[dTal]

>Angle of attack for example can be approximated with an accelerometer and gyro

I'm prepared to be wrong but that sounds impossible to me. A steady-state descending stall is inertially indistinguishable from cruise.

[londons_explore]

You're right - you need to combine with altimeter or GPS, and for more accuracy you can also combine with wind direction forecasts or airspeed measurements.

The point is, there are lots of data sources, and with even a subset of them, it's possible to fly the plane to a safe landing.