What event corresponds with the second level of integrity?

The second level of integrity typically refers to a more significant failure within an aircraft's electrical system that can lead to loss of essential power. In this context, a dual generator failure would indeed correspond to a higher failure state compared to other listed scenarios. When both generators fail, it has dire implications for the aircraft’s ability to maintain essential systems, making it a critical event.

In contrast, a single generator failure would not reach the severity of the second level of integrity because the aircraft can often continue operations on backup sources or the remaining generator. Losing only the main bus or avionics 2 bus might affect certain non-essential systems, but it doesn't equate to the complete loss of power that dual generator failure represents. Similarly, the loss of cabin power, while disruptive, does not indicate the level of operational integrity loss that a dual generator failure would entail. Thus, considering the severity and implications associated with various types of electrical failures, dual generator failure is aptly recognized as corresponding to the second level of integrity.