Incident Cause Analysis Method (ICAM)

All incidents, whether they result in loss or not, must be fully investigated. A formal definition of what is regarded as an aviation incident or accident can be found in ICAO Annex 13 .
The data gathered and organised during an investigation should be analysed using an established methodology, such as Incident Cause Analysis Method (ICAM). The ICAM analysis draws on the work of organisational psychologist and human error expert Professor James Reason to identify the underlying causes of the incident which are systemic in nature (e.g. related to factors such as failures in design, procedures, training, auditing or risk management). This process ensures that the investigation is not restricted to the errors and violations made only by the people directly involved. An ICAM analysis can identify the workplace factors that contributed to the incident and the organisational deficiencies within the system that acted as forerunners to it.
Forming the important ‘check’ part of a plan-do-check-act process, important lessons can often be learned from such investigations. As best practice, all involved in aviation are required to plan a safe operation, do what they said they would in the plan, check that what happened was what they expected to happen and if not, investigate to find out why not, and then act on those findings to better plan the next event; and so on. In this way, aviation maintains the continuous improvement cycle necessary to ensure the future viability of the industry and required level of safety in the public’s eyes.

Diagram by Karn G. Bulsuk (http://www.bulsuk.com)

The ‘flow’ of an event as it passes through the various defences already in place, can be represented as energy penetrating porous layers, as in Jim Reason’s Swiss Cheese model [1].
Current thinking is that it is unlikely that the incident happened in isolation from the organisation. So if the investigator looked for the root causes of an incident without considering the system within which the events occurred, it would likely mean that the investigation findings were of dubious value [2].

ICAM Analysis

The purpose of the ICAM analysis is to systematically arrange the information gathered during the investigation to identify the root causes. These are typically classified according to five categories:

  • Non-contributing
  • Absent/failed defences
  • Individual/team actions
  • Task/environment conditions
  • Organisational factors

A flow chart can then be constructed showing how gaps or failures at each level flowed-on or contributed to the next. This is a very powerful way of illustrating how events conspire towards an incident and aligns well with Reason’s Swiss Cheese model.

When reporting on complex causal models, diagrammatic methods such as bow-tie analyses can also be used. An indicative example is shown below for a simple kitchen fire. The left side of the bow tie represents the contributing factors and underlying causes that failed to prevent the incident, the centre is the incident or undesired event and the right side is the contributing factors and underlying causes that failed to mitigate the incident, resulting in loss.

1. Reason, J. (1997). Managing the risks of organisational accidents. Ashgate, Burlington USA.
2. Baker, S. (2010). Incident and accident investigation, in Wise, J. A., Hopkin, V. D., & Garland, D. J. (Eds), (2010) Handbook of aviation human factors. CRC Press, USA.

Want to know more?

ICAM Facilitation
For more information on ICAMs and providers of suitable training, search the internet under “ICAM investigator training”.

Contributors to this page

Author: Mike Impey / Editors:

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License