The operation of civil aircraft in the Terminal Movement Area is a very complex subject. Many disciplines are involved and, certainly in Europe, there are problems of international agreements on standards and procedures for the various airline operators, airport authorities and regulatory bodies. For this reason there has been a tendency for certain aspects of the Operational System to be studied and improved without fully evaluating the interactions and hence overall effectiveness of new technological developments.

Noise and economics are major interlinking factors which are likely to have an impact on the whole future pattern of civil air transport development. In the past decade environmental pressures increased the need to design for low community noise levels; however, the fuel crisis and inflation have now shifted emphasis back towards fuel economy and lower operating costs.

The rate of growth achieved by air transport during the past three decades far exceeds that of any other transport system; this considerable rate of growth is clearly illustrated by, for example, the overall increase in total annual passenger movements at London's Heathrow airport, as shown in Fig. 1. It will be further noted that, despite the tendency for aircraft size to increase, the total annual aircraft movements at the same airport also show an overall growth pattern.

Opinions have been expressed in the past by such eminent people as the Duke of Edinburgh and E. A. Gibson and the NZ Civil Aviation Authority to this Society that there is a need throughout the world for an airborne equivalent of the tractor, or Land Rover. Current observations and market survey confirm that there is an expanding market in which this new aircraft has a huge role to play in agriculture and general land development because the existing specialist crop sprayers and converted conventional aircraft can only play but a part.

Increasingly stringent operational demands on military aircraft, together with the widening flight envelopes made possible by advances in aerodynamic, structural and propulsion technology, have forced the complication of stability and control augmentation systems (S/CAS) upon the aircraft designer. The early SAS configurations were conceived as devices to enhance the natural response characteristics of the aircraft; later, CAS evolved as a way of making the desired response more independent of the basic aircraft characteristics. Many recent examples of S/CAS are very complex, with equations of twentieth or higher order commonly being used for linear handling qualities analysis. In view of the fact that aircraft of this complexity have been part of the handling qualities picture for ten years or more, it is surprising that no widely accepted criteria for these aircraft have evolved.

A problem, commonly met in scientific and engineering experiments, is the determination of the damping of a system, given a recorded trace (such as that from a uv recorder) of the free damped oscillation following a disturbance. The simplest and most tedious method is to plot the logarithm of the peak amplitude at each half cycle against cycle number. Other methods have been given by Hogley and Gimmestad, Bratt and Wilcox and Crawford. However, the problem is so common, and the experiments and methods of recording the results so diverse, it is felt that a further method could find a place in the range of those available.