Noise and Pollution levels review at East Midlands Airport    

29th September  2010

Noise and Pollution levels review at East Midlands Airport.

A study at East Midlands Airport has shown that planes using an advanced Continuous Descent Approach (CDA)  when landing, they  can cut noise levels by between three and six decibels - around a 50 per cent drop in acoustic energy.

Fuel consumption would also be reduced, resulting in lower emmissions.It can take a very long time  for a new aircraft design that's quieter, and kinder on the environment, to be built from scratch and put into service airline. Finding ways to modify existing aircraft can bring similar benefits much more quickly.

The standard procedure for approaching an airport  involves a number of sections of level flight. Since the behaviour of the aircraft is well-defined during each of these, they simplify air traffic controllers' task of merging closely-spaced flights.

However, they also require greater use of the aircraft's engines, flaps, and speed brakes compared to a CDA procedure. Each of these operations creates more noise, which can be heard on the ground.If the aircraft can be kept as high as possible for as long as possible, the noise levels will be less. 

Using CDA would lessen the need of intervention by the Air Traffic Controllers, so any new proceedures would have to be suitable for most types of aircraft, and varying weather conditions.

East Midlands Airport is located close to the major urban areas of Nottingham, Leicester, Loughborough and Derby.

For the trial, the CDA waypoints were set in existing approach zones, which had been deliberately chosen to stop aircraft from flying over the most heavily-populated areas.

The new approach has been tested at several airports, and is now routinely used at  Los Angeles International Airport.During an earlier trial at Louisville International Airport in Kentucky, most pilots and air traffic controllers who took part welcomed the CDA procedures. 

They agreed that once the spacing of the aircraft had been established, there would be less need for controllers to issue frequent instructions to pilots.

It can be more difficult to implement CDA methods at busier airports which must deal with larger volumes of incoming aircraft, but there are techniques that can help manage this problem, and even at the biggest airports CDA might be useful at low-demand times of day.

People living around East Midlands Airport should have noticed a drop in the noise levels whilst the trials were taking place.