A Noise and Track Keeping (NTK) system provides information on:

• what aircraft are flying in the vicinity of an airport;
• where they fly;
• when they are in the air;
• how high and how fast they are;
• what runways and routes they are using;
• how much noise they make on the ground; and
• the corresponding weather conditions.

ERCD uses a system known as ANOMS (Aircraft Noise and Operations Monitoring System), which is supplied by Brüel & Kjær, one of the world’s major suppliers of such systems. The same system is operated at Heathrow, Gatwick and Stansted airports.

Typical uses of NTK data in ERCD are:

• annual noise exposure contour input data for Heathrow, Gatwick and Stansted, such as ground tracks, height/speed profiles, noise levels and route/traffic analyses;
• studies on behalf of DfT’s Aircraft Noise Management Advisory Committee (ANMAC), e.g. departure limits review, arrivals noise study, QC monitoring;
• descent profiles study;
• ad hoc studies.

Heathrow, Gatwick and Stansted airports use ANOMS principally to monitor:

• aircraft exceeding the departure noise limits;
• night flights restrictions;
• departure track deviations from the Noise Preferential Routes (NPRs);
• achievement of the Continuous Descent Approach (CDA) procedure.

ANOMS also provides input to the airport complaint handling teams and a variety of local studies of aircraft noise, procedures, track-keeping etc, and provides the source of 'Webtrak' aircraft tracking websites.