Investigation of the handling qualities of fighter aircraft with relaxed static stability at high angles of attack using a holistic simulation approach

The increasing demand on high performance fighter aircraft has introduced areas of concern associated with the aircraft´s handling qualities, control and safety. This calls for new initiatives in order to investigate critical combat flight scenarios using today´s available means. This paper presents the results of the work undertaken for analysing the F-16 aircraft´s handling characteristics during combat and near stall scenarios using a holistic simulation approach. Studies conducted previously show that there are two types of control problems when flying at high angles of attack. These are the `pitch departures´ caused by coupling and the `deep stall trim´. Avoidance of these problems requires that the aeroplane have sufficient nose-down pitch and roll control. However, sometimes the control is designed in a way that restricts the aircraft´s roll capabilities. This paper investigates critical operating conditions during high angles of attack and high speed G-force manoeuvres in order to determine design improvements in current aircraft flight management systems. This is accomplished by the use of a detailed flight simulation model developed to analyse the aircraft under any conditions and investigate its behaviour in a quantitative way