'Gathering Clouds' A Study of Plan Continuation, Risk, Rules, and Pilot Behaviour

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Dekker, Sidney
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Murray, Patrick S
Lohmann, Guilherme M
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The problem of general aviation pilots continuing flight into adverse weather has been recounted and endured since at least 1968. The problem is known as conducting a visual flight rules (VFR) operation into instrument meteorological conditions (IMC). When pilots operate an aircraft in IMC, the visual reference to the Earth’s horizon is lost or significantly reduced, and the pilot must change the way they determine which way is up. When operating in IMC, pilots turn to the aircraft’s flight instruments, like the ‘artificial horizon’ for the information they need to maintain control of the aircraft. That is, assuming the instruments that are necessary for this are fitted to the aircraft. The human vestibular system functions poorly when pilots cannot see the Earth’s horizon and yields a powerful physiological problem of false sensory illusions. Advanced pilot training, minimum experience requirements and a specialised instrument rating are required to remove the regulatory restriction that precludes pilots from operating in these adverse conditions. Each year, for decades now, the accident and incident data associated with VFR flight into IMC tells the same steadfast story. Weather is regularly cited as the so-called causal factor in general aviation accidents. Statistics routinely show VFR flight into IMC represents a small proportion of all general aviation accidents, and yet, the problem accounts for a disproportionate representation of the fatalities. In one five-year period in the United States, the VFR flight into IMC problem resulted in 583 deaths from 276 accidents. Analysis undertaken as part of this research project showed that between 2010 and 2019 in Australia, the problem was increasing, and around 28% of the problem occurred during commercial operations with fare-paying passengers onboard the aircraft. The pilots who enter the adverse weather may do so intentionally or unintentionally, and each of these cases has unique influences and geneses. This research project explored an understanding of the intentional cases. Why would a good pilot break the rules? Three studies were conducted to discover the latent beliefs that differentiate those who might intentionally conduct VFR flight into IMC and to identify which of these have the greatest influence. By uncovering these cognitive attributes, theory-based behavioural interventions can target the specific psychological constructs that have the greatest leverage on the behaviour. This research project applied the theory of planned behaviour as a theoretical framework, given its success in domains such as road safety, and oil and gas, to understand the psycho-social influences of rule-related behaviour. The theory of planned behaviour posits that the most immediate cognitive antecedent to performing a distinct behaviour is the formation of an intention. The theory suggests that behavioural intentions are formed and can be predicted, predominantly from just three kinds of beliefs that a person holds in relation to the behaviour: attitude toward the behaviour, social norms, and perceived behavioural control. This research project hypothesised an extended model of the theory of planned behaviour, which included the constructs of personal norms and anticipated affect. It was hypothesised that constructs which reflected a pilot’s self-expectations, and the anticipated affect associated with these expectations, were likely to provide a greater explanation of the variance in this particular context. The hypothesised model was referred to as the compliance behaviour model. The model fit results from a structural equation modelling analytical framework demonstrated a respecified version of the compliance behaviour model was a valid, reliable, and sufficient model to explain and predict the formation of intentions to conduct VFR flights into IMC. The compliance behaviour model achieved better model fit statistics than the unmodified theory of planned behaviour. The results showed that beliefs associated with social pressures and those associated with a pilot’s perception of their skills and ability were the primary influences on behavioural intentions. The results also showed that, surprisingly, those beliefs related to the hazardous consequences of conducting VFR flight into IMC (i.e., behavioural beliefs) had limited influence on a pilot’s intentions. The study uncovered the psychological beliefs that are most influential amongst pilots who might intentionally conduct VFR flights into IMC and explains why past attempts at intervention have been unsuccessful for so long.

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Thesis (PhD Doctorate)
Degree Program
Doctor of Philosophy (PhD)
School of Hum, Lang & Soc Sc
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The author owns the copyright in this thesis, unless stated otherwise.
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pilot behaviour
visual flight rules (VFR)
instrument meterological conditions (IMC)
plan continuation
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