As someone said, would be nice to know why this default wasn't chosen? It might have been due to more complexity and yet another relay being required in the chain...
The odd thing (to me) is that many systems receive Air/Ground logic from two independent relays fed from two independent buses. I assume that the signal is commoned at single target systems so one relay failure won’t have a dramatic affect.
These systems include Stall Warning; AC Cross Tie; Approach Idle; ATC.
But look at the Take Off Warning. One relay only, when relay R2-106 on the opposite bus has unused contacts which could easily have been used to give TOWC dual inputs.
… and yet another relay being required in the chain... Not so, it seems.
I'm missing something here. If previous Air/Ground TOWC incidents could have been prevented by a
very simple Mod then it would have been done. Wouldn't it?