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An international team of crash investigators as well as safety experts at Airbus are forwarding the theory that malfunctioning airspeed indicators touched off a series of events that apparently made some flight controls, onboard computers, and electrical systems go haywire. The developments helped lead Airbus to remind airlines with any Airbus planes that their pilots should check backup systems including GPS any time they suspect their airspeed indicators are malfunctioning several days after the disaster.
automation update | News from the Field Pitot tube theory advances in Air France disaster I nvestigators are focusing on the air- excessive air speed, potentially spurred by to Airbus points out it has improved their speed indicator of Air France 447 as a ice building up on electronic speed sen- power and drainage “in order to meet major factor in the crash of that plane, sors, contributed to the ocean crash of the Airbus extreme icing conditions speci- which killed 228 people. Modern aircraft the Air France Airbus A330. ﬁcation.” use a pitot tube as their primary tool to The theory is ice from the storm built Pitot-tube icing was the suspect in the measure their speed. up unusually quickly on the tubes and October 1997 crash of an Austral Lineas A pitot tube is a pressure measurement could have led to the malfunction wheth- Aereas DC-9 in Uruguay that killed all 74 instrument used to measure ﬂuid-ﬂow ve- er or not the heat was working properly. people onboard. The ﬂight-data recorder locity. Invented in the early 1700s, it not If the tubes iced up, the pilots could have showed odd airspeed readings and that only is in wide use in aeronautics, but we quickly seen sharp and rapid drops in their also use it to measure air and gas veloci- airspeed indicators, according to industry ties in industrial applications. ofﬁcials. The basic pitot tube consists of a tube An international team of crash investi- pointing directly into the ﬂuid ﬂow and gators as well as safety experts at Airbus that measures a pressure. That pressure are forwarding the theory that malfunc- can then translate via Bernoulli’s equation tioning airspeed indicators touched off to velocity. a series of events that apparently made Pt Ps Pitot tubes on aircraft commonly have some ﬂight controls, onboard computers, Total pressure Static pressure Pressure heating elements to prevent the tube and electrical systems go haywire. Pitot tube transducer from clogging up with ice. The failure The potentially faulty readings could of these systems has catastrophic conse- have prompted the crew of the Air France quences. ﬂight to mistakenly boost thrust from the crew had adjusted settings in ways The Air France Airbus A330 met heavy the plane’s engines and increase speed suggesting they thought they were ﬂying turbulence and intense storms at an alti- as they went through possibly extreme much slower than the plane, built by Mc- tude of more than 30,000 feet minutes turbulence. As a result, the pilots may in- Donnell Douglas, was actually moving. before it sent a series of automated mes- advertently have subje
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