amos2

Does this thread really need to continue?
All the pro's know what happened.
All the amateurs want to drag it on.
Let's just drop it, shall we?

oldchina

They didn't follow company procedures and took a perfectly flyable plane into a stall.

Dont Hang Up

We do not know what caused three professional pilots to behave like "clowns" (to use someone else's unfortunate term).

To dismiss this as pilot error is to abandon thirty-odd years of Human Factors wisdom that has done a very great deal to promote flying safety [best summarised as "if we don't know why they did that we dont know it can't happen again"] , and to go back to the bad old days of "blame and move on".

infrequentflyer789

You are reading (or not) a different report to everyone else.

Stall warning went on (continuous) at about 2:10:50, at that point the command and elevator were nose up.

From that point the nose was never "pushed" down - the elevators never went nose down let alone trim. Slightly less nose-up was commanded briefly but not enough to even push the elevators through neutral. And nowhere is there any indication they knew they were stalled let alone were pushing to recover from it.

Thinking that the on-off stall warning, when the plane is far beyond any tested envelope, caused the problem missed the point that the only reason they got so far stalled is that they pulled up, hard, despite (or in response to) continuous stall warning.

HazelNuts39

A33Zab;

Three questions RE your post #1120 explaining the BUSS scale:
1. The red upper area corresponds to CAS > VFE. Assuming that VFE is flap limit speed, would that be Vmo/Mmo in clean configuration?
2. The red lower area corresponds to CAS < VLS?
3. At the bottom of your post you write:Does the BUSS take Mach effect into account?

Lonewolf_50

That doesn't just apply to flying. Thanks for that pithy little summation.

HazelNuts39

Would this be better? >>>

HazelNuts39

EDIT:: The graph presented in this post has been deleted. New information posted by A33Zab in post #1185 has invalidated the assumptions used in the graph.

Machinbird

IMHO it would.

Now all they need is to visually separate the upper Red area from the lower Red area so that someone walking in on a situation cannot possibly get the two confused.
Maybe a different color, or stripes?

Too bad you weren't on the original design team for that item.

On the AOA chart following, the brief bump in the fast direction had to be turbulence. That is the kind of thing you would visually average out.

The BUSS indication probably moves around more than airspeed indications do but it is still a valuable indication.

mm43

Could be the answer.

EDIT :: After considering A33Zab's post #1184, the graphic originally posted here has been removed.

A33Zab

I've to revise that one, with the - AOA limit - I meant to say AOAsw (stall warning)
and for your information, I found today, switching to the BUSS comes with a backup stall warning too.
based on Flap/Slat configuration only and NOT MACH.

Seems to be logical since you switched of all AIR DATA.

With S/F retracted the AOAsw is 8.6° while in CONFIG FULL it will be 13.6°.

The FCOM:

The backup speed scale is based upon AOA and depends on the Flap/Slat configuration.

1// The RED FAST area: Indicates the excessive speed range.

2// The AMBER 'fast' area: is representing excessive speed range
while keeping an appropiate margin to the maxium structual speeds.

3// The GREEN area indicates the safe speed range.

4// The GREEN Target symbol: This symbol indicates the optimum target speed.

5// The YELLOW line: This fixed reference line, next to a yellow triangle, indicates the aircraft's current speed.

6// The AMBER 'slow' area: indicates too low speed while keeping a appropiate margin to the stall speed.

7// The RED SLOW area: indicates the speeds that are lower than the stall speed.

I did send you some detailed information for your valuable graphs.

infrequentflyer789

My thoughts too.

I'd also maybe want to look at some sort of graduated marking such that you get feedback that your actions are in the right direction even if you've managed to get the green off the end of the screen. A non-moving needle over a moving solid red (or even red-white check) background doesn't tell you much.

From a UI point of view, I'd also raise concern over "slow" and "fast". Icons, colours, arrows ok, english text - not so ok. Yes, I know everyone at the pointy end is fully trained in ICAO level-whatever english, but this isn't an interface for situation-normal with all user brain functions working in calm non-panic mode.

I have similar concern about stall warning being an aural "stall"... stick shaker requires no translation.

I think the HF report is going to be interesting, and I think speed tape (normal vs. alt) is going to be in there - they might not consider the BUSS UI. That report is also considerably overdue now (from the estimate they gave). I don't think it is going to be short.

Hamburt Spinkleman

There will be partial green and all amber showing whenever the tape is at extreme ends, not full red.

This isn't a display that jumps out of nowhere to everyone's surprise, it comes at the end of a checklist after an unreliable airspeed condition have been identified and acted upon.

Keep it simple.

CONF iture

mm43

@ CONF iture

If you can't remember what to do, your solution seems to be the easiest to implement - a software mod.

chrisN

Is there any intention to submit these suggestions to BEA or Airbus?

Organfreak

chrisN said:
Well, let's think this through:
Who here would elect to do that? Somebody on their own volition, or "by committee"? There is very little consensus here, even after all that's been written, with the possible exception of: the pilots did not recognize the stall, and even that much is not entirely agreed upon, judging from some of the more crude comments.

Having said that, IMO, there's ZERO chance that these threads aren't being read by at least a few members of those organizations. Also zero chance that we would ever know who. It would be a PR disaster if word ever got out that "they" were listening to "us." All we are doing is speculating based on the published evidence, and even beyond that. They are going to have to draw conclusions from the available facts and make determinations based on their analyses, not from ours. Also, even if they do determine that the pilots' confusion was based partly on weaknesses in the interface, I'd be surprised if they would go so far as to redesign the displays, inasmuch as that would be a frank admission of liability. (Hope I'm wrong.)

If there are flaws in my summation of this issue, discuss, argue!

bubbers44

So we haven't gone far enough. Now we will hire inexperienced pilots like the Af447 flt crew and just say push or pull so they will know what to do? Why don't airlines just hire qualified pilots and the problem is solved.

Organfreak

Well, bubbers, I think that AF447 demonstrates that there is a problem with how "qualified" is being defined these days, both by some penny-pinching airlines, and even the regulatory authorities as well, since they have allowed this.

I'm hoping for a drastic re-definition of the term "qualified."

jcjeant

Schramm (AF chief of pilots) in a interview to french TV network made this statement:
"There was in command of AF447 a crew with competency"