What will occur if the BUS TIE switch is set to OFF?

When the BUS TIE switch is set to OFF, the result is that the electrical buses within the aircraft will be isolated from each other. This allows for the management of power distribution in certain scenarios, such as when one bus may be experiencing issues or if specific redundancy is required to ensure that vital systems remain operational.

Isolation of the buses means that they cannot share power resources, which can help protect sensitive electronics on one bus from potential faults or failures that may occur on another. The design and operation of the electrical system require this capability to maintain control over power distribution, particularly in emergency situations where managing electrical sources is crucial for safety.

In this context, battery power may still be used depending on the overall power management strategy, but the primary function of setting the BUS TIE switch to OFF is to ensure that the buses do not interact, ultimately enhancing reliability and safety during flight operations. The other options do not accurately capture the functionality and safety protocols that come into play with the BUS TIE switch set to OFF.