Hi folks, first post. I've been following PPRuNe for a couple of years now, Spanair , Colgan 3407, and AF447. Not a pilot but I am an interested frequent flyer. Thank you to all pilots and aviation people for the many contributions to these forums. Better training for pilots and having a clearly visible AOA indicator do seem like common sense improvements.
I do have an idea, a plan maybe, that I have not heard anyone discuss. It is this ---- Provide a shield system for the pitot tubes in potential icing conditions----. How do you do that ? The speed sensors on modern big jets are state of the art . If a more advanced design were available it would be used. Someday scientists may create a new material called unobtanium . It will be immune to ice buildup at all speeds and conditions. That would be great but that day is not here yet. In the meantime what planes need is an Apollo 13 type of a solution.
One way this could be done is to design small aerodynamic bullet shaped shields for all 3 pitot tubes. The two part shields would normally be left in an open retracted position along the sides of the pitot tubes. When a plane is about to enter bad weather one or maybe two of the shields would be moved forward and together protecting the speed sensors from ice buildup. There are a lot of different ways a shield system could be engineered. When flying through an area like the ITCZ one shield could be left open and one shield closed , that pitot tube being held in reserve , and one shield could cycle open for a few seconds, just long enough to get an accurate reading and then closed for maybe 7 seconds It would be better to get intermittent but accurate readings then none at all. You could also add a smaller diameter 4th pitot tube with no shield. It would be designed to fail in half the normal time in icing conditions and would serve as an early warning system for the pilots and computers that all speed indications and the AP may soon be lost.
Sometimes bad weather can't be avoided. If airlines are going to fly people across the ocean at night in stormy weather then the speed sensors need better protection from icing , pilots should get an AOA display like the military guys have, and some kind of real practice in hand flying at high altitude in difficult circumstances. I am waiting to see what the BEA will recommend.