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.