Cyberspace Airport and Airways Design

The past solution of creating another airport to separate traffic is an incredibly expensive and complicated venture. Suitable real estate is often a long way from the city the airport is designed to serve, creating a need for costly transportation routes. To add to the complexity, modern society has created vocal lobby groups which in times of close fought elections, can hold the balance of power and thus sway decisions away from meeting the broader needs of the general community to meeting the specific needs of an unrepresentative minority. Life was not meant to be easy and as our society becomes more complex, so do the management problems.

So how do professional bodies such as AirServices Australia optimise the use of scarce airport and airways resources? The ubiquitous computer is one modern tool that has the power to provide solutions to these complex problems. Simulation techniques are used to design and test theoretical operations from existing and proposed facilities. There are many approaches that can be taken. One general method is to treat aircraft operations as a series of queues. Aircraft queue for a place on a taxiway, then for a take off on the runway, then a place in the airways, a slot on an instrument approach, a landing, then back to the taxiway and finally the parking bay. This type of simulation uses special computer languages and is good for a ‘rough cut’ approach to planning.

However, the queuing theory falls short of providing the complete answer because of the complexity of aircraft operations. The aircraft in the queue must be able to accurately portray the mix of operations profiles experienced today. A good example is mixing Dash 8 and 737 aircraft on the Canberra to Sydney run. The 737 is much faster than the Dash 8, but the guys in the turboprops pull a mean trick when close to the airfield. They try to minimise the transit time, so keep descent and approach speeds as high as possible close to the airfield, turn onto a tight base leg, then pull the throttles to idle and let the big props act as big speed brakes. Meanwhile, the 737 that left later has had to track a wider base and longer finals, as the slippery jet lacks the speed brakes to produce the same rate of deceleration as the Dash 8 – and starts from a higher speed. Thus, the Dash 8s duck inside the flightpath of the 737s, which must make for some interesting conversations in the flight planning offices. Most queuing languages cannot cope with this level of complexity.

The solution is to conduct what is known as an ‘orthomorphic’ simulation. Every taxiway, runway, navigational aid, operational procedure and aircraft characteristic is simulated. Aircraft are launched into this ‘cyberairspace’ and proceed to taxi, take off, navigate, approach, land, taxi and park using the same rules and flight characteristics as in the real world. As facilities become overloaded, the simulation cyberairspace will generate queues on taxiways and holding patterns in the airways, all according to the flight rules we currently observe.

How is safety assessed? The ICAO standards of separation are used worldwide as the standards which, if observed by pilots and air traffic controllers, will yield acceptably safe and expeditious air travel. Hence, there is a high concentration on rules and regulations that define minimum separation under various conditions. The simulation language can have these rules designed into the way the cyberaircraft move from place to place. Complexity is increased, but the problem is ‘computable’.

Clearly, it is possible to use this type of technology to determine the ultimate capacity of airports and airways. All complex traffic systems have ‘bottlenecks’, and to find them, the staff running the simulation load the cyberairspace with increasingly higher densities of traffic until symptoms of overload appear. These will be the same as in the real world – long taxiway queues to get a takeoff slot, or a tall stack in a holding pattern to get an approach and landing slot. Professional airways design staff then devise alternative procedures until the particular constraint is eliminated. Through a series of experiments of this type, it is possible to balance the use of the limited airport and airways facilities. There might be some remaining delays, but the outcome will be an increase in throughput and more cost effective use of the scarce airport and airways facilities.

How does AirServices Australia solve this problem? Once again, we can be proud of being part of the ‘clever country’ as AirServices Australia uses software developed in-country that is superior to any other cyberairspace simulator. This software has generated an international reputation, for example Boeing bought a copy to help China develop and optimise its national air transport system.

The simulation group consists of a small team of professional engineers in the Research & Development Section of the Planning & Development Division of AirServices Australia. They are equipped with some very powerful computers designed to run the complex software required for this cyberairspace simulation. They have complete models of the Australian airspace simulation and the facility is regularly used to develop and assess the capacity of our airports and airways.

Why then is there such a debate over the capacity of Kingsford Smith Airport at Sydney? Why can’t the simulation definitively determine the capacity of the facility? The answer is that, if the staff are given the time to run all the required simulation, it can. The question is one of criteria. What is the objective of the simulation? Is it to determine the maximum number of movements possible using ICAO separation standards, or to determine the consequences of using only part of the available facilities (say as banning the use of the East West runway) and routing aircraft away from sensitive areas and hence on long and inefficient approach and departure paths? In each case, the simulation will give a definitive answer; however, the two answers will be definitively different.

The debate that needs to be fostered is one of community benefit. With Australia seeking to enhance its tourist revenue and increase the pace of its economy, an efficient air transport system is vital to our nation which has a small population and large distances. This debate has been hijacked to some extent by the vagaries and realities of the political system. When a Government has a substantial majority, it can enjoy the opportunity to take a long term approach that maximises community benefit. However, when power is won or lost on a seat or two, then the focus shifts to sectional issues. When a handful of people hold the balance of power, politicians will inevitably arrange matters to win their votes. In meeting the needs of a few, overall community benefit in both the short and long term can suffer.

Australia has the technology and the skilled professionals to evaluate a range of options. If the people of Sydney and Australia are to receive the maximum community benefit from their considerable investment in air transport resources, then the debate over the use of Sydney Airport needs to be broadened to cover the more general community benefits.

AirServices computer modelling suggests that if KSA was used to its full capability as a three runway airport using typical international practices that it would be able to operate up to a maximum of 110 movements an hour. (FAC)

A strategy for making the most efficient use of all these resources in the Sydney basin would be a sound way to start. We have the technology and the skills, now all we need is the vision and the will to succeed.