Re: Air France Flight 447: loss clearly

Msg # 2195 of 2202 on RelayNet Aviation discussion
Time: Wednesday, 3-27-13, 2:52
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On Mar 27, 3:24=A0am, Orval Fairbairn  wrote:
> In article
> ,
> =A0Eunometic  wrote:
> > Air France Flight 447 (abbreviated AF447) was a scheduled commercial
> > flight from Gale o International Airport in Rio de Janeiro, Brazil to
> > Charles de Gaulle International Airport in Paris, France. On 1 June
> > 2009, the Airbus A330-203 airliner serving the flight crashed into the
> > Atlantic Ocean, killing all 216 passengers and 12 aircrew.
> > It took two years to find the black box flight data recorder.
> > Essentially what happened is this: =A0the aircraft flew into a storm.
> > Poorly designed and tested pitot-static tubes that provide air speed
> > data (Properly called Prandl tubes iced over and as a result the fancy
> > fly by wire system disconnected most of its functions and
> > protections. =A0 With the auto pilot disconnected and no air speed data
> > and the aircraft at coffin corner (just below the speed of sound and
> > just above stall speed) the aircraft were unable to fly the aircraft.
> > The tragedy, apart from the atrocious air speed indicators was that
> > there were 4 redundant angle of attack instruments on the side of the
> > fuselage. =A0 The idiocy of Airbus is this: the angle of attack is not
> > displayed in the cockpit.
> > In a July 2011 article in Aviation Week, retired airline captain,
> > aviation safety expert and accident investigator C. B. "Sully"
> > Sullenberger was quoted as saying the crash was a "seminal accident."
> > "We need to look at it from a systems approach, a human/technology
> > system that has to work together. This involves aircraft design and
> > certification, training and human factors. If you look at the human
> > factors alone, then you're missing half or two-thirds of the total
> > system failure ..."
> > Sullenberger suggested that pilots would be able to better handle
> > upsets of this type if they had an indication of the wing's angle of
> > attack (AoA). "We have to infer angle of attack indirectly by
> > referencing speed. That makes stall recognition and recovery that much
> > more difficult. For more than half a century, we've had the capability
> > to display AoA (in the cockpits of most jet transports), one of the
> > most critical parameters, yet we choose not to do it."[212]
> > In the Final Report (Section 4.2.2 - page 205) [9] the BEA recommends
> > that EASA and the FAA evaluate the relevance of requiring the presence
> > of an angle of attack indicator directly accessible to pilots on board
> > aeroplanes.
> > Blaming the crew or crew training is idiocy. =A0The instruments were
> > inadequate for safe operation of such a control system.
> It was also a failure of basic airmanship.

How can that be.  Three pilots with instrument ratings, commerical
liscence and tens of thousands of hours of flying were unable to fly
this aircraft with its air speed sensors knocked out by ice.

They apparently needed special training.

If they were amateurs one migh understand.

Angle of attack sensors are clearly more reliable instruments than
pitot static air speed indicators as they are a simple vane type

If one knows that a wing stalls at 22 degree angle of attack and that
the angle of attack sensor is ready 23 one knows one is stalled.  This
information was not provided to the pilots.

It's only silly tradition and conservatism within the industry and
pilots that is the cause of this.   The Wright brothers used a piece
of thread as an AOA sensor.  Had it been easy to transmit
a position from a vane type sensor as to convert a pressure to speed
and transmit this as a pressure in 1920s we perhaps would have been
using AOA sensors all along.  The systems to transmit
a position reading were simply a little more complicated.

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