Part 3—Producing and Delivering the Information
- 16. Producing the information
- 17. Delivering the information
Producing aircraft noise information requires the commitment of resources. However, much of the material shown in this document is deliberately based on adapting, and/or representing in a different way, data that has already been gathered for other purposes. In many cases the incremental costs of producing useful and effective aircraft noise information may not be high.
The options for producing the types of information shown in Part 2 are strongly enhanced if an airport has an installed NFPMS. This does not mean that good information cannot be produced for those airports without an NFPMS.
As a general rule these airports have the more persistent aircraft noise management issues—this may involve responding to community concerns and/or trying to protect the airport from encroachment by noise sensitive land uses. Flight path data is generated by the NFPMS on a continuous basis. Information on measured noise levels is also recorded on a continuous basis. Therefore this information is available for every operation into and out of an airport, except at times when the equipment is malfunctioning or is being calibrated/serviced.
Data on the times of operations and on the runways used at an airport is generally available from the airport's air traffic management system.
Given that all the necessary input data is generated on a more or less continuous basis, in theory it would be possible to produce all of the types of information shown in Part 2 on, say, a daily basis if this were considered desirable.
While these airports have all the necessary equipment in place to produce the information shown in Part 2, some parties interested in producing aircraft noise information have only limited access to the data underlying the information. As a result, their ability to produce the information may be curtailed.
Some airports without an NFPMS do have to deal with significant aircraft noise issues and would clearly benefit from the ability to produce effective aircraft noise information.
In particular, over the years there have been strong community pressures on urban GA airports which have housing located directly beneath busy training circuits. Conventional monitoring of noise at these airports using an NFPMS is not effective due both to the relatively low sound pressure levels generated by aircraft in
training circuits and also to the fact that many of these aircraft are not equipped with radar transponders.
In addition many regional airports are interested in establishing noise buffers to ensure that options for the long-term development of the airport are not compromised. Experience has shown that if a fully informed debate is to take place on the establishment of a buffer it is essential that comprehensible aircraft noise information is produced which covers areas extending beyond the conventional ANEF land use planning contours.
While these airports do not have an NFPMS, many of them do have published ANEF contours. The files that were used to produce the contours contain data that can be extracted to produce effective aircraft noise information and therefore these airports are in a different situation to those without an ANEF contour.
Airports with ANEF contours
The following comments relate to ANEF modelling that has been undertaken relatively recently and with later versions of the noise contouring software INM. It would probably not be practical, or meaningful, to extract data from ANEF files which were generated more than five years ago.
In developing the noise contours the modeller will have determined the design of flight paths and allocated movements to those flight paths. This information can be extracted relatively easily from the model, for example using TNIP, and a form of average day flight path movements chart (Section 9) could be produced based on the information in the ANEF. The INM files can also be used to produce N70s (Section 12) and single event contours (Section 11).
In producing this information it is important to bear in mind the difference between current and future scenarios (see Section 6). The information in an ANEF may need significant adjustment if it is to be used to provide information on the current situation. In some circumstances it may not be possible to extract any useful information about the present from the ANEF files.
Airports without ANEF Contours
Provided that an airport uses relatively standard operating procedures it should be possible to carry out ‘one-off’ surveys to establish the general location and spread in flight paths and typical aircraft noise levels at nominated monitoring sites. Combining this with local knowledge about the times, numbers and origins/destinations of ‘normal’ flights should enable some broad indicative information about the noise exposure patterns around an airport to be produced, for example, in the form of a flight path movements chart or a measured N70 chart.
As indicated in Part 2, the US Federal Aviation Administration's INM is required to produce the single event and N70 contour information. INM is used throughout the world by acoustic consultants working in the aircraft noise field.
A person should be well trained in the use of INM before the output can be treated with confidence. There are many consultants in Australia who can competently carry out INM work.
Most of the examples of information in Part 2 can be produced very rapidly using TNIP.
In order to set up TNIP a number of files and graphic templates need to be produced. Importantly, monitoring data needs to be available in a specified format in order to produce output from TNIP. Expert advice is likely to be needed in setting up the package. However, once established TNIP can be maintained on an ongoing basis without the need for expert assistance, provided arrangements are in place for the monitoring files (which update the databases) to be provided in the correct format.
Once TNIP is set up the examples of noise information shown in Part 2, which use TNIP, can be produced by a person with little or no computing skills or training. TNIP has been designed to be particularly flexible and allows an unskilled person to interrogate databases and produce output based on a wide range of user selected parameters. For example, information can be produced for specific days, for any nominated aircraft type operating on any selected runway, etc.
TNIP is freeware and DOTARS is available to give advice on setting up the package at individual airports.
Using transparent aircraft noise information presents the opportunity for a win/win situation. In the past there has often been a total disconnect between the different parties when discussing aircraft noise. Airports have stated that the noise situation is improving while members of the public have expressed an opposite view. In fact, both sides have been correct when viewing the issue from their own perspective. Conventional noise contours have been shrinking over the past decade as the noisy ‘old generation’ aircraft, for example B727 and F28, have been replaced by much quieter ‘new generation’ aircraft, for example B737-400 and B717. However, on the other side of the coin aircraft movement numbers, and hence the numbers of noise events, have been increasing and the gaps, or periods of respite, between periods of aircraft overflight activity have been decreasing.
Ideally, the focus now needs to move from a debate on whether things are getting ‘better’ or ‘worse’ to one where both sides recognise that the nature of aircraft noise exposure patterns is changing and adopt noise descriptors which establish a common understanding on what is actually happening. Experience in recent years has shown that the transparent aircraft noise descriptors, as discussed in this document, provide the opportunity to establish this common understanding. Some form of agreed language needs to be in place before a meaningful dialogue can take place between the parties on strategies for managing aircraft noise.
As indicated throughout this guidance material aircraft noise information can be produced in several different forms and, due to the fact that it describes aircraft noise in non-technical terms, can be used in a wide range of circumstances. In broad terms the information can be delivered in two distinct modes—reactively or proactively. While it is important that good quality information is available to respond to requests or to assist in resolving complaints, it is equally important that proactive efforts be made to ensure that transparent information is readily available to any member of the community.
Examples of the types of uses which suit each particular aircraft noise descriptor have been given in the cover sheets in Part 2. Figures 17.1 and 17.2 are ‘mind maps’ designed to give an overview of the relationship between the different descriptors. The first of these views the descriptors in terms of the type of information being sought, the second looks at the descriptors from the viewpoint of the functions being carried out.
The following sub-sections give some elaborations on the uses for the examples suggested in Part 2 and focuses on ways in which the information can be delivered to the target audience.
Responding to complaints
Experience has shown that short-term flight path maps, for example for one or a small number of flights, are the most appropriate tool for providing information to a complainant about individual flights or a particularly noisy day. These types of complaints tend to be made to airport noise enquiry services—ideally, noise enquiry units need to be able to provide copies of these maps to the complainant either through hard copy or electronically.
Written complaints to government departments and/or ministers tend to focus more on longer-term trends, such as claims that it has become noisier over the last two months. When responding to the complainant's letter, attaching copies of flight path movement and respite charts, coupled with N70 contours, has proven useful as this allows the cited time period to be placed in a macro context, such as, comparison between the last two months and the last year.
Disclosure—providing advice to prospective house buyers
Conventionally aircraft noise disclosure has meant appending advice about aircraft noise on property titles, or property transaction notices, of houses situated within the 20 ANEF noise contour at some Australian airports. While this strategy is positive it is not without weaknesses. Firstly, the advice tends to be of a general form which conveys little ‘real’ information on what the noise is like—the advice may typically say the house is in a ‘high noise area’. This approach does not catch houses outside the 20 ANEF contour but which are under a busy flight path. People buying in areas away from an airport often do not expect to be subject to aircraft noise. Clearly if a person buys a house expecting no aircraft noise and then receives a ‘surprise’ they are likely to be highly annoyed even by relatively low levels of aircraft noise.
It is therefore important that airports are able to provide copies of comprehensive transparent aircraft noise information on request to prospective house purchasers in order to minimise such surprises. Ideally this reactive approach can be supplemented by proactive approaches. For example, Melbourne Airport has for some years taken action to have information on flight paths outside the noise contours published in street directories. Publishing aircraft noise information on an airport's website is another excellent way to publicise the fact that there is noise outside the contours.
San Francisco Airport has recently indicated that real estate agents in the area are recommending to customers that they view the airport's ‘near live’ flight paths (Section 15) before they make property purchase decisions.
Providing advice to planners/prospective developers to place ANEF contours in context
Land use planning contours are specifically designed to ensure that land around airports is developed in a way that is compatible with aircraft noise. Under the ANEF system and its associated land use compatibility advice, land with an aircraft noise exposure of less than 20 ANEF is treated as ‘acceptable’ for any land use (with respect to aircraft noise). Land use planning decisions based on the 20 ANEF have been useful. However, as indicated in Section 2, relying solely on noise contours in the land use planning process is likely to result in less than optimal outcomes. In looking to future planning needs, it is now considered highly desirable that those involved in land use planning decisions should also be provided with transparent noise descriptor information. This then allows the planners and the decision-makers to have an understanding of the noise environment covering the general, as well as the specific, geographic area under consideration.
Ideally, land use planners should also have an understanding of the assumptions underlying the land use planning noise contours they are using and be aware, for example, of the sensitivity of the location of the ‘planning line’ to changes in forecasts, aircraft types, flight path locations, etc. TNIP has built-in features which allow a user to readily ascertain this type of information. It would therefore be beneficial for an airport to sit down with the planners and interactively demonstrate how the ANEF contours have been arrived at.
Noise assessment reports/EISs
This is another important area of use for transparent aircraft noise information. In the past these types of documents have tended to be treated purely as ‘technical’ documents conveying information between noise experts. However, it is now very apparent that non-experts use these documents, particularly formal EISs, as a prime source of information on future noise exposure patterns. There is a need for this information to be presented in a form that a non-expert can understand and relate to. It has been demonstrated in several recent documents that the concepts in this guidance material can be successfully incorporated into aircraft noise assessment reports.
Due to the speed at which TNIP can examine information and produce output, it is an excellent tool for carrying out ‘what-if’ analyses for EISs and noise assessment reports. It is now feasible to rapidly examine the noise outcomes of a wide range of different operating regimes for an airport and to produce this information in a form which is readily comprehensible to key persons who are not noise experts, for example airport management and senior bureaucrats. TNIP therefore facilitates the examination of many more options in EIS processes than has hitherto been practical.
In a similar vein it should now be possible to draw on these rapid ‘what-if’ capabilities to achieve much greater levels of community involvement in noise assessment processes than has previously been the case. In many circumstances it should be possible for a more or less interactive session to be held with community representatives which allows examination of how the patterns of noise exposure around an airport would change if certain changes were made to an airport's operating regime.
It is not uncommon for airports to produce some form of public relations informational material on a range of matters associated with the airport, including the management of aircraft noise, which is directed at the communities living in the vicinity of the airport. This may take the form of annual reports, ‘one-off’ publications on particular issues such as land use planning, or may form part of an airport’s website. The target audience for this type of material is almost always non-experts and, as a result, the transparent aircraft noise descriptors discussed in this paper are well suited to this application.
However, this can be a difficult area—‘information’ can be seen to be ‘propaganda’ if it is not presented in a neutral way. Unsupported claims of ‘world's best practice’, ‘things are much better than they were’ and the like, are likely to generate negative responses. Providing regular comparative information based on data gathered and/or collated by an independent body, without any interpretation, is likely to attain a more positive result. In particular, the data will achieve a greater level of acceptance if the message is expressed in a way that a member of the public can verify for themselves, for example, the number of overflights a day.
Use in the media
Flight path movements charts have been used in a number of Australian newspapers to describe noise exposure patterns around airports. This would appear to demonstrate that journalists, who communicate with audiences with non-specialist knowledge, have considered flight path movement charts in particular to be a good way to portray aircraft noise exposure patterns.
Routine environmental reporting
The importance of routine environmental monitoring and reporting was discussed in Section 2.
Some form of routine environmental monitoring and reporting is carried out at most major airports in Australia. Noise and flight path monitoring systems are in place at these airports and the data generated by these systems, combined with data derived from the airports' air traffic management system, is used to produce regular monitoring reports. Quarterly reports are produced for all airports with an additional monthly report for Sydney Airport.
The quarterly reports contain information for the period on the distribution of flight paths as well as detailed information on runway use. The reports also include data on noise measurements—both in a summary form through the use of the N70 (plus N80 and N90) and in a more disaggregated form. In addition to detailed runway use data, the monthly report for Sydney includes flight path movement, respite and measured N70 charts. These reports have received positive comments from community representatives and have demonstrated that transparent noise descriptors are particularly suited to giving a ready appreciation of both short-term variations and long-term trends in aircraft noise exposure patterns.
The reports are generally delivered through the various airport community consultative committees, however, this represents a relatively limited audience. Placing the report on an airport's website, for example, would give the report a much greater potential audience. If a wider audience is sought, a summary of the report could be included as a regular feature in an airport's community newsletter.
Airport Internet sites
Most organisations, including airports, now have an Internet site which contains key information about that body's activities. This is an avenue which appears to offer great potential for communicating with the public on aircraft noise issues. However, in Australia to date, there has been little development in this area.
A number of major international airports now use websites to provide communities with routine information on aircraft noise exposure patterns. The most recent development has been the introduction of the Internet flight path sites in the United States (see Section 15).
The database interrogation and high quality graphical output concepts in TNIP would appear to offer an attractive way for the public to access noise exposure data. If a database and an appropriate interrogation/graphical output program were established on an airport's website it would potentially allow a level of access to data far beyond that currently available in Australia.
Only a limited number of charts can feasibly be included in the normal printed routine airport noise monitoring reports. However, if a tool such as TNIP were enabled for the Internet it would allow a member of the public to personally and remotely interrogate an airport's aircraft noise database and present them with the option to generate multiple charts specific to their circumstances at a time of their choosing.
State of the Environment Reporting
Formal ‘State of the Environment’ reports are now generally being produced at national, state and local government levels on a regular long-term cycle as a means of tracking long terms changes in the environment. In the past, the reporting of aircraft noise exposure has been somewhat limited and typically restricted to computing the numbers of persons within certain noise contours. The new descriptors present the opportunity to throw a different light on trends in community aircraft noise exposure patterns.