ABSTRACT
Notwithstanding the second epigraph cited above, we do not usually think of accidents as being caused by an absence of stress, much less by insufficient amounts of 'danger' or 'unpleasantness'. What is apparently meant by AO PA's remark is that accidents can stem from a lack of alertness, attention, or arousal. The concepts of stress, arousal, and performance will arise repeatedly in the following chapters, and it would be a mistake to proceed as though the relationships between these often vague categories were somehow intuitive or obvious. Indeed, the aviation literature abounds with curious statements like the one above, which seem to require explanation rather than providing it.
