Airspeed and altitude : why not GPS as a backup to pitots ?

[imriozer]

GPS inputs are great

While in cruise you are supposed to have an estimate wind direction and speed, if your pitot static system freezes in cruise or even during climb/decent the GPS ground speed will do the job. If in cruise at lets say FL370 while doing 450 KTAS you lose your airspeed/altimeter you know approximately what should be the wind and you can calculate what is approximate KTAS, if the GPS is telling you your GS is 200 knots while in cruise and at the last check point the wind wasn't 250kts headwind then you know you are too slow and I was exaggerating...

As for GPS altitude, great indication for your altitude-+ 1000ft

You can even shoot an approach just by using the GS, you know the wind and do the correction for it. Maybe you'll mistake few knots but you'll land...