When is it necessary to issue hold short instructions to a pilot?

Issuing hold short instructions to a pilot is typically necessary when the pilot specifically requests it, particularly if they are unsure about the clearance to proceed onto a runway or taxiway. This request indicates the pilot's intent to ensure safety while navigating the airspace and avoiding any potential conflicts with other aircraft.

While it is important to issue hold short instructions during various circumstances for safety reasons, such as when visibility conditions are poor or when operations are busy, relying solely on a request from the pilot ensures that they feel confident in their clearance and are actively participating in maintaining situational awareness. Regular communication and confirmation of intentions between controllers and pilots foster a safer and more efficient operational environment.

In contrast, while safety is a priority at all times, hold short instructions are not necessarily required "at all times for safety" since it depends on the specific situation and the actions of the pilot. Therefore, the need for such instructions is more effectively triggered by the pilot's proactive engagement through their request.