Earlier this year the Civil Aviation Safety Authority introduced a number of changes to operations at six general aviation aerodrome procedures (GAAP) airports. CASA’s Peter Gibson explains the changes.

Why has CASA changed procedures at the six GAAP aerodromes?
During 2008 and 2009 CASA examined a range of safety issues relating to GAAP aerodromes. A number of studies and reports were completed, with surveillance of air traffic services also carried out. In addition, there was a review of the teaching of GAAP procedures and reports were issued by the Australian Transport Safety Bureau into mid-air collisions at GAAP aerodromes. These reports and studies culminated in the release of the so-called GAAP Utility Review report. This report was completed for CASA by the Ambidji Group and it looked at the appropriateness of current GAAP airspace classifications and procedures, overseas best practice and International Civil Aviation Organization airspace classifications and procedures. After carefully studying of all this material it was clear to CASA that safety improvements at GAAP aerodromes were required.

Which aerodromes are affected and what the key changes to procedures?
Procedures have been altered at six GAAP aerodromes: Archerfield, Bankstown, Camden, Moorabbin, Parafield and Jandakot. The main changes are a limit on the number of aeroplanes in the circuit for one runway, controlled by one air traffic controller, to six. If two runways and two controllers are available then the number of aeroplanes in the circuit is limited to 12. An additional departure aircraft is permitted and individual air traffic controllers can increase the number of aircraft in the circuit if they consider this is necessary for safety reasons. There is now a requirement for all aircraft to obtain an air traffic control clearance to enter, cross or taxi along any runway, active or inactive.

Why change procedures that have seemed to work well for many years?
The changes to procedures were an appropriate and measured response to all the information available, including the studies and reports into GAAP safety. Extensive qualitative and quantitative analysis was undertaken. CASA determined the changes were required to reduce identified risk levels in specific areas of operations to as low as practicable. The changes to the procedures at the six GAAP aerodromes complement an extensive pilot education and awareness campaign that had already been initiated by CASA on a range of key safety issues. This campaign covers issues such as preventing mid-air collisions, weaknesses in pilot knowledge about GAAP procedures and education on situational awareness.

Will the changes to procedures actually improve safety?
CASA has calculated the changes will reduce identified risks at the six GAAP aerodromes. With caps on the number of aircraft in the circuit at these locations, the risk of a mid-air collision will be lowered due to the decreased density of aircraft in the GAAP airspace. The re-introduction of the requirement to obtain an air traffic control clearance to enter, cross or taxi along any runway builds a stronger defence against runway incursions, which is a major safety issue. By April 2010 aerodrome air traffic services will be required daily for the hours of daylight without any reduction in the service currently provided during the hours of darkness. This will improve safety by providing greater air traffic management at the six aerodromes.

How were the caps on circuit movements set?
The caps were calculated on the average speed and rate of climb of typical training aircraft normally operating in the circuit at these six aerodromes. In general, the effect of the caps will be to reduce the peak density of traffic, rather than to reduce the total possible number of movements. The caps do not apply to helicopter movements. The caps are considered a temporary measure while other initiatives to manage the identified risks are developed, assessed and implemented.

Will these aerodromes now move to Class D airspace and how will that happen?
CASA is requiring Airservices Australia to provide Class D air traffic services at the six GAAP aerodromes during the hours of daylight on or before 21 April 2010. This will align Australia with International Civil Aviation Organization airspace standards. The change will also introduce surface movement control at these GAAP aerodromes, further decreasing the risk of runway incursions. The move to Class D will simplify regulatory requirements on both pilots and air traffic controllers, making the standards easier to teach, learn, practice and apply.

Is it true there’s still confusion over the changes and pilots are not following the new requirements?
CASA put a great deal of effort into communicating and explaining the changes to pilots. Printed material has been sent to all pilots, special pages were created on the CASA web site and CASA’s aviation safety advisors have been active at the six locations answering questions and providing advice. CASA has been carrying out operational surveillance at the aerodromes and the evidence is that pilots adapted quickly to the changes and operations are smooth. Given these are busy training aerodromes, the pace at which the aviation industry responded to the new requirements was very pleasing.