TNX, Formula
Toaster may not recall the days of old, like 30 friggin' years ago.
Hard to say when the computers saved the day or when a skilled operator/pilot saved the day ( thinking of Sully).
Problem is when the "crew" has lost the skills required to aviate without a lotta computer navigation and flight path control. And yes, the "protections" that are not really protections unless rule 5,c,i is in effect and sensor 4 (d) is still operational and airspeed is above "x" knots and ..... the beat goes on.
I am not a dinosaur in the aviation business, but seems to me that there are too many confusing reversion modes on the latest jets that do not follow an easy path and allow a high degree of human control until the crew figures out if they can move up to a higher degree of automation ( grrrrrr). Just look at the Airbus FCOM and latest supplements. Sheesh.
I do not advocate a simple reversion to "direct" mode. There are previous FBW systems that have a simple back up control law using "notional" gain inputs ( static and dynamic pressures), or even existing AoA if one or more vanes are moving about.
But the current 'bus design seems to offer more protections after the "normal" laws are gone than is necessary. No need to go to pure "direct" as some have advocated, nor is it advisable.