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Drawing up a list of of classifiers for the ASL-based SMS

May 8, 2013

According to the classic definition of ICAO (DOC 9859), safety - is “the state in which the risk of harm to persons or of property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and risk management”.

Thus, with respect to safety, there are introduced the concept of acceptable risk and the method of risk management - identification of hazards and the management of risk factors.

In practice, a number of questions arises - who and how will define the acceptable level of risk, what level of risk may be considered acceptable, what factors should be considered dangerous, and what risk factors need to be managed? Furthermore, whether it would be reasonable to reduce risks below acceptable levels? The answers to these and many other questions are contained in the Safety Management Manual (ICAO DOC 9859), which is included in the list of "mandatory reading" for anyone involved in safety management.

In this article, we will use the concept of acceptable risk, but definition of safety will be somewhat expanded:

Safety - is an internal perception.

This wording is useful for a clear understanding of the subjective nature of safety and risk management process.

The sense of danger was generated in the course of evolution and is inherent in all living things. This basic perception is supplemented and adjusted by training, education, and personal experience. The subjective sense of safety significantly determines actions and deeds of a separate live beings, as well as their communities.

At the airline level, the collective sense of safety is formed by sensations of all employees, but it is not their simple sum - informal groups of employees have different "weight" on the safety and different understanding will have different effect on the collective sense of safety. In this case, it is not the fact that the opinion of the senior management will have a decisive priority.

Thus, the safety as the control object is not something quite determined and may resemble the "cloud" without the exact borders.

To manage this "cloud" it is necessary to define exactly what the airline has in mind when talking about safety. To do this, the safety criteria shall be determined:

  • define a list of undesirable events in operation (based on the personal experience of the staff and information from other sources);
  • analyze the compiled list to remove irrelevant details and combine individual cases into groups (ASL-classifiers);
  • determine an acceptable frequency of classifiers at which the airline is willing tolerate with them (for example, based on the previous year).

Let us explain the difference between the indesired cases in opeartions and ASL-classifiers:

Undesired cases in operation: There was discovered in catering meal … (a detailed description of when and what was discovered).

Classifier: A foreign object in catering.

By their meaning, classifiers - are typical deficiencies in operation. They are used as keywords to find specific information in the database and to build statistical models of events.

After compiling a list of ASL-classifiers, the term "safety" takes defined shape and structure within the airline.

Because of the subjective nature of risk management (as discussed above) the list of classifiers will be subjective, but the safety criteria will be equally understood by employees and will correspond to the position of senior management. This is a definite advantage.

The subjectivity of a list of classifiers is very important:

  • this means that it will be continually updated and refined;
  • this explains the importance of the voluntary reporting from personnel as a source of information to adjust the list of classifiers;
  • this indicates that in drawing up the preliminary list of classifiers it is not a task to "embrace the unembraceable" and to anticipate all the possible cases and relationships - the list of classifiers can always be supplemented and adjusted without prejudice to the existing safety database information.

ASL-classifiers should be considered as a constructor that contains a set of components of which the events “are made" (we mean the events which fall within the field of the airline interest). If any component is missing, it may be added to the list for future issues. If the component becomes not relevant, it can be removed or disabled.

Each classifier must be assigned to a specific level of the hierarchy - this will give an opportunity to describe and store information about events in the form of cause-consequence relationships which are typical for the airline (event models). Generally speaking, the higher frequency of a classifier - the lower its level. In addition, each higher-level classifier must match at least one classifier of the previous level, being with him in a cause-consequence relationship. Here we must note an important detail - airlines could have different event models of the same event due to the differencies in operational procedures, staff training, safety culture, etc.

In the formation of ASL-classifiers it should be understood that the safety management system requires generalized data. Therefore, you should avoid too detailed classifiers - all the necessary details for the analysis and development of preventive actions will be contained in the text of a message from the staff. Too detailed classifiers will complicate their understanding and use by personnel, will reduce the recognizability of systemic weaknesses (there could arise a situation when the forest will be "hidden by trees").

We have already mentioned that it is recommended to start developing of classifiers from analysis of adverse events in operation, which are known to airlines, with the main interest in those events which by they nature are much lower than incidents.

From the very beginning it is recommended to formulate the classifiers of the lowest level and concider the cases which occur very frequently in the airline and do not seem to have direct impact on safety. An example of low-level classifier (area of frequent negative factors) - lack of time, fatigue / malaise, the scope of pre-flight briefing, the recording of aircraft defects, ageing of components in operation, etc. Such cases are the "operational background" and based just on them it is not possible to say whether they are good or bad. Management of these "background" cases could be required only upon results of analysis of the higher level cases.

After the formation of classifiers on the lower level, you can go to the next level and consider the cases that occur less frequently in the airline and have a greater impact on safety. The number of such cases may be higher. For each new classifier it shall be ensured that the previous level has at least one classifier that may be associated with it by a causal relationship.

This procedure shall be repeated sequentially for each next level and, finally, the initial list of ASL-classifiers will be formed.

To the extent of gathering safety information, a list of classifiers will be expanded. In parallel, the level of classifiers could be changed as well as formulation, applicability to the area of operation, etc. Over time, the list of classifiers will cover all types of threats (human factor, the environment, training and qualifications, operational procedures, all kinds of maintenance operations, etc.).

In conclusion, below is a schematic classification of safety reports from the staff, giving the idea how the list of classifiers will expand:

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