*6.2.3 Potentially unsafe zone with ideal environment*

This zone represents situations wherein the management has provided ideal environment for the personnel to carry out their duties, but the fitness of the personnel who are carrying out the tasks is far from satisfactory. Hence the personnel may not be able to carry out the duties assigned to them, without committing errors. The reasons for errors or violations committed in this zone are internal to the person, attributable to his/her physical, physiological, psychological, or psychosocial condition. An example is that of a person who had some serious argument with his family members before coming to work, or a person who did not have adequate rest before coming to work, and so on. The work carried out under such a situation can lead the output to potentially unsafe zone.

#### *6.2.4 Potentially unsafe zone with ideal environment*

This is a very dangerous zone that every safety-conscious organization tries not to enter. If personnel, not adequately fit to undertake the activity, are made to work *Role of Human Factors in Preventing Aviation Accidents: An Insight DOI: http://dx.doi.org/10.5772/intechopen.106899*

under flawed environments, the end result is a disaster, resulting in loss of precious lives, or hull, or both. All the aviation accidents that have hitherto taken place can be attributed a combination of human errors and environmental factors. Pilots alone cannot be blamed for the accidents, but the latent errors that have crept into the system from the potentially unsafe zones will also have to be considered.

#### **6.3 Modified HFACS model**

The HFACS framework adapted from [33] and shown in **Figure 6** is suitably modified by adding additional layer to account for external influences such as market demand, economic and profit motives, inter-segment coordination, and political pressures. The modified HFACS framework is shown in **Figure 10**. To cite an example, due to an increased market demand, aircraft manufacturers may hike up the production rate of aircraft without adequately enhancing the resources required to achieve the targeted production. This will result in additional work pressure and can result

**Figure 10.** *Modified HFACS framework.*

in human errors. In the process of increased competition from other aircraft manufacturers, aircraft design agencies may resort to suggesting quick modifications to an already existing design in order to save time and money. Many a times, there may be lack of coordination between the various segments in the seven-segment model. There may also be situations where a VIP overrules the suggestions given by the pilot and pressurizes him to fly the aircraft. In all these cases, holes are added to the cheese in the system, thus increasing the probability of accidents.

**Figure 11** shows schematic of modified HFACS framework for a sample segment 1 and its mutual interaction with rest of the segments 2 through 7. The same concept is applicable to every other segment, and the mutual interaction for the complete domain is depicted in **Figure 12**. It is necessary to cover all the segments

**Figure 11.** *Modified HFACS framework for a sample segment.*

**Figure 12.** *Mutual interaction paths in the seven-segment model.*

during aircraft accident investigation in order to converge onto the root cause(s) for the accident.
