barry54, that is an Interesting idea.
If you look at the discussions in the three earlier AF 447 threads, and posts that address the improved Goodrich pitot tubes, the "build a better pitot" approach seems to have in part succeeded. That this hull had not yet gotten the new probes is an unfortunate factor in this crash. The new design looks to have been begun after some years of the industry reporting issues with various pitot tube malfunctions.
From the FAA airworthiness E9-21368 of 02 September 2009:
Federal Aviation Administration, 14 CFR Part 39, [Docket No. FAA-2009-0781; Directorate Identifier 2009-NM-111-AD; Amendment 39-16004; AD 2009-18-08] RIN 2120-AA64// Airworthiness Directives; Airbus Model A330-200 and -300 Series Airplanes, Model A340-200 and -300 Series Airplanes, and Model A340-541 and -642 Airplanes
The EASA PAD also states that a new Thales Avionics pitot probe having part number (P/N) C16195BA has been designed, which improves the airspeed indication behavior in heavy rain conditions on Model A320
airplanes. This same pitot probe standard has been made available as an
optional installation on Model A330 and A340 airplanes, and although
this has shown to be an improvement over the previous Thales Avionics
pitot probe, P/N C16195AA standard, it has not yet demonstrated the
same level of robustness to withstand high-altitude ice crystals as
Goodrich pitot probes having P/N 0851HL. We are issuing this AD to prevent airspeed discrepancies, which could lead to disconnection of the autopilot and/or auto-thrust functions, and reversion to flight control alternate law and consequent increased pilot workload. Depending on the prevailing airplane altitude and weather, this condition, if not corrected, could result in reduced control of the airplane.
A shortcoming I see in the "shielding" solution is that if you get it slightly wrong, you interfere with airflow around the pitot tube and thus interfere with its normal function. (A fix worse than the problem makes the engineer a sad fella ... as he has to do it again and now gets funny looks due to the budget overrun ... )
Note also, from the same document:
On February 4, 2004, we issued AD 2004-03-33, Amendment 39-13477 (69 FR 9936, March 3, 2004), for certain Airbus Model A300 B2 and B4 series airplanes; Model A300 B4-600, A300 B4-600R, and A300 F4-600R
series airplanes (collectively called A300-600); Model A310 series airplanes; Model A319, A320, and A321 series airplanes; Model A330-301, -321, -322, -341, and -342 airplanes; and Model A340 series airplanes. Paragraphs (g)(1) and (h)(1) of that AD require, for some Model A330 and A340 airplanes, replacement of certain pitot probes with Goodrich pitot probes having P/N 0851HL. For other Model A330 and A340 airplanes, paragraphs (g)(2) and (h)(2) of that AD require replacement of certain pitot probes with Thales Avionics pitot probe having P/N C16195AA.