Noise

The aviation industry has made great strides in reducing the noise impact of airport operations over the past few decades. Aircraft coming off the production line today are around 50% quieter than they were 20 years ago and the aircraft manufacturers are working to reduce this even further. The new generation of aircraft – the Airbus 380 and Boeing’s 787 – are among the quietest yet.

Aircraft noise can be very disruptive to the lives of those who live close to airports. The effects are not uniform around the world and can be influenced by the type of aircraft that operate at an airport, the location and type of housing under a flightpath, the hours that an airport operates and the number of flights. As airport operations continue to grow, their impact on the community may also grow. However, the aviation industry is working together to address the issue through:
   • Noise reduction at source: aircraft and engine manufacturers using research and development into new technology solutions have been very effective in reducing noise from jet engines
   • Land use planning: working with local authorities and purchasing tracts of land to ensure that future expansion of the airfield is not precluded by current developments. Future noise impacts are mapped using ‘noise contours’ which show how the increase in aircraft movements at an airport will affect communities over time.
   • Use of noise abatement operating measures: at a number of airports, special operational procedures can lessen the noise impact on the local community, whether through using certain flight paths that avoid built-up areas, favouring runways with flight paths over uninhabited areas or techniques to reduce engine power soon after take-off.
   • Operational restrictions: in certain situations, specific aircraft types may be restricted in the use of an airport sometimes just during noise sensitive periods such as the night time or early morning.

Although aircraft operators rather than airport operators are the actual noise producers, negative attention is usually focused on airports. Often in close cooperation with local communities and local governments, airports are introducing a number of techniques to reduce the impact of noise on those who must live close to the airport, or underneath flight paths.

A large number of the world’s airports have been investing in noise mitigation programmes in their local community. Techniques vary, according to the local circumstances, but these mitigation methods can include providing sound insulation, alternative ventilation or air-conditioning for houses, schools, hospitals and other noise-sensitive buildings and funding community compensation programmes.

The ACI Noise Index
ACI has developed a noise index to assist airports wishing to introduce charges that will encourage airlines to move towards less noisy aircraft. This noise index is already used in Japan and ACI is encouraging other airports to take it up as a way of reducing noise factors through economic incentives. The ACI Aircraft Noise Index provides guidance for members and other interested parties on noise impact of various types of aircraft in operation today. It has been designed to achieve the following objectives:
   • Encourage global consistency in the implementation of effective airport noise management programmes;
   • Enable airports to communicate effectively with communities and governments about noise issues;
   • Provide an effective tool that is compatible with the ICAO system of noise certification standards;
   • Provide a consistent reference point to encourage manufacturers to develop and market the quietest possible aircraft and encourage airlines to upgrade their fleets as rapidly as possible.

 download the ACI Noise Index document.

ICAO and the ‘Balanced Approach’
A global industry needs a global view on regulations and impact. This is where the International Civil Aviation Organisation (ICAO) can be of service. Annex 16 of the Chicago Convention deals with aircraft noise.

ACI supports an integrated approach for addressing aircraft noise at airports, including the reduction of noise at source, land use planning, noise abatement procedures and operating restrictions at airports. The International Civil Aviation Organisation’s (ICAO) Committee on Aviation Environmental Protection (CAEP) provides guidance on this, known as the ‘Balanced Approach’, which appears in Annex C of Assembly Resolutions 35/5.

   • Reduction of noise at source: ICAO is the body that can enforce the reduction of noise at source for new aircraft designs through its noise certification scheme. ACI participates at CAEP and advocates the development of a new noise stringency scheme. To truly address the needs of airports, any stringency increase should require minimum reductions at all three of the assessment points (take-off and landing centreline, and take-off sideline), rather than just the current compromise of a reduction of the cumulative sum of the three.

ACI also has a firm position that CAEP should enforce a phase out of the noisiest Chapter 3 aircraft, including the old Chapter 2 aircraft that were re-certified rather than retired.

   • Land use planning: Land use planning is usually the responsibility of local government authorities and airports work with them to get in place zoning and land use rules that prevent or minimise noise-sensitive activities in the areas surrounding airports. In many cases, existing land use conflicts are being addressed by noise management and mitigation schemes including sound insulation of noise sensitive buildings such as houses, schools and hospitals, and by land acquisition in extreme cases.

  • Noise abatement procedures: Operational measures such as limitations of power and flap management, preferential flight track or runway use, flight re-scheduling, restrictions on engine run-ups and/or ground equipment use, rotational runway use and continuous descent approaches can be used for noise abatement. ACI recommends that such measures should be backed up by monitoring and enforcement procedures, and sanctions should be considered for repeat violations.

   • Operational restrictions: The introduction of a total curfew at airports is not advocated by ACI. Curfews also lead to under-utilisation of infrastructure, as airports are congested during the day and not used properly at night and may have financial and social effects far beyond national borders. Night time operational restrictions including curfew have flow on effects on many airports in other countries. However, restrictions of noisy aircraft may be introduced, in application of the principles of the ICAO approach.

   • Other noise sources and their mitigation: Major ground-based noise sources include aircraft engine run up and in-situ engine testing. Mitigation procedures range from the construction of screens and bunds, and the scheduling of activities to less noise-sensitive periods, to the construction of sound insulated and ventilated hangars for indoor run-ups.

Case Studies:  
     • Narita Airport - noise index for differentiated landing charges based on aircraft noise

Downloads:  
    • The ACI Noise Index

Links:
   • Air Transport Action Group  
   • ICAO 
   • Boeing airport noise tracker