Personal protection

This page provides information about personal protection for anyone involved in a Flight Safety Accident Investigation. It describes the new DFS new approach to Crash Scene Hazard Management and the Personal Protective Equipment requirements for Flight Safety Investigators.

• Crash Scene Hazard Management: An updated approach
• Personal protective equipment for Flight Safety Investigators

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.

† Although the injury from Radiological hazards could be severe, the probability of exposure is considered improbable and therefore the risk is considered LOW.

†† The potential for severe traumatic exposure may increase the assessed risk level to HIGH in certain circumstances.

††† Advance vaccination is encouraged and could be mandatory for all personnel who attend a crash scene.

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.

• Download a workable word copy of the CraSH Matrix here (.docx)

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.

The CraSH Matrix, introduced in the “From the Flight Surgeon” article on the management of crash scene hazards, identifies various methods of controlling hazards at an aircraft crash scene including elimination, engineering, administrative measures and the use of personal protective equipment (PPE). Additionally, exposure to all categories of hazards may be reduced by strictly limiting and controlling access to the site.

While PPE is considered the last line of defence for our personnel, it remains an essential tool for flight safety personnel. When used properly, PPE protects individuals from all categories of crash scene hazards by preventing:

1. Direct skin contact;
2. Ingestion or inhalation;
3. Absorption through mucous membranes; and,
4. Injury due to sharp, penetrating, or crushing hazards.

PPE may also offer psychological protection by providing physical separation from the crash scene and reducing exposure to distressing stimuli, such as smells. PPE can be damaged or fail therefore a decontamination process should always be available.

When the flight safety crash scene hazards management approach was updated, the Directorate of Flight Safety (DFS) identified the need to improve the training as well as the process of properly using PPE.

The military issued gas mask system (C4 gas mask and C7A canister filter) is a viable respiratory protection option for investigators at an aircraft crash scene provided that the individual has been trained in its use and properly fit tested to ensure they have the correct size. The military issued rain jacket and pants (or equivalent civilian attire) provides similar or better protection than the coveralls issued by DFS, provided they are properly prepared as described later in this article. DFS has developed a Low Risk and High Risk flight safety PPE Orders of Dress (see poster below) that is intended to allow flexible choices that match the conditions of a crash scene.

Low Risk PPE is for relatively clean sites like intact aircraft interiors and hangar spaces with little to no contamination and only nuisance dust. Recommended PPE items include non-impermeable coveralls, N95 dust masks, nitrile gloves, hard hats and boots with boot covers.

High Risk PPE is for contaminated sites, such as a crash involving a post-crash fire, injuries or fatalities, and broken or fragmented aircraft wreckage. Recommended PPE items include impermeable coveralls, full face masks, hard hats, nitrile gloves with leather outer gloves and steel toe rubber boots. Permissible alternatives to the standard High Risk PPE order of dress include military issued rain jacket and pants (or equivalent civilian attire), gas mask system, helmet, nitrile gloves with leather outer gloves and steel toe work boots.

Tightly taping closures increases the performance of the closure and significantly reduce (and possibly eliminate) the penetration of particulates. Whether using the issued rain jacket and pants or equivalent civilian attire, the rain suit should be of an appropriate sized for the user. A tailored fit avoids the bellowing effect that draws in particulates. In a dry environment, the jacket should be tucked into the pants and the “tuck line” at the waist should be taped. In a wet environment, the jacket should be left untucked in a loose and layered style to allow the particulates to be directed down and off. The ankle and wrist closures and the front zipper of the jacket should be taped, including a small patch along the neck line over the top of the zipper. Any passive venting under the armpits should be tightly zipped closed. All passive venting should be taped to reduce the air flow through the closures due to the bellowing effect. If the hood fits loosely to the respirator, it should be taped, and if the hood is separate from the jacket, it should be taped at the neck line. It is important to ensure that the rain jacket that is used as PPE is not designed in a way that leaves a gap that exposes the skin at the neck, or prevents the hood from being tightened against the respirator. The rain suit option should provide moderate to high protection to trained personnel working in a hazard zone, depending on the activity level.

Depending on the conditions of the crash scene, flight safety personnel will not necessarily be required to wear all PPE items specific to the Low and High Risk categories. The PPE Orders of Dress are intended to serve as a framework that the investigator-in-charge uses to determine the PPE required to be worn at the crash scene.

While DFS will continue to supply standard PPE items as listed in the A-GA-135-001/AA-001 Flight Safety for the Canadian Armed Forces, units now have more flexibility as the military issued rain suit (and civilian equivalent) and gas mask system have been added to the approved list of PPE options.

In addition to the enclosed articles and poster, DFS is producing a series of short videos to increase awareness of crash scene hazards, introduce the new flight safety PPE Orders of Dress and improve training on the use of PPE! These videos are available on this page.