Div Surg Div Surg | Canadian Armed Forces



On 21 January 2016, DFS introduced an updated approach to crash scene hazard management. This approach is rooted in the risk management process recommended by the International Civil Aviation Organization (ICAO) and is designed as a comprehensive yet straight-forward evidence-based approach to managing crash scene hazards.

From the early 2000’s, crash scene hazard management in Canada focused largely on biohazard protection. This was the logical consequence of changes in the late 1990’s to workplace health and safety guidelines aimed at protecting the worker from exposure to infectious diseases such as Human Immunodeficiency Virus (HIV), Hepatitis B, and Hepatitis C. To emphasize the perceived risk, the annual “Personal Protection” training for aviation accident investigators was specifically called “Blood Borne Pathogen (BBP) training.” Unfortunately, the emphasis on biohazard protection sometimes overshadowed other potential hazards at aviation crash scenes. Anecdotally, there was concern at DFS that some CAF flight safety personnel were emerging from training with the impression that infectious diseases were the primary hazards at a crash scene. Over time, DFS attempted to supplement BBP training with instruction on other hazards - such as chemical, explosive and radiological hazards – but this led to ever-growing “shopping lists” of specific hazards, which were difficult to remember and not contextualized in terms of the actual risks they posed.

DFS reviewed the ICAO guidance provided in Circular 315 “Hazards at Aircraft Accident Sites,” which discusses specific crash scene hazards and groups them into categories. DFS adopted this consolidated hazard categorical approach, but made slight modifications to the individual ICAO categories after broad consultation with DFS accident investigators and CAF aviation medicine and occupational medicine experts. Thus, the previous “shopping lists” of hazards were reorganized into five easy-to-remember categories: 1) Physical, 2) Chemical, 3) Environmental, 4) Psychological, and 5) Biological. DFS then conducted a risk analysis of the five hazard categories using a Risk Management (RM) process. ICAO recommends applying a RM process to crash scene hazards involving the cycle of: 1) identifying hazards, 2) identifying exposure routes, 3) assessing risk, 4) introducing controls, and 5) reviewing and revising the risk assessment. Rather than applying RM at the time of a crash, DFS decided to take the ICAO recommendations one step further and pre-assess the likely hazards. With primary focus on CAF aircraft fleets, DFS gathered evidence from scientific and medical literature, hazardous material safety data, and expert consensus to assess the overall risk of each hazard category. The pre-assessment was intended to give investigators a “head-start” when confronting a crash scene, allowing faster and more accurate risk assessment, safer scene hand-over, and improved safety measures. Applying this RM process, DFS ultimately assessed that there was a low risk associated with biohazards (i.e. Human Immunodeficiency Virus (HIV), Hepatitis B, and Hepatitis C) at a crash site. This assessment was based on reassuring information from the US Centers for Disease Control, the Public Health Agency of Canada, and a thorough literature search for documented cases of disease transmission from aircraft accident sites. Moreover, consideration was given to advances in medical science since the creation of health and safety guidelines in the 1990’s. For instance, Hep B transmission can be prevented with vaccination, HIV transmission can be prevented with post-exposure prophylactic treatment, and Hepatitis C can now be medically cured. Thus, the relatively low risk of biohazards can be put in proper context for accident investigators.

DFS produced the following matrix describing the minimum expected risk level of each of the five crash scene hazard categories. The CraSH Matrix is intended to serve as a quick-reference and simple starting point for crash scene hazard management. At the same time, investigators remain free to modify the risk levels when necessary based on specific crash site circumstances. DFS has rewritten the chapter on Crash Scene Hazard Management (previously entitled “Blood Borne Pathogens”) in its Airworthiness Investigation Manual. The new approach is being taught on the CAF Flight Safety course for aircraft accident investigators and the medical course for Aviation Medicine providers.

The first practical application of the CraSH Matrix occurred in November 2016 as a result of a CF188 Hornet crash in an unpopulated area near Cold Lake, Alberta, where the pilot sustained fatal injuries. Based on reported conditions, the accident investigation team used the CraSH Matrix while enroute to the crash scene to pre-assess the hazards. The resulting assessment indicated a probable high risk level due to the type and quantity of physical hazards and required the investigators to adopt the wearing of full Personal Protective Equipment (PPE). Upon arrival, it was determined that conditions were not as initially reported and the physical risk was downgraded to a medium level. This re-assessment resulted in the investigators having to wear less PPE thereby increasing their maneuverability and efficiency and easing the level of difficulty in conducting their on-scene investigation. As the investigation progressed, the level of risk had to be adjusted due to environmental hazards (e.g. changing weather), physical hazards (e.g. unexploded ordnance), and psychological hazards (e.g. human remains).

Overall, awareness of hazards, their associated risks and the application of control measures was simplified and enhanced by using the CraSH Matrix. As a practical tool, the CraSH Matrix allowed the team to keep up with changes in risk levels, anticipate and modify plans, and successfully complete the on-scene investigation. In addition, the CraSH Matrix served as a vital tool when handing over responsibility of the crash scene to the Aircraft Recovery and Salvage Team. Crash Scene Hazard Management for this case also included the first-ever follow-up medical screening for all 109 personnel who worked on the crash site, a process that was well-received by personnel and their supervisors. Screening took place for potential injuries from all five hazard categories in the CraSH Matrix, with particular attention to potential psychological injuries.

The second practical application of the CraSH Matrix occurred due to an engine failure of a CT156 Harvard II trainer in January 2017, which forced both occupants to carry out an ejection and caused the aircraft to crash in a farmer’s field. Again, the aircraft accident investigators used the CraSH Matrix tool to pre-assess the expected risks and, as a result of the analysis, made the decision to wear minimal PPE. Deteriorating weather forced a re-assessment of the hazards and associated risks, resulting in a change of control measures to enhance PPE, modify the recovery plan and ultimately resulted in the move of the wreckage to an indoor location.

In both cases, the CraSH Matrix allowed the accident investigation teams to pre-brief and safely prepare their crews on the anticipated hazards and associated risks of the crash scenes, then allowed for rapid yet comprehensive re-assessments of the crash scenes upon their arrival. The matrix proved to be an excellent tool for briefing off-site supervisors on local conditions and increased the effectiveness of the crash scene handover to new personnel arriving on-site.

DFS will continue to use the CraSH Matrix when investigating accidents; however, its use has highlighted areas that need to be strengthened and updated particularly in the application of controls measures.

The first area that underwent review was the rationalization of appropriate PPE. DFS’ current process involves the provision of items to CAF flight safety units located across Canada. The challenge is to align the standardized equipment with the actual requirements of the crash scene and requires an understanding of the environment in which the equipment is to be used and knowledge of the capabilities and limitations of the equipment. This matter is discussed in greater detail in the Personal Protective Equipment for Flight Safety Investigators section of this page.

The provision of PPE does not mean that every crash site will require the investigator to wear all the items for proper protection. Rather the crash scene investigators need to know and understand the hazards to which they are being exposed and then they need to be able to pick the appropriate protective items from a menu of available resources. Understanding that flight safety investigators have limited time to deal with the intricacies of PPE at the time of an accident, DFS personnel have refined the selection of available PPE to better protect against known hazards and have developed a PPE poster to compliment the CraSH Matrix tool.

Another area for review is the need to develop education and training products that complement the updated approach to Crash Scene Hazard Management. For instance, the effective use of a PPE pocket-card relies on flight safety investigators understanding the hazards that they might encounter at a crash scene and knowing the limitations and capabilities of their equipment. To promote this understanding and knowledge, DFS has developed short training videos available on this page. The intent of these videos is to provide accurate, standardized, current and accessible information to flight safety personnel so that they can easily educate themselves at the time and place that is convenient to them.