Among the various environmental concerns, the aircraft noise item has been constantly growing in importance over the past years. Indeed, unlike a Mozart’s symphony, airplane noise is one of those sounds which are undesirable to most of the observers. Its various effects on man, especially on the people living in the vicinity of civilian and military airfields must be studied to be better accounted for.
This shall allow the determination and continuous refinement of indices reflecting noise impact, in order to develop an appropriate noise policy. The latter has the difficult mission to conciliate both the noise reduction around airfields while not penalizing too much the airlines operations, that is to say the air transport industry as a whole.
Consequently it is necessary to bear in mind this philosophy of continuously improving the ways of alleviating the noise exposure in a consensual way, namely the “balanced approach” concept :
– by adopting an appropriate land use and urban development
– by promoting ways to improve the aircraft design (noise reduction at the source)
– by establishing specific operating procedures
– by restricting operations (if needed)
The purpose of this document is to provide Airbus operators with a general background for a better understanding of what is behind the current regulations/recommendations.
In October 2002, the original ACI (Airports Council International) Aircraft Noise Rating Index was adopted by ACI’s Governing Board. The Index was designed to achieve the following objectives:
– Encourage global consistency in the implementation of effective airport noise management programs;
– 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.
The Index combined cumulative reductions with reductions at the three measurement points. The Index thus matched current trends and technologies and remained simple, while at the same time it reflected more faithfully the specific situation at each individual airport and was therefore of greater use for noise management policies.
The Index applied to aircraft certificated under ICAO Annex 16 Chapters 2, 3, 4 and 5, using the corresponding noise certification data. The Index placed aircraft into six categories of noise performance, ranging from A to F. An aircraft is required to meet both criteria concurrently in order to qualify for the corresponding noise category.