ABSTRACT
The human pilot would generally be very successful in flying an airplane if he or she blends maximum performance and adequate handling qualities (HQs) [1]. For an efficient flight operation satisfactory HQs are essential. Cooper and Harper [2] state that ‘‘handling qualities are those characteristics of an aircraft that govern the ease and precision with which a pilot is able to perform the tasks required in support of an aircraft role.’’ In the opinion of the pilot, the HQs (of an airplane) depend on aircraft dynamics, control system performance, cockpit environment, outside view, and instrument display [1]. In the early years of HQ research the pilots’ evaluations in various types of existing aircrafts, variable stability research aircraft=in-flight simulation (IFS), and ground-based simulators have helped in the development of HQs criteria. Certain government agencies would usually and often compulsorily demand compliance with certain HQs requirements for military as well as transport aircraft. The purpose of the military requirement is to ensure a certain level of mission performance and also safe operation of a new aircraft, whereas for the civil aircraft it is the safe operation (rather than the mission effectiveness) which is much more important. Modern aircraft development requires comprehensive evaluation of HQs for different controller modes, loadings, and operational missions at various points in the flight envelope. Flight testing would be nearly impossible or it will consume lot of time and effort to cover in all these conditions. Therefore, it becomes necessary to supplement the test results obtained by the pilots at several critical conditions with those obtained from analytical evaluation, using mathematical models of the aircraft as well as the human pilot to describe the performance on computers. The main objective of a good aircraft design and control system is to provide an aircraft-control system with good HQ throughout the flight envelope.
