Browsing by Author "Huddlestone, J."

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    Business jet safety and accident study
    (Cranfield University, 2013-08) Sears, R. W.; Huddlestone, J.
    As world transport has grown in complexity, so has public pressure for safe flight. The scheduled airline industry has a consistently good safety record. Unfortunately, the business jet industry has not kept pace with the airline safety statistics and lags far behind. During safety surveys and reports over the past 5 years there has been increasing comment and concern over the perceived safety standards of business jets operations compared with normal scheduled airline services. The UK Civil Aviation Authority (CAA) has reported that based on flight hours flown, the fatal accident rate for smaller jet aircraft below 15 tonnes was twice that for large passenger aircraft (CAA 2006a). The CAA also identified that the majority of the accidents occur during the approach and landing phase of the flight. There is however, a lack of research concerning business jet operations. Due to the unique and varied style of operations, business jet flights have many factors that differentiate it from normal scheduled airline operations. Business jet accidents have been reported but they have not been further investigated for any overall causes. The study described in this thesis, a Grounded Theory analysis of accident data was conducted to develop a model of the factors that contributed to the accidents. The model that was developed demonstrated that Pilot skills, Command and Crew Resource management are the key central elements, with the ground organisations such as engineering and ground operations personnel as a contributory influence. As piloting skills were determined as a key factor in the accident statistics and the accident model, a simulator trial was also conducted to assess the manual flying skill levels of business jet pilots. The trial was both a challenging manual flying task and a profile that is included as part of the Pilot Skill test prior to the issue of a commercial pilot’s licence. The simulator trial confirmed that although all the pilots were correctly tested and certified commercial pilots, a significant proportion did not fly an accurate airspeed on approach within the CAA examination tolerances. The simulator trial data and the grounded theory model found that there are concerns for the piloting skills of business jet pilots in their ability to fly an accurate airspeed on approach. The results from this investigation yield findings concerning the piloting skill and accuracy of the business jet pilots that had not previously been identified. The results also emphasise the need to include adequate testing and supervision during business jet operations. It is recommended that further research be conducted to evaluate actual piloting skill and accuracy during the licence skill test.
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    The Loss of Manual Flying Skills in Pilots of Highly Automated Airliners
    (Cranfield University, 2009) Ebbatson, Matthew; Huddlestone, J.; Harris, Don
    Anecdotal and subjective evidence suggests that the manual flying ability of pilots operating highly automated aircraft is declining owing to a lack of opportunity to exercise such skills in the modern air transport environment. However, there is a paucity of objective evidence to support this safety concern. Consequently, the work presented in this thesis aims to provide empirically derived data to evaluate the extent and causes of the speculated manual skills decline and guide possible intervention strategies. Initially a cognitive task analysis is undertaken to determine the cognitive demands of performing manual flight in a large jet transport aircraft. Expert pilots report employing highly refined mental models structures which enable them to predict the aircrafts performance whilst causing minimal burden to their mental capacity. The study concludes that when measuring manual flying performance careful consideration must be given to designing a task which challenges both the cognitive and physical aspects of manual flying skill. Secondly, relatively novel pilot performance measures based upon the frequency analysis of control input data are evaluated. An empirical study finds that these techniques are both reliable and sensitive to manual flying performance. Furthermore, when studying large transport aircraft, such measures of the pilots control strategy are found to contribute valuable information about performance which is missing when just traditional ‘outer-loop’ performance measures are applied. The study concludes that these measures of control strategy are valuable in evaluating manual flying performance. Finally, the manual flying skills of a sample of pilots of highly automated aircraft are evaluated on a challenging manual flying task. A significant proportion exhibit poor manual flying performance as judged by a type rating examiner. Further analysis reveals that the performance of the pilots is significantly influenced by the amount of recent manual handling experience they have accumulated, rather than their longer-term manual flying experience. Significantly, airspeed tracking ability is influenced which is cited elsewhere as a causal factor in many manual flying skill related accidents. The results support the previous anecdotal and subjective concerns relating to the loss of manual flying skills.