A friend, John Talbot, has designed a simple system where a valve shuts off the ASI from the pitot tube and engine bleed air is blown back through the pitot system to the pitot head, clearing any ice, moisture, insects, etc. If this is done on each pitot head one at a time by a sequence system of some kind the ASI reading will not be lost.
The patent for this is now in the public domain so a developer would not have to pay royalties, etc. but I`m sure John would appreciate an acknowledgement. We have tried sending the idea to most of the manufacturers but no luck so far.
Publication number:
GB2418739
Publication date:
2006-04-05
Details can be found on
http://v3.espacenet.com/textdes?DB=EPODOC&IDX=GB2418739&F=0&QPN=GB2418739