Lyman

xcitation. Without too much comment, there is a possibility nomenclature is not being understood. "On the right, 'side seat' (#4)", there was no belt attached. This may mean there was no remnant of belt attached to the seat frame. It would not mean there was no belt attached to a body, since without restraint, there would be no body remaining attached to the seat frame. BEA would ordinarily identify each seat by number, and RHS would be #2.

You say they identify "his mic". Not necessarily. They say "the mic". This could mean the ambient mic (one of, eg).

Either way, having found no belt attached to the seat, strictly speaking, it means that the belts were lost from their attachments (at impact?).

infrequentflyer789

The original post clarified (cut from the quotes):

that means the fact that a small stick input will give much more important nose up or down effect than at a lower altitude.

i.e. claiming the real thing is a lot twitchier than the sim.

It shouldn't be - ample data should be available for that, and if that statement is true, I would say the sims need fixing.

BWV 988

Having read most posts since the recovery of the recorders, and coming from a medical-statistical background, DozyWannabe in #833 raises an important issue:

When checking for errors/illnesses, the false negative type is typically the one that gets most attention, while false positive alarms may be more harmful in the long run.

False negative in this case would mean not to report a stall, that is indeed happening, while false positive would be to report one that isn't there. A false positive alarm is a cry wolf, insensitizing pilots to a particular warning. The "shut up gringo" incident, the tripped circuit braker on NW255 and (maybe) AF447 reactions are indications of this happening.

Actual stalls are very rare, so even though a system may have a low propabilty of reporting false positive, that scenario is still more likely than a real stall (true positive). In general, minimizing both types of errors may not be so simple, and lowering one type can lead to a rise of the other one.

TyroPicard

@Lyman...
And nor will they. From their homepage...

The sole objective of the technical investigation is to collect and analyze useful information, to determine the circumstances and the certain or possible causes of the accident or incident and, if necessary, to make safety recommendations in order to prevent future accidents and incidents.

Lyman

TyroPicard, re: "objective"

Except when it becomes necessary to support a manufacturer with a Press Release, and in doing so, laying Blame on crew by default. That Press release was a complete embarrassment, and an abdication of the very charge you quote.

A Mission Statement can be a promise made in Haste, prior to the challenge of the Real World.

The responsibility of those who are served is to challenge the Mission.

Them's the 'Rules'.

CONF iture

Why not ???

To the contrary, it is paramount the warning does not quit before the stall exit is complete. More than a question of regulation, it is a question of common sense.

But I’m curious here : When would you stop it otherwise ?

CONF iture

AFAIK 'dynamic pressure' applies on both side of the vane ... but please tell me more.

rudderrudderrat

Hi CONfiture,

I think IF789 was joking at the language translation.

If you are stalled, then the warning can not possibly be permanent, because if AOA is not recovered, then the crash would stop it.

AlphaZuluRomeo

Yes, but perhaps it should be a good idea to have a stall warning, even if the IAS is NCD / < 60kt.
If you have a NCD / invalid AoA... well... I don't know. But that's not the point.

I totally agree with you, here.
But I was not proposing to limit or override the pilot, but to limit nose up autotrim.
I cannot imagine a situation where it would be dangerous not to autotrim nose up, when stall warning is ON:
- if the stall warning is correct (i.e. most of the cases), one would not trim up, but lower the nose
- if the stall warning is incorrect (e.g. wrong AoA sensed...) => false positive:
---> would it be a problem/dangerous to inhibit autotrim NU? (note: manual trim always possible)
---> is this scenario likely versus the above one?

DozyWannabe

Lyman, you may be in need of a "chill pill" again. Not only was there nothing in the "note" released prior to the 3rd interim report (which is presumably what you are referring to) that was in support of the manufacturer, either explicitly or implicitly. All it said was that there appeared to be no technical or mechanical failure of the aircraft before the departure from controlled flight over and above the pitot blockage/UAS issue we already knew about.

Firstly, it's a logical fallacy to say that making a statement of that nature "lay[s] blame on crew by default" - that is simply not true, and an example of what many on here will recognise as a "false dichotomy" - a neophyte debating tactic.

Secondly, the press release did not directly lay any responsibility on the crew (nor was it a "cynical ploy" to get the public to do so). All it did was state the facts of the matter, among which was the indisputable fact that the crew appeared to mishandle the aircraft following a UAS incident, leading to a stall and loss of control. It was but one factor in the holes in the cheese/chain/graph of events that led to the accident. That the press may have oversimplified what was actually said in order to provide a more sensational story (and thus sell more papers) cannot be laid at the door of the BEA. Remember that the press have skin in the "face-saving" game here, having popularised the "baby pilot crashes aircraft" meme a couple of years back when the facts were very thin on the ground - to go back on that would make them look very foolish.

In part, it was this constant attempt to re-tread things that you have already brought up several times under several aliases that got the R&N thread closed down and transferred to Tech Log. Do you want the mods to shut down this discussion too?

infrequentflyer789

rudderrudderrat has it right.

The impact (ground/water/whatever) will stop it. Until stall exit is complete you are falling, not flying. Falling is not a permanent state (unless you are in orbit).

It is common sense that the manual cannot mean the warning is permanent without qualification.

Lyman

Someone is taking a disagreement a bit too far. BEA's Press Release allowed Airbus to claim no "new" issues with the a/c. That they did, and since no one was available to prompt no "New" issues with the crews, there you go. It was cynical, callous and sly, imo.

You disagree? Awesome....... A difference of opinion is healthy, up to the point where personal slander and hyperbole get slung. Not one time have I attacked you or your "chill" quotient. You seem intent on expanding ad nauseum on things not being discussed.......

A disagreement is not an insult, so there we are. You continue to have my respect and my admiration for such a complete grasp of the topic.

I tire of being "warned" that I am somehow compromising the thread.

Are you saying the thread disappeared due my posts? That would be odd, since ordinarily it is the poster who garners the ban, not the discussion, and you may have an issue not with me, but with the mods.

DozyWannabe

Back up a second - the BEA "note" was the first time *anyone outside of the investigation* had any idea what the crew did, so if there was no further technical failure highlighted by the flight recorders then there could be *nothing but* "'New' issues with the crew" presented. That the pitot tubes had failed and caused a UAS incident was something that the investigation and the public already knew, so this was not "cynical", "callous" or "sly", this was simply a release of the information gathered from the new evidence available. I'm sure that if an obvious technical or mechanical failure presented itself then they would have mentioned that.

Not at all, but let's be honest here, you've consistently popped up every few pages to reiterate your pet opinions or theories, thus leading to the "hamster wheel" effect that the mods described. I'm not entirely innocent of that either, but I'm pretty sure I've only ever repeated myself in response to questions or suppositions put forward that had already been asked and answered multiple times.

jcjeant

I'm in disagreement with the release of this note
The BEA mission is not to make some "dummy interim report" in a note to the public (and press)
It's not the rule ...
They have not to answer to press articles (they answer the press in meetings)
If they are in disagreement with the press (lies .. defamation .. etc ..) the court of justice is available and is the place for such dispute
The release date of this note .. is at least suspicious .. and it's easy to link the dots
This note was a error of the BEA .. and this added nothing to their credit of transparency or independence

Machinbird

Clandestino. This is all very irrelevant to the accuracy of the AOA vane as far as being useful. The AOA transmitters only send out an angular measurement. Nothing that is rocket science.

If the aerodynamic forces on the vane are enough to override the inherent friction in the mechanism, the vane will swing to very closely align with the relative wind. At very small AOA relative to the local air velocity vector, the inherent friction may be sufficient to create a small error provided the velocity is just above the 'come alive' speed. But in reality, once a vane comes alive, it is pretty accurate.. As I mentioned earlier, 'come alive' speed is typically in the 15-20 mph range. By the time you get to 60 knots, dynamic pressure is about 12 times higher than 'come alive' speed. More than sufficient to point the vane with extremely high accuracy. (much more than you need for basic stall warning)

The primary mode of failure that I've seen has been sticky transmitters due to contamination of the bearings and physical damage. They are really interesting gadgets. If you haven't already done so, find an opportunity to handle one.

grity

BUT for this non electric tool you need a compensation orifice..... might also icing like pitot tube

Lyman

Not every pressure sensing kit needs be an orifice. I still rather like the flexible membrane, or Tympanum. For that matter, a nicely calibrated skin would suffice, were it connected to a sensing rod, and pot.

Linktrained

Grity,

Thank you for your comment.

In sixty years there have been improvements in battery performance in terms of capacity and weight.

A battery powered Pitot/ Static system might have been invented by now, to go with the more modern GPS fitted gliders which already in THIS century have flown higher than FL50.0. Ask elsewhere about wing deicing ! ( I am out of touch.)

Ian W

This may be a silly question... but the captain returned to the flight deck and apparently from the BEA transcript did not receive any briefing from the PNF or PF on what had happened and what they had tried, just questions.

So - would it be immediately apparent that the aircraft was in Alternate Law or would the captain assume that it was still in Normal Law and had a plethora of unexplained 'errors'.?

It would explain his calls to the PF to 'pull up' despite obvious indications of a stall.

sandos

The non-acknowledgement of Alt Law seems to me to be a major issue. Either the pilot did not understand Alt Law, or more likely in my opinion, he did not understand that it was activated. Maybe he sort of filtered away that information as "not important enough" when the PNF called it out.