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skills, rules and knowledge in aircraft maintenance: errors in contextAutomatic 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.
Document ID
Document Type
Reprint (Version printed in journal)
Hobbs, Alan
(Bureau of Air Safety Investigation PO Box 967, Civic Square, Canberra ACT 2608, Australia)
Williamson, Ann
Date Acquired
August 21, 2013
Publication Date
March 15, 2002
Publication Information
Publication: Ergonomics
Volume: 45
Issue: 4
ISSN: 0014-0139
Subject Category
Life Sciences (General)
Distribution Limits