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(...) They make it sound as if the pilots would have been trying to fly absolutely blind. (...)
Well - once again - main stream journalists know nothing about aviation and how it works. Just like the general public, basically.
Of course every aircraft has analogous back-up instruments so that speed, altitude and attitude/bank angle are displayed, even if all electric power is lost.
Does the flight computer just throw it's hands in the air and switch off it's screen when it encounters problems? They make it sound as if the pilots would have been trying to fly absolutely blind. Possibly effectively so, yes, but very nicely dramatised I must say.
Does a computer have "hands"? My understanding is that failures like pitot tubes and flight management systems sound warning alarms that let pilots know there is a need for immediate action. The danger I've understood is too many things failing in too short a time, with the plane in severe weather systems. What I've read or seen dramatized of past disasters show that mechanical systems can overwhelm human beings. I guess everyone involved in any aspect of aviation at some level realizes that and considers it part of the acceptable risk level.
Well - once again - main stream journalists know nothing about aviation and how it works. Just like the general public, basically.
Of course every aircraft has analogous back-up instruments so that speed, altitude and attitude/bank angle are displayed, even if all electric power is lost.
Not every aircraft. And the A330 is one of those who don't.
The tendency now it to have third PFD that shows speed, altitude, attitude and heading, with it's own and isolated battery as back-up power.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
Apparently, the ONLY INSTRUMENT that failed was the airspeed indicator (well, all three of them).
They had attitude (artificial horizon), altitude, heading, engine readings, and else.
The added problem to the problem of loosing airspeed information is that not only this information disappeared from the display, but from other various systems that use it to compute their own functions: The autopilot, autothrottle and rudder limiter all stopped working, and the flight control computer reverted from normal law to abnormal alternate law, changing the way the sidestick inputs are translated into control surface commands (not that the plane will roll when you try to pitch up or something like that, the sidestick will wor as usual but the control response would be just a bit different than usual), and removing most envelope protections from the control logic (which shouldn't be such a problem since even today most airplanes are not fly-by-wire and have no envelope protection).
Now put all that in a flight at an altitude where not too much faster can be too fast and not too much slower can be too slow, at night with obscured skies (i.e. absolutely zero visual cue), add a good bunch of thunderstorm, pouring rain and turbulence, put the captain in the crew-rest area, mix with some anxiety and nervousness of the remaining two oveloaded pilots maybe not in their very best day, and I can see things going out of hand.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
A short post by Gabrilean standards immediately above.
Man......what you say there and how you say it is really making some sense and explaining what might have happened.
The "near-coffin-corner" fairly critical airspeed envelope- no airspeed indicator, turbulence and the controls behaving strangely (and erratically) and I could see "top" pilots losing it.
Fat, dumb, warm, safe, dry 0 ft AGL 0 MPH armchair PPL says, "I guess the response should have been to monitor attitude CRITICALLY and carefully descend to where you have some airspeed slop."
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
Tragically misinformed and shamefully under-researched piece of neo-journalistic trash.
Cox says: 'There is a good possibility that at some point in the last four minutes, it did stall.'
An unlucky series of events caused the accident, then, culminating in the automated systems failing and engines stalling.
Engines stalling. Really.
They were not looking at blank pfd's (Where do they get this crap?). They simply had no airspeed data, possibly incorrect OAT and no autoflight systems. They still had attitude data from the aircraft's internal reference unit ring laser gyroscopes. They had barometric altitude. They had engine N1 and EPR. They knew their GTW and their fuel burn. All you need is weight, attitude, altitude and engine data to stay within the flight envelope. You fly by pitch and power. As we've been over a thousand times on this thread, the issue is the confusing cascade of failures on the airbus logic in the absence of airspeed data and the inadequate memory item procedures for unreliable airspeed in place at that time. Add in the turbulent conditions they were likely dealing with and it's a nightmare scenario for even the best pilots. But with proper training and safeguards (the A380 has a back-up speed system, offered as an option on the A330), it could possibly have been manageable.
Bottom line here, they should never have traversed that weather system. As long as commercial aircraft navigate away from this kind of meteorological phenomena, the incident will not repeat itself.
Now put all that in a flight at an altitude where not too much faster can be too fast and not too much slower can be too slow, at night with obscured skies (i.e. absolutely zero visual cue), add a good bunch of thunderstorm, pouring rain and turbulence, put the captain in the crew-rest area, mix with some anxiety and nervousness of the remaining two oveloaded pilots maybe not in their very best day, and I can see things going out of hand.
This sounds reasonable. In addition to that, the investigation team found out that the aircraft was intact prior impact and hit the water with the belly first. that indicates that an aerodynamic (aileron?) stall might have occured - maybe beause there was no (reliable) airspeed data and the plane became to slow.
I think I'm never going to understand how you can avoid a stall if you don't know your airspeed.
Well, data like FL, Engine Power Ratio, Gross Weight of the AC were available. As far as I am informend, having key parameters, there are tables that show the engine power in order to get a certain airspeed.
Does the flight computer just throw it's hands in the air and switch off it's screen when it encounters problems?
There's the first incorrect assumption. There are multiple computers, so if one does go offline, the other two can continue with one or more shut down.
Evan, do you know something no one else does? you are of course ass-uming that weather caused the accident...
Well, I guess I don't think basing your theory on all the known evidence and the findings of the BEA after one of the most exhaustive investigations ever conducted "ass-uming". The weather seems to have been the initiating factor in a chain of events.
Now guess what happens to a chain of events when you remove the first link.
I think I'm never going to understand how you can avoid a stall if you don't know your airspeed.
Easy. Just keep the angle of attack below stall.
In other words, if the airplane's trajectory is more or less horizontal and the pitch is more or less horizontal, you are not going to stall.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
That's IMHO uncertain - airspeed affects altitude computations. I wonder what such A330 shows in such case. Perhaps no altitude at all, who knows. It would be worth looking at.
They probably had GPS altitude (and then radalt), better than nothing.
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