Still kinda under the weather, between What's Going Around and the change of seasons, and spending unproductive time skimming through the Air Crash Investigation stuff.
Coupla examples of planes that crashed due to a blocked pitot tube, or taped-over static ports. (Taped over with plane-colored tape? Couldn't the plane-washing crew use fluorescent orange masking tape?)
And, yeah, those were several years ago. More recently, though: Air France 447 (airspeed sensor problem, followed by the pilot doing a Ben-Bernank at the controls), and that oh-so-modern stealth bomber that crashed due to an airspeed sensor problem. So the problem hasn't been fixed.
And yet: all the newfangled planes have GPS... which will happily provide you with pretty darn accurate readings for altitude and ground speed. Given even a vague notion of current wind, the computers can do a sanity check on the airspeed indicator, and coming up with the actual altitude (within several feet) should be a no-brainer.
True, knowing ground speed won't keep you out of coffin corner... but if you're high enough to be worrying about that, and you don't have an accurate airspeed indication, why not just be conservative about speed and angle of attack, and live with the loss of altitude for the nonce?
(For that matter: if you know weight, angle of attack, and sink rate, surely it's possible to calculate indicated airspeed, right?)
And, of course, if your pitot tube is blocked at takeoff, the computers bloody well ought to notice that indicated airspeed isn't keeping up with ground speed while you're still on the runway, and give a great big "critical flight instrument malfunction" warning while there's still time to abort the takeoff.
Update: hoo boy! Consider, further, Turkish Airlines Flight 1951. Pressure altimeter, GPS, and right-seat radar altimeter agree (taking local terrain into consideration): plane is about 2000 feet AGL. Left-seat radar altimeter claims 8 feet BGL. Stupid robot under the hood decides the plane is about to touch the runway, or has already landed, or perhaps is underground, and that in any case it's time to cut power, regardless of the pilot's opinions on the matter. One of several instruments gives a wrong reading, and it has the deciding vote. Brilliant!