A project was recently completed that investigated the ability to predict the onset of flutter using tools like the flutterometer. This project used an experiment called the aerostructures test wing that was flown while mounted to the flight test fixture on an F-15. Several flight tests were conducted to expand the envelope and determine the aeroelastic dynamics of the experiment. The final flight ended with destruction of the experiment due to the onset of flutter. The flutterometer attempted to predict this onset by analysing the flight data. The results indicate the flutterometer is able to generate a conservative estimate of the flight conditions associated with flutter. This paper details the flight tests of the experiment and the resulting predictions from the flutterometer.

The aim is to explore the philosophy of air traffic management with different strategic visions of the future: to answer the key question: ‘Who is to prevent mid-air collisions and how are they to accomplish this?’ The best strategic vision may just be the one that has the best match with the consensus on the desired strategic direction. Nevertheless, it must satisfy the main safety, financial, human performance etc. constraints. To explore the question, a blend of concepts from a range of disciplines has been used. These include risk analysis, financial decision-making, ‘cognitive engineering’ research and simple cybernetics. ‘full delegation’ – with pilots being responsible for all the tasks related to separation assurance – appears to meet most of the constraints. Some important issues for safety analyses of full delegation are sketched. Research into the nature and rate of future conflicts in a full delegation environment, using models of error processes, is crucial.

A dynamic backpropagation training algorithm for an adaptive fuzzy gain scheduling feedback control scheme with the application to missile autopilots is developed. This novel design methodology uses a Takagi-Sugeno fuzzy system to represent the fuzzy relationship between the scheduling variables and controller parameters. Mach number and angle-of-attack are used as measured, time-varying exogenous scheduling variables injected into the control law. By incorporating scheduling parameter variation information, the adaptation law for controller parameters is derived. Results from extensive simulation studies show that the presented approach offers satisfactory controlled system performance.

This paper describes an optimisation study concerning arrival trajectories that has been conducted using a recently developed tool for the analysis and design of noise abatement procedures around airports. This new tool combines a noise model, a geographic information system, and a dynamic trajectory optimisation algorithm. The optimisation algorithm generates routings and flight-paths that minimise the noise impact in the residential communities surrounding the airport, while satisfying all imposed operational and safety constraints. The study on arrival trajectories presented herein complements an earlier study involving departure trajectories. Although the numerical results shown pertain to a particular example airport, viz Amsterdam Airport Schiphol, the study actually focuses on the development of a generic methodology that could be applied to any given airport. The results clearly demonstrate the effectiveness and flexibility of the developed tool.

A series of active flow control experiments were recently conducted at high Reynolds numbers on a wall mounted ‘Hump’. The model simulates the upper surface of a 20% thick Glauert-Goldschmied type airfoil at zero incidence. The flow over the model is turbulent since the tunnel sidewall boundary-layer flows over it, eliminating laminar-turbulent transition from the problem. The main motivation for the experiments was to generate a comprehensive data base for validation of unsteady numerical simulation as a first step in the development of a design tool, without which it would not be possible to effectively utilise the great potential of unsteady flow control. This paper focuses on the dynamics of several key features of the baseline as well as the controlled two- and three-dimensional flows.

It was found that the two-dimensional separated flow contains unsteady waves centered on a reduced frequency (Strouhal number based on the length of the separated region and free-stream velocity) of 0·8, while in the three-dimensional separated flow, reduced frequencies of 0·3 and 1·0 are active. Several scenarios of resonant wave interaction take place over the separated shear-layer and in the pressure recovery regions. The unstable reduced frequency bands for periodic excitation are centered on 1·5 and 5, but these reduced frequencies are based on the length of the baseline bubble that shortens due to the excitation. The conventional swept wing-scaling works well for the coherent wave features. Reproduction of these dynamic effects by a numerical simulation would provide benchmark validation.

Flight simulation has become an indispensable tool for aviation training. Important decisions relating to the acquisition and certification of aircrew proficiency are made based on performance in simulated flight conditions. Such a high dependency on simulation can invite questions about the validity of the assumptions on which their employment is founded. If these should be shown to be in any way deficient, those who consider that they have suffered as a result may seek redress. The paper considers the possibility that such conditions could arise and require those involved in the design, manufacture, regulation and operation of flight simulators to justify their decisions. The paper suggests that the culture should be one which acknowledges that simulation has its limitations and, consequently, exercises a duty of care for those who undertake training and assessment in flight simulators.