; Pitot tube theory advances in Air France disaster
Documents
Resources
Learning Center
Upload
Plans & pricing Sign in
Sign Out
Your Federal Quarterly Tax Payments are due April 15th Get Help Now >>

Pitot tube theory advances in Air France disaster

VIEWS: 19 PAGES: 2

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.

More Info
  • pg 1
									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
								
To top