Reduce nighttime noise from arriving aircraft
London Gatwick, through its Noise Management Board, has been investigating and implementing noise mitigation measures since 2016. In 2018, it commissioned an independent study from the University of Sussex, which investigated the relationship between an aircraft's height and the perception of its noise. The study identified that ‘outlier’ noise events, defined as aircraft that are significantly lower or noisier than the mean average, are responsible for a disproportionate impact on communities.
To try and reduce the number of these lower-flying noisier aircraft, London Gatwick engaged Egis to design and run a six-month trial in the first half of 2024. Called the Reduced Night Noise Trial, it was the first trial of its type in the UK.
The aim was to see whether modern aircraft navigation procedures could be used to reduce noise by keeping aircraft higher for longer and by reducing engine thrust. Although noise models can be used to predict the noise impact of aircraft, these are considered less accurate beyond 12 nautical miles (around 22 km) from an aircraft’s touchdown.
Nighttime was chosen as it is a time when communities are especially sensitive to noise disturbances and because airline and air traffic control (ATC) procedures are best trialled when the airport is less busy. Traffic volumes are low at night, making the procedure easier to manage. Ambient noise is also reduced, which allows the noise from quieter aircraft to be measured further away from the airport.