Heathrow airport has begun trials of a steeper landing approach that it hopes will cut noise levels for residents under the flight path.
Until March 16 next year, flights will have the option of making the final approach to the airport at 3.2 degrees, compared to the international standard 3-degree glide scope. Noise monitors will be placed along the route to see if the steeper descent means fewer residents are affected.
The change to the angle of descent means that at eight nautical miles from the runway, aircraft will be 170 feet higher than usual. Heathrow says that recent trials at Frankfurt airport have reduced noise for people living nearby.
The airport plans to trial slightly steeper approaches if this first attempt is successful. “We believe approaches of up to 3.5 degrees are feasible in the longer term,” said a spokesman. London City airport uses a 5.5-degree approach in order to avoid tall buildings in the Docklands area, but the majority of aircraft types that fly into Heathrow are unable to perform to this standard.
The steeper approach does not affect the hold patterns of aircraft waiting to land, which at Heathrow, are separated into four vertical ‘queues’ depending on the direction the flight has come from.
The latest experiment follows a switch to Continuous Descent Approach at the London hub, which is replacing the traditional stepped approach where aircraft fly at lower levels for longer. Heathrow says more than 85% of daytime and over 90% of night time flights use the CDA method.