Team-Based Human Factors Challenges

The HFACS and SHELL Models

        In aviation, there are many work-related activities that require a group of people to get the job done. Inside the cockpit of an aircraft is a good example of teamwork. There are many reasons why accidents or incidents happen in aviation, and the outcome of most of them are concluded as "Pilot Error". That is why nowadays, we hear the term Human factors in aviation.

        Humans commit errors, and that is normal, but in aviation, we try to mitigate all of these errors by using checklists, standard operating procedures, intensive training, or even pilots need to be fit to fly. The Human Factors Analysis and Classification System or HFCAS and the SHELL models, where created to analyze both the potential risks that the flight is associated due to pilots error, and analyzes the relationship of the humans with various factors that could affect the safety of the flight.

        The HFCAS model is very similar to the more popular model, the Swiss cheese model, where you have different levels of potential threat, and at the end of all these levels, if the errors are seen on every level, an accident or incident is to happen. Within each level of HFACS, causal categories were developed that identify the active and latent failures that occur. In theory, at least one failure will occur at each level leading to an adverse event. If at any time leading up to the adverse event, one of the failures is corrected, the adverse event will be prevented.

        The SHELL model gets its name from its initials, Software, Hardware, Environment and Liveware. Software is representing the rules, procedures, documents, or even standard operating procedures. The Hardware could be the aircraft, airport, the seat on the cockpit, the instruments, etc. Environment can be most effectively be described as those things that may be out of the direct control of humans, like weather. Finally Liveware are the humans, in the form of pilots, air traffic control, etc. The SHELL model describes the interaction of the humans, or the Liveware with the other components of the model. For example the Liveware-Liveware relationship is describe as the interaction of both pilots in the cockpit, or the pilots with other people. This could potentially create a hazard to safety, because let's say the pilots do not get along, they are both putting the flight at risk simply by thinking about the anger instead of focusing on the flight.

        Humans play a huge role in aviation, and as of today there are many accidents due to human factor, but it has decreased significantly through the years by the creation of various analysis tools, and the implementation of regulations and by new ideas to promote safety.

References

Skybrary (2022). Human Factors Analysis and Classification System (HFACS).

        https://skybrary.aero/articles/human-factors-analysis-and-classification-system-hfacs

Skybrary (2022). ICAO SHELL Model. https://skybrary.aero/articles/icao-shell-model