What type of inspection occurs at prescribed intervals other than daily or phase?

The right choice is the Special Inspection. Special Inspections are performed as needed at specified intervals that do not fall under daily checks or phase inspections. This type of inspection is typically scheduled in advance according to the aircraft's maintenance program and is aimed at addressing specific components, systems, or conditions that require closer scrutiny.

Special Inspections are crucial for ensuring that particular elements of an aircraft are maintained effectively, often due to regulatory requirements, service bulletins, or manufacturer’s recommendations. They can cover a wide range of targets, from non-routine service history to recommendations laid out in a maintenance manual, thereby contributing significantly to the overall safety and reliability of the aircraft.

By contrast, Daily Inspections are routine, short-checks made on the aircraft every day it's in use, typically assessing the general condition and safety of the aircraft, while Conditional Inspections are triggered by specific events, such as damage or an unusual operational occurrence. Unscheduled Maintenance refers to repairs or inspections that occur outside the regular schedule, usually in response to unexpected failures or defects.