Image: Line marking at Kalgoorlie Boulder
Aircraft may be the sexy icons of the aviation industry but at the end of the day they all need somewhere to land and managing that infrastructure is not without its challenges.
A dearth of local independent peer reviewers, the variability of bitumen quality, the lack of Australian design standards and specifications, and ever-increasing aircraft tyre pressures are among the sometimes complex issues facing those charged with managing runways, aprons and taxiways, according to pavements expert Bruce Rodway.
Rodway has more than five decades experience in the design, construction and maintenance of aerodrome pavements, starting his career with the Commonwealth Department of Works and spending almost a decade as chief pavement engineer with the Federal Airports Corporation.
He has been a consultant since 1998 and has worked at airports in Australia and at a diverse range of international locations, including Hong Kong, Malaysia, India, Kuwait and New Zealand.
He also represented Australia on the expert pavement design group convened by the International Civil Aviation Organisation to devise design methods for aircraft such as Boeing’s 777 and the Airbus’ A380, and co-developed the aircraft pavement design computer program, APSDS.
A speaker at May’s Australian Airports Association (AAA) Pavements and Lighting Forum, he says a major difficulty for airport pavement managers is the absence of Australian design standards, practice manuals and standard specifications for aircraft pavement design and construction.
“This can lead to situations where, to the frustration of contractors, construction specifications for identical aircraft pavements can be arbitrarily different, even on the same site,’’ he says.
“Initially all Australian aerodromes were owned by the Australian Government so the design and construction expertise was largely developed and held by the Commonwealth Department of Works (CDW). Aerodromes were progressively transferred to local ownership and, with the exception of Defence Department aerodromes, the remainder have now been privatized.
“Standards and specifications had been produced by the CDW but these were withdrawn in 1985 leading up to the department’s closure. In the absence of local standards there is an increasing tendency to adopt, sometimes uncritically, overseas practices that are not fully suited to Australian conditions and experience.’’
Training for aircraft pavement engineers, once provided by the government, is also an issue.
Rodway notes the government system allowed senior specialists to make overseas study tours to update and advance Australian practice. But for many years training opportunities within Australia had been limited.
He is hopeful that a post-graduate course for airfield pavement engineers at the University of the Sunshine Coast will help address the problem and says the AAA conferences also played an important role.
“Prior to the AAA conferences there had not been an aircraft pavement conference in Australia since 1995,” he adds.
The closure of Australian oil refineries and changes in the world oil market poses another challenge. While Australia once obtained crude oil from the Middle East and made bitumen in local refineries, it now imports refined binder. The imported bitumen has been refined from oils that now come from a variety of global sources, leading to a variability that makes it difficult to predict runway performance.
“Currently this uncertainty is possibly the most troubling unresolved issue for pavement managers,” Rodway said.
A “sleeper” problem for many airport managers is the disruption to airport operations that occurs when long-lived concrete pavements eventually reach their end-of-life condition and must be replaced. Long-term planning is required, says Rodway.
Another emerging problem stems from the tendency for aircraft manufacturers to keep boosting tyre pressures with each successive model of aircraft. The Airbus A350 and Boeing’s Dreamliner are particularly problematic in this regard. Practically all of Australia’s runways are surfaced with asphalt, not concrete. But asphalt surface temperatures during hot periods can exceed 70 degrees Celsius and Rodway worries that we are nearing asphalt’s limit to sustain the new tyre pressures at these temperatures.
Also on his list is the management and reliable measurement of the runway friction available to braking aircraft, something he says remains problematic in Australia.
“Like the rest of the world we rely on the friction research done and the guidance provided by NASA and the US Federal Aviation Association,” he says. “But we should heed the firm warnings of both these organizations that friction values measured by currently available devices should be used only as guidelines for evaluating the surface friction deterioration of a runway and for scheduling maintenance actions rather than imposing mandatory friction requirements.’’
An award-winning journalist, Steve began covering aviation in the United States in the early nineties before returning to Australia later that decade and editing The Australian’s aviation section for 17 years. He is editor of Airline Ratings and has co-authored books on industry initiatives aimed at reducing greenhouse emissions.
Steve has joined the AAA to write interesting and informative editorial on the aviation industry.