The Silent Aircraft initiative

A steeper descent, for example, would keep the aeroplane higher (and therefore out of earshot) for longer, and requires the plane to fly more slowly, the airframe team says. Making a steeper descent provides more power to fly the aircraft – just as you can take your foot off the accelerator in a car going down a steep hill – so the engines of the airplane are throttled back. The power has to be reduced even more, as the plane also has to slow down so that it is at the right speed for landing, and it is this slower approach that helps make it quieter. The noise generated by the airframe reduces very quickly as you slow down, so even a slightly slower approach can make a big difference in terms of noise.

The operations team are undertaking trials at airports in the UK and the US to test out different descent approaches and to measure the impact on ground noise levels and fuel efficiency.