What can result from a failure of the primary navigation's consistency?

A failure of the primary navigation's consistency can lead to a loss of situational awareness because pilots rely heavily on accurate and consistent navigation information to maintain an understanding of their position, heading, and intended trajectory. When the navigation system provides unreliable data, it creates uncertainty and can mislead the pilots about their aircraft's orientation with respect to their intended route or stability in the airspace around them. This confusion can prevent them from effectively assessing their surroundings, responding to changes, or making informed decisions during critical phases of flight.

The other choices highlight potential issues that may arise in less direct ways, but a direct consequence of inconsistent navigation data is the impact it has on a pilot's situational awareness, which is crucial for safe and effective flight operations.