Skills, rules and knowledge in aircraft maintenance: errors in context

Abstract

Automatic or skill-based behaviour is generally considered to be less prone to error than behaviour directed by conscious control. However, researchers who have applied Rasmussen's skill-rule-knowledge human error framework to accidents and incidents have sometimes found that skill-based errors appear in significant numbers. It is proposed that this is largely a reflection of the opportunities for error which workplaces present and does not indicate that skill-based behaviour is intrinsically unreliable. In the current study, 99 errors reported by 72 aircraft mechanics were examined in the light of a task analysis based on observations of the work of 25 aircraft mechanics. The task analysis identified the opportunities for error presented at various stages of maintenance work packages and by the job as a whole. Once the frequency of each error type was normalized in terms of the opportunities for error, it became apparent that skill-based performance is more reliable than rule-based performance, which is in turn more reliable than knowledge-based performance. The results reinforce the belief that industrial safety interventions designed to reduce errors would best be directed at those aspects of jobs that involve rule- and knowledge-based performance.

A Circadian Rhythm in Skill-Based Errors in Aviation Maintenance

“…Task pacing, as defined by Broadbent (1953), has been long-recognized as an important mediator of the impact of fatigue on performance (Williams et al, 1959). Unlike pilots or vehicle operators, aircraft maintenance personnel largely perform self-paced tasks involving the use of hand tools, interactions with paperwork, and the direct manipulation of non-functioning system components (Hobbs & Williamson, 2002). An airline mechanic faced with a challenging task can resort to strategies, such as pausing, trading speed for accuracy, consulting colleagues, or attempting the task several times until it can be accomplished correctly (Hobbs & Williamson, 2002).…”

“…Unlike pilots or vehicle operators, aircraft maintenance personnel largely perform self-paced tasks involving the use of hand tools, interactions with paperwork, and the direct manipulation of non-functioning system components (Hobbs & Williamson, 2002). An airline mechanic faced with a challenging task can resort to strategies, such as pausing, trading speed for accuracy, consulting colleagues, or attempting the task several times until it can be accomplished correctly (Hobbs & Williamson, 2002). These strategies are likely to offer some protection against mistakes involving consciously controlled processing; however, simple tasks that are controlled largely by unconscious automatic skill routines are, in general, less amenable to such conscious interventions.…”

Identification and Assessment of Factors Influencing Human Reliability in Maintenance Using Fuzzy Cognitive Maps

“…In view of this, organizations are shifting focus from technical and design issues to human oriented aspects such as leadership, alertness, communication skills, and employee motivation. Hobbs and Williamson mentioned that knowledge‐based activities such as diagnose or decide (detection and decision making) and functional testing (problem‐solving) demand greater human involvement, and consequently, the greater the risk of failure. Martin elaborated on the role of motivation, job satisfaction, and commitment in enhancing efficiency of work.…”

Quelle marge de manoeuvre faut-il laisser aux utilisateurs d’animations 3D techniques en maintenance aéronautique?

“…Hobbs (2008) montre que ces incidents surviennent lorsque l'opérateur se trompe dans la procédure sans en avoir conscience, qu'il réalise la tâche demandée sans en avoir la connaissance nécessaire, ou bien parce qu'il choisit délibérément de ne pas appliquer la procédure écrite [10]. 80% des techniciens avouaient déjà s'en être ainsi éloignés au moins une fois l'année précédente en 2002 [11]. L'amélioration de la documentation de maintenance aéronautique vise donc la réduction de ces trois sources accidentogènes.…”