Hi,
Anticipating what we expect to hear about Pitot tubes from BEA there are many of us "looking" to the sensor. The invention of Henri Pitot is in the spot light.
Actually is a very simple and reliable invention. So good that is used in every a/c. And until now, a "killer product" (A trully K.I.S.S. invention)
The current a/c Systems (used by Airbus SAS, Boeing, etc.) need a reliable information of air speed. Certainly much more (than the logged 38, since 2003) cases occurred and created problems.
It seems to me there is an error when dealing with Redundancy in this issue:
(in the "extreme cases")
Why you put Redundancy in a design? When the fail rate of a single critical element is not compatible to your spec of (System) Availability. The need is obvious for "complex items" like computers (that can "fail" by Hardware, Software, etc.). EADS put 3X Redundancy ("acting as 5X")
In the case of a (vital) sensor extremely simple i donīt understand (
and not agree) to use "on line" more than one! It seems an unjustifiable use of Redundancy. Perhaps "amplifying" existing limitations of current Pitot sensors (that could create a complex "soup" mixing SW, HW, Laws, etc.)
with potential to result in stressful (even lethal) scenarios for pilots.
One may ask: And if the device breaks? (Bird impact, etc.). And if the device becomes the nest of the wasp? And if the heater fail? And if the Transducer fails? And if the wiring breaks? etc.
Any of those possibilities IMO not justify to have 3 on line (allowing a voting scheme) (being monitored/scanned) and "capable to degrade" the a/c when there is a AS "disagree". There are other possibilities or reasons to justify the redundancy? Please list! You can do "averaging, etc, by "software", for identical sensors, submitted to quite identical conditions? Why?
If you prefer to have redundant Pitot, no problem: You may put 2, 3..n
with just one "on line". You could (should) "interrogate" the others to check if they are alive. Energy to them? Can be supplied. We can optimize this. Ideal number? May be 3.
If the "US made" is better (IF really is) letīs analyze and make ASAP a joint effort (US-EU) to improve the existing models. This is good for the entire Aviation industry.
We need (to deal with the rare "extreme cases") ASAP R&D for better Pitotīs. Redundancy (for identically unreliable sensors) is almost useless. Just tell you (immediately? not sure!) the
important sensor(s) are failing.
The reading of n sensors could be used to "anticipate" the Main sensor is going to fail. Alerting the crew before the a/c starts to "degrade". (Iīm using the term "degrade" just to simplify). As an alarm of "closeness of extreme conditions".
(to be continued)
Question:
If we make a bigger (size) one (scale 2X, 3X, nX) the "ice issue" could be improved? A bigger one, power modulated (up to 1KW) could solve the issue? No tiny holes easy to clog? (Up to 1KW? Or a non electrical, heater? Or dual heater?)
Why not to test (in real world) the "anti icing" characteristic of new designs (new size, geometry, max power, similarity to "US" model, etc) comparing (in actual flights) to the existing ones. (Checking in real time against the current US and Fr. existing models).
It seems there is a "deadlock" among the players (Cert., Mfrs.,Operators). Time now (and opportunity) to competent technicians to work and SOLVE* the issue. Keeping "bean counters" just waiting the results of the necessary R&D.
*I mean, a Pitot with better characteristics when facing the "extreme conditions"