After takeoff, when should military turboprop/turbojet aircraft contact departure if instructed?

Military turboprop/turbojet aircraft should contact departure when they are half a mile beyond the runway end if instructed to do so. This guideline is based on standard separation procedures in air traffic control, which require aircraft to maintain safe distances from the airport environment and other aircraft during their initial climb. By contacting departure at this specific point, the aircraft ensures that they are at a safe altitude and distance from the runway, allowing air traffic control to effectively manage the flow of air traffic and provide necessary instructions or clearances for the next phase of flight.

The other options, while they may be relevant to other situations or aircraft types, do not specifically align with the standard procedures for military aircraft after takeoff. For instance, contacting departure after reaching a specific altitude like 2000 ft AGL is not a defined requirement for all military operations. Similarly, waiting for an instruction from ATIS, or after receiving landing clearance, does not apply to the timing for contacting departure immediately post-takeoff. Each of these other scenarios does not provide the timely communication needed for maintaining air traffic flow and safety shortly after an aircraft departs from the runway.