In order to estimate the amount of fuel burnt in an extended area surrounding and including a main terminal an investigation was undertaken in cooperation with the UK-CAA.

The main objectives were as follows :

• Development of a method to derive sufficiently accurate consumption information from ground observations;
• Collection of a sample of actual data covering all flights inbound to a high-density airport over a sufficiently long period;
• Comparison of several control strategies for the transit of inbound traffic through the area;
• Preparation of estimates of the potential fuel savings in an extended area (Zone of Convergence) where the control integrates both the approach phase and part of the enroute phase.

The results presented in this document pertain to the London zone and cover the traffic inbound to Heathrow during a two-hour peak period one morning in July 1980.