If you’re looking for an example of how innovation and policy-making can combine to great effect, noise abatement in the airline industry is a good start.

In 2017, the International Civil Aviation Organization’s (ICAO) Chapter 14 noise standards will come into play for high-weight aircraft, with those for low-weight aircraft to follow in 2020. Overall, by 2026, the regulations will reduce the total land area exposed to aircraft noise by 2%, removing 500,000 people from the noise zone – a figure expected to double by 2036. There has been little fanfare about the impending deadline, however, due in part to the fact that aircraft manufacturers have been so successful at reducing noise output that they have been prepared for the new rules for years.

During the past 40 years, the noise output of aircraft has decreased by more than 75%, with 50% of that reduction occurring in the last decade alone. This is largely due to small aerodynamic innovations: for example, the placing of chevrons (metal teeth) on the trailing edges of the jet engine nozzles of the Boeing 747-8, which enhances the mixing rate of the shear layer (the layer of air between the hot exhaust and the cold outside air). This path of gradual innovation is likely to continue, with each new generation of aircraft anticipated to be 15% quieter than its predecessor.

Under the ICAO’s “balanced approach” to aircraft noise management, however, noise from the source is only one of five areas that should be considered when putting an abatement strategy in place – the others being land-use planning, operating procedures, operating restrictions and noise charges. These are in the hands of local and national governments, regulators and, most significantly, the airports.

Airports are somewhat limited as to their freedom of action, hamstrung as they are by their fixed locations and the fact that poor government planning often sees housing encroach on what was once an unambiguous aircraft noise zone – inevitably leading to complaints. However, there are measures that can be taken; some motivated by regulatory requirements, others going above and beyond these considerations.

Meticulous planning

Helsinki Airport is in fact located in the nearby city of Vantaa, 10.6 miles north of the Finnish capital’s centre. The airport saw record footfall in 2015, as more than 16 million passengers passed through the gates. Helsinki Airport has also quietly been expanding its long-distance routes – it currently serves more routes to Japan than any other European gateway – and is investing heavily in facilities to accommodate wide-bodied aircraft, such as new boarding bridges and additional wider parking spaces.

From a noise abatement standpoint, the growth of wide-bodied aircraft has been advantageous for airports, allowing them to benefit from greater passenger numbers without having to schedule more flights – exactly what has taken place in Helsinki. The airport also benefits from the location of a large rural tract to the north, which it can use for night-time approaches, orienting flights away from the suburbs of the capital to the south.

Nevertheless, the airport’s management has been especially proactive and meticulous in the planning of its flight tracks, collecting large amounts of data and using it to tweak operational procedures to maximum effect.

During peak hours, planes land on Runways 1 and 3 from the direction of Kerava, a nearby town of 35,000 residents, while outside these hours only Runway 1 is used from that direction. In November 2013, the intermediate approach height of Runway 1 (on which 30% of landings take place) was increased by 330m, and that of Runway 3 (3% of landings) decreased by 270m during peak hours and at night. While Runway 3 would have slightly weaker noise control, the changes made to Runway 1 have had
a notably positive impact on noise emissions in Kerava and another nearby town, Sipoo.

During the past 40 years, the noise output of aircraft has decreased by more than 75%, with 50% of that reduction occurring in the last decade alone.

“We have fine-tuned the departure flight tracks to avoid the densely populated areas,” says Mikko Viinikainen, Finavia’s sustainable-development director. “We have undertaken a lot of cooperation with the land-use planners, looked closely at the population density around the airport, and have fine-tuned the departure tracks according to the geography and location of suburbs. This has been done during the past
15 years, bit by bit, and is very well optimised at the moment.”

The smoothness of this process has been helped by the fact that Finavia, the owner of Helsinki Airport, is also a navigation services provider – an unusual situation in European airport operations. Having all the expertise in-house means that all noise mitigation planning can be easily combined with airspace planning and the daily operations of air traffic controllers.

Finavia also maintains effective cooperation with Vantaa’s local government, which has led to a consensus forming on route-planning and runway use. Once this consensus is in place, the key to successful implementation, according to Viinikainen, is to proceed step by step.

“It’s very important that no drastic changes are made in the way the airport operates,” he says. “This is important from a noise management point of view because major changes always surprise people, no matter how well you inform them beforehand. Your message will never be heard by each and every citizen in the community. So when implementing any changes in the way runways operate or how flight tracks operate, or whatever, one should avoid trying to make drastic movements in one go.”

Reaching out

Two and a half thousand miles away in Lisbon lies Humberto Delgado Airport, which handled 20 million passengers in 2015. Predominately a European-focused airport, Lisbon also runs routes to the former Portuguese-colony cities in Brazil and Africa, as well as an increasing number of North American services.

Unlike Helsinki, Humberto Delgado is surrounded by densely populated suburbs, and so doesn’t have the
same degree of flexibility in terms of runway use.

In fact, so contentious is the issue of noise that plans have been in development since 2007 to build a new airport. In 2008, Alcochete – a military training facility located approximately 17 miles away, on the other side of the River Tagus – was announced as the new site, but the plans were shelved due to the Portuguese Government’s austerity programme. All the while, traffic at the existing airport has continued to grow at a rapid pace: passenger numbers hit 18 million in 2014, a two-million year-on-year increase.

Despite this challenging set of circumstances, the airport does its best to mitigate noise and mollify local residents. Beyond regulatory requirements to create a strategic noise map for every five-year period, Humberto Delgado undertakes constant noise monitoring through a network of seven fixed monitoring stations, as well as a portable station to monitor less accessible spots. This allows a decent impression to be formed of how the noise picture changes in real-time, providing a more accurate overall approach.

Outreach and incentives

Humberto Delgado has also learned to excel at the soft side of noise mitigation. Under the airport’s noise action plan (NAP) for 2013–18, airlines are encouraged to improve their environmental performance, with a reward for those who reveal the best of best practice.

The airport also provides acoustic insulation for residential buildings with sensitive uses that happen to be in areas most exposed to noise. According to Nuno Ferreira, the airport’s deputy director, this kind of outreach is of great importance.

“>Midfield Concourse houses cutting-edge technology according to an environmentally friendly design, with more than 35 green features to maximise the use of natural light and regulate indoor temperature.

“There’s a big concern with the dialogue between Humberto Delgado, local government and residents,”
he says. “In fact, the NAP and strategic noise maps are always submitted to public opinion, and to environmental authority approval, considering the community inputs… Likewise, the communities are also advised of air traffic changes, due to construction works or other factors, which can cause different noise levels from usual.”

Ferreira continues, “It’s also planned to carry out surveys addressed to residents and the public in general about the implementation of the measures in the plan, and then the publication of the results. Public
opinion is quite important to consider when defining action plans or noise abatement measures.”

Airport operators only have so much control over the environment and how that environment changes. Many airports that were built in remote areas eventually come up against the challenges of population growth and movement from city centres to suburbs. However, careful planning, plenty of data, and clear consultation and communication can go a long way towards mitigating this problem.