Using RNP AR for Noise-Abating Approach Procedures

Abstract

This paper describes RNP AR approach procedures which have been designed by the German Aerospace Center (DLR) Institute of Flight Guidance in the course of the LufoIV project HETEREX. The approaches purpose is to reduce the noise impact of approaching aircraft at an airport. Approaches with vertical guidance need a straight segment of about 10 NM prior to touchdown due to technical and operational, i.e. safety reasons. In case settlements are located on the extended centreline nearer than 10 NM to the airport, these settlements can not be circumnavigated. With GPS and vertical navigation based on the barometric system, approaches with vertical guidance do not need a straight segment of 10 NM prior to touchdown anymore. Those approaches have first been developed and certified for mountainous regions, where straight segments of up to 10 NM were impossible due to the terrain around the airport. Operations to these airports were limited to good weather situations only. With the precision of GPS in conjunction with a barometric vertical navigation system (BARO VNAV), those airports can now be operated to in much more inclement weather situations regarding visibility and cloud bases. In 2010, ICAO released a certification guideline for those approaches with curved segments nearer than 10 NM to the airport, called RNP AR for Required Navigation Performance, Authorization Required. In Germany, no airports with the need for RNP AR approaches due to mountainous terrain exist. Nevertheless, RNP AR approaches with their possibility of curved segments nearer than 10 NM prior to touchdown provide the possibility to design approaches which avoid settlements that lie under the extended centreline of a runway and are nearer than 10 NM to an airport. In this paper, five approaches to the airport of Nuremberg are presented which lead approaching aircraft around several towns near Nuremberg which with the currently applied approach procedures can not be circumnavigated and thus are impacted by the noise of arrival traffic. These approaches show how RNP AR can be used to improve airports’ acceptance by surrounding communities. The five example approaches at Nuremberg are presented together with the design rules that determine their exact shape as well as the population areas that can be circumnavigated with these approaches. Their potential to further reduce fuel consumption and thus production of CO2 by shortening the length of approach procedures is also presented. The approaches have undergone a first flyability assessment in a full-flight simulator.