The only "partial" solution you have for being able to see aircraft in the radar display is unfortunately to give the existing SJ surface radar the capability to detect airplanes. Side effects like the inability to differentiate the contact can be solved by keeping the existing SD radar. Since the crew will tell you that there is an aircraft ocntact, you can identify what you see in the SJ display as such. If there are more contacts, it will depend on wether you had already identified some before, and wether you want to risk staying some more seconds surfaced to watch the blip fly across the screen (the speed of movement is very telling of the nature of the contact)
