It is well documented that accidents are often the result of an unfortunate chain of unpredictable events (e.g. Reason, 1990). Pilots are often the last link in the chain therefore they are open to blame being attributed to them. Some of this ‘blame’is not without reason, pilot judgment during critical decision making situations is usually the deciding factor as to whether an event will become an accident (McFadden & Towell, 1999) therefore understanding the processes involved in pilot decision making and why their actions made sense to them at the time is essential if a fully causal (i.e. why not what) understanding of pilot-error is to be achieved. Without which attempts can not be made to mitigate these causes and reduce accidents. Whilst there are many attempts to understand, categorise and classify pilot-error these approaches have not gone far enough at providing a causal account. Dekker (2003) is a notable critic of traditional error classification approaches, arguing that these approaches all lack the very thing they pertain to un-cover; the underlying reason why an error occurred. It is also noted that finding this deeper understanding of an observed error requires the understanding of other errors usually inside the head of people. Dekker makes a further point that a lot of what is recorded in the error literature is the result of what can be observationally measured, rather than what necessarily should be measured.