What is a condition under which the MAJCOM commander may authorize deviations from flight rules?

The condition under which the MAJCOM commander may authorize deviations from flight rules is when it is essential to defense. This means that in situations where national security is at stake or when the operational effectiveness of a mission is critical, the commander has the latitude to adjust flight rules to meet those needs. This is in line with the application of military authority and the necessity to adapt to rapidly changing situations where strict adherence to standard protocols may hinder defense efforts.

The other options suggest scenarios that do not carry the same level of necessity. Deviations for convenience imply a lack of urgency or critical need, while during pilot training exercises, standard procedures are likely to be designed to ensure safety and compliance with established rules. Lastly, citing safety as a reason for deviations can lead to inconsistencies and confusion, since safety procedures themselves are typically designed to prevent risk. In contrast, essentiality to defense carries the weight of responsibility and acts as a justifiable reason to alter flight rules.