AF447 final crew conversation - Thread No. 1
Joined: Jan 2005
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From: W of 30W
Originally Posted by Hamburt Spinkleman
Numbers have simply been replaced by colors. How is that confusing or counterintuitive?

Disregarding the attitude and GPS altitude here that don't necessarily fit the situation, my gut reaction, without too much thinking, seeing that big up red arrow would be to pull, at least initially.
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From: Phuket
I would like to know what the GPS speed is doing there in the 1st place. It does not tell you a darn thing about the aircraft as far a flying goes. The aircraft does not fly on GPS speed, nor does it fly on TAS (Unless you are talking MMO) BUT it does fly on IAS (or CAS if you are a purist) However a good AOA gauge should tell you everything you need to know, IF you knew a little about aerodynamics and knew how to read the gauge. (And pull yourself away from the FMS and actually fly the thing)

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From: CYUL
I don't think it's reading GPS Speed but rather GPS Altitude.
Speed is on the left side of the ADI and is replaced by a coloured tape indication.
On the right side we usually find altitude information and my guess is the 000 is sea level and the 010 is a thounsand feet with the 520 being mid way on that scale so it's a 520 foot GPS Altitude read out.
Edited... Just noticed is actually says GPS ALT at the bottom of the scale so my assumption is correct!
Speed is on the left side of the ADI and is replaced by a coloured tape indication.
On the right side we usually find altitude information and my guess is the 000 is sea level and the 010 is a thounsand feet with the 520 being mid way on that scale so it's a 520 foot GPS Altitude read out.
Edited... Just noticed is actually says GPS ALT at the bottom of the scale so my assumption is correct!
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
This BUSS speed tape is confusing me big time! What exactly does 'SLOW' mean? What is the required response? Since we are talking AB, why does it not just say 'push your side stick forward and increase power'?
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From: invalid value
First you are confused and ask what it means only to show you know exactly what it means. A bit disingenous perhaps.
It is a speed tape, it operates as a speed tape. Are anybody here confused about how to read a speed tape or respond to it?
It is a speed tape, it operates as a speed tape. Are anybody here confused about how to read a speed tape or respond to it?
Per Ardua ad Astraeus
Joined: Mar 2000
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From: UK
I am still not understanding
It is driving me towards a 'speed' marker (green)?
It cannot itself compute speed due to failures?
How does it compute the green marker?
How does it know when I have got there?
As far as I can see this is AoA driven. The AoA is too high. What is needed is reduction in AoA in fairly short order, not just an increase in 'speed' towards a dubious green mark.
Would not a 'DOWN' arrow, flashing perhaps, on the AI be far simpler and realistic? After all is is a matter of simplicity to compute an AoA at any altitude/Mach at which the wing will unstall.
It is driving me towards a 'speed' marker (green)?
It cannot itself compute speed due to failures?
How does it compute the green marker?
How does it know when I have got there?
As far as I can see this is AoA driven. The AoA is too high. What is needed is reduction in AoA in fairly short order, not just an increase in 'speed' towards a dubious green mark.
Would not a 'DOWN' arrow, flashing perhaps, on the AI be far simpler and realistic? After all is is a matter of simplicity to compute an AoA at any altitude/Mach at which the wing will unstall.

Joined: Jun 2009
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From: somewhere
@BOAC:
What exactly does 'SLOW' mean?
What is the required response?
And to bring the green down, you lower the nose......
Since we are talking AB, why does it not just say 'push your side stick forward and increase power'?
Do anyone need more clues?
Joined: Jan 2008
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From: uk
I am still not understanding
It is driving me towards a 'speed' marker (green)?
It cannot itself compute speed due to failures?
How does it compute the green marker?
How does it know when I have got there?
As far as I can see this is AoA driven. The AoA is too high. What is needed is reduction in AoA in fairly short order, not just an increase in 'speed' towards a dubious green mark.
Would not a 'DOWN' arrow, flashing perhaps, on the AI be far simpler and realistic? After all is is a matter of simplicity to compute an AoA at any altitude/Mach at which the wing will unstall.
It is driving me towards a 'speed' marker (green)?
It cannot itself compute speed due to failures?
How does it compute the green marker?
How does it know when I have got there?
As far as I can see this is AoA driven. The AoA is too high. What is needed is reduction in AoA in fairly short order, not just an increase in 'speed' towards a dubious green mark.
Would not a 'DOWN' arrow, flashing perhaps, on the AI be far simpler and realistic? After all is is a matter of simplicity to compute an AoA at any altitude/Mach at which the wing will unstall.
[images credit to google search and a site I know nothing about - but it's not mine, just to be clear]
I think this is more or less an AoA indicator dressed up as a speed tape, but I think it does do the "compute an AoA at any altitude/Mach at which the wing will unstall" without the pilot having to remember or read tables (I guess).
By the time you've been pulling up through the stall warning for best part of a minute, it's going to look like the previously posted image and probably isn't helpful (green ? what green, where ?). But if you kept it in the green in the first place, you wouldn't have that problem.
Also, look at the conventional AoA gauge (which option AF didn't give them either):
At the same point in the timeline, that needle would have been firmly pegged at 25, and the size of the nose-down inputs they made would not have shifted it. Pull or push, the needle doesn't move - must be broken gauge... no ?

Joined: Dec 2006
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From: The No Transgression Zone
I've read the whole thread...
It seems that the crew simply had no understanding of the anatomy of a stall and therefore an AoA gauge may not have helped....was there pre-stall buffeting noted? for it seems that the A330 has very docile stall characteristics perhaps further misleading the crew
were AF's A330s actually equipped with 'BUSS'? I seemed to have missed where it was first mentioned in the thread

It seems that the crew simply had no understanding of the anatomy of a stall and therefore an AoA gauge may not have helped....was there pre-stall buffeting noted? for it seems that the A330 has very docile stall characteristics perhaps further misleading the crew
were AF's A330s actually equipped with 'BUSS'? I seemed to have missed where it was first mentioned in the thread
Joined: Aug 2005
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From: fl
I don't think a competent pilot needs green arrows or any computer generated warnings to recover from a stall. It is so basic, you push down. Stall warning goes off, push down, works every time. Not with these clowns.

Joined: Jul 2009
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From: Not far from a big Lake
Originally Posted by fantom
It's the arrow.
Up? What am I supposed to do?
Up? What am I supposed to do?
The whole display is intended to look as much like the airspeed tape as possible. What I see as an issue with this approach is that this requires mental interpretation before you respond and it leans on the visual mode of information input like everything else on the 'Bus does. You will have to go through a thought process something like this:
- I'm getting near the 'Slow' arrow tip.
- Shall I add power or shall I push the nose down?
Plastic PPRuNer

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From: Rochechouart, France
If it said "TOO FAST" and "TOO SLOW" it would be a lot clearer.
(The system knows what power the engines are putting out so maybe a "GET THE NOSE DOWN!" or "AOA TOO HIGH" would help too.....)
(The system knows what power the engines are putting out so maybe a "GET THE NOSE DOWN!" or "AOA TOO HIGH" would help too.....)
Joined: Aug 2005
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From: Canberra
"I don't think a competent pilot needs green arrows or any computer generated warnings to recover from a stall. It is so basic, you push down. Stall warning goes off, push down, works every time. Not with these clowns."
Ptretty strong language considering you obviously haven't read the transcripts carefully enough to avoid putting your foot in your mouth.
If you take the trouble to read back you will see that the stall warning was off, UNTIL the nose was pushed forward to get out of the stall and at that point the stall warning came on.
In a pitch dark environment with everything seeming to be in conflict with everything you thought you understood about your aircraft's behaviour, perhaps it was all too easy to become a clown as you so eloquently and kindly put it.
Ptretty strong language considering you obviously haven't read the transcripts carefully enough to avoid putting your foot in your mouth.
If you take the trouble to read back you will see that the stall warning was off, UNTIL the nose was pushed forward to get out of the stall and at that point the stall warning came on.
In a pitch dark environment with everything seeming to be in conflict with everything you thought you understood about your aircraft's behaviour, perhaps it was all too easy to become a clown as you so eloquently and kindly put it.




