The numerical simulation of aircraft evacuation and its application to aircraft design and certification

Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, the implementation of safer and more rigorous certification criteria, in cabin crew training and post-mortem accident investigation. As the risk of personal injury and the costs involved in performing large-scale evacuation experiments for the next generation ultra high capacity aircraft (UHCA) are expected to be high, the development and use of these evacuation modelling tools may become essential if these aircraft are to prove a viable reality. This paper describes the capabilities and limitations of the airEXODUS evacuation model and some attempts at validation, including its successful application to the prediction of a recent certification trial, prior to the actual trial taking place. Also described is a newly defined performance parameter known as OPS that can be used as a measure of evacuation trial optimality. In addition, sample evacuation simulations in the presence of fire atmospheres are described.

The airEXODUS evacuation model and its application to aircraft safety

Computer based mathematical models describing the aircraft evacuation process have a vital role to play in the design and development of safer aircraft, the implementation of safer and more rigorous certification criteria, in cabin crew training and post-mortem accident investigation. As the risk of personal injury and the costs involved in performing full-scale certification trials are high, the development and use of these evacuation modelling tools are essential. Furthermore, evacuation models provide insight into the evacuation process that is impossible to derive from a single certification trial. The airEXODUS evacuation model has been under development since 1989 with support from the UK CAA and the aviation industry. In addition to describing the capabilities of the airEXODUS evacuation model, this paper describes the findings of a recent CAA project aimed at investigating model accuracy in predicting past certification trials. Furthermore, airEXODUS is used to examine issues related to the Blended Wing Body (BWB) and Very Large Transport Aircraft (VLTA). These radical new aircraft concepts pose considerable challenges to designers, operators and certification authorities. BWB concepts involving one or two decks with possibly four or more aisles offer even greater challenges. Can the largest exits currently available cope with passenger flow arising from four or five aisles? Do we need to consider new concepts in exit design? Should the main aisle be made wider to accommodate more passengers? In this paper we discuss various issues evacuation related issues associated VLTA and BWB aircraft and demonstrate how computer based evacuation models can be used to investigage these issues through examination of aisle/exit configurations for BWB cabin layouts.

Trust, leadership and economic necessity in post-compulsory education

Trust is a complex concept that has increasingly been debated in academic research (Kramer and Tyler, 1996). Research on 'trust and leadership' (Caldwell and Hayes, 2007) has suggested, unsurprisingly, that leadership behaviours influence 'follower' perceptions of leaders' trustworthiness. The development of 'ethical stewardship' amongst leaders may foster high trust situations (Caldwell, Hayes, Karri and Bernal, 2008), yet studies on the erosion of teacher professionalism in UK post-compulsory education have highlighted the distrust that arguably accompanies 'new managerialism', performativity and surveillance within a climate of economic rationalisation established by recent deterministic skills-focused government agendas for education (Avis, 2003; Codd, 1999, Deem, 2004, DFES, 2006). Given the shift from community to commercialism identified by Collinson and Collinson (2005) in a global economic environment characterised by uncertainty and rapid change, trust is, simultaneously, increasingly important and progressively both more fragile and limited in a post compulsory education sector dominated by skills-based targets and inspection demands. Building on such prior studies, this conference paper reports on the analysis of findings from a 2007-8 funded research study on 'trust and leadership' carried out in post-compulsory education. The research project collected and analysed case study interview and survey data from the lifelong learning sector, including selected tertiary, further and higher education (FE and HE) institutions. We interviewed 18 UK respondents from HE and FE, including principals, middle managers, first line managers, lecturers and researchers, supplementing and cross-checking this with a small number of survey responses (11) on 'trust and leadership' and a larger number (241) of survey responses on more generalised leadership issues in post-compulsory education. A range of facilitators and enablers of trust and their relationship to leadership were identified and investigated. The research analysed the ways in which interviewees defined the concept of 'trust' and the extent to which they identified that trust was a mediating factor affecting leadership and organisational performance. Prior literature indicates that trust involves a psychological state in which, despite dependency, risk and vulnerability, trustors have some degree of confident expectation that trustees will behave in benevolent rather than detrimental ways. The project confirmed the views of prior researchers (Mayer, Davis and Schoorman, 1995) that, since trust inevitably involves potential betrayal, estimations of leadership 'trustworthiness' are based on followers' cognitive and affective perceptions of the reliability, competence, benevolence and reputation of leaders. During the course of the interviews it also became clear that some interviewees were being managed in more or less transaction-focused, performative, audit-dominated cultures in which trust was not regarded as particularly important: while 'cautious trust' existed, collegiality flourished only marginally in small teams. Economic necessity and survival were key factors influencing leadership and employee behaviours, while an increasing distance was reported between senior managers and their staff. The paper reflects on the nature of the public sector leadership and management environment in post-compulsory education reported by interviewees and survey respondents. Leadership behaviours to build trust are recommended, including effective communication, honesty, integrity, authenticity, reliability and openness. It was generally felt that building trust was difficult in an educational environment largely determined by economic necessity and performativity. Yet, despite this, the researchers did identify a number of examples of high trust leadership situations that are worthy of emulation.