Air France is replacing pitot tubes on its airbuses. These are external tubes that collect the pressure of atmosphere as plane flies and based on indicated air pressure it shows up as indicated air speed on the main airspeed/artificial horizon instrument. Charles Linbergh's plane had a pitot tube, its a basic airspeed instrument. But here is where I am confused. The airbus is all digital instruments, fly by wire controls. Airspeed is calculated by an GPS instrument, powered by electric grid in plane. Pitot tube might be a good back up air speed indicator, but I cangt understand why an Airbus would have a pitot tube as THE airspeed indicator and not an electric generated instrument, like the digital instruments display. So why is Air France changing the pitot tubes? To show it is doing "something" about the crash, to reassure customers? Pitot tubes are heated on commerical all weather planes, so why did it freeze up? Why didnt this happen before? Why didnt designers of Airbus ask, "what if the pitot tube freezes up?" Something is missing here. I dont believe the pitot tube is to blame. And they cant find any crash debris, just ocean garbage. This whole story is very very myseterious.
UPDATE: an anonymous comment explains that pitot tube gives indicated airspeed, GPS is ground speed, two different speeds (presumably). That is correct. I am trying to come up with a way to measure indicated airspeed other than pitot tube, and I can't. Pitot tube is the most simple, straightforward way of measuring indicated airspeed. Searchers are now finding wreckage, and bodies, mystery I guess is over. Still amazes me that something like a blocked, iced pitot tube could cause such a terrible disaster. The last minutes on board that plane must have been terrifying.
1 comment:
GPS gives groundspeed.
Pitot is still the primary sensor for airspeed, and that is what is important for flight.
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