de Havilland, in their infinite wisdom, put only one red anti-collision beacon on the Q400: top of fuselage just forward of the wing 'hump' ... so it can only be seen from the forward quarter. It cannot be seen from vehicles waiting to pass behind on apron roadways or ramp vehicles/personnel unless in front of aircraft.
Airborne at night ... if you can see a red beacon, it's not a Q400; if it's got wingtip white strobes, it's not a Q400.