Error Management: Detection & Prevention in Normal Line Operations


  • The study recorded 246 errors during an observation of 102 sectors of normal flight operations. The data was grouped quantitatively according to Error Occurrence or Error Management. Highlights were:
    1. Error Occurrence
      • The descent-approach-landing phase was where most errors happened
      • Unintentional deviations from normal operating procedures accounted for the most common type of error
      • Less than half or errors were detected
    2. Error Management
      • Captains were more effective than First Officers (FOs) in error detection
      • This difference suggests the effect of expertise and authority on the flight deck that might have contributed to FOs being less prone to pointing out errors of senior flight members
      • However, Captains demonstrated a greater tendency to detect errors committed by them as compared to FOs
      • Low general occurrence of fairly negligible and insignificant errors
      • Overall, monitoring and crosschecking led to higher rates error detection than self-checking
  • The results of the study by Thomas, M.J.W, Petrilli, R.M., & Dawson D. (n.d.) determined that a sizeable amount of errors stayed undetected during normal operations and demonstrated that error detection is more easily achieved by the crewmember that did not commit the error
  • This study exhibited (1) the importance of crew cooperation in the multi-crew environment and (2) the merits of monitoring and cross-checking to keep a high level of safety
  • Finally, the results showed the need for stronger error detection strategies in error management training programs; specifically, pilots’ metacognitive skills of categorising, scrutinising, assessing, and anticipation of errors created by themselves or other crewmembers


Research approach

  • The research approach of this study by Thomas, et al. (n.d.) was to qualitatively deliver a methodical study of error recognition procedures during normal flight operations in a commercial aviation setting
  • The study focused on the roles of scanning, monitoring, crosschecking and checklist-based approaches to error detection


  • The normal flight operations of an airline operating a single-aisle fleet on mainly short-haul flights


  • Trained observers collected data from a sample of 102 sectors of normal line operations
  • Observers obtained two days of observational methodology training and practice to hone their reliability in recognition and analysis of errors
  • Observers provided a qualitative and quantitative assessment through a written narrative of each error event and a structured coding technique

Data analysis

Generalization potential

  • Study was based on a small commercial operation
  • Results might differ depending on strength of error management training of other organisations
  • Study shows important role systemic defences play in high-risk operations


Thomas, M.J.W., Petrilli, R.M., & Dawson, D. (n.d.) An Exploratory Study of Error Detection Process During Normal Line Operations. Centre for Applied Behavioural Science, University of South Australia.

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