February 2006

CAST/ICAO Common Taxonomy Team - An international safety partnership

The International Civil Aviation Organization (ICAO) and the Commercial Aviation Safety Team (CAST) have jointly chartered the CAST/ICAO Common Taxonomy Team (CICTT). The CICTT includes experts from air carriers, manufacturers, pilot associations, regulators, and safety boards. ICAO, Canada, the European Union, France, Italy, Japan, Netherlands, United Kingdom, and the United States are represented. CICTT is co-chaired by representatives from ICAO and CAST (a government - industry cooperative effort within FAA's Safer Skies program). The goal of CAST is to reduce the risk of fatal accidents by 80% by 2007.

The CICTT is charged with developing common taxonomies for aviation accident and incident reporting systems. Common taxonomies establish a standard industry language thereby improving the quality of information and communication amongst all parties. Using common taxonomies also allows groups such as CAST to develop a more accurate event count and facilitates the metrics to determine the success of a safety program. The CICTT taxonomy may be used in place of, or in addition to, the database owner's current taxonomy. It is not expected that owners of existing databases will replace their current structures or change data, but there may be scope for such owners to adopt the target taxonomies in addition to their own to facilitate information sharing. The CICTT has developed clear and unambiguous definitions that describe individual components of the taxonomy to help organisations make the transition. This common taxonomy can be implemented when reporting systems are designed or updated.

One benefit of developing and using the common taxonomies will occur as information is shared across different reporting systems and organisations. In particular, where ICAO has a role in collecting data from States, it will streamline the data entry process if information received from each State is supplied using common definitions. In addition to ICAO, the European Coordination Centre for Aviation Incident Reporting Systems (ECCAIRS), has adopted the definitions. ECCAIRS was set up to integrate data from the occurrence reporting systems of a number of EU countries. Aviation safety database managers and users are urged to visit the CICTT website to review and consider adopting the current definitions.

To date, the team has developed taxonomies for occurrence categories, aircraft make / model / series and phase of flight. The aircraft make / model / series lists, as well as engine make / model / series lists, continue to be developed and refined.

Occurrence categories
The occurrence categories are used to classify accidents and incidents at a high level to permit analysis of the data in support of safety initiatives. Categories, such as CFIT and "loss of control" have been developed specifically for this purpose. An organisation may develop subcategories of occurrences to suit their own needs. An example would be a manufacturer using the CICTT category of CFIT and using sub categories to record whether an aircraft was put into service before or after a particular GPWS/EGPWS software load.

Aircraft make / model / series
The purpose of an aircraft master model list is to create a grouping of similar aircraft models for analytical purposes and to identify models that share airworthiness properties. The master model is derived by combining the original aircraft make (DOUGLAS) and aircraft model (DC-3), creating (DOUGLAS-DC3). Current users of the aircraft make / model / series data identified a need to group related aircraft models. Users described situations in which two or more aircraft are related, but it is not evident to someone without a comprehensive knowledge of those aircraft. Military forces can have aircraft that are based on a civilian model. Persons who analyse aircraft safety data may wish to review reports of military and non-military operations of the aircraft model. In addition, over time, former military aircraft enter civilian registries and accident/incident databases. For example the Master Model DOUGLAS-DC3 applies to the civilian DOUGLAS-DC3 as well as the military versions: DOUGLAS-C47 and DOUGLAS-R4D.

Phase of flight
Many aviation occurrence reporting systems capture the phase of operation or the phase of flight in which an event occurred, but not all systems use the same criteria for these categories. The list of flight phases developed by the CICTT provides guidance for this classification. The list provides unambiguous definitions of what constitutes each phase of flight. This allows individual organizations to record events in their databases, but facilitates the exchange and comparison of events. By using a common phase of flight taxonomy, organisations can be assured that similar events are being grouped together when looking at trend information.

For more information on the CICTT products or if you wish to become involved in the process, you can visit the CAST/ICAO Common Taxonomy Team Web site or contact Corey Stephens (CICCT CAST co-chair).

This article was kindly written by Corey Stephens, CAST CICTT Co-Chair & Staff Engineer, Engineering & Air Safety Department, Air Line Pilots Association, Intl

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