Why use only pitot-static system for altimeter/airspeed
Hello all,
Yesterday I was watching AF 447 documentary on natgeo. What crossed my mind:
Why there is no backup system if all pitot systems fail - i.e. radio altimeter or at least GPS. I know this is not too precise, but it is better than nothing or even worse, false indications?
Other words, in 21st century, with computerized airplane, we still rely fully on "hole-and-pipe" technology, with no alterantive backup?