I think one of the main reasons that the RAF has 'Talking Baggage' in the back of it's large Helis is precisely that it is impossible to use a whizz wheel while flying a heli.
If we were doing too well on a navex, we used to get the 'overturned Landrover, x stretcher cases at grid Y, can you deal' thrown in, and I had the luxury of spreading out the map on the aircraft floor and doing all my tracks, drift calcs and Fuel/weight/range computations without being encumbered with sticks and levers.
On the negative, I had no forward view, so had to rely on a sideways view of the world and the pilot narrating what he could see, OK at 1500', but somewhat exciting at 50-100'/90 kts, going across a 1:25,000 at alarming speed shouting 'Wires' sporadically!
