A design methodology based on the principles of system analysis was used to design a noise abatement
approach procedure for Louisville International Airport. In a flight demonstration test, this procedure was
shown to reduce the noise at seven locations along the flight path by 3.9 to 6.5 dBA and reduce the fuel
consumed during approach by 400 to 500 lbs. The noise reduction is significant given that a 3-decibel
difference represents a 50% reduction in acoustic energy and is noticeable to the human ear, and the 7%
reduction in the size of the 50 DNL contour that would result if all aircraft were to perform the procedure.
The fuel saving is also significant given the financial benefit to airlines and the accompanying reduction in
gaseous and particulate emissions. While the analysis of aircraft performance data showed how pilot
delay, in combination with auto-throttle and flight management system logic, can result in deviations from
the desired trajectory, the results confirm that near-term implementation of this advanced noise
abatement procedure is possible. The results also provide ample motivation for proposed pilot cueing
solutions and low-noise guidance features in flight management systems
