Pilot impact on the noise abatement effect on steeper approaches - Initial analysis of wind and flight data

One potential way to reduce perceived aircraft noise level on ground around airports is to introduce a steeper approach path which keeps the noise source further away from the ground. There are result from trials with steeper approaches that confirm that noise levels on the ground can be reduced. However, none of these studies consider a potential contribution or even counterbalancing effect caused by flight crews operating behavior on a steeper glide path. For example, the timing of landing gear and flap extension may heavily influence the aircraft as a noise source, possibly redistributing the noise footprint along the approach path and alter the desired effects. A study using flight data from a European airline is addressing the issue of pilot operational flight path management behavior during the approach at various glide slope angles. Since most approaches are conducted at the standard glide slope angle at 3º, it is difficult to gain larger amounts of relevant data. The approach in this study is to use the actual recorded wind during standard approaches to calculate an equivalent zero-wind glide path angle and correlate that angle to the pilot operational behavior. One essential step of this greater study is how to use the recorded wind, often varying with position and altitude, to calculate the equivalent zero-wind glide path. The purpose of the study presented in this paper is to develop an equivalent zero-wind calculation method. A user-centered approach was applied which included a pilot workshop, and interviews with airline pilots regarding their flight behavior using different scenarios. Results validated the selection of an equivalent zero-wind calculation method. This will be used in subsequent research analyzing flight crews' operational behavior. This will increase the knowledge about how to minimize the actual noise footprint around airports considering varying glide slope angles and meteorological conditions.