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7 CHAPTER 2 Research Approach The development of this study included 11 tasks. These Functional Hazard Analysis steps are illustrated in Figure 5. The project started with a kick-off meeting and collection of As part of the literature review for this project, the research updated information, particularly to review the literature asso- team reviewed information on operational experience to de- ciated with runway veer-off incidents, which was not part of the velop a functional hazard analysis (FHA) for the types of in- cidents relevant to this study. A similar analysis conducted by previous ACRP study. Following the literature review, the re- Eddowes et al. (2001) was used for overruns and undershoots search team collected information to develop the risk models, in the ACRP Report 3 study, and a summary is presented in including accident and incident information, aircraft data to Appendix A. build a criticality factor into the frequency models, as well as An FHA is a formal and systematic process for the identi- complementing the normal operations data (NOD) for general fication of hazards associated with an activity. The purpose of aviation (GA) flights of aircraft with MTOW below 12,000 lb. the FHA was to determine relevant causal and contributing Three parallel tasks were carried out after the model data factors of veer-off, overrun, and undershoot accidents and were completed and reviewed: the development of risk models hazards to aircraft associated with aerodrome operations and for aircraft overruns, veer-offs, and undershoots; the develop- the physical design of airfields. ment of a test plan to validate the approach, the models, and the Overrun, veer-off, and undershoot incidents may be consid- analysis software; and the development of a software outline to ered in terms of the deviation of the aircraft from its intended present to the panel. An interim report was prepared and sub- path. The definition of the deviation for each incident type may mitted to the panel for discussion during the interim meeting. be summarized as follows: Following the meeting, the research team pursued tasks on two fronts. The first was the development, testing, and review For overrun incidents, the "longitudinal deviation" is de- of the analysis software, and the second consisted of the prepa- scribed by the longitudinal distance traveled beyond the ration of data and actions to validate the study. expected accelerate/stop distance (for takeoff events) and The approved software framework was implemented using beyond the landing distance available (for landing events). Microsoft .Net and Microsoft Office tools (Excel and Access), For veer-off incidents, the "lateral deviation" is described and a user manual was developed. Eight industry volunteers by the lateral distance traveled from the runway longitudi- were selected to test the beta version and provide comments nal edge. to enhance the solution and eliminate bugs. In parallel, the For undershoot incidents, the "longitudinal deviation" is software team conducted tests to identify and eliminate bugs. described by the longitudinal distance from the point where A revised version of the software was used to run the analysis the aircraft actually touched down to the runway threshold. for airports selected for validation. For both overrun and undershoot events, the "lateral de- Eight airports were selected to run the analyses for valida- viation" is the lateral distance to the extended runway tion. Accident and incident data for these airports, as well as centerline. operations and weather information covering 1 year, were col- lected. The risk estimates were then compared to the actual ac- The identification of factors associated with aircraft over- cident and incident rates for the airports. The research tasks, runs, undershoots, and veer-off was an important step prior to the models, and the results are summarized in this report, the collection of accident and incident data, as this information last task in this study. was required to develop the risk models presented in this study.