Update by Charles Kirwan-Taylor, Corporate Affairs & Sustainability Director

8 July 2016  

Charles Kirwan-Taylor

As I write this blog entry, our team at Gatwick is busily collating the first month’s data for analysis and consideration by the Civil Aviation Authority, this includes over 800 pieces of feedback received from the local community, which will be forwarded in full.

As well as community feedback, we have also received feedback from a number of our airline partners. A number of them feel that the amended route is difficult to fly in a compliant manner while others are exploring further possible ‘in house’ solutions to better fly the route. We have always maintained that there exists no perfect solution for Route 4, and while the majority of aircraft now remain within the confines of the Noise Preferential Routes, some airlines still seem to struggle somewhat to do so. We continue to follow this up with the airlines concerned as well as our airspace designers in order to identify possible improvements in track-keeping.

A number of correspondents with the airport utilise mobile applications such as Flightradar 24 which may indicate some aircraft are exceeding the recommended speed limit as they fly round the turn These applications display ground speed and not indicated airspeed, as does our own flight tracker, Casper.

The ground speed of an aircraft can vary significantly from its airspeed

  • Ground Speed is the speed of the aircraft over the ground; often measured in Knots (nautical miles per hour)
  • Indicated Airspeed is the air speed taken directly from air speed indicator without any corrections for temperature or pressure.
  • Calibrated Airspeed is the airspeed corrected for position and instrument error and is equal to True Airspeed (TAS) at sea level.
  • True Airspeed is the airspeed of an aircraft corrected for position and instrument error and taking pressure and temperature into account.

We are also receiving comments from communities located beneath the Noise Preferential Route regarding their new exposure to overflight. While we remain sympathetic to those who are experiencing new instances of overflight, the location of the Route 4 Noise Preferential Route has not changed, just the location of aircraft within it, and one objective in the design of the new procedure was that there should be some dispersal of traffic within the NPR. As illustrated on the maps in previous blog entries, there is now greater dispersal across the Noise Preferential Route than was previously the case. In the interests of transparency, I can share the following information:  

Route 4 track compliance (10 June to 3 July 2016)

Density map for all Route 4 departures 10 June to 3 July 2016

Map showing all Route 4 track violations for the period 10 June – 3rd July 16

Map illustrating Route 4 departures 3rd July 16 (to illustrate a typical day)