mitigation hierarchy for airspace and traffic services;

b) UNICOM is not necessarily a dedicated service that will always be available when called; the nature of UNICOM is that it may be a secondary function to the commercial activities of the operator, e.g. refuelling, aircraft hire, pilot shop. Indeed provision is made for CTAF broadcasts should the operator not respond;

c) In Australia, as in the USA, Canada and New Zealand, the standards for UNICOM services limit the information that may be provided. The service is approved only to provide basic aerodrome and basic weather information, not to provide assessed, relevant traffic details, or meteorological observations. These limitations have been placed on UNICOM services because the operators are not necessarily certified to any standard other than that of a basic radio operator. CASA is not prepared to have UNICOM standards unique to Australia;

d) In regard to above point, the FAA AIM (4-1-9 d & e), makes a clear distinction between the ‘known traffic’ that may be passed by a FSS and the general traffic information that can be passed by a UNICOM, e.g. five aircraft operating in the pattern;

e) The higher level services such as CA/GRS have certified, or licensed operators which provide a dedicated, continuous service provided by the aerodrome operator. Because of the higher level of competence that is required to obtain certification, CASA permits the assessment of traffic so that only relevant traffic is passed.

In addition, the CA/GRS operators are qualified and authorised to provide meteorological observations includingcloud and visibility assessments, and an approved source QNH which can be used for the purposes of lower nstrument approach minima.

Those CA/GRS now in operation have been shown to enhance safety and have received a high level of pilot acceptance. CASA intends to retain the standards for CA/GRS service provision, as a cost effective service for use at high traffic density regional non-controlled aerodromes.