When is it permissible for a controller to vector an aircraft in uncontrolled airspace?

A controller can vector an aircraft in uncontrolled airspace primarily upon pilot request because this respects the pilot's authority and decision-making in an environment where they have more autonomy. In uncontrolled airspace, the responsibility for separation and navigation typically falls to the pilot. Therefore, controllers are expected to offer assistance only when requested, ensuring that the pilot is in command and comfortable with any changes to their flight path.

This practice aligns with the principles of ensuring safety and preserving the autonomy of pilots operating in uncontrolled areas. By responding to a pilot's request for assistance, a controller can provide necessary guidance while respecting the operational context of uncontrolled airspace.