Nonsense. What is the purpose of resurrecting a thread when all that is happening are people repeatedly repeating what has already been repeated repeatedly? Including a lot of nonsense.

Hazelnuts39, I had the same reaction as you. As I understand it, that response is to a stall warning (warning of impending stall) and the remedy implies that
1. you aren't yet stalled and
2. following that should get you out of trouble and keep you from stalling when all protections are in play.

When stalled reducing AoA is typically the correct response.

I predict that the "why is there no AoA indicator" hamsterwheel begins in 3, 2, 1 ... :E

In all fairness to Capn, the THS would have trimmed nose down if the PF would have commanded nose down with his stick forward for whatever time constant the computers use. I beg all the "new" folks I have seen this past week to go thru the thousand posts on the other thread.

The THS implementation was discussed at length, and several of us agreed that it did not help things if the pilot continued to hold aft stick. Otto tries to reduce your stick position to achieve one gee corrected for pitch attitude, even in some of the reversion modes. 'Direct law" is a different story, and the AF crew never got there.

I shall continue to argue that seeing or feeling the other guy's stick or column or whatever was not the primary contributing factor to the crash. Tried to explain this, but I guess some folks don't understand.

At FL350 and -40 °C the presence of significant quantities of supercooled liquid water is highly unlikely. Therefore the blockage of pitots in AF447 was almost certainly caused by ice particles.

Some examples are shown here. How does one test pitots to ensure they are able to deal with such variety? Is it really sufficient to quantify icing conditions in terms of IWC (ice water content) and mean particle size?

I wanted to post this a while back, but didn't have a chance to . . .
 

But as long as this thread is seeing activity again, there are two things I wanted suggest as things I see as factors in AF447 - and both of them are design related.

The first has been discussed many times (including just recently) before, and that is I think there needs to be some form of mechanical feedback between the control inputs (whether actual or simulated). People are inherently tactile beings and they very much - despite training to overcome it - depend on haptic feedback when the brain is processing higher level intellectual tasks. Look at touch keyboards, musicians, even surgeons using robotic instruments. While they can function without it, people work better with it.

The second may have been mentioned, but I might have missed it in the thousands of posts on this thread. And that is the way that the stall annunciator logic operates. It is pretty clear that the audible "stall, stall" means just that - you are stalling. But in the Airbus, the stall annunciation can be silenced by either recovering from the stall, or in the case of AF447, when the system loses key data inputs (the pitot tubes clogged), yet the system does indicate which.

While the actual cause for the silencing of the warning could have been deduced from various other indicators, in a rapidly changing and unusual system, I think it would be easy for the mind to get into the wrong feedback loop. Warning=on, I'm stalled. Warning=silent, I have recovered from stall. I think that is exactly what happened on AF447 (read the transcript of CVR).

If the system was designed something like, warning="stall", you have stalled; warning=silent, you have recovered and the system knows it because it is fully functional; warning="stall warning suppressed", you can no longer rely on the stall annuciator for the status of your aircraft, I think the outcome may have been different.

Just my thoughts.

UAS checklists on any airliner do not include pull full back. Depending on altitude and weight you select an attitude and power setting which is quite simple and is in your check list. All pilots should be able to do this easily.

bubbers, do you recall any evidence that the UAS (current in June of 2009) checklist was used by this crew?

You're misinterpreting the significance of stall warning. It's function is to alert the pilot that he is approaching stall. The warning is given sufficiently in advance of the stall to allow the pilot to avoid stalling by taking the appropriate stall avoidance actions, i.e. stop pulling, reduce pitch until stall warning stops..

No, but it should have been used and they didn't.

Thanks for that. Would be nice to have them the other (to me logical) way round, although I suppose I could turn my monitor upside down when looking at those parameters! :ok: :)

By rules .. the "Stall Warning" must activate near the point that the aircraft will stall .. and continue if the aircraft (for any reasons) go in the stall mode
The stall warning must continue .. until the aircraft is no more stalled or no more near of the stall mode
By Airbus design the AF447 stall warning stopped when the aircraft was in stall ..
BEA notice in conclusions that this is a contributing factor for the accident

Sorry, I should have been more accurate with my description. But I think the false feedback effect would be the same - hear warning, take some action, warning stops, conclusion = action successful. That conclusion would be false if the warning was suppressed for reasons other than the corrective action.

Please close this thread now
 

I think just about everything that can be known about this tragedy is known. Everything that can be said about it has been said.

It is an important incident in the history of commercial aviation and, of course it will never happen again. There is no point having any more circular discussions about pitots, or center column vs side stick, automation vs hand flying, or B vs A in the context of this incident.

But there will be new incidents like this (hopefully without loss of life) involving the whole system of pilots, CRM, automation and basic equipment faults. There are lessons for everyone. It was especially shocking for me reading the final report on AF447 to see that apart from the pitots, nothing actually failed on the aircraft, until everything did. A simple LOC grew out of all proportions into a major disaster. It happened in a manner that is a foretaste (a bitter one) of the kind of challenges that aviation is going to face. Every extra subsystem adds complexity. Failures, when they occur will be increasingly complex and ever harder to anticipate.

I think future discussions wrt AF447 should focus on this in general, not on the specifics of what happened to the pitots or what was in PF minds during the incident. Let them rest in peace.

It will do just that, except when the pilot ignores the stall warning and continues to pull until the AoA exceeds 40 degrees.
It doesn't.

glenbrook
I enjoyed your summary and your points, but let's not forget the trigger event: something did in fact fail (or become impaired): the pitot system. As noted numerous times in this four year long discussion, Air France had changed to the Goodrich pitot tubes on some of their fleet, but that particular hull had not yet gotten the change. Granted, a system malfunction need not become an emergency (nor an upset) as previously noted hundreds of times. That seems to be a key point of great interest to the flying public, to professional pilots, to regulating authorities, and hopefully the management of airline companies.

The pilots failed to maintain control with a simple pitot tube problem. They had a procedure to maintain attitude and power but they didn't use it. They chose to pull full back on the side stick against all procedures. They killed hundreds of people for no reason because they did everything wrong.

What's it say?

The objective of the SNPL is, and always has been, to support their members and to demonstrate that they were not at fault.

It has the merit of being clear.
.

@desiter And they had a plane that had little control feedback, basic instruments in the zone of view, and a system of Hal 9000 computers that for some reason they were told would protect them or they were made to believe that would allow them to act in a fashion such as pulling the stick back as necessary and that the ship was unstall-able.

Titanic 2.0 sans the Leo and Kate.

Hal 9000 vs Basic Flight Dynamics/Physics - the latter won.