Air France 447 is a powerful example of what a serious situation unreliable air data indications can be if not handled properly by a crew. Still, whether crews are properly trained or use that training, unreliable air data presents a dangerous situation. Pitot tubes are fallible devices susceptible to errors caused by environmental factors such as ice crystals. With this in mind, what technical alternatives to pitot static systems exist or might be developed that are more accurate and less prone to interruption?
A number of systems are under development- most are optical systems- determining airspeed using LiDAR. NLR, for example has developed an Optical Air Data System for this purpose:
The developed system applies the LiDAR technique to measure air speed in four different directions. The aircraft’s TAS (True Air Speed), AOA (Angle Of Attack) and SSA (Side Slip Angle) are calculated from these speed measurements.
Other systems are in prototype stage- including a photonic system that is based on back scattering of light, but none of them are yet operational.
While there are different possibilities to measure pressure (e.g. pressure sensitive paint), all can be influenced by environmental factors.
So the question might be: What is the best trade-off between cost of the sensor(s) and reliability of the whole measurement system?
One solution might therefore be to compare different sensor readings (Air speed, control surface position, weight, altitude etc. ) and compare those with a (machine learned) model of how the aircraft should behave. This would enable a algorithm to decide if a sensor does not provide realistic data and should therefore not be trusted any more.