The Equatorial Mid-Atlantic is Known to be Stormy
Tradewinds flowing toward the equator form the Inter-Tropical Convergence Zone (“ITCZ”). Winds in the northern hemisphere flow toward the southwest, while winds in the southern hemisphere flow toward the northwest. During the northern hemisphere’s winter months, the tradewinds come together, or converge, south of the equator. During the northern hemisphere’s summer months, tradewind convergence occurs north of the equator. At the point of convergence, air is forced up, increasing convection, creating lines of rain and thunderstorms that can extend for hundreds of miles. As depicted below, these conditions were ocurring at the time of flight 447’s loss. Get the current Atlantic Tropical Weather.
Image credit: Tim Vasquez, WeatherGraphics.com ©2009 – All rights reserved. Reproduced by permission. For a comprehensive analysis of the conditions probably encountered by Air France 447, see Tim’s Air France Flight 447: A detailed meteorological analysis.
Depicted above is a radar simulation, based upon weather data in the mid-Atlantic, of the flight conditions probably being experienced by Air France 447. The flight proceeded northeast from the INTOL intersection, picking its way through an area of thunderstorms, several hundred miles wide, just north of the equator on its way to Paris. Its flight in the turbulent area probably lasted ten minutes. The aircraft was almost through the weather as it passed between two of the more powerful cells, or clusters of thunderstorm cells, when it stopped transmitting data.
Thunderstorms over warm water draw in a tremendous amount of most air, which can be lifted by rising air currents (updrafts) to great heights, sometimes exceeding 50,000′. Air France 447 was flying at FL350, or 35,000′. Did the flight encounter relatively warm (above -40 deg. C) super-saturated air, as it passed between the two areas of activity depicted? If so, did the relatively warm, moist air overcome the ability of one or more of the aircraft’s pitot tubes to remain ice free, resulting in conflicting data being sent to the air data computers? The next section discusses known problems with the pitot tubes originally installed on Airbus A-330’s.