Why Understand the Stages of Safety Events?
Understanding the fine lines between various stages of safety events in aviation risk management processes is extremely important.
Aviation safety management systems (SMS) have become so successful if not for the sole reason that they have taken an analytical, systematic approach to risk.
Understanding each stage of a safety event exemplifies a systematic approach to risk on a detailed level.
Knowing different phases of safety events involves three very important elements:
- Understanding the stages;
- Being able to identify the stages in real-world operations; and
- Knowing how to use the data to improve safety performance.
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We will be looking at what each stage is on a conceptual level of understanding, and provide an example of a ground operations driver who loses control and crashes a vehicle. Here are the 8 stages of safety events in aviation risk management programs.
1 – Precursors
Precursors are where all safety situations originate. Precursors:
- Are the underlying causes of safety events;
- Have a direct correlation to risk; and
- Become problematic when they interact with hazards.
When we are talking about what precursors are, we are talking about the underlying:
- Quality of the bureaucratic elements of the SMS implementation(e.g., policies and procedures);
- Attitudes;
- Behaviors; and
- Norms.
Precursors are monitored with aviation leading indicators. Many undesirable safety events can be completely avoided by monitoring and subsequently improving those underlying causes.
Example: Norm of showing up for work at all costs, despite being sick;
- pressure to perform despite the risk.
2 – Hazards
Hazards in and of themselves are harmless but have the potential to become dangerous. Hazards can be almost anything in the operation environment:
- An object, such as a machine or natural object;
- A behavior; or
- A person.
Relevant hazards in your operational environment should be:
- Accounted for in a hazard register;
- Analyzed and risk assessed; and
- Controlled with risk controls.
Precursors and hazards will interact to produce threats, which are shown below.
Example: sickness and illness.
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3 – Threats
Threats are hazards that have an elevated level of danger, which is an:
- Increased likelihood of leading to undesirable safety events; and
- Increased severity, potential for causing damage.
In the James Reason Swiss Cheese model, we might describe threats as being the “holes” in the Swiss cheese. Threats are the key items that front-line employees should be looking out for and trying to identify in day-to-day activities. When threats go unchecked, they combine, or “line up,” to lead to downstream events.
Example: operating an airport vehicle while fatigued and “brain fog” from being sick; broken headlight; forgetting to wear a seat belt.
4 – Downstream Events
Downstream events are the events that happen when threats line up to produce events that come directly before the risk event. With downstream events, the risk hasn’t actually materialized, and if employees are able to identify the problem and take action, the risk will be avoided.
When downstream events are not identified, they lead directly to the risk situation.
Example: because of the fatigue and brain fog from being sick, the driver does not recognize that one headlight is broken; is also unaware of how fast he/she is driving (speeding), and does not notice forgotten tools in the roadway.
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5 – Risk Event
A risk event is the point at which safety control is lost and requires immediate reaction to regain control or mitigate damages. A risk is:
- NOT undesirable events (such as a bird strike);
- NOT consequences (such as damage to a plane); and
- A single event, known as the Top Event, in a sequence that starts with underlying causes and ends with consequences.
Risks are what aviation SMS programs actively try to:
- Avoid risk controls on underlying causes and threats; or
- Mitigate (after risk occurs) with risk controls designed to regain safety control or lessen the severity of consequences.
Example: the driver loses control of vehicle.
6 – Undesirable Event(s)
Undesirable events are often confused with risk events. An undesirable event is what happens when you are not able to regain safety control directly after the risk event occurs. You can recognize undesirable events because they are the moment(s) when negative things happen.
The reason we separate undesirable events from the risk event is that a safety situation may have multiple undesirable events, but only one risk event. Furthermore, when undesirable events happen, it's an indication that unlike a risk:
- Safety control can still be regained, but there will be some damages/consequences; or
- Safety control cannot be regained, and all one can do is “brace for impact.”
Another important difference between risks and undesirable events is that risks may or may not lead to consequences, but are almost always a side effect of undesirable events.
Example: the vehicle rolls and strikes an aircraft; and the driver is thrown from the vehicle.
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7 – Damages
Damages in a safety event are purely the damages done. Damages can be:
- To people;
- Negative media attention;
- To equipment; or
- Financial.
Damages are different from consequences in the sense that damages are what happens to a person/company/aircraft/etc., whereas consequences are what results because of damages. In real-world scenarios, there is often overlap between damages and losses, but more often than not you will probably be able to distinguish differences between damages and consequences.
Example: totaled vehicle; considerable damage to aircraft; and serious injury to driver.
8 – Consequences
Consequences are the final, negative results that arise because of damages. We might also call consequences “losses.” As said, it’s common for consequences to overlap with damages. In general, consequences are often:
- Loss of financial resources (i.e., stocks, cash flow, etc.);
- Fines;
- Loss of permits;
- Loss of privileges;
- Litigation;
- Loss of reputation.
Example: lawsuits from drivers; rise of insurance premiums; damages not covered by insurance; and purchase of new aircraft and vehicle.
If you found this article helpful, I also suggest that you download the free hazard and risk assessment test, which you can use to test your knowledge and ability to identify hazards and risks.
Last updated in September 2023.
