by Bruce Byron, Independent Aviation Consultant

Aviation expert Bruce Byron highlights the constant evolution of airport safety standards, and argues that risk assessment must be a continuous process.

shutterstock_124713472The vast majority of Australian airports can trace their origins back to the decades of aviation activity in the first half of last century. In those days, airports were built on existing cleared farm land relatively close to the edges of existing urban development.

Up until the 1960s, air travel was characterised by a certain amount of risk that was focused on the airport itself. Essentially, if an aircraft was going to crash, there was a good chance it would occur during takeoff or landing.

Although planners probably took possible aviation growth into account, the realities of accidents meant most airports were allocated much more land than was required for supporting infrastructure and the business of getting airborne and back down again.

In today’s environment of population growth, expanding urban boundaries and relative economic bounty, it was inevitable that pressure would mount for other uses of all that airport land. This is particularly the case for most of the leased federal airports adjacent to our largest urban centres.

Unlike some decades ago when you only went to an airport to go somewhere or marvel at some new jet airliner, you can now go to an airport to visit a warehouse, office complex or shopping centre. You can even park your kid at a childcare centre on airport turf.

But as those in the airport business know, you can’t build anything you like at an airport. Fortunately, apart from local planning requirements, new structures need to leave some room for the aircraft.

Runways are protected from encroaching development by defined runway strips that extend up to 150 metres laterally from the runway centreline. Further out from the runway, and off extended centrelines, there are imaginary surfaces that slope up from the runway above which structures should not penetrate.

All these defined limits are the standards that are imposed through legislation designed to protect aircraft and the 150 million passengers who take-off or land at an Australian airport every year.

But the reality is that these standards are based on what was considered safe in the past. Like the technology that drives new aircraft development, these standards have evolved, and will continue to evolve, over time based on past experience.

A bad outcome in aviation may well lead to a change in a standard, which may mean a change to possible infrastructure location and height.

In many ways, the aviation industry hasn’t been good at predicting future risks and has relied on a purely reactive approach.

A good example of this is the type of accident known as controlled flight into terrain. Although aircraft had occasionally been hitting hills for decades, the development of larger high speed jet aircraft being involved in this type of accident wasn’t anticipated to be the major problem that the statistics proved by the 1990s.

As a result, major regulators, accident investigators and manufacturers put the issue in the spotlight. The result? Predictive terrain database avionic equipment fitted to all airline aircraft that has largely eliminated this type of accident over 20 years.

This type of solution to one part the aviation system – aircraft equipment – has minimal impact of other parts of the system.

There is increased cost of course, but there is no need to change aviation infrastructure as a result of this type of fix and associated imposed regulatory standard. But fixes to safety standards around airports are going to have knock-on effects.

Although runway related accidents have always occurred, accidents on airports, particularly runway excursions, are now shown to be one of the top five airline safety issues.

This type of accident, notably the runway over-run, has been receiving increasing attention from leading aviation safety organisations, led by the International Civil Aviation Organisation (ICAO).

Although runways have required a safety buffer of 60m at each end for decades, awareness of this type of accident led to a regulatory requirement for an additional Runway End Safety Area (RESA) of 90m some years ago.

Despite the additional imposed standard, this type of accident didn’t go away, leading ICAO to recommend a RESA of 240m, in addition to the original 60m clearway.

The US Federal Aviation Administration has moved to impose this recommendation as a firm standard only recently, although if the space is clearly not available the provision of a reduced length Engineered Materials Arresting System may be approved.

This is a good example of a standard that seemed a good idea at the time being changed in response to real events.

For an airport operator, this type of change to a standard is not quarantined to just one part of the aviation system.

Clearly an increased RESA requirement may impact on existing or planned infrastructure development that, although considered ‘safe’ last year, may not be so next year.

In the same way, it is possible that other defined airport safety parameters, such as obstacle surfaces, may be subject to imposed regulatory change if dictated by aircraft safety performance.

The best way of minimising the impact of possible future changes is by taking a predictive approach when looking at hazards and associated risks of planned development at a particular airport.

It sounds like extra effort and cost, but in fact such processes are required as part of an airport’s safety management system (SMS) that has been required at certified aerodromes for a decade.

Although the safety standards detailed in regulations are designed to provide a safe outcome, they may be excessive – or inadequate – for a particular location.

In the same way that mandating crash helmets for riders of quad bikes in agricultural operations didn’t address the risk to riders at commercial salmon farms who accidentally drove into a pond, risks are best assessed by looking at individual circumstances.

Assessment of local terrain, water courses, existing development, prevailing winds and the performance characteristics of aircraft that use the airport will best define the hazards and associated risks.

It’s called a risk assessment and should be the bread and butter of any good SMS.

In the best case, it may provide the basis for a particular development. In the worst case, a development that proved to present an unacceptable hazard may indicate that an airport operator has not exercised the appropriate care and diligence that is also required under safety legislation.

Bruce Byron has held senior operational management and safety positions in three Australian airlines and spent over five years as Chairman and CEO of the Civil Aviation Safety Authority. He currently provides consulting services to the aviation industry.

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