PPRuNe Forums - View Single Post - AF 447 Thread No. 7
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Old 11th Nov 2011, 16:45
  #99 (permalink)  
Join Date: Feb 2005
Location: Correr es mi destino por no llevar papel
Posts: 1,395
My main point is that even in "direct" law the elevator does not follow the stick inputs as most think.
Problem one: those "most" include the ones who designed Airbus, the ones who certified and the ones who fly it. Direct law in pitch is proportional stick-to-elevator displacement.

Problem two: AF447 went into ALT2 so it wasn't in direct pitch. To oversimplify: ALT2 in pitch is basically G demand. That the aeroplane remained in ALT2 is indication inertial reference was working.

Problem three, which really is mostly limited to fora: Airbus control laws are difficult to understand for someone with just a passing interest in aviation. Those with dedication and capability can master them without giving too much thought to them. Bad news is that not everyone can be an airline pilot. Good news is: those who really can have extremely good chances of getting to grips with Airbus.

Originally Posted by DozyWannabe
Yes, the Airbus sidestick design drops the tactile feedback channel, but whether that is a big deal or not largely depends on your opinion
Opinion of certifying authorities is that it matters not.

Originally Posted by DozzyWannabe
when stalled, the tendency is for the aircraft to respond to aileron input with a roll in the *opposite* direction, and as such it is advisable to use the sidestick for pitch only and to control roll with gentle rudder
Correct for almost any aeroplane. Caveat is that it works as long as there is enough rhoveesquared and controls are not blanketed. No transport aeroplane has ever been put intentionally far beyond stall AoA therefore while sim behaviour is extremely realistic just above stall AoA, it turns into guesswork as AoA is increased, which is not a problem at all. Sims, just like aeoplanes, re not meant to be operated outside the envelope.

Originally Posted by DozyWannabe
but if we are to believe what the BEA is saying then this little bit of life-saving knowledge was something that these professional line pilots had never been told, or at least not recently.
Say what?!? Professional line pilots are trained to avoid stall, roll control via rudder while stalled is domain of flight testers and those bent on serious aerobatics! Life saver would be push forward!
Originally Posted by DozyWannabe
Air France was routinely sending up 3-man crews, two of whom had no manual handling instruction at high altitude, in a type that they were aware had a known problem with the pitot tubes that in a worst-case scenario would force the handling crew into handling the aircraft manually at altitude. That's almost priming the system for an accident eventually, and no amount of debate over automation or interconnection will alter that fact
So? There are thirty-seven cases of unreliable airspeeds on 330/340 aeroplanes listed in interim2. Companies are de-identified, however, given registration and date, it is easy to find out who was the operator at the time of the incident. On a few occasions it was AF crews, that despite having no training at manual handling, actually lived through the experience. This might lead the AF into believing that all of their crews would cope with the problem under any circumstances.

Of course, it would be mistake to interpret this as "It was deceased pilot's fault". There definitively were organizational precursors but pilots were not lambs lead to slaughter by tricky aeroplane and inadequate training.

Originally Posted by Machinbird
And some people have very little grasp of the varied ways in which people gather and process information.
There are strict demands how one who wants to fly and avoid getting killed flying has to "gather and process information". As I said: not everyone...

Originally Posted by Retired F4
By the way, i still wait on the answer to my question, how the PF or the captain could have seen on the instruments, that despite the continuous right bank PF had full left SS.
He couldn't. No one flying FBW Airbus can know what exactly is his significant cockpit other doing with the stick. If it's such a big deal, why would it get overlooked by those allowing thousands of Airbi flying passengers commercially?
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