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The first cross-industry guidelines for the implementation of structural health monitoring for aerospace applications have been created as a SAE International Aerospace Recommended Practices document: SAE ARP 6461 ‘Guidelines for Implementation of Structural Health Monitoring on Fixed Wing Aircraft’ [1]. These guidelines have brought together manufacturers, operators / users, systems integrators, regulators, technology providers and researchers to produce information on the integration of SHM into aircraft maintenance procedures, generic requirements and advice on validation, verification and airworthiness. The take-up of SHM in the aerospace industry has been slow, in part due to the lack of accepted industry practices surrounding not just the technology itself (sensors and sensor systems) but also the associated issues arising from the introduction of new methods into aircraft maintenance.

Global aviation is growing exponentially and there is a great emphasis on trajectory optimization to reduce the overall environmental impact caused by aircraft. Many optimization techniques exist and are being studied for this purpose. The CLEAN SKY Joint Technology Initiative for aeronautics and Air transport, a European research activity run under the Seventh Framework program, is a collaborative initiative involving industry, research organizations and academia to introduce novel technologies to improve the environmental impact of aviation. As part of the overall research activities, “green” aircraft trajectories are addressed in the Systems for Green Operations (SGO) Integrated Technology Demonstrator. This paper studies the impact of large commercial aircraft trajectories optimized for different objectives applied to the on board systems.

The paper presents an innovative approach for the functional specification of complex and highly integrated aircraft control systems, such as the Environmental Control System (ECS), by applying model based specification methods. Complexity and effectiveness of modern ECS have significantly increased during the last few years along with development of new technologies and innovations in control engineering as well as digital data distribution and processing. Efficient management of cabin air flows on the one hand makes the ECS more energy-saving and on the other hand more complex with regard to its functionality and interaction with other interfaced aircraft systems. Numerous data interfaces to other systems and a high degree of automation are typical for a modern ECS. The aircraft manufacturer specifies the entire ECS functions and its interactions within the aircraft.

The work describes a concept application to aid a safety engineer to perform an audit of a production aircraft against safety driven installation requirements. The capability is achieved using the following steps: A) Image capture of a product and measurement of distances between datum points within the product with/without references to a planar surface B) A digital reconstruction of the fabricated product by using multiple captured images to reposition parts according to the actual model. C) The projection onto the 3D digital reconstruction of the safety related installation constraints, respecting the original intent of the constraints that are defined in the digital mock-up.

The aviation sector has played a significant role in shaping the world into what it is today. The rapid growth of global economies and the corresponding sharp rise in the number of people now wanting to travel on business and for pleasure, has largely been responsible for the development of this industry. With a predicted rise in Revenue Passenger Kilometers (RPK) by over 150% in the next 20 years, the industry will correspondingly be a significant contributor to environmental emissions. Under such circumstances optimizing aircraft trajectories for lowered emissions will play a critical role amongst various other measures, in mitigating the probable environmental effects of increased air traffic. Aircraft trajectory optimization using evolutionary algorithms is a novel field and preliminary studies have indicated that a reduction in emissions is possible when set as objectives.

Currently the wing box rib assembly process requires the manual location and temporary fixing of components within product specific jig or fixtures for drilling. After drilling and reaming, parts are separated, cleaned, deburred prior to adding sealant, reclaiming and final bolting, but this may significantly increase cost, manufacturing lead-time, reduces flexibility and cannot usually be economically modified for use on other aircraft types. Due to potential increase in demand for the next generation single isle aircraft, existing tooling solutions have to be improved and new technologies have to be developed. This paper describes the development and testing of flexible tooling to provide clamping and support for drilling wing box ribs to mating rib posts within a restricted environment. Results are presented along with a discussion of the problems that may be encountered during clamping trials.

The main study illustrated in this paper deals with the computation of commands which allow an aircraft to recover a nominal energy trajectory from a low/high energy state during the approach phase. The commands taken into account in this paper are the slat/flap aerodynamic control surfaces which allow the aircraft to maintain the best lift performance for low velocities during the approach phase. In this study, it is supposed that the aircraft maintains a known vertical trajectory, simplified by a constant ground slope, while no engines and airbrakes are used. A non-linear optimization approach is studied in this paper and two methods are tested: a) Hermite-Simpson, trapezoidal collocation methods, b) Sequential numerical integration method. These different methods are tested and simulation results are given for comparison, with different initial velocities permitting to change the initial energy state.

The vision of SESAR is to integrate and implement new technologies to improve air traffic management (ATM) performance. Enhanced automation and new separation modes characterize the future concept of operations, where the role of the human operator will remain central by integrating more managing and decision-making functions. The expected changes represent challenges for the human actors in the aircraft and on ground and must be taken into account during the development phase. Integrating the human in the ATM system development starting from the early design phase is a key factor for future acceptability. This paper describes the adaptation of currently applied Cockpit Human Factors processes in order to be able to design the aircraft for the future ATM environment.

The Environmental Control System is a relevant element of any conventional or More Electric Aircraft (MEA). It is either the key consumer of pneumatic power or draws a substantial load from the electric power system. The objective of this paper is to present a tool for the design of Environmental Control Systems and to apply it to an unconventional system. The approach is based on a recently proposed methodology, which is improved with respect to flexibility and ease-of-use. Furthermore, modeling and simulation of vapor compression cycles is discussed, which are candidate technological solutions for More Electric Aircraft concepts. A steady-state moving boundary method is presented to model heat exchangers for such applications. Finally, the resulting design environment is applied to optimization of an unconventional ECS architecture and exemplary results are presented.

This paper discusses the design of a model-based fault detection scheme for robust and early detection of runaways in aircraft control surfaces servo-loop. The proposed scheme can be embedded within the structure of in-service monitoring systems as a part of the Flight Control Computer (FCC) software. The final goal is to contribute to improve the performance detection of unanticipated runaway faulty profiles having very different dynamic behaviors, while retaining a perfect robustness. The paper discusses also the tradeoffs between adequacy of the technique and its implementation level, industrial validation process with Engineering support tools, as well as the tuning aspects. The proposed methodology is based on a combined data-driven and system-based approach using a dedicated Kalman filtering. The technique provides an effective method ensuring robustness and good performance (well-defined real-time characteristics and well-defined error rates).

There is an ever growing demand for blind fastener in the aerospace industry. This demand is driven not only by the advantages of single sided installation, but also by the potential to fully automate their installation process. Blind fasteners can easily be integrated with innovative end-effectors that combine drilling, installation and inspection systems, enabling the reduction of process cycle times and their associated cost savings. Clearly the advantages of single sided installation are a key benefit, but it cannot be forgotten that currently the mechanical performance of these systems is reduced compared with conventional threaded or swaged parallel shank fasteners. There are other important drawbacks existing around them which could penalise significantly the optimised design and performance of the structures. Specific key characteristics that take into account some of these drawbacks have been established by Airbus which will be referenced in this paper.

Testing real-time vehicular systems challenges the tester to design test cases for concurrent and sequential input events, emulating unexpected user and usage profiles. The vehicle response should be robust to unexpected user actions. Sequence Covering Arrays (SCA) offer an approach which can emulate such unexpected user actions by generating an optimized set of test vectors which cover all possible t-way sequences of events. The objective of this research was to find an efficient nonfunctional sequence testing (NFST) strategy for testing the robustness of real-time automotive embedded systems measured by their ability to recover (prove-out test) after applying sequences of user and usage patterns generated by combinatorial test algorithms, considered as “noisy” inputs. The method was validated with a case study of an automotive embedded system tested at Hardware-In-the-Loop (HIL) level. The random sequences were able to alter the system functionality observed at the prove-out test.

Industrial requirements imply optimizing the development cycle, reducing manufacturing costs and reaching marketable product maturity as fast as possible. The design stage often involves multiple sites and various partners. In this context, the use of computer simulation becomes absolutely necessary to meet industrial needs. Nevertheless, this activity can be effective only if it is integrated correctly in the industrial organization. In the aeronautical and space systems industry, mechanical specifications often require the use of composites reinforced by continuous carbon fibers. The goal of this article is to describe how, on a time frame of nearly twenty years, a series of scientific and technical tasks were carried out in partnership in order to develop, validate and implement Resin Transfer Molding (RTM) flow simulation and cure analysis for high performance composites. The research stage started at the university in 1991.

The paper describes the methodology of contact problem solving that is used in specialized software code aimed at simulation of aircraft assembly process. For considered class of problems it is possible to radically reduce the number of unknowns without loss of accuracy. The results of validation of developed code against physical experiments and commercial FEM codes are also given.

Fuel on-board dehydration during flight technologies has been modeled and experimentally studied on a laboratory testing setup in normal specific gas flow rates range of 0.0002-0.0010 sec-₁. Natural air evolution, ullage blowing and fuel sparging with dry inert gas have been studied. It has been shown that natural air evolution during aircraft climb provides a significant, substantial, but insufficient dehydration of fuel up to 20% relative. Ullage blowing during cruise leads to a constant, but a slow dehydration of fuel with sufficient column height concentration gradient. Dry inert gas sparging held after the end of the natural air evolution or simultaneously with natural air evolution provides rapid fuel dehydration to the maximum possible values. It potentially may eliminate water release and deposition in fuel to -50°C. It has been found that for proper dehydration, necessary and sufficient volume of dry inert gas to volume of fuel ratio is about 1.

The installation of essential systems into aircraft wings involves numerous labour-intensive processes. Many human operators are required to perform complex manual tasks over long periods of time in very challenging physical positions due to the limited access and confined space. This level of human activity in poor ergonomic conditions directly impacts on speed and quality of production but also, in the longer term, can cause costly human resource problems from operators' cumulative development of musculoskeletal injuries. These problems are exacerbated in areas of the wing which house multiple systems components because the volume of manual work and number of operators is higher but the available space is reduced. To improve the efficiency of manual work processes which cannot yet be automated we therefore need to consider how we might redesign systems installations in the enclosed wing environment to better enable operator access and reduce production time.

The progress of silicon integration has led to the ability to integrate complex systems on a single die. Integration of applications and different application software components on a distributed system-on-chip can be demanding unless one follows a structural system integration approach with architectural support from hardware. The ACROSS Multi-Processor System-on-Chip platform provides architectural means for integration, such as well-defined communication interfaces, deterministic communication schedules, fault-containment and error-confinement support. We present the non-functional requirements of a degraded vision landing system for a helicopter and show how the ACROSS Multi-Processor System-on-Chip research platform alleviates integration of software and system components.

Airbus is a leading aircraft manufacturer with the position as technology driver and a distinct customer orientation, broad commercial know-how and high production efficiencies. It is constantly working on further and new development of its products from ecological and economical points of view. Fuel Cell Systems (FCS) on board of an aircraft provide a good opportunity to address both aspects. Based on existing and upcoming research results it is necessary to find trend-setting measures for the industrial implementation and application of this technology. Past and current research efforts have shown good prospects for the industrial implementation and application of the fuel cell technology. Being an efficient source of primarily electric power the fuel cell would be most beneficial when used in conjunction with electrical systems.

A test has been performed using a scaled aircraft wing section in an icing tunnel facility. The model had an electro-thermal ice protection system installed. The tests performed considered both anti-icing and de-icing modes of operation. The results have been assessed using numerical codes and the effect of model scaling has been considered. The non-scaled skin thickness of the model was found to modify the predicted behaviour of a full-scale installation, predominantly due to lateral conduction effects. The extent of this has been assessed and recommendations are made as to the performance that may be expected at full-scale.

The Cranfield Icing Research Tunnel was used to carry out a preliminary study whose objective was to identify whether or not the introduction of flight-path variability could generate accretions notably different to the critical ice shape. A reference (critical) ice shape was generated under conditions obtained from Appendix C before variability was applied, firstly to LWC and secondly to temperature. The approach is presented and selected results are introduced in this paper. Results show that ice accretions produced under variable conditions can be notably different to the reference profile, and are potentially more detrimental aerodynamically.