Alternative speed scales
Hi there. There is already an alternative speed scale, the BUSS (Back Up Speed Scale). Not true airspeed though. I don't know how it works, maybe it relies on the interplay between the pich & thrust to derive a scale ? Maybe that the airspeed scale, when it is failing, can be replaced by other usefull scales (for the crew decision) like scales displaying an aerodynamic authority with the aerodynamic margins ?
Jeff