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AF 447 Thread No. 12

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AF 447 Thread No. 12

Old 24th Aug 2014, 06:48
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The simulators have no accurate model to duplicate the behavior of the airplane post stall. Sure, they will exhibit a some sort of behavior (and I have personally flown it in several A-330 simulators), but if it reflects the actual airplane is unknown.
There are however, efforts to design at least a generic stall response for inclusion in flight simulators. Recent US FAR changes (that go into effect in 5 years) will require training in recovery that depends on this and other simulator enhancements just now being hashed out.

AF447 was a wake-up call in many ways. Many parts of the industry have woken up, but the fix is not complete.

For now, practice by turning off the flight directors and autothrust and flying some good old basic attitude instrument flying.

The flight directors are doing 85% of the brain work if you're hand flying with them on. Don't be a flight director addict!
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Old 24th Aug 2014, 06:55
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The flash of light contributes to the theory that an explosion is what brought down AF447, which was carrying 228 people from Rio de Janeiro to Paris.”
There is absolutely no evidence in the flight data to support this theory. Where was this aircraft that they could have possibly seen them?

Check out this animation that shows the other aircraft in the area deviating around the weather that helped bring AF447 down. (note the animation does not load with Chrome - works good in IE
Flight Paths of Flight AF 447 and of the flights that crossed the zone around the same time
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Old 25th Aug 2014, 10:05
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Mont Ste. Odile

Originally Posted by DozyWannabe
OK, we're off-topic here, so I don't want to get too much into the subject, but from what I understand (based on what I've read and the portions of the report I've translated), the controller offered radar vectors to the ANDLO beacon (from which the VOR-DME approach could be made), but turned them slightly too early, and then used non-standard language when asked to confirm their position. This is in everything I've ever read on the subject.
Off-topic indeed, but this might be a good opportunity to mention that that accident (and Bangalore, too, btw.) is featured on the FAA "lessons learned" web site. They have an animation of the flight path and even an English translation of the full report (from which I'd recommend section 21.5, "Reconstruction of the most probable scenario").

Lessons Learned
Air Inter Flight 148 Flight Path Animation
http://lessonslearned.faa.gov/AirInt...Report_Eng.pdf
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Old 25th Aug 2014, 15:41
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The investigation concluded that, based on conversation on the cockpit voice recorder, the descent was intended to be performed at a flight path angle of 3.3 degrees. However, the investigators noted that the actual commanded descent was 3,300 feet per minute, and may have been the result of having inadvertently selected the vertical speed mode on the autopilot control panel. In this case, minus 33 would have appeared on the autopilot display, implying a 3,300 foot per minute descent, while in the flight path angle mode, minus 3.3 would have appeared in the same window.
That is the anti Airbus brigade theory! We don't CFIT due to high vertical speed but descending under the bottom of the approach !

Flying at 220 Kts a 15% slope requests 3300 Ft/minute, as we pilots all know (220 x 15 = 3300)
The crew was not aware that , descending step by step the VOR-DME approach and not the derogatory CDA, altitude 3660 FT was mandatory at 7 NM to STR VOR as "FAF" was not indicated.
The crew respected "don't descend 4300 FT before 9 NM to STR due to possible false GPWS warning", and the next mandatory step seemed to be 1340 FT passing STR , without the three magic letters "FAF". Descending the 15% slope from 4300 FT to 1340 FT they met the ground.

Sorry for off topics.

Last edited by roulishollandais; 25th Aug 2014 at 15:50. Reason: 220x15=3300
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Old 25th Aug 2014, 17:20
  #305 (permalink)  
 
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Bon soir roulishollandais,

I am not following this current AF447 discussion - just occasionally dipping in - and I certainly do not want to get involved in a latterday argument about Mont St. Odile and the ergonomics of the FPA/VS switching and displays on the original A320 FCU and FMAs. Suffice it to say that they were much improved by modifications resulting from the investigation into that accident, as I remember only too well.

But I think you might have another look at your sentence:
Flying at 220 Kts a 15% slope requests 3300 Ft/minute, as we pilots all know (220 x 15 = 3300).

I do not think so. You may remember that the rule of thumb for a 3-degree slope is that the required VS (in ft/min) is five times the groundspeed in knots. (I think most of us mentally divide the speed by ten, and then halve the answer to obtain the VS in hundreds of feet-per-minute.) At 220 kt that gives 1100 ft/min (add a tenth of that for a 3.3-deg slope.) Using the one-in-sixty "rule" (approximation), a 15-deg slope would demand about about five times as much, i.e., 5500 ft/min.**


** Non instrument-rated readers please note, the above are approximations only.
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Old 25th Aug 2014, 19:52
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Dear Chris,

220 kts. 3° = 5% (standard ILS) 220 * 5 = 1100 Ft/men

220 kts. 15% 220 * 15 = 3300 Ft/min

The protection /limit slope is 15%, not 15° (PROMIN)
The crew displayed that VOR-DME 15% limit as Vs 3300 FT/Min, not the CDA 3.3° they did not want to use.

Are we together now?

Of course they improved the ergonomics and displays, that does not prove it was a factor or cause in the CFIT.A question had emerged, why not do better ? That is the logic of annex 13 recommendations.

Last edited by Jetdriver; 25th Aug 2014 at 21:08.
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Old 25th Aug 2014, 23:49
  #307 (permalink)  
 
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Apologies, roulis,

Yes, I misread your 15% slope as 15 degrees. (Maybe I need new reading spectacles!) Must admit I am not accustomed to seeing descent profiles or glide-slopes expressed as percentages... Climb gradients always have been, of course.

As already stated, I am not commenting here on the ergonomics of the A320 FCU, but do not disagree with your last paragraph. Having flown similar approaches on the type before and after the modifications, I'm broadly familiar with the accident scenario and the main hypothesis.
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Old 26th Aug 2014, 18:15
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Originally Posted by roulishollandais
That is the anti Airbus brigade theory!
Actually, I'd disagree with that. It was a very valid criticism of the FCU display, and one which had occurred before - but on those previous occasions the mistake had been caught in time. For another thing, I think the same issue was present on other mfrs types which had Honeywell hardware with a FPA/VS descent mode on the glareshield interface.

Of course there were other issues as well, but from a technical perspective this non-intuitive aspect of the FCU interface was probably the most glaring issue that needed to be fixed.

The crew respected "don't descend 4300 FT before 9 NM to STR due to possible false GPWS warning"
Except, of course, that (IIRC) due to a regulatory loophole regarding domestic commercial flights, the Air Inter A320s were not fitted with GPWS, and that was another *massive* issue that needed to be fixed.

Victims were less happy and let me add that they took a wrong way :
1. Creating an association of victims after a crash cannot be used in French Law to get damage (we don't have Class Action)
That appears to be changing now (article from Feb 2014):
France Finally Embraces Class Actions | Publications | McDermott Will & Emery

[EDIT : It appears the court did nevertheless find AF and Airbus liable for damages in 2006 : http://www.aviationpros.com/news/103...-in-1992-crash ]

2. Trying to manipulate the Court "to get more money" (from Airbus) was a very very bad idea.
Right, and I have to wonder whether the SNPL were involved in the decision to pursue Airbus but not AF (Capt. Asseline's legal representatives did the same in the Habsheim court case and in doing so missed an open goal - to this day I can't fathom why).

@Winnerhofer - re: contaminated blood, it didn't just happen in France, but also the UK and other places. In fact a good friend of mine (he's a fair bit older than me) sadly now carries Hep C as a result of a transfusion of contaminated blood in the early '80s.

Anyways - I think that's about as far off-topic as I dare to go! Back to the gallery...

Last edited by DozyWannabe; 26th Aug 2014 at 19:55.
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Old 27th Aug 2014, 14:11
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Actually, Winnerhofer, it seems that Air France's imposition of English on its pilots is only for communications with ATC at Roissy (CDG). I don't think there are any existing or proposed French auto-callouts in AF cockpits? On the other hand, the AF checklists, including their QRH, seem still to be in French, and (as the AF447 CVR demonstrated) AF cockpit business is conducted in the native tongue. Far be it from me to offer an opinion on that.

Those of us who have observed some of the actions of SNPL over the decades can understand that pilots forming the residue within AF of the ancien Air Inter, the former French domestic airline, might find it distasteful to adapt to ATC comms in English. It's almost unknown at any French airfield to hear a Francophone pilot speaking English for ATC comms, so this French anomaly is not specific to CDG. As the Liberation article indicates, Air France has been the only non-Anglophone flag-carrier outside the former Soviet bloc refusing to speak English for ATC comms at its home airfields.
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Old 3rd Sep 2014, 03:35
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Which is the Air France UAS procedure today?
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Old 4th Sep 2014, 16:04
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Hello Winnerhofer,

That would all benefit from a definitive translation into English.

Quote from Stéphane Gicquel, secrétaire général de la Fédération nationale des victimes d'attentats et d'accidents collectifs:
" « Les acteurs de l'aérien ont une culture de l'entre-soi. Les familles de victimes ont une vraie difficulté à croire à leur indépendance. » "

By "l'aérien", is he referring to ICAO, the regulators, the manufacturers, the airline industry, or individual airliner crews? Whichever it is. no doubt it could provoke some lively debate.
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Old 4th Sep 2014, 16:18
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Some will like .. some not
Spoiler:
French
http://henrimarnetcornus.20minutes-b...1875577343.pdf
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Old 4th Sep 2014, 18:49
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Originally Posted by Marnet-Cornus
Airbus et l’EASA ont demandé aux pilotes d’assumer la responsabilité du défaut d’un équipement de l’A 330 en sous-estimant le risque.
Underestimating the risk to deepstall that plane or the risk to be unable to recover from the stall ?
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Old 4th Sep 2014, 18:53
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Originally Posted by Chris Scott
By "l'aérien", is he referring to ICAO, the regulators, the manufacturers, the airline industry, or individual airliner crews? Whichever it is. no doubt it could provoke some lively debate.
it includes passengers too. "Vaste programme !"* of course.
* Charles de Gaulle

Last edited by roulishollandais; 4th Sep 2014 at 23:21. Reason: add notam *
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Old 4th Sep 2014, 19:21
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RH
Underestimating the risk to deepstall that plane or the risk to be unable to recover from the stall ?
I think the two are linked ....
en sous-estimant le risque.
But I think the risk that mean Cornu is:
Décembre 2002 : La FAA rend obligatoire le remplacement de la sonde Rosemount par les sondes
Goodrich et Thalès AA en précisant le risque de sortie du domaine de vol et qu’il s’agit de la réponse
à une « unsafe condition »
December 2002: The FAA mandates replacement of the Rosemount probe probes
Goodrich and Thales AA specifying the risk to go out of the flight domain and that is the answer to
an "unsafe condition"
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Old 5th Sep 2014, 01:30
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Originally Posted by roulishollandais
Underestimating the risk to deepstall that plane or the risk to be unable to recover from the stall ?
If you'll excuse the Google translation of the original HMC PDF:

Originally Posted by HM-C
Airbus and EASA have asked drivers to take responsibility for default equipment of the A 330 underestimating risk.
For one thing, the Thales AA probes were *not* a default fit, they were an option.

For another, there's an interesting sideline here:
Pitot probes : Air France - Corporate

Following the fluctuations and/or inconsistency in aerodynamic speed indications on the long-haul A330 and A340 reported by some airlines, the French Civil Aviation Authorities published an Airworthiness Directive (AD) per type of aircraft to impose the replacement of the ROSEMOUNT P/N 0851GR Pitot probes, either with the GOODRICH P/N 0851HL probes, or by the SEXTANT (THALES) P/N C16195-AA probes. This operation had to be completed by 31 December 2003.
Even more interesting:
The authorities did in fact attribute these incidents to the presence of ice crystals and/or quantities of water which exceeded the specifications of the P/N 0851GR Pitot probes, manufactured by ROSEMOUNT, which was acquired in 1993 by GOODRICH.
So in effect, the Goodrich probes which were recommended to replace the Thales probes after the accident were in fact a development of the original Rosemount probes which were also known to be problematic.

As for the overriding premise of M. Marnet-Cornus's PDF, it's the standard SNPL modus operandi of indignant tone, selective presentation of information and questionable attempts at misdirection.

(again please excuse Google Translate)

..the Autopilot and auto-thrust are disconnected, flight controls move ALTERNATE into law.

While control of the aircraft is reduced, the crew must keep them in a very small area of flight and face a incredible number of alarms in a very short time. This is an excessive workload.

The ALTERNATE, which was imposed their law and using which they had never been trained at high altitude, is a mode degraded flight controls. The A 330 was no longer consistent with all regulations of the basis of his certification, he was just "Controllable" very unstable in roll. The loss of information speed entailed the risk of asking its flight.
The second paragraph is incorrect - in fact the likelihood is that the aircraft would have stayed more-or-less on course had the crew done absolutely nothing with the controls in response to AP disconnect.

The third paragraph makes reference to a claim that Alternate Law makes the aircraft unstable in roll. Again, this is a fabrication. Alternate 2 makes roll control direct - so the aircraft will be *more sensitive* in roll, but that's a long way from unstable.

In the space of 49 seconds, to 02h10.54, the A 330 wins and can not be recovered
He uses this phraseology a few times - implying that the aircraft's systems forced themselves into an uncontrollable state from which the pilots could not recover. This completely ignores the fact that it was the PF's control inputs that put the aircraft into that situation in the first place.

For over four years, the media relentlessly dogs custody of the politico-industrial system cowardly tried to make dead drivers solely responsible for this tragedy
Yet another fabrication. The BEA report implicitly criticises the airline, the regulator, the manufacturer and the system as a whole.

All these points of very questionable veracity occur in the introduction, three pages in. I have a very difficult time believing that the rest of the document is much better in that regard.
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Old 5th Sep 2014, 01:56
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Dozy, Re:Pitot tubes

Could you explain to all of us why Goodrich pitot tubes, that worked very well on Boeing jets, were not considered as replacements in 2007? Now quite honestly, Airbus and Air France are experienced entities, not new-bees to this business of aviation and how speeds are measured and which devises are best. I think there is much more to this story from a technical point of view that isn't being revealed.

The Air France time line is nothing more than a talking point or "positioning", that is to say, "Who me? I didn't do anything wrong." I am sure Airbus has a similar talking point. Lawyers like talking points.
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Old 5th Sep 2014, 02:34
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Originally Posted by Turbine D
Could you explain to all of us why Goodrich pitot tubes, that worked very well on Boeing jets, were not considered as replacements in 2007?
Goodrich tubes were standard fit on Airbus types (including the A330) as well, and to the best of my knowledge still are. The Thales pitot tubes were an optional fit.

This is illustrated in M.Marnet-Cornus's document:
In 2008 175 Airbus A 330 of 32 companies Airlines are equipped with the [faulty] sensor.
A quick archive.org dive indicates that there were:
555 [A330s built] as of 31 July 2008
which in turn indicates that around 70% of A330s built were not equipped with the Thales probes (meaning they were standard Goodrich fit) as of 2008. Some of the remaining 30% would have been equipped with a mix of Goodrich and Thales units as well.

[EDIT : HM-C's focus on the pitot tubes is itself a misdirection of sorts. The aircraft did not crash simply as a result of the UAS condition, in fact there's a good chance that had there been no manual input, the aircraft would have bumped its way through the turbulence with the speed indications returning in a minute or less. The aircraft crashed because the PF's instinctive response of pulling back on the stick without any discussion or notification was inappropriate, and became more and more inappropriate as the sequence unfolded.]

Last edited by DozyWannabe; 5th Sep 2014 at 02:51.
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Old 5th Sep 2014, 22:36
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Read the original threads. The manufacturer/certification status of the AoA vanes state that the readings given from the vanes are not sufficiently reliable below 60kts IAS. Certainly not a situation where you want inappropriate hard protections making things more difficult.

Last edited by DozyWannabe; 5th Sep 2014 at 22:48.
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Old 8th Sep 2014, 21:00
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I was taught early in my career as a fighter pilot
That expert and former USAF's aerobatics pilot is perhaps not the best to claim that aerobatics was of no use to emphasize hand flying skills and basics helping the B757 crew to survive.
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