Chris,

The document is a presentation made to CAAC, illustrated with an image taken out of a MOI.
MOIs respect the general "look and feel" of Airbus' Flight Ops documents.

But the FDR data show that the System had no intention to deliver Alpha Max ...

Quote from Clandestino:
"Now if anyone thinks exact mechanism of disabling alpha floor is of concern in the accident where narrowbody full of passengers was deliberately flown below 100ft at 120 kt and idle thrust - feel free to entertain me further."

To which Chris Scott commented:
Very much associate myself with that sentiment, My base training at Blagnac with AI in March 1988 - around the same time as the Habsheim crew - naturally included that part of the flight envelope. The differences from Habsheim included: safe altitude, no rushed manoeuvering and energy disposal to botch, and NO PASSENGERS. Seeing the Habsheim video a few months later suspended belief, but suggested the protections had worked well.

As shown in my piece on the subject NEW A320 CRASHES AT AIR SHOW (HABSHEIM 1988) in Air Crashes and Miracle Landings the situation was worse than "less under 100 ft" would suggest as the trees in front of them were 40 ft high. It points out that although the captain had performed the "stunt" many times it would have been in the safe conditions mentioned by Chris Scott.
Though the engines did spool up from idle (though not in time), the manufacturer did take measures to improve their reaction time following the disaster. In view of the many other negatives, that improvement might not have been enough, but worth bearing in mind.

Quote from llagonne66:
The document is a presentation made to CAAC, illustrated with an image taken out of a MOI.
MOIs respect the general "look and feel" of Airbus' Flight Ops documents.

Thanks for confirming that an MOI is not a glossy brochure! "No 35811" suggests they may appear at a rate of more than one a day?

If anyone can provide access to a sample, I think several of us here would appreciate it.

*sigh* - If we clear this up now, can we get back on topic?

Right CONF - we know, as you repeatedly point out, that the system's Alpha Prot computations allow for an AoA just (probably just a fraction of a degree) shy of true Alpha Max. This is probably to provide a little extra safety margin - after all we are talking about the boundary of stall here. Your contention is that if the protection wasn't there, Capt. Asseline had the skill to finesse that extra fraction of a degree and cleared the trees. Am I correct so far?

So - let's look at some other evidence. Leaving aside the rather dubious notion of performing that maneouvre with passengers aboard in the first place (for which AF should be - and were - censured) - Capt. Asseline elected, having found himself off course (expecting the paved runway), fast and high, to fudge the approach rather than turn around and try again. This rather correlates some of the anecdotal evidence we have of the guy being somewhat arrogant. The mistranslation I've been working from regarding disabling of A/THR (and thus A. Floor) means that while fudging that approach, Capt. Asseline forgot to follow the protocol and did not cross-check with the crew. This arguably makes him both arrogant and incompetent - and it also demonstrates that his handling skills were not particularly well-developed. He then allowed the engines to spool down, and the aircraft to drop below 100ft - leaving an aircraft that was carrying passengers low, slow and out of options. Arrogant, incompetent *and* careless - qualities reflected in the judicial decisions that went against him.

Arrogant, incompetent and careless pilots have a nasty habit of getting people hurt and killed - and there is no mitigating excuse in the world that can counter the *facts* described in the paragraph above.

There - Habsheim is now discussed for the umpteenth time on a thread that bears little relation to the subject at hand. Permission to move along?

Habshame
 

2.5 deg is NOT a 'fraction of a degree'.

The 'little extra safety margin' is already in Alpha Max, that is why Alpha Max is Alpha Max and not Alpha Stall.

You are NOT.
The contention is that such supplementary restriction is NOT mentioned in the FCOM and not even in the BEA Report that had the duty to list it at a contributory factor.

You can even call him criminal if you wish but not before ALL facts are put on the table.

As you obviously don't know the Report, it would be hard to 'clear anything up'.
You don't have to stick around either ...

CONF - he wouldn't have cleared the trees anyway, and even if he had, he'd still probably have ended up losing his licence on the basis of the video evidence.

Where do you get 2.5 degrees from?

You certainly do not have the knowledge to state so.
The BEA had the necessary tools to get some numbers.

Who cares ?
I'm not reading Paris Match here, I am interested in the technical side.

*sigh* - From the documentation you don't read but still think entitled to make statements on ...

1. no swiveling pitot probes generally and on 330 in particular 2. trigonometry.

Well, that's the beauty in simplicity of the Airbus FCS: it doesn't need q. Pilot inputs G demand, elevator moves to meet it (as measured by IRS) and that's all there is to it. No need for taking q from ADC or elevator pitots to adjust stick stiffness, there is just non-adjustable spring. You might have all air data shot up and still have G command and protection - that's what is meant by obscure (to some) term "Alternate law". Of course, simpler means cheaper but also means there are far less components to break down.

Much ado has been made around here about complexity of reconfiguration laws and how to enter and exit protections. Operationally, all conditions listed in FCOM are of not much significance. What to do if your controls have gone alternate in flight? Nothing, keep on flying as you were. Just don't perform windshear or GPWS escape with full stick back, keep an eye on the airspeed, OK? How much stick and for how long is needed to combat the unwarranted alpha prot pitching you up? Who cares, push the stick to get the attitude you need and prot disconnection will take care of itself, it is meant to be instinctive and it is.

I'm sorry Chris, if my caustic style caused you to believe I was going for a cheap shot here. To make my position clear: I do not find any of the theories that there was anything remotely rational in CM2's action and it was just misunderstanding and misapplication on his part plausible. He meant just to return to altitude? He busted it by a couple of thousand feet. He followed the flight directors? He pulled whether they were there or not. He was cognitively overloaded? For a while the only thing picked up by the CVR is stall warning. The aeroplane developed roll oscillation? Oh sure: maximum amplitude 11°, period approximately 10 seconds, damped actively and completely in 1:30 min. He tried to perform UAS procedure for very low level in cruise? He didn't say so and was persuaded by CM1 to ease a bit anyway but stall warning sent him into another pull-up frenzy.

Now let's have a look at the general state of the aviation safety; despite all the doom-sayers that overuse of automation is going to be the end of us all, year after year we are enjoying the record lows of accident rates, so we must be at least doing something right. Of course, not all or even the most of improvement in the safety record is attributable to automation but there is no evidence it reduced safety, especially if besides the dry statistics we choose to pay attention to all too numerous incidents where automation went ballistic and pilots saved the day, often without anyone noticing except their colleagues informed via internal safety bulletins. So if we (and I mean we as aviation community, not as PPRuNers) want to improve the chances of everyone landing safely by applying the lessons of AF447, we better make sure we understand what really happened, lest we apply the cures that are inappropriate and can turn out to be poisonous.

I do not know what made the whole crew to act as they did but I am pretty sure there are two things that won't prevent AF447-like accident from reoccurring: more raw data manual approaches and more practice in unusual attitudes recovery. Practicing any of them involve preparation and anticipation, things sadly lacking in AF447 case where onset of the trouble was very fast. Again: issue with AF447 is not the pilot unable to handfly the aeroplane; it was pilot unable to understand the situation, implication of his actions and pretty precisely handflying just the wrong way, while his assisting pilot was, unfortunately, as lost as him. Nothing of it can be prevented by practicing eye-to-hand coordination in friendly skies. Also this kind of reaction is very rare and trying to present AF447 as typical of the current state of affairs is misinformed at the best.

I have mentioned that this is just another child-of-the-magenta case and this might be too imprecise; despite significant differences (performance and aerodynamics vs. lateral navigation) both AF447 and AA965 are subsets of the same archetype of accidents: pilots who find themselves on unfamiliar territory, are unable to recognize where they are and how to return to normal, eventually performing the action that results in their premature termination. That is absolutely not to say they were bad pilots: I'm pretty sure if they were presented with the scenario of their final flight, they would vehemently deny they would ever act according to it. As many around here very well know, difference between thought process in the air and on the ground is stupendous, especially at 4AM. Our unfortunate colleagues were suddenly thrown on scales and found lacking and even after final report we are not much smarter regarding what was missing.

To what end? He wasn't censured for failing to clear the trees, he was censured for taking unnecessary risks by improperly conducting an approach, then making a pig's ear of the approach itself - putting him (and his passengers and crew) low and slow with absolutely no safety margin whatsoever.

Then your criticisms of the BEA are unwarranted. They are tasked with providing a technical explanation of what happens in an accident and hopefully formulating recommendations to prevent a recurrence of that accident - nothing more.

What you're demanding - either computations or practical demonstrations to show at what pitch angle the aircraft could have cleared the trees with the airspeed at that point, or indeed if the extra 2.5 degrees (by your reckoning) could have made any difference - does not fall within that remit.


I do have the manuals and FCOM kicking around somewhere, and I'm as interested in the technical side as you are - a reference would be handy.

The pitots don't measure the angle of attack!
Itr's the AoA vanes which swivel.

rrrat - I eventually found the thread trail (25 Oct) you refer to! I think Clandestino will recognise his error in the light of day and realise he has been confused by the IAS inhibition on the stall warning. Indeed, 100kts TAS is well enough to register an AoA on a balanced probe (I assume they are balanced?), even allowing for density, I would reckon.

Hi BOAC,
Unfortunately, I don't think so as this is his 16th attempt (according to his count.)
It will just be another page of copy and paste of random parts of incomplete quotes.

AF Standards
 

@ Clandestino
Again: issue with AF447 is not the pilot unable to handfly the aeroplane; it was pilot unable to understand the situation, implication of his actions and pretty precisely handflying just the wrong way, while his assisting pilot was, unfortunately, as lost as him.

This is exactly the problem with AF's training whose safety record speaks unenviable volumes.
The problem is that AF haven't undertaken the recommendations of the ISRT because of the entire way that AF is run by having overpaid and underworked Generals with no Corporals.
This is reflected by the numerous incidents post-AF447 which indicates that safety culture doesn't run in AF veins.
Now here comes the rub: since 2012, AF has hired A342 instructors from the Estérel squadron at Airbus' behest to retrain AF instructors but so far in vain.
Worse, AF's parlous finances makes it even harder to get on with safety.
I expect DL or SU to leave SkyTeam.
Now watch this space: SU to join SkyTeam...yep Putin's heart pounds for Merkel.

Quote from BOAC (my emphasis):
rrrat - I eventually found the thread trail (25 Oct) you refer to! I think Clandestino will recognise his error in the light of day and realise he has been confused by the IAS inhibition on the stall warning. Indeed, 100kts TAS is well enough to register an AoA on a balanced probe (I assume they are balanced?), even allowing for density, I would reckon.

I'm hoping to find time to answer the rest of his post later (got a car to wash), but I respectfully suggest that you two may be missing Clandestino's point here.

His key word is "trigonometry". Think about it. Compare the pitch attitude of the aircraft, and therefore the pitots, with its steeply-downward trajectory. Haven't got time to check the figures right now, but, although the vertical component of its trajectory is (say) 10,800ft/min (180ft/s, or just over 100kts TAS), the pitot tube is at more than 90 degrees to that.

That's why - I think - he made a cryptic, light-hearted reference to "no swivelling pitots... on 330" (i.e., they DON'T SWIVEL...)

Hope this helps.

Chris, OG, HN39DonH
I can see the discussion has changed track. However I am producing the MOI for your information.
MODIFICATION OPERATIONAL IMPACT (M.O.I)
Aircraft Type
A340
SB Number
27-4101, 27-4116, 27-4131
Modification Number 48753
Modification Title
FLIGHT CONTROLS - FCPC - INTRODUCE NEW L16 SOFTWARE STD ON FCPC HARDWARE 2K0
Issue Date 04-AUG-2005
This information was initially introduced by:
Doc
Volume 1
Volume 2
Volume 3
Volume 4
QRH
FCOM
REV20
OEB
TR
FCOM sections impacted:
Volume 1, Volume 2, Volume 3,Volume 4
QRH. FCOM
1.27.20
OEBs or TRs cancelled by this modification:
Doc
Volume 1, Volume 2, Volume 3, Volume 4, QRH
OEB
TR
Summary of Operational Changes:
This modification consists of introducing the new L16 Software Standard on the Flight Control Primary Computer (FCPC) hardware 2K0. This software introduces a new condition that enables the aircraft to leave the Angle-of-Attack protection.
STLS (FS/EGM) MOI: 48753 (A340) Page 1 of 2
AIRBUS
1 ROND-POINT MAURICE BELLONTE
31707 BLAGNAC CEDEX FRANCE
TELEPHONE 05 61 93 33 33
TELEX AIRBU 530526 F
Modification Operational Impact
STLS (FS/EGM) MOI: 48753 (A340) Page 2 of 2
Description of Operational Changes:
In-flight experience has indicated that strong gusts of wind could unduly activate the Angle-of-Attack (AOA) protection. Therefore, this new FCPC logic is implemented to easily enable the aircraft to leave the AOA protection, when this protection is unduly activated.
With this new standard, the AOA protection is no longer active , when alpha is less than alpha prot, and the sidestick has not been deflected since the last autopilot disconnection.

Technical side is my concern, not Asseline, will you ever get it ?

Ok then where's the technical explanation on why the System refused to deliver Alpha Max ... ?

If you were you would read the Report first before spreading disinformation.

A330 AOA VanesWhat's the point there? In the worst case The AOA vane would be stuck at the maximum AOA (design value). Who cares if that is 30 or 60 degrees, it would be stalled anyway. That is at least true as long as the jet is not stalled inverted.
Or do we have any evidence, that the vane would reverse its travel against the airflow?

If the trigonometry concern is for the pitots, then it may be again fair to ask, why besides the AoA a speed indication is needed to determin wether you are in a full stall.

Hi Chris Scott,
I completely agree. So why would you want to turn off the stall warning when stalled like that?
The 60 kt logic is to prevent false warnings on the ground when the AoA vanes could take up any random position at low speed. Why keep the 60 kt logic when airborne?