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Old 25th May 2011, 17:00
  #2378 (permalink)  
Join Date: Jan 2005
Location: France
Posts: 2,316
Originally Posted by Graybeard View Post
Maybe one reason for not testing the pitot for icing at high altitude is the lack of an objective test.
I was on the point of posting something similar....

I'm baffled by those who want to replace the pitot by something else.
Nothing wrong with the principle, except the possibility of clogging up by icing (or wasp nests, but that's another story).
Re icing, the solution exists... it's called "pitot heat".

As already mentioned pages back, the certification standards for pitot sensors and pitot heating are ancient and totally obsolete, and I'm amazed that subject was not pursued further..
What's needed is not another gadget, but enough research and hard work to bring those standards up to a satisfactory conformity with the present-day operating environments.
In a way, UAS procedures are a joke... a band-aid on a big open sore. They shouldn't be needed... air data are basic and simple, and should be reliable, not need guessing by the crew "what is it doing now...?"

With Thales and Goodrich both mentioned repeatedly... I'm sure both companies would be delighted having unequivocal and reliable certification standards, rather than being hauled over the hot coals time and again.

Graybeard, you're right about testing.... "proper" icing conditions are not always easy to find, as we found out with Concorde.
And spraying from an aircraft in front doesn't really create the right conditions either.... there are comments in the flight test reports of great chunks of ice and "bloody great snowballs" only barely missing the windshield.
I think the knowledge about the various forms of ice and supercooled water at current operating altitudes (such as in the ITCZ) is still very sketchy, if not anecdotical. Reproducing the same conditions reliably at ground level (wind tunnel or otherwise) isn't evident, either.
ChristiaanJ is offline