On October 4, 1992, a Boeing 747-200F freighter airplane lost its right wing engines after departing from Amsterdam Schiphol Airport. Due to severe performance and controllability problems caused by this the aircraft crashed, 13 km east of the airport, in the Bijlmermeer, a suburb of Amsterdam. In recent years, several similar incidents have occurred in which aircraft were successfully recovered after encountering a separation of one or more of the engines. This report presents an overview of an independent analysis of the accident and applied modelling and simulation techniques. The investigation, including the development of the software for the accident analysis, was performed at the Division of Flight Control and Simulation of the Faculty of Aerospace Engineering of the

A high fidelity aircraft simulation model, reconstructed using the Digital Flight Data Recorder (DFDR) of the 1992 Amsterdam Bijlmermeer aircraft accident (Flight 1862), has been used to evaluate a new Fault-Tolerant Flight Control Algorithm in an online piloted evaluation. This paper focuses on the piloted simulator evaluation results. Reconfiguring control is implemented by making use of Adaptive Nonlinear Dynamic Inversion (ANDI) for manual fly by wire control. After discussing the modular adaptive controller setup, the experiment is described for a piloted simulator evaluation of this innovative reconfigurable control algorithm applied to a damaged civil transport aircraft. The evaluation scenario, measurements and experimental design, as well as the real-time implementation are described. Finally, reconfiguration test results are shown for damaged aircraft models including component as well as structural failures. The evaluation shows that the FTFC algorithm is able to restore conventional control strategies after the aircraft configuration has changed dramatically due to these severe failures. The algorithm supports the pilot after a failure by lowering workload and allowing a safe return to the airport. For most failures, the handling qualities are shown to degrade less with a failure than the baseline classical control system does.

The contents of this report may be cited on condition that full credit is given to NLR and the author(s).

In this simulator study eleven pilots rated their motion perception during a series of decrab maneuvers of a twin-engine passenger aircraft. Platform yaw, sway, and roll motion were varied independently to examine their relative contribution to the pilots' judgements. In one set of conditions, the washout algorithms were bypassed so as to reproduce unfiltered aircraft motion. This was compared with washout-filtered motion in another set of conditions. Moreover, the effect of visual cues was studied by testing the unfiltered motion cues once under simulated VMC, and once under IMC. The results show that the simulation of heading alignment was positively affected by platform sway and roll, and also by the visual stimulus. Platform yaw was poorly recognized, and remained under the perceptual threshold in the presence of platform sway. Interestingly, unfiltered sway motion was perceived as too strong, even though the simulator workspace required downscaling to 70% of the actual aircraft motion. Finally, the subjective data was used to validate our human motion perception model. Due to the fact that the model does not yet account for the observed interaction between sway motion and the perceptual threshold for yaw, the model output did not quantitatively correlate with the magnitude ratings. However, a multiple regression analysis showed that, qualitatively, the model did predict the way pilots interpreted the platform motion. We conclude that better understanding of perceptual thresholds in a flight simulator setting is necessary to enable quantitative analysis of the effectiveness of ground-based motion cues.

A high fidelity aircraft simulation model, reconstructed using the Digital Flight Data Recorder (DFDR) of the 1992 Amsterdam Bijlmermeer aircraft accident (Flight 1862), has been used to evaluate a new Fault-Tolerant Flight Control Algorithm in an online piloted evaluation. This paper focuses on the piloted simulator evaluation results. Reconfiguring control is implemented by making use of Adaptive Nonlinear Dynamic Inversion (ANDI) for manual fly by wire control. After discussing the modular adaptive controller setup, the experiment is described for a piloted simulator evaluation of this innovative reconfigurable control algorithm applied to a damaged civil transport aircraft. The evaluation scenario, measurements and experimental design, as well as the real-time implementation are described. Finally, reconfiguration test results are shown for damaged aircraft models including component as well as structural failures. The evaluation shows that the FTFC algorithm is able to restore conventional control strategies after the aircraft configuration has changed dramatically due to these severe failures. The algorithm supports the pilot after a failure by lowering workload and allowing a safe return to the airport. For most failures, the handling qualities are shown to degrade less with a failure than the baseline classical control system does.

The contents of this report may be cited on condition that full credit is given to NLR and the author(s).

NLR is a leading international research centre for aerospace. Bolstered by its multidisciplinary expertise and unrivalled research facilities, NLR provides innovative and integral solutions for the complex challenges in the aerospace sector. For more information visit: www.nlr.nl NLR's activities span the full spectrum of Research Development Test & Evaluation (RDT & E). Given NLR's specialist knowledge and facilities, companies turn to NLR for validation, verification, qualification, simulation and evaluation. NLR thereby bridges the gap between research and practical applications, while working for both government and industry at home and abroad. NLR stands for practical and innovative solutions, technical expertise and a long-term design vision. This allows NLR's cutting edge technology to find its way into successful aerospace programs of OEMs, including Airbus, Embraer and Pilatus. NLR contributes to (military) programs, such as ESA's IXV re-entry vehicle, the F-35, the Apache helicopter, and European programs, including SESAR and Clean Sky 2.Founded in 1919, and employing some 650 people, NLR achieved a turnover of 71 million euros in 2016, of which three-quarters derived from contract research, and the remaining from government funds. UNCLASSIFIED EXECUTIVE SUMMARY Problem areaLoss of control in-flight (LOC-I) accidents, caused by an upset followed by a failure of the pilot to control and recover the aircraft, remain the largest contribution to fatal aircraft accidents worldwide. A reduction of crew stress (e.g., caused by an unexpected event in a safety critical situation) and high workload will contribute to further reduction of LOC-I related incidents. Modern civil transport aircraft are currently equipped with a flight guidance system that allows the aircraft to be flown automatically for most part of the flight. Future requirements from a flightdeck system-safety point of view include a more integrated design of information systems available to the pilot, including displays and interactions, flight decision support systems (e.g., advisories during upset conditions, including automatic recovery), and the allocation of functions between the pilot and automatic systems during nominal and degraded flight conditions. This new "intelligent" flight deck should be able to sense onboard (flight control) system and environment-induced hazards in real time, and provide the necessary and timely actions to prevent or recover from an upset. KNOWLEDGE AREA(S) Safety Cockpit Training, Mission Simulation and Operator Performace Aircraft Systems Engineering DESCRIPTOR(S) CockpitUpset recovery Autoflight systems UNCLASSIFIED EXECUTIVE SUMMARY NLR Anthony Fokkerweg 2 1059 CM Amsterdam p ) +31 88 511 3113 f ) +31 88 511 3210 e ) info@nlr.nl i ) www.nlr.nlautomation to relieve crew workload and stress under peak operational conditions.The system is designed to recover the aircraft from upsets that bring the aircraft beyond the conventional flight-envelope-protection boundaries that provide a first layer of safety to preven...

The introduction of active control technology and modern, full authority, fly-by-wire (FBW) systems demonstrated an increase of adverse interactions between the human pilot and aircraft dynamics. This phenomenon, also known as Aircraft Pilot Coupling (APC) or Pilot-in-the-Loop Oscillations (PIO), can result into major aircraft handling qualities problems or loss of flight control. Recognition of handling qualities deficiencies related to APC/PIO early during the flight control system design process is therefore mandatory. In support of this process, a practical design guideline should be available that provides well established APC/PIO analysis and experimental techniques in order to prove that a highly augmented aircraft is sufficiently free from APC/PIO proneness. To address the industrial needs for such a guideline, the Group for Aeronautical Research and Technology in Europe (GARTEUR), recently established an Action Group on APC/PIO analysis and experimental techniques. An emphasis during this research was to extend the current technologies with new analysis and experimental methods for non-linear APC/PIO (Category II) assessment. This paper presents an overview of the simulator campaign, conducted as part of the project, that focussed on the development of new experimental techniques to evaluate non-linear APC/PIO susceptibility. The effectiveness of the proposed non-linear APC/PIO experimental techniques is evaluated along with some lessons learned during the campaign. Results of the Action Group were presented in a concept handbook, supported by analysis tools, that provides a profound basis towards design of aircraft free of adverse APC/PIO characteristics.