Speed on HUD?

Sometimes when just cruising, the speed stops displaying on the HUD, and instead displays on the targeting scope. What's up with that, and how can I stop it?

That happens when you go into "tactical mode" (for the lack of a more precise term), which occurs when you uncage the SHKVAL or select a weapons station.

Just hit the reset button on the targeting panel (the panel on the left just aft of the VHF-2 console) to get your full HUD back.

They aren't even the same speed anyway. One is airspeed and the other is the ground-Doppler (INS?) speed.

Cheers! The strange thing though is that it happened without uncaging or selecting a weapon, but I suppose that the reset button should fix it nonetheless if it happens again.