These are elementary parts of the infrastructure of special works of art located in places that are difficult to access, such as very high and steep slopes, large and deep valleys, where it is not possible to lay the foundations with conventional market equipment.
External loading by aircraft takes place when, due to a particular feature of the site, there is no suitable access available for loading and transporting materials or small/medium-sized equipment, such as extremely high slopes with no access to the crest and railroads within self-rescue zones. On the other hand, inspections of level 3 dams - maximum emergency level with imminent collapse - are carried out with climbers specially trained in this skill to access the dam structure from the roped access via aircraft.
It is an area that has not been designed for continuous human occupation, with limited means of entry and exit, or with a configuration that could cause entrapment or asphyxiation, where ventilation is insufficient (or even non-existent) to remove dangerous contaminants.
In areas where the presence of people is forbidden, where there is not enough time for the competent authority to intervene in the event of an emergency. Unmanned equipment controlled by remote control is used in these areas. Examples of remote equipment include vegetation suppression services and 360° camera monitoring of dams that are about to burst.