Flybywire44
Flies With The Hat On
- Joined
- Mar 31, 2006
- Posts
- 991
Just wanted to share this. It starts off weighing in heavy on Airbus, but ends with a level headed conclusion. FBW is the future. I personally enjoyed the article and want to hear you guys throw your first hand experience into this...
[SIZE=-1]Airbus, Unsafe at any speed??? l'll wait for a Boeing.[/SIZE]
[SIZE=-1]Interesting read for pilots and concerned passengers. Seems that Airbus has gone all out on flight computer priority vs. pilot priority in flying the Airbus aircraft. Using great amounts of composites...even in critical flight control surfaces and hinges...maybe they want to try to prevent any over-stress possibility to their planes by limiting flight control by the pilots. Their computers can and do overrule some pilot inputs. Fly-by-wire via computer has made many of us pilots very uneasy about the possibility of losing control of the aircraft at times, without manual reversion. This article gives a historical background on this trend by Airbus.[/SIZE]
[SIZE=-1]Probably more than most folks would like to know but a very interesting read about some of the differences between Airbus and Boeing.
Computer Piloting & Air France Crash
By William John Cox
June 12, 2009
How the Air France Flight 447’s Airbus A330 crashed into the Atlantic Ocean remains a mystery, but what is known is that Airbus’s heavy reliance on computerized piloting has a history of some bizarre or unexplained crashes when the technology failed, misread the circumstances, or complicated efforts by human pilots to react to an emergency. Share this article
And as commercial aviation becomes increasingly dependent on computerized digital technology and less reliant upon hands-on human control, the crash of Air France Flight 447 presents some difficult questions about the future of commercial aviation. This latest mystery began in the late evening hours of May 31, 2009. Air France Flight 447 operating an Airbus A330 carrying 216 passengers from Rio de Janeiro to Paris was four hours into its flight and was above the Atlantic Ocean about 400 miles off the coast of Brazil. Its speed was about 550 mph at an altitude of 35,000 feet when the pilot reported that the plane was approaching a towering thunderstorm containing black, electrically charged clouds. Satellite data showed the thunderstorm was sending 100 mph updraft winds as high as 41,000 feet. [/SIZE]
[SIZE=-1] Ten minutes later, Air France received a four-minute series of automatic failure and warning messages from the Airbus’s Aircraft Communication Addressing and Reporting System, relayed by satellite, reporting serious problems aboard the aircraft. The autopilot had disengaged and control had shifted to the pilots. The computerized control system had switched to alternative power, and there was a deterioration of flight control systems. Then came warnings that the systems to monitor air speed, altitude and direction had failed and that there was a failure of wing spoilers and the main flight computer. The final message reported a complete breakdown of the electrical and pressurization systems as the plane apparently fell apart and plunged down almost seven miles. [/SIZE]
[SIZE=-1] The helpless terror experienced by those aboard the aircraft during the long seconds it took to strike the ocean surface is beyond imagination. That final message also reported faults with the plane’s Air Data Inertial Reference Unit that, among other things, provides speed warnings. In addition, as a result of earlier incidences involving a loss of airspeed data during the cruise phase of Air France A340s and A330s and recent tests, it had been determined that icing of the external speed monitors known as “Pitot tubes” could be a factor in a loss of speed data at high altitudes. Although Airbus had issued a recommendation in September 2007 to replace the tubes, replacement was not considered a mandatory safety concern. Air France did not commence the replacement of the airspeed indicators with an improved Pitot tube in its fleet of A330s until April 27, 2009, and it did not get around to the aircraft operated by Flight 447 before it encountered a violent thunderstorm over the Atlantic Ocean in the middle of the night. [/SIZE]
[SIZE=-1] False Readings? Irrespective of the cause of the “inconsistency in measured air speeds,” the inability of the flight control computers to accurately calculate speed while flying at a high altitude could have contributed to the disaster. If it was falsely believed that the airplane was going too fast, particularly if the plane had already been slowed down to enter the thunderstorm, the plane could have easily stalled and a recovery in a storm would have been difficult or impossible. Or, if it was falsely believed that the speed was too slow and a stall was imminent, an unnecessary increase in speed could have taken the plane beyond its design capacity. The plane’s tail fin was found floatingin the ocean indicating that the aircraft broke up in midair. Otherwise, the plane would have been torn into small pieces and sunk immediately when it struck the ocean surface. Also, 44 bodies have been recovered thus far from the ocean surface, some of which were separated by as much as 53 miles, also indicating a midair disintegration of the aircraft. [/SIZE]
[SIZE=-1] The fact that the stabilizer was relatively intact also provides similarities to the loss of Airbus craft from the crash of American Airlines Flight 587 in 2001 and the Air New Zealand crash last year. Although the Airbus A330 is equipped with a “rudder limiter” to restrict the movement of the rudder at high speeds, a failure of the computerized control system and disengagement of the autopilot might have allowed the rudder to exceed its limitations, particularly if the plane erroneously exceeded its design speed in the high turbulence of a thunderstorm. Aided by a French nuclear submarine, the search for the plane’s flight data and cockpit voice recorders continues, even though such recorders have never been recovered from ocean depths as deep as 12,000 feet where Flight 447 crashed. Unless the “black boxes” are recovered, we may never know if the crash resulted from a failure of the computerized flight control system, including its sensors, or if the system was unable to assist the human pilots cope with an emergency, such as the catastrophic loss of the stabilizer. [/SIZE]
[SIZE=-1] As the world waits, Airbus continues to deliver more and more aircraft each year. It has more than 5,000 planes flying, including its new A380, the largest passenger plane in history. First flown commercially on Oct. 25, 2007, and depending upon its seatingconfiguration, the A380 can carry between 555 and 853 passengers on two decks. The A380 has 330 miles of electrical wiring involving 100,000 separate wires and 40,300 connectors. Cockpit instrumentation has been simplified and made easier to use, and a new Network Systems Server is the file cabinet for a paperless cockpit that does away with paper manuals and charts. The entire electrical power system is computerized and many electrical components have been replaced by solid-state devices. As we move into the future of commercial aviation, pilots may find themselves increasingly supplanted by computers and ultimately replaced in the cockpit. [/SIZE]
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