Explanations of the flight noise contour maps

With the aid of the computer program CadnaA (Computer Aided Noise Abatement) the noise can be made “visible”. Simply click on a point on the map and then read the corresponding value:

- Equivalent continuous A-weighted sound pressure level (LAeq),

 - Number of the noise events over a certain time (NAT) or

 - Number of the additional, not necessarily remembered EEC wake-up reactions (AWR)  induced by air traffic noise.

These results give you a good initial overview of the noise burden situation in the region, although the frequent individual levels are perceived as particularly disturbing by local residents and are thus of special interest.

The representation is based on calculations. Please note that routes may change in the future and thus also the noise contours. In the overview you can select various scenarios. Click on “Display” to show the desired noise situation.

To the Flight noise contour maps

Questions and answers on the representation of the UNH air traffic noise contour maps

1. What does the application represent?
The air traffic noise contours show a forecast noise contour according to AzB 08 within a range of 40 dB to 75 dB and a class width of 5 dB. The class width is delineated by the coloured areas. Outside of the red delineation no data are available. 

2. Which detailed information is available?
If you click on the map inside of the outermost colour contour you will receive the noise level forecast for this location including designation, frequency evaluation and, as applicable, the assessment period of the selected scenario. 

3. Which views can be selected?
At the top right you can select various backgrounds. The views map, satellite or terrain are available.

4. How can I move the map?
At the top right you will see the navigation bar for the map. Here you can zoom in and out and move the map in all directions. You can also move the map with the mouse.

5. What do the colours mean in the calculation results?
The colour-highlighted areas show the noise contours from 40 dB to 75 dB with a class width of 5 dB.

Information on noise calculation
In principle, the calculation result of an air traffic noise forecast is always less accurate the greater the distance to the airport. This is due, on the one hand, to physical effects and, on the other hand, to effects of the calculation procedure. The individual aspects are briefly outlined in the following.

Physical influence factors

1.1    Meteorological influences
The greater the distance between the aircraft and the respectively observed incidence location, the greater the meteorological influence.

1.2    Description of air traffic
The greater the distance to the airport, the greater the individual deviations of an aircraft from the position based on the calculation can be. This applies for the lateral dispersion and for the height of the aircraft above the ground. The resulting effects can be adequately represented with the usual approaches for the description of a dispersion. In the case of departures, this affects the whole flight path.  In the case of arrivals, it particularly affects the merging zone until reaching the final descent to the airport. 

2.    Calculation model
For air traffic noise calculation Germany currently uses the AzB (instructions for the calculation of noise protection zones) dated 19.11.2008. This calculation routine was developed to fill out the law on the protection against air traffic noise.

Like any calculation model, the AzB represents an abstraction and simplification of the reality. This simplification and abstraction are necessary due to the fact that nature has so many different manifestations that a generalisation and categorisation is unavoidable for practical purposes alone. Although the AzB by no means takes account of all effects, an air traffic noise calculation for the Frankfurt region in accordance with the law for the protection against air traffic noise takes more than 24 hours even on modern computers. 

As the AzB was developed as a calculation routine to the air traffic noise law, in view of the restrictions outlined above, this calculation routine takes account mainly of those effects which are important for the purpose of the law and from a physical point of view. This is the most accurate calculation possible of the incidence of air traffic noise in the protection zones specified by the law, i.e. the highly burdened areas.

The lowest noise levels which, according to the law for the protection against air traffic noise, must be determined amount to (outside at the window) LAeq,Day = 55 dB(A), LAeq,Night = 50 dB(A) and LAmax,Night = 6 x 68 dB(A). For areas with these or higher incidences of air traffic noise, we can assume a high degree of accuracy of the air traffic noise determination.

For areas with lower noise incidence we can assume an increasing inaccuracy of the calculation results. A precise quantification of the inaccuracy is currently not possible as in this level range no systematic studies on accuracy have been carried out. 

Insofar as the air traffic in these areas can, however, be described with adequate accuracy, we can assume that the calculated values for incidence locations which lie directly below the flight routes are a relatively good reflection of reality. For incidence locations to the side of a flight route, however, we can expect a tendency towards overestimation of the air traffic noise incidence as the AzB always assumes relatively favourable conditions for noise dissemination. Noise reductions such as occur in the case of a cross wind or head wind situation are not taken into account in the AzB. 

But even within the protection zones subject to the air traffic noise law, deviations are possible between a calculation in accordance with the AzB and measurement results, not least due to the effects cited under point 1 above. However, according to the Federal Administrative Court (BVerG 11 A 9.97), such a deviation is insignificant relative to the purpose of the calculation routine. According to the court: "The scope for action of the legislator thus also extends to the establishment of the method for the calculation of the incidence burden which is to be compared with the incidence limit values. In this area in particular, simplification and generalisation are unavoidable."

© 2010  Umwelthaus gGmbH
This website is exclusively for demonstration purposes. We do not accept any liability for the data contained therein, their correctness, accuracy or any resulting conclusions about actual flight movements in the airspace shown.
The information about public transport in Google Maps is provided by Umwelthaus GmbH and serves only to demonstrate the air traffic over the Frankfurt region. Umwelthaus GmbH does not assume any guarantee or liability for the correctness or the completeness of this content.