What must be included in a note for a clearance that is not valid until further instructions are received?

In the context of air traffic clearance notes, including departure delay information is crucial when the clearance is not valid until further instructions are received. This information informs pilots of any expected hold-up before they can commence their flight operations. It ensures that pilots can make informed decisions about their aircraft status, plan their time effectively, and manage any necessary communications with their respective airlines or operations teams.

Departure delay information serves multiple purposes; it helps in maintaining situational awareness for both pilots and air traffic control. It also assists in managing overall air traffic flow, enabling controllers to coordinate departures efficiently and minimize any disruption to the air traffic system.

Other options like aircraft type details, flight crew information, and weather advisories, while important in different contexts, do not specifically address the need for clarity concerning delays in clearance activation. These details would generally be part of standard communication practices but do not directly relate to the contingencies surrounding a clearance that is not immediately valid.