AF447 [Archive] - Page 16

Lemurian

17th Jul 2009, 23:40

Aguadalte
Further, I understand your explanation of the fuel figures used by AF. I just don't think they are in the spirit of the law.
As that fuel calculation method has been validated by the DGAC and all the aurthorities AF operates into in Europe, your comment is moot.

These guys had one hour and six minutes of flight worth in fuel
Sorry. I should have said : these guys had one hour and six minutes extra fuel in hand to use as they chose.

having in mind the completeness of the flight, provided they would have to re plan, having in mind (EU OPS 1 (again...)
If you looked at the annexes of the BEA report, you'd find the different plans proposed to them : one with a refile possibility, using Borfeaux as initial destination, one at M.81 direct and the last one at M.82 direct, which they decided on, leaving a few passengers behind (Those that the news called "miraculously saved at the last minute" ), because of the extra 900kg or so that the Captain decided on.

A last point, the "arrogant" bit was not addressed to you. You and I may not agree on details but I resent comments by some people whose only link to aviation is a flightsim and think they are entitled to pass judgment on a crew perceived actions...generally with nothing else but prejudice.

Jag6 :
Actually, I think that this statement needs examination.
ADS-C is reporeted "on test" in the Dakar FIR, and generally, it doesn't work.
So HF is used...They're still with Atlantico, with whom they received a positive selcal check...Calling Dakar is altogether another matter and generally, the most successful way would be to monitor the VHF frequency and ask for a relay from a preceding aircraft. so you're stuck in a catch 22 situation : to get an ADS contact, you'd need a positive HF contact with Dakar who then generates an actual flight plan.
And no communication for 25 minutes is certainly not unheard of in those regions.
So what's your point ?

Hyperveloce

18th Jul 2009, 00:00

Lemurian,
The BEA report states that some crew had many problems to contact Dakar ATC via the HF (on 5565 KHz, 6535 KHz, and all the HF frequencies available in the onboard documentation.). At 02:01Z, it was the 3rd and last connection to the Dakar ADS-C to be attempted by the AF 447 crew: would it be possible that these repeated com. attempts may have diverted the PNF from a more carefull met analysis with different weather radar settings approaching the MSC ?
Jeff
PS) is there an explanation for the 3 Atlantico requests (for TASIL estimates) that remained unanswered by the AF 447 at 01:36Z ?

FLY400

18th Jul 2009, 00:49

Hyperveloce

The CPDLC logon is really simple and takes very little time. The pilot enters the ICAO identifier on the ATC LOGON/STATUS page of the CDU and presses SEND. The result does not take continuous monitoring. This page is shown below.
http://members.optusnet.com.au/~cjr/FMC4.gif

Tha ADS-C contract is set up by the ground station. The flight crew have nothing to do with it.

What we do not know is if AF447 attempted to contact DAKAR on HF. And we will not know until the CVR is recovered. It is possible that any attempts to contact DAKAR may have been recorded on the ATALANTICO tapes, but we don't have those either.

For those interested in CPDLC and ADS-C there is very good coverage available at ATC DL News Home (http://members.optusnet.com.au/~cjr/index.html)

atakacs

18th Jul 2009, 06:07

Has anyone calculated the likely ocean drift of the piece? Is that distance possible?Not a specialist myself but it would be truly amazing.

Ariane 5 seems much more likely IMHO.

Lemurian

18th Jul 2009, 09:49

Hyperveloce,
PS) is there an explanation for the 3 Atlantico requests (for TASIL estimates) that remained unanswered by the AF 447 at 01:36Z ?
Having successfully tested the Selcal, the crew left the audio HF watch, relying on Atlantico -or others on the same frequencies- to contact them via Selcal.

Fly400,
What we do not know is if AF447 attempted to contact DAKAR on HF. And we will not know until the CVR is recovered. It is possible that any attempts to contact DAKAR may have been recorded on the ATLANTICO tapes, but we don't have those either.
The calls to Dakar would have been made on 6535 and Atlantico was on the 6649 family. Had Atlantico picked-up some transmissions, they would have reported it.

cribbagepeg

18th Jul 2009, 12:52

HF must be longer than a meter or so; just idly wondering on what part of the a/c it / they are deployed..

John47

18th Jul 2009, 14:17

FLY400

I see from ATC DL News Home that
"Once a periodic contract is established, it remains in place until it is cancelled or replaced by another periodic contract."

So when one wants to switch from one ground station to another do you cancel the first station and then try to logon to the next one?

When it cannot logon what happens then? Does it keep trying at intervals or does the operator have to initiate a retry?

vovachan

18th Jul 2009, 14:42

Having successfully tested the Selcal, the crew left the audio HF watch, relying on Atlantico -or others on the same frequencies- to contact them via Selcal.

Did ATC tell them to do that? Did they tell ATC they were going to switch to SELCAL?

Me Myself

18th Jul 2009, 14:53

Did ATC tell them to do that? Did they tell ATC they were going to switch to SELCAL?

It would be a hell of lot easier if people knew what they are talking about.
ATC doesn't tell you to. It's just standard procedure. One doesn't swithch to SELCAL, one IS on SELCAL watch unless the test proved negative.
Since the dark age of aviation in this area, radio contact remains flimsy, always have always will. ADS is supposed to be the magic bullet and it is when it's working, which is most of the time.
No radio contact would have prevented the loss of this aircraft and as far as mayday call goes, they had thousands of other things to to do like try to save the aircraft, be afraid and stressed like most of you won't ever be in 3 life times.

I think this thread should be closed until the BEA comes up with something new. It is getting both boring and repetitive.

FLY400

18th Jul 2009, 15:23

In both Boeing and Airbus airplanes there is one HF antenna shared between 2 HF transceivers. It is located just behind the leading edge of the Vertical Stabiliser.

There are 2 other components between the HF transceivers and the antenna. One is a coupler that connects the transmitting HF to the antenna. The other is an antenna tuner that optimises the antenna to the transmitting frquency.

While only one HF is able to transmit at a time, both HFs are able to receive simultaneously.

You are correct. The physical antenna is about a metre long.

Lightning6

18th Jul 2009, 18:44

HF must be longer than a meter or so; just idly wondering on what part of the a/c it / they are deployed..

I believe it's mounted on the VS, but it's an active antenna, so it doesn't need to be long.

See post 984 on page 50 for diagram.

ArthurBorges

19th Jul 2009, 08:02

I've only copied the first three paragraphs; to post more would be to patronize most everyone here.

Guyana fisherman finds possible debris from Air France crash; officials contact Brazil
July 18, 2009 - 11:34
THE ASSOCIATED PRESS
GEORGETOWN, Guyana - A fisherman in Guyana apparently has found a large piece of a plane that authorities suspect might belong to the Air France jet that crashed in the Atlantic Ocean, an aviation official said Saturday.
The 30-foot-long piece of what appears to be aircraft fuselage washed up on a beach in the South American country this week, said Paula McAdam, deputy director of Guyana's Civil Aviation Authority.
The Brazilian Embassy said it would send experts to examine the debris, she said.
Pasted from <Guyana fisherman finds possible debris from Air France crash; officials contact Brazil | Macleans.ca - Canada - Features (http://www.macleans.ca/article.jsp?content=w176069132)>

There is also Bruno at CRASH-AERIEN.COM - Le Site Français des Accidents et Incidents Aériens (http://www.crash-aerien.com) who says there are 3 MLA accelerometers on the A330, all of which come in square casings and none of which are made by Sensorex. See full posting below:

bruno7
Principicule de Taxiway

Inscrit le: 21 Mar 2009
Messages: 101
Localisation: ILE DE FRANCE

Posté le: Ven 17 Juil 2009 23:36 Sujet du message:

Il y a 3 acceleromètres sur A330 pour la fonction Maneuver Load Alleviation (MLA) et Turbulance Damping.
Ces accelero Nz et Ny sont logés en soute avionique (juste devant le logement de TAV) pour les deux concernant la fonction verticale et au plafond du fuselage tout à fait au fond de l'avion c'est à dire sous la dérive.

Ils n'ont pas cette allure là,le boitier est carré et le fabricant n'est pas Sensorex.

Pasted from <WWW.CRASH-AERIEN.COM :: Voir le sujet - Air France AF447 : Après l'arrêt des recherches (Partie 2) (http://www.crash-aerien.com/forum/91-vt11878.html?postdays=0&postorder=asc&start=1350)>

BJ-ENG

19th Jul 2009, 09:26

Covered in posts # 3742 & # 3751 - compare the paint job on the Ariane nose fairing with the wreckage.

Hyperveloce

19th Jul 2009, 14:20

Art Deco, what are the rain attenuation values you have used for your estimation ? Do you make use of a cloud model (a spatial distribution of water, ice,...) ?
Jeff
PS) this article maybe of interest:
A prediction model that combines rain attenuation and other propagation impairments along Earth-satellite paths, Dissanayake, A.; Allnutt, J.; Haidara, F., Antennas and Propagation, IEEE Transactions on Volume 45, Issue 10, Oct 1997 Page(s):1546 - 1558 Digital Object Identifier 10.1109/8.633864
but there also may also be attenuation from the a low gain LOS due to the antenna itself (partially masked by the airframe, LOS in a low gain direction of the radiation pattern, rotating plane & antenna axis)

DJ77

19th Jul 2009, 21:37

At the beginning of the Air Caraibes (ACA) incident that happened last fall, the situation looks rather close to that of AF447, at least with regard to these elements: same FL (350), about same gross weight (206 t), ADR disagree, Alternate law.
As you know, during the incident the ACA crew experienced two stall warnings which the PF considered spurious and disregarded. That probably saved his day.
The analysis of this incident, which was published earlier, states that given the configuration, the threshold to trigger a stall warning is AoA = 4.2°.

Question: do you people with flying experience on A330 think that at 4.2° AoA this airplane is so close to max AoA that it is reasonable to throw a stall alarm, especially in the situation at hand ?

HarryMann

20th Jul 2009, 00:59

DJ77

Surely that's a question for the aerod and systems dept at AI. This wouldn't be a matter of 'stall' as much as initial buffet onset. Pilots wouldn't have much if any experience of flying into that AoA regime during cruise, surely, to be able to assert 4.2 is too early, 4.5 is about right. These things are figured out from detailed consultation of test-flight crew/flight-test engineers and examination of buffet/maneouvre limits of the wing from plotted Lift~Drag~PM/Mach boundaries.

Squawk_ident

20th Jul 2009, 08:42

Radiocokpit has published an ASR. AF908 CDG-TNR (Antananarivo) FGNIH A340-303X
F-GNIH was on her way at FL370 between OBD 13°06'40.5 E 30°13'53.3 and MLK N09° 33' 47.4 E31° 39'11.4 on the UB612 (Khartoum FIR) when this incident occured.
There are a lot of similiraties with the chain of events of the 447.
The report is in French and I have unfortunately not enough time to translate in English but most of you should easily understand or use automated translation tools.
RCC editors have "translated" the report in plain French (blue color).
Please note:
CDB= Captain
OPL = F/O
PF Pilote en Fonction (left seat)
PNF Pilote Non en Fontion (right seat)
At the time of the incident the Captain was in command at the left seat and one F/O at the right seat. The second F/O was at rest.

Link :

Eurocockpit - Archives (http://www.eurocockpit.com/archives/indiv/E009479.php)

Scroll down to
AIR SAFETY REPORT - 1/6

FGNIH AF908 CDG - TNR - ALARME STALL ET PERTE DES INDICATIONS DE VITESSE SUR LES PFD

Hyperveloce

20th Jul 2009, 14:54

Isn't there a past case, on an A340 in cruising phase (at FL370) between Paris and Antananarivo (F-GNIH) during which the pilot decided a nose down when stall alarms were sounded ?
Eurocockpit - Archives (http://www.eurocockpit.com/archives/indiv/E009479.php)
added after reedition__________________________________________
before the problems with the airspeeds, the PF had reduced the speed to Mach 0.80 ("a little bit over the green dot") after the plane had entered turbulences not detected by the radar. So that when the stall alarms sounded (due to rolling back airspeeds due to Pitot freezing), maybe it was logical that he thought that they were justified (being just "a little bit over the green dot") and reacted accordingly ? (nose down & descent)
____________________________________________________________
I am also trying to see whether the A/THR could have had a similar reaction just before its disengagement (increasing thrust level to correct a spurious airspeed decrease just before being put off line), diminishing the upper aerodynamic margin. And also at A/P level (disengagement => an ongoing phenomenon compensated by the A/P before its disengagement is let free to drift/amplify when the A/P goes off).
Jeff
PS)
-these stall alarms occured approx. 30 s after the sequence of fault reports incl. AP & A/THR off in the Air Caraïbe case, a critical phase during which the crew are already busy to understand/isolate the faults, to apply the check lists/procedures and to pilot manually.
-the stall alarms immediatly follow the AP & A/THR off for the flight FGNIH AF908 CDG - TNR

ttcse

20th Jul 2009, 17:06

Regard one little piece of all of this, something occured to me. I wonder.

I'm thinking the 'twist to the left' component indicated for the fin-failure in the preliminary report might simply result from a deflected rudder at the moment of impact. A deflected rudder would impose a twisting force on the base. A deflected rudder could also be one of the factors in where the freed fin traveled after impact. Of course there are definitely other possibilities for the twist.

frequency change(i.e., not fishing for dialog, i'll just drop-off the card and go do my other things)

HazelNuts39

20th Jul 2009, 19:24

RE: HarryMann (#3774)

These things are figured out from detailed consultation of test-flight crew/flight-test engineers

Actually, these things are governed by airworthiness requirements, e.g.:

FAR/JAR 25.207 Stall warning (a)Stall warning with sufficient margin to prevent inadvertent stalling (...) must be clear and distinctive to the pilot in straight and turning flight.

Subparagraphs (b) through (f) of this section define the required margin in more detail.

regards,
HN39

Hyperveloce

20th Jul 2009, 19:35

HazelNuts39
Then add flight safety engineers to the investigation pool.
Because the alarm can be "clear" and "distinctive" (meaning a signal you can not miss ?), but if there can be "undue stall alarms" (see ECAM messages) or due stall alarms (see SOPs), a variable meaning/interpretation according to a situation which is very difficult to assess in a few sec. or even min., then the alarm signal and more importantly the reaction it should induce is not so much "clear" and "distinctive"
Jeff

HazelNuts39

20th Jul 2009, 20:17

RE: Hyperveloce #3779

I am quoting from a requirement that must be met by all large (transport category) airplanes. Before the FBW age, the requirement was met by natural pre-stall buffet or, if the airplane didn't have that, by a stick shaker triggered at a certain AoA. I assume that the aural warning "STALL STALL STALL" meets that requirement for the A-330. Quoting from the ASR FGNIH AF908:

Suivi immédiatement de l'alarme STALL STALL STALL (sans l'alarme cricket associée) avec indication de TOGA LK.Any system in the airplane should be designed to prevent "undue" stall warnings.

I would be interested to know if the A-330 stall warning, for any given configuration, is triggered solely by the AoA signal, or that it depends on the airspeed (pitot) -signal.

Regards,
HN39

PS: I should have added that other requirements specify that operational speeds, i.e. the minimum speeds flown intentionally by the pilot during takeoff, enroute and landing must have sufficient margin above the stall warning speed to prevent interference during normal maneuvering.

ArthurBorges

20th Jul 2009, 23:25

From a July 8 posting at Eurocockpit:

UPDATE: We're getting lots of emails telling us stall warnings are only triggered by the AOA windows. There are numerous documented cases of stall warnings caused by icing of Pitot tubes. Moreover, "risk of undue warning" is cited in cases of ADR DISAGREE.
It seems the AOA threshold for triggering a stall warning depends not only on SLATS/FLAPS position, piloting law but also speed (or Mach number).
As a reminder, the ACA crew had already applied severe turbulenece procedure, which consists of disengaging A/THR and displaying thrust appropriate to flight level, but they nonetheless faced a stall warning when trying to maintain flight level despite altitude variations due to speed adjustments.

ORIGINAL TEXT

UPDATE : Nous recevons un abondant courrier nous indiquant que l'alarme de décrochage n'est générée que par les palettes AOA (Angle Of Attack, sondes d'incidence). L'alarme décrochage apparaît dans de nombreux cas documentés de givrage des sondes Pitot. La mention "risk of undue stall warning" apparaît d'ailleurs en cas d'ADR DISAGREE.
Il semble que le seuil d'AOA de déclenchement de l'alarme Stall soit fonction de la position des SLATS / FLAPS, de la loi de pilotage, mais aussi de la vitesse ou du Mach.
Pour rappel, l'équipage ACA avait préalablement appliqué la procédure "severe turbulence" consistant à débrayer l'A/THR et à afficher une poussée correspondant au niveau de vol, mais a pourtant été confronté à l'alarme Stall en essayant de maintenir le niveau de vol compte tenu de la variation d'altitude (liée à la correction de Mach).

Pasted from <Eurocockpit - Accueil (http://www.eurocockpit.com/)>

Hyperveloce

21st Jul 2009, 00:08

I would be interested to know if the A-330 stall warning, for any given configuration, is triggered solely by the AoA signal, or that it depends on the airspeed (pitot) -signal.

So would I.
If this stall alarm is computed from AoA only (and not also the airspeed, the altitude, the aerodynamic configuration: flap ext.,...), maybe it is linked to the AoA law (the alpha prot) ? And then the next question is: how is the alpha prot computed ? Wouldn't the threshold "alpha prot" be a table depending on the flap configuration, airspeed and altitude ?
And if there is an indirect link between stall alarms & airspeeds (via the alpha prot values), in the Air Caraïbe case, there is a lag of 30 sec. between the CAS drop+sequence of FLRs and the stall alarm: maybe an underlying filtering process ?
Jeff
PS) Increasing Pilot's authority over automated systems via the AoA law:
http://www.pn.ewi.tudelft.nl/education/et4-138/notes/loc.pdf

wes_wall

21st Jul 2009, 01:06

There seems to be several postings missing. Someone posted that there have been several recent incidents all involving the A330, which in turn generated numerous ACARS during a potentially alarming time in flight. All similar to AF447. This posting prompted a quick and curt reply suggesting it was the ire of a legal firm looking to make publicity in order to turn favor for a rewarding litigation. Then, alakazam, they vanished. This post as well may go away.

But I would like to add, aviation has a history of similar incidents involving various aircraft type. Just staying with the turbo age, whirl mode with the Electra, metal fatigue with the Comet, the 707 stability and dutch roll issues, the sink rates of the 727, the DC9 tail, the DC10 was grounded, and hard-over’s with the 737 to name a few. A lot of tragedies, but I don’t recall it taking a bunch of lawyers to get government/industry to get it fixed.

Now, it sure seems you have an airplane that has a given problem repeated often. You can point figures at the legal community, but unless someone gets their arms around the obvious problem with this airplane, and soon, then I fear more accidents are likely. It has nothing to do with politics, nothing to do with Air Bus vis vis anyone else, nothing to do with law suits, it is simply common sense.

vapilot2004

21st Jul 2009, 01:24

@Hyperveloce

The flight warning computer uses only AOA data and flap/slat position in normal law. In alternate law, the speed becomes part of the threshold calculation along with AOA information.

Hyperveloce

21st Jul 2009, 01:30

@Hyperveloce
The flight warning computer uses only AOA data and flap/slat position in normal law. In alternate law, the speed becomes part of the threshold calculation along with AOA information.
vapilot2004:
You mean airspeed becomes part of the calculation even if the alternate law has been triggered by an ADR disagreement ?! (corrupted airspeeds)
This would justify the ECAM status message "risks of undue stall warning" (that should be discarded according to certain SOPs, because the stall alarms are supposed to be based on the AoA and not the airspeeds)
Jeff

HarryMann

21st Jul 2009, 02:35

Actually, these things are governed by airworthiness requirements, e.g.:

FAR/JAR 25.207 Stall warning (a)Stall warning with sufficient margin to prevent inadvertent stalling (...) must be clear and distinctive to the pilot in straight and turning flight.

They may be governed by AW Requirements, but the actual alpha and the interpretation of sufficient margin (which is what the question was getting at) is established first during design and subsequently by flight test (engineers/test pilots).

If these are found to be insufficient in any way, then discussion and resolution/agreement by both parties would be expected. But 'sufficient margin' indicates we are in an area of subjective judgement rather than predicated figures.

ArthurBorges

21st Jul 2009, 03:29

Leading French daily Le Figaro says this morning a "Last Attempt" has been started to recover the flight recorders using sonar at the end of a 1,500m cable to "visually scan" for the wreckage down to 6,000 metres. The search will go back over the 16,000 sq.km. search zone and take four to weeks.

For the anecdotal laff, I have to add some source's complaint that pingers sounded like whales, or whales too much like pingers.

Source: Le Figaro - France : AF 447 : ultime tentative pour retrouver les boîtes noires (http://www.lefigaro.fr/actualite-france/2009/07/21/01016-20090721ARTFIG00008-af-447-ultime-tentative-pour-retrouver-les-boites-noires-.php)

JD-EE

21st Jul 2009, 04:57

vapilot2004
The flight warning computer uses only AOA data and flap/slat position in normal law. In alternate law, the speed becomes part of the threshold calculation along with AOA information.

Do you notice something ironic about this considering it appears one of the ways you find yourself in alternate law conditions is loss of airspeed indication? :\

JD-EE

LeandroSecundo

21st Jul 2009, 05:23

Hi,

The flight warning computer uses only AOA data and flap/slat position in normal law. In alternate law, the speed becomes part of the threshold calculation along with AOA information.

Do you notice something ironic about this considering it appears one of the ways you find yourself in alternate law conditions is loss of airspeed indication?That's part of the great Airbus protection system ... never fail :eek:

Bye.

Hyperveloce

21st Jul 2009, 15:46

From what was said, can we conclude that stall false alarms are a very natural outcome from an ADR disagree ? (and the subsequent alternate law 2). It may go hand in hand with overspeed alarms in certain cases.
If we assume there is a high probability that the AF 447 may have been subjected to false alarms, we could then try to figure out how a pilot could react to these stall alarms given the known contextual elements. Or try to find past cases of false alarms of stalling and the associated crew reaction. There are basically two main possibilities: either the crew discard the stall alarms and do not consider them as justified, or the crew makes the opposite choise ? The first possibility would lead to something similar to the Air Caraïbes scenario (not exactly the same though). Don't you think we should explore the second scenario ?
Jeff
PS) We could assess the aerodynamic margins as a function of time from this opposite crew decision & action (beyond whether a pilot could take this opposite decision or not given the context), to try to see how long could it take from the initiation of an overspeed situation to a loss of aerodynamical control, how much time the crew had to recognize and correct this situation gradually leading them out of the flight envelope, to get some timing references. We could try to see which were the clues or indicators that crew may have relied upon to make a correct assessment of the situation, even in the absence of airspeeds (taking in account past cases, we can also make hypothesis so as to the Pitot freezing event duration, or the time when the airspeeds may have recovered their normal values). We can compare this timeline to the ACARS sequence chronology (keeping in mind that the PRIM and SEC failure at 02:13Z may result from an intentional crew attempt to reset the faulty Master flight computer to regain the normal law for the rest of flight).
We would need inputs from experienced pilots for the crew reactions to the multiples signals given the context.
PPS) The Birgenair flight 301: Pitots problems due to maintenance, corrupted airspeeds, false overspeed alarm, and high altitude stall:
http://www.youtube.com/watch?v=vDd2fL5XYSA&feature=related (http://www.youtube.com/watch?v=vDd2fL5XYSA&feature=related)

Hyperveloce

21st Jul 2009, 17:59

Has anyone ever had to reset his PRIM ?
How long does it take between the manual switching off/on and PRIM being back on line and operational ?
How long does it take for the related ECAM or ACARS (from the manual reset) to appear ?
If the crew was already hand flying, could the PRIM reset have interfered with the pilot's manual flight controls ?
Jeff

thermalsniffer

21st Jul 2009, 18:01

Could not the A/THR OFF been as a result of crew action??

Hyperveloce

21st Jul 2009, 18:10

Hi. the BEA report states that this ACARS alarm (AUTO FLT A/THR OFF) is the result of an unintentional disconnection (not the result of an "instinctive disconnect" buttons use, nor of a thrust lever put on idle).
In the case of Air Caraïbe it was already/intentionaly off (severe turbulence proc.) when the problems arised, same thing in the Paris-Antananarivo (AF A340), and in TOGA LK state after the sequence of problems. Jeff
AUTO FLT A/THR OFF (Single chime Master caution)
Signification : ce message indique une déconnexion de l’auto-poussée autrement que par l’utilisation du bouton prévu à cet effet sur les manettes de commande de poussée (instinctive disconnect) ou par un déplacement de celles-ci sur le cran ralenti (idle). (BEA report page 52)

LeandroSecundo

21st Jul 2009, 18:48

Hi,

There are basically two main possibilities: either the crew discard the stall alarms and do not consider them as justified, or the crew makes the opposite choise ?

Why it's necessary to trow the dices in case of emergency :confused:
Anyways it's 50/50 .. not bad for a game of chance :rolleyes:

Bye.

lomapaseo

21st Jul 2009, 20:25

Why it's necessary to trow the dices in case of emergency
Anyways it's 50/50 .. not bad for a game of chance

A minding numbing question.

But we haven't decided yet between man and machine in emergencies.

Man follows a thought process sometimes influence by softer things like from reading PPRune. The machine follows simple logic and rules which may not always consider the interface with man.

Thus the result is not anymore predictable than chance. (hopefully not nearly as bad as 50-50).

Right now the best the design of the product can do is to give you a chance that you can influence the outcome.

HazelNuts39

21st Jul 2009, 22:06

wes_wall

21st Jul 2009, 23:21

Looking at two men walking a few steps on the surface of the moon on french TV, i wonder how much it would cost to send an instrumented business jet equipped with an assortment of pitot probes on a few flights across the upper layers of the ITCZ?

I too wonder what the results might be to take away the glass and inact alarms in the ITCZ, revert to Alt Law and monitor crew actions. Sooner or later, this question as yet has not been asked, but it still has to be resolved.

singpilot

22nd Jul 2009, 00:39

I hate to state the obvious, but that was just done and we are all pretty sure how it turned out.

I know that sounds flippant, but who would pay for it? Who would fly it? Who would do what the 300lb Gorilla in the room would say needs to be done (again).

I suspect the results would be the same.

Every night since this crash, 8 to 10 heavy transports procede along this route uneventfully and manage to avoid CNN.

5 did it the exact same night within +/- 6 hours. Along the same route. Same exact weather. They managed it without incident.

The answer to this crash is not in the DFDR. It probably has nothing to do with any design philosophy or defect. Have been through this area more times than I ever care to remember. In several different types of aircraft.

The answers are in the CVR.

Obie

22nd Jul 2009, 07:49

The post above by singpilot says it all, to all professional pilots the world over!

To all the armchair, fifth quarter, wise after the event, non pilots on Prune, please take note.

Your views are useless, ignored, disregarded and treated with patronising contempt by all professional pilots!!

Singpilots post should close this thread.

Porker1

22nd Jul 2009, 07:50

A simple question.

Considering all the AB 330/340 pitot related incidents that have resulted in the AC control systems going to alternate law and throwing stall alarms at the flying crew - from the information discussed here and on Eurocockpit we seem to be looking at between 5 and 9 incidents.

Was AF447 the first such incident to happen in darkness when the flying crew will have had less visual feedback from their environment?

BOAC

22nd Jul 2009, 08:15

Indeed, singpilot's post is spot on, but do not forget we do not know if any other 330s had the same series of 'failures' that night on that route, nor does the fact that 1 Qantas 330 suffered a serious pitch excursion while others flew happily along mean there is not an underlying technical issue. Unfortunately the chances of the CVR being of use are practically nil, so we have to go on what is 'known'. You cannot just fold your arms and say "crew issue, full stop"

Obie

22nd Jul 2009, 09:05

"Indeed, singpilot's post is spot on, but do not forget we do not know if any other 330s had the same series of 'failures' that night on that route"

Well, that's an incorrect statement as you well know, BOAC!

If other operators had problems on that route we would know about it by now!

You know that!? :confused:

BOAC

22nd Jul 2009, 09:22

Good - now that is clear, so that suggests that something 'unusual' happened with 447 which did not happen to the others. If others had had the same problems and 'survived', that would tend to point your way. Since they didn't it is not really relevant, I feel.

Can you put your cards on the table please. I believe you are endorsing sp's suggestion that it was a crew error? Is that your position?

mickk

22nd Jul 2009, 10:19

Dani

22nd Jul 2009, 10:50

Everyday 300 Toyotas of the same type crash!

There is a statistical difference between 300 examples of the same type experience the same technical malfunnction or one only one example with 300 pax does the same.

If you would have grounded every aircraft that crashed, there wouldn't be any aviation anymore. The only aircraft that never crashed is the A380, and it is only a matter of statistics until one does! (Heaven forbids.)

Dani

LeandroSecundo

22nd Jul 2009, 12:09

Hi,

If you would have grounded every aircraft that crashed, there wouldn't be any aviation anymore

Can remind you the school case of the Concorde ..
Only one crashed .. and the entire fleet was grounded.
Explain me this with statistics :hmm:

Bye.

PilotsOfTheCaribbean

22nd Jul 2009, 12:25

Can remind you the school case of the Concorde ..
Only one crashed .. and the entire fleet was grounded.
Explain me this with statistics

There were only around 12 of them flying for only 2 airlines worldwide. The cause of the accident was rapidly established and a rectification programme was formulated. One of the two airlines did not wish to ground its fleet. The manufacturer was looking for a reason to withdraw from the expensive investment needed to keep this tiny and specialized fleet flying. Economically the aircraft had been badly affected by the reduction of premium class air travel post 2001. The political will had evaporated to simply postpone the inevitable.

infrequentflyer789

22nd Jul 2009, 12:57

If 300 Toyotas crashed and killed the occupants, the model of vehicle would be taken off the road.

Toyotas crash every day, as do other makes and models. Only when a consistent fault in the car is identified as a cause across a large number of accidents would action be taken and even then it would most likely be a recall and fix (which is unlikely to pick up all runing cars of that model). Ford Explorer rollover deaths due to the car/tire (take your own side) design are alleged to be in the hundreds of, with thousands of serious injuries. Has the explorer ever been "taken off the road" ?

I just dont understand how this type of a/c can continue to fly as if nothing happened when 300 people have died. I have a feeling theres another disaster on the way.
We don't know (and may never know) what caused the crash. It may be something completely unrelated to the aircraft model. Perhaps we should be banning thunderstorms in the ITCZ ?

Secondly even if the cause was an issue with this aircraft model, we don't know what the probability of recurrence is to decide whether grounding the fleet is the right response.

Has the 777 been grounded ? They fall out of the sky with both engines rolled back, remember (and we still don't have final report on why - in fact the silence is...). Well, one 777 fell out of the sky anyway - do you have your "feeling" another one is "on the way", or does that feeling just apply to one particular aircraft manufacturer ?

wes_wall

22nd Jul 2009, 14:30

The answers are in the CVR.

And, if the CVR or FDR are not recovered, what do you propose? Might I suggest caution be used prior to sticking you head in the sand. There is a serious problem associated with the simular repeated incidents experience with this airplane.

No, waiting for the recovery of the CVR is not the answer. I urge all to continue looking elsewhere. Why close the thread simply because no one wishes to thread on more sensitive issues?

vovachan

22nd Jul 2009, 14:59

f others had had the same problems and 'survived', that would tend to point your way.

We are told in the report abt another AF flight in the vicinity which flew into a bit of a mess which they failed to spot on the radar. After which they put the radar on full blast and saw another much bigger mess which they avoided. These guys lucked out, maybe AF447 didn't

GHOTI

22nd Jul 2009, 16:07

"Can remind you the school case of the Concorde ..
Only one crashed .. and the entire fleet was grounded.
Explain me this with statistics"

I know this is off-topic, but for the curious, the Concorde went, with just one crash, from being the safest a/c to being the most deadly; from 0 to 1/80,000 flights per crash, or 12 per million miles traveled, compared with the B737's rate of 0.41 per million.

The kicker is, the 737 has flown some 105 million flights compared with Concorde's 80,000 lifetime.

Such are statistics. (Explanation courtesy of Peter Olofsson, author of "Probabilities."

admiral ackbar

22nd Jul 2009, 16:33

If 300 Toyotas crashed and killed the occupants, the model of vehicle would be taken off the road.

I just dont understand how this type of a/c can continue to fly as if nothing happened when 300 people have died. I have a feeling theres another disaster on the way.

The silence is deafening.

It must be very hard for you to drive to the airport then since that is the most dangerous part of flying...

I would ride on an A330 every day for the next 5 years rather than drive every day for the next 5 years, complete no-brainer...

That line of thinking must be what got us to the Moon, or maybe it is what has prevented us from returning... :ugh::yuk::*

rgbrock1

22nd Jul 2009, 16:37

If the day comes where the CVR and/or FDR are not found (i believe they will eventually be found but perhaps not for a long time to come) what would be the next step toward solving this enigma? Will this be relegated to the "unsolved" files or do you think the accident investigators might approach it from a different way?
I'm curious as to how this may progress absent a CVR or FDR. (Without which I would imagine no definitive resolution would be possible?)

BOAC

22nd Jul 2009, 17:07

rgb - it depends really on how much more information AF and ABI have that we do not know. More 'wreckage' does not have the potential to 'solve' the puzzle. I guess without the recorders, 'most probable cause' will be determined, and a fair bit of work on reviewing the software, hardware and pilot training issues.

llagonne66

22nd Jul 2009, 17:30

Mickk,

As already stated on 1st July :

Since entry into service the A330/A340 (same design / two A/C) fleet has accumulated :
- over 27 700 000 flight hours,
- in over 5 200 000 take-offs.

As the AF447 accident is the first one (one too much of course) with no obvious root cause, I do not see how any Airworthiness Authority could mandate a grounding of the fleet.

Hyperveloce

22nd Jul 2009, 17:45

rgbrock1, to answer this question, maybe we should look back to past cases for which there was no CVR/FDR recovered ?
The outcomes/conclusions of the official investigations can be debated or challenged (with alternative scenarii/explanations being put forward that are equally convincing) even when the CVR/FDR is recovered, a reconstruction of the aircraft is enabled by a wealth of debris, and many data are available.
From the current available data (debris/autopsies), maybe the conditions of impact can be more accurately known (analysis conducted at the CEAT Toulouse) but from this, how could they figure out, with a satisfying degree of confidence, the sequence of events (crew action incl.) that lead a plane in high altitude cruise flight to the surface ?
The absence of new data would just be very sad for those who are desesperate to know how their relatives have left this world, and sad for the air safety (possibly not learning what it should).
Jeff

jungle drums

22nd Jul 2009, 17:47

The body of the aircraft and the tail fin must have landed in the sea reasonably close together. The aircraft could not have been controllable without it attached.

Given that the farthest separation of the two would occur if the tail fin detached at altitude, and an aircraft then struggling for control wouldn't proceed more than 50 miles, the body of the aircraft should lie within a 50 nm radius of where the tail fin was originally found (with drift for current resolved).

This area cant be too great for a detailed search with modern equipment.

singpilot

22nd Jul 2009, 18:36

From BOAC, whose opinions I respect highly...

Indeed, singpilot's post is spot on, but do not forget we do not know if any other 330s had the same series of 'failures' that night on that route, nor does the fact that 1 Qantas 330 suffered a serious pitch excursion while others flew happily along mean there is not an underlying technical issue. Unfortunately the chances of the CVR being of use are practically nil, so we have to go on what is 'known'. You cannot just fold your arms and say "crew issue, full stop"

You have to understand how difficult it is for one crewmember to suspect another ESPECIALLY when the suspect crew is not here to defend themselves. I abhor the thought that someone would do that to me.

The CVR is my friend. Automation, properly understood and with training and diligence attached is an even better friend. There are previous instances of 'incidents' that might fit the AF447 scenario, and almost no imagination is required to make these incidents 'fit'. But I still believe what we see in the ACARS messages is a result of the upset at cruise. This aircraft behaved as ANY aircraft would on a night like that presented with the same scenario. Is why I answered the post about 're-creating' AF447.

So here we are, long time, no concrete answers. A lot of speculation (including mine), and most of the speculation centers on technical issues ad nauseum.

What I tried to present was where we stand at the moment. We won't know much from the DFDR beyond what we already have from the ACARS. Both probably lost power at the same time. What we WILL learn is from the CVR... what was going on in the cockpit up to and including the departure from cruise flight.

If it is not found, we will be where we are now. Toulouse may find something in the debris inspection that the Braziliians missed, but I doubt it, even with motivational differences.

Every night since this crash, I have pictured the route and it's special challenges, and can empathise with the relatives of the pax AND crew.

Lest we forget, there but for the grace......

LeandroSecundo

22nd Jul 2009, 20:01

Hi,

admiral ackbar (http://www.pprune.org/members/55827-admiral-ackbar)

I would ride on an A330 every day for the next 5 years rather than drive every day for the next 5 years, complete no-brainer...It's not really a universal answer ...
Think about ..
Certainly some passengers of the AF447 had drive cars all their lifetime and still alive able to take place in a plane (some certainly for the first time in their lifetime) and now are no more there for make the most dangerous thing (as you tell) .. drive their car.
Can we speak of bad luck ?
And can we speack of bad luck for one who was not allowed to board the plane and lost life day after in a car crash ?

Bye.

lomapaseo

22nd Jul 2009, 20:18

This area cant be too great for a detailed search with modern equipment.

Bingo:ok:

But over what time period:confused:

PJ2

22nd Jul 2009, 20:43

singpilot - superbly stated.

Hyperveloce

22nd Jul 2009, 21:19

So here we are, long time, no concrete answers. A lot of speculation (including mine), and most of the speculation centers on technical issues ad nauseum.

True, but beyond the technical issues, there are the AF 447 crew and its reactions.
And I understand this is a delicate question. Some experimented pilots have their intimate view but a public forum may not be appropriate to express them.
But pilots on this forum could share their views about how they think they (themselves) could have reacted in a given context, which clues/signals/indicators they would have relied upon, or how they (themselves) could have been deceived, or overwhelmed, by some specific combinations of failures and/or false alarms (instead of presuming what others could have done).
And if the BEA has questions about possible crew reactions in given contexts, there won't be any speculation or reluctance: there will be multiple crews of similar composition & experience formed and tested in simulators under varied hypothesis.
Jeff

Razoray

22nd Jul 2009, 21:59

AF447 crash may have similarities to Aeroperu flight 603. Both had Loss of vital instruments during flight and subsequent loss of control. Both AC were lost over water at night. Both AC had false warnings.

The difference is that AF447 was not in radio contact with anyone and was in bad weather. Would a study of Aeroperu flight 603 be worth consideration?

I'm not saying someone covered AF447's instrument probes with tape, but the end results of these two accidents seem to have some similarities.....

singpilot

22nd Jul 2009, 22:08

The Aeroperu 603 crash had something AF447 doesn't (yet).

They had recovered a piece of the fuselage that had speed tape covering the static ports, done to protect them during an aircraft wash. That was THE smoking gun. Case closed.

The crews' actions (and the planes' responses to crew input) were entirely consistant with the blocked static ports. The possibility of a triple redundant failure (all 3 static systems), was unheard of, and was never trained for, or even discussed. But it happened. If it had been during daylight hours, perhaps the tape would have been spotted in the walkaround, or a horizon would have been seen and used by the crew out the window.

Razoray

22nd Jul 2009, 22:13

Thanks....singpilot.......

And the question is what happened this time...we dont know, but we can assume (or, I can) that it was something that was never supposed to happen. Thats why it is such a mystery!

But what is the smoking gun? :ugh:
What happened that was not planed for, is it the unexpected that needs to be looked at?

singpilot

22nd Jul 2009, 22:27

Well, Razor....

We don't have a 'smoking gun' yet.

PJ2

22nd Jul 2009, 22:30

Jeff;
there will be multiple crews of similar composition & experience formed and tested in simulators under varied hypothesis.
I am sure you will know this intuitively but it requires stating. A simulator is precisely that - an electronic, software-driven "look-alike" with wonderful fidelity to the aircraft under normal and known abnormal conditions. It is programmed not through "sampled" data but using software that mimics, very well, the aircraft's cockpit arrangements. The aerodynamics of the aircraft are extremely well done and within expected flight regimes, I should think reliably mimic the aircraft.

However, the simulator's very best qualities are also its greatest fault. Its very veracity can mislead an experimenter into believing that "this is how the airplane would respond". These are very complex machines and we simply cannot know, in my view, that what the simulator does in all circumstances, is what the aircraft would do.

So, programming failed pitots and permitting the speed to bleed sufficiently to enter an initial stall, as one experiment, with very heavy gusts from either side or from below, possibly with hail, (programmed noise), may or may not yield interesting answers in terms of aircraft stall behaviour under these specific circumstances.

I am emphasizing limitations here on purpose - these are very good machines, and I suspect Airbus's has special algorithms for taking the airframe beyond expected airline operational limits. Still....it is not an airplane and the storms and the radar are not real. Just a caution, that's all.

Hyperveloce

22nd Jul 2009, 22:58

PJ2
Aren't there several kinds of ground simulators: those used by pilots for their regular training, and some Airbus industrial simulators ? for design & research, with a finer modelling (possibly also accurately describing the aerodynamics outside the flight enveloppe) and maybe a greater flexibility to set up some specific scenarii ?
A clue about how the plane departed from its high altitude cruise would be a first good step ? (even if we don't how it transited from H.A. to surface.)
Razoray
This Aeroperu had lost both altitude & airspeeds, would rather look to birgenair (six month earlier I think), but it did not occur suddenly and at high altitude.
Did you read the Air Caraibe safety report or the Air France Paris-Antananarivo flight report ?
Jeff

Art-Deco

22nd Jul 2009, 23:39

ACARS interruption & rain attenuation
Art Deco, what are the rain attenuation values you have used for your estimation ? Do you make use of a cloud model (a spatial distribution of water, ice,...) ?
Jeff

Sorry for a late answer:
Re: my post 3397 on page 170 regarding ACCARS attenuation.
My calculation was approx 1,8 dB per 1000m (1km) at given elevations for L-band freq. The book you referre to is Ka-Ku link budgets that are in a much higher band 10-25Ghz, so the attenuation then is much higher.

link: http://www.pprune.org/rumours-news/376433-af447-now-added-preliminary-report-170.html#post5052419

Robert Campbell

22nd Jul 2009, 23:41

Aren't there several kinds of ground simulators: those used by pilots for their regular training, and some Airbus industrial simulators ? for design & research, with a finer modelling (possibly also accurately describing the aerodynamics outside the flight enveloppe) and maybe a greater flexibility to set up some specific scenarii ?

How could an accurate simulation be created of unknown situations unless the AB test pilots intentionally put the aircraft into those situations, which, in my opinion, might lead to vacancies in the test pilot ranks?

I think it might be prudent to just put notices in the flight manuals saying, "Unknown territory, don't do this!"

Perhaps some results of wind tunnel testing would be informative.

Tree

22nd Jul 2009, 23:58

Has the 777 been grounded ? They fall out of the sky with both engines rolled back, remember (and we still don't have final report on why - in fact the silence is...). Well, one 777 fell out of the sky anyway - do you have your "feeling" another one is "on the way", or does that feeling just apply to one particular aircraft manufacturer ?

This should answer your query as of 13 July 09:

http://ad.easa.europa.eu/blob/easa_ad_2009_0142.pdf/AD_2009-0142_1

EASA Airworthiness Directives Publishing Tool (http://ad.easa.europa.eu/ad/2009-0142)

PJ2

23rd Jul 2009, 00:09

How could an accurate simulation be created of unknown situations unless the AB test pilots intentionally put the aircraft into those situations, which, in my opinion, might lead to vacancies in the test pilot ranks?
Well I tried to convey this notion - you can't just go into a "fancier" simulator and do better - it's electronics and software, all the way down, not a molecule of air to be had... It's good, but it's not an airplane.

Wind-tunnels work well I am informed but have their limitations as well, as I am similarly informed. In short, there are no magic bullets in this kind of research/experimentation, just hard work slugging through a lot of data, with few true insights.

In pondering this over the past few days while staying away and discussing this with others we were wondering if an initial stall entry, perhaps through vertical/lateral gusts sufficient to take one wing further into the stall than the other, leading to a developing partially-stalled spiral - some forward motion, very high vertical motion, slight nose down, possibly hobbled by reduced/no hydraulics due to high incidence of airlfow over the inlets and the RAT, but really, who knows? We know it was at 350 and that later it hit the ocean. The rest of the conjecture has filled the thread.

Smilin_Ed

23rd Jul 2009, 00:11

How could an accurate simulation be created of unknown situations unless the AB test pilots intentionally put the aircraft into those situations, which, in my opinion, might lead to vacancies in the test pilot ranks?

Aircraft design engineers provide their best estimates of the limits (maximum airspeed, stall speeds in various configurations, bank angles, g-loading, etc.). The manufacturer's test pilots, who are usually also have engineering degrees, then approach these limits slowly, being alert for bothersome (squirrely) behavior. Then they make a judgment as to how close the typical line or fleet pilot should be allowed to come to the limit. How close varies with the type of aircraft. Then the user's (airline/military) own test pilots verify the manufacturer's proposed limits and decide what additional limitations, if any, should be imposed on line or fleet pilots. Aerodynamically precise simulators are designed by extrapolating the experiences of test pilots so, of course, they can't be perfect and can only be expected to predict aircraft behavior within certain limits. In the past 50 years, very few test pilots have bought the farm. That only happens when they rush the program.

HarryMann

23rd Jul 2009, 00:50

How could an accurate simulation be created of unknown situations unless the AB test pilots intentionally put the aircraft into those situations, which, in my opinion, might lead to vacancies in the test pilot ranks?If you're talking aerodynamically, then of course, behaviour outside the normal flight enveleope can be simulated. All the data e.g. mass/inertial distributions, lift, drag pitching moment of indiviudal components and the whole integrated a/c as well as all the pertinent stability derivatives, thrust and even aerolastic effects - would be available from initial CFD work, w/t refinement/cross checks and corrected within the flight tested envelope, a fair bit wider than certified limits.
The predicted beahviour could be simulated well past any flight test/certification flight limitations

There wouldn't be too many what ifs behaviour-wise, the whats are what the actual character and level of disturbance was, what were the auto and/or crew responses/inputs.

PJ2

23rd Jul 2009, 00:58

HarryMann, Smilin'Ed, very helpful thank you. So the roll I did in the 320 sim with all the FACs and SECs off was what it woulda been like...good to know - :)

HarryMann

23rd Jul 2009, 01:22

In the past 50 years, very few test pilots have bought the farm. That only happens when they rush the program.

Very much due to the accuracy of CFD/Wind tunnel and other methods of quantifying whole a/c behaviour up to and beyond any likely flight conditions, test or operationally. The high Mach upper certification limits might possibly produce the most uncertain (& disturbing) behaviour, but still pretty well mapped out beforehand.(think the A380 was about M.92 ?)
Not taking anything away from test pilots, but of course the job must be by nature very different to say the early 50's when much less was known, and CFD was just a dream!

JD-EE

23rd Jul 2009, 02:03

singpilot

Indeed we don't have a smoking gun. I just wish some of those bent and twisted bows and arrows strewn around here could be definitively debunked and tossed aside.

JD-EE :sad:

Mad (Flt) Scientist

23rd Jul 2009, 03:13

HarryMann, Smilin'Ed, very helpful thank you. So the roll I did in the 320 sim with all the FACs and SECs off was what it woulda been like...good to know - :)

Not necessarily "like"....

BUT had AB's aerosim guys been stood in the back of the cab, and told you that they had taken data gathered during the exceedences part of the cert programme and used it to SUBSTANTIALLY extend the sim matching beyond the VERY rudimentary requirements of Level D (or whatever we're supposed to call the top end training devices now) then maybe it would be "like". They'd certainly be able to review the manoeuvre post-session and tell you where you were in the interpolated aero data envelope, where it was extrapolated, and where it was likely nonsense.

The Level D QTG basic requirements are very thin indeed. Most OEMs will go a bit further, because there are qualitiative tests to pass too. But there's a LOT more goes into validating the math models for specific engineering purposes than the basic sim models, and not all of that necessarily gets into the production sim.

Mad (Flt) Scientist

23rd Jul 2009, 03:18

Very much due to the accuracy of CFD/Wind tunnel and other methods of quantifying whole a/c behaviour up to and beyond any likely flight conditions, test or operationally. The high Mach upper certification limits might possibly produce the most uncertain (& disturbing) behaviour, but still pretty well mapped out beforehand.(think the A380 was about M.92 ?)
Not taking anything away from test pilots, but of course the job must be by nature very different to say the early 50's when much less was known, and CFD was just a dream!

I'd attribute the somewhat safer flight test environment to changing attitudes towards test safety as much as anything else, rather than to any great whizz-bang technology. There's been more than enough flight test casualties in the last generation, in any case. (And if you factor in the very much reduced number of development programmes these days, and that much of the development that there is is systems driven, rather than flight envelope stretching ...)

PJ2

23rd Jul 2009, 04:03

MS,
The Level D QTG basic requirements are very thin indeed. Most OEMs will go a bit further, because there are qualitiative tests to pass too. But there's a LOT more goes into validating the math models for specific engineering purposes than the basic sim models, and not all of that necessarily gets into the production sim.
For my money that is really valuable knowledge, thank you. So modeling is far more advanced in the specialized sims than the production D models, (the ones the airlines have to certify checkouts for new crews on new aircraft (to them) and to renew IFR and PPC qualifications. I've learned something new and I thank you all. Jeff, I stand corrected.

They'd certainly be able to review the manoeuvre post-session and tell you where you were in the interpolated aero data envelope, where it was extrapolated, and where it was likely nonsense.
That would be absolutely fascinating to see. It wasn't that difficult a maneuver - 250kts, a lot of push at the top and a gentle pull-through to avoid alpha-prot. I always wondered if it was "as if".

Given the chances of finding the recorders, (I still think they'll find them, and the main wreckage), and this capability, almost certainly, a number of scenarios have been run at Toulouse then.

singpilot

23rd Jul 2009, 04:10

From JD-EE

Indeed we don't have a smoking gun. I just wish some of those bent and twisted bows and arrows strewn around here could be definitively debunked and tossed aside.

I watch everything going by in here, a lot of it repetitious, but some of it very insightful. I have learned a lot of the 'why's' of the interactions between hardware that, while completely explained in school, training and sims, falls short of the detailed failure analysis in here. After verifiying some of what I've seen in here, I am much better at these hardware and software interactions.

The bent arrows, while plentiful, can usually be examined by source and motive, and not too much expended effort to dismiss.

I have spent a great deal of time trying to put myself there (as I was last summer at this time) and trying figure out how this magnificent airplane and crew/pax got so far afield. I think back to times approaching the ITCZ when distractions would arise, be dealt with and prepare for the hour or two of real, 100% work to get thru the band of weather. My instructions were that meal service was to end prior (giving the cabin crew 4-ish hours from T/O) to crossing the wx, and that we were not to be disturbed until we signalled that we were clear. I was always up front when I was junior, and learned that lesson when I got senior.. to be there as well. There would be plenty of time on the other side to rest, eat and deal with Dakar. The same for the reverse (southbound) leg.

Some of the F/O's I flew with took this area as seriously as I did, and some did not. I know I'll read/hear about the ones that did not someday.

We are all truly hoping for a miracle of some kind, an answer with a smoking gun. If I was asked what could be my 'perfect solution/resolution'...

The CVR.

I'd want to know what was going on in that cockpit prior to anything going wrong, and what it was that they encountered. We all know we will never hear the actual sounds and voices, but only a transcript. I firmly believe the answer is there.

P.S. I wanted to add that this (or anything I've posted prior) is not necessarily an endictment of the flight crew per se. I think they encountered something beyond what they were expecting, and discovered, too late, how best to deal with it. That IS a wide open statement that covers what we know so far.

TIMA9X

23rd Jul 2009, 06:47

I agree with singpilot, what has been said on this thread, some of it great and some not so great and some of it so confusing veteran pilots may be thinking "enough is enough!"

At the end of the day we simply don't have enough evidence to come to any conclusion no matter how much we use our bank of combined knowledge.

Ar-men!

SPA83

23rd Jul 2009, 06:53

Safety Report on the Treatment of Safety-Critical Systems in Transport Airplanes

http://www.ntsb.gov/publictn/2006/SR0602.pdf (http://www.ntsb.gov/publictn/2006/SR0602.pdf)

HazelNuts39

23rd Jul 2009, 09:25

RE: vapilot2004 #3782
In alternate law, the speed becomes part of the threshold calculation along with AOA information.That is rather vague. Can you be more specific? How would the SW AoA be affected by erroneous airspeed?

Added in reedit: Quote from ACA memo:
En effet, dans sa partie développée en 3.02.34 page 17, celle-ci stipule «RELY ON THE STALL WARNING THAT COULD BE TRIGGERED IN ALTERNATE OR DIRECT LAW. IT IS NOT AFFECTED BY UNRELIABLE SPEEDS, BECAUSE IT IS BASED ON ANGLE OF ATTACK ».

regards,
HN39

BJ-ENG

23rd Jul 2009, 09:49

Relevant to topic..

Civil Simulator Special: Reality check for civil simulators (http://www.flightglobal.com/articles/2009/04/24/325608/civil-simulator-special-reality-check-for-civil-simulators.html)

livermore

23rd Jul 2009, 11:07

Four french pilot unions wrote a letter to AF CEO Gourgeon, relate to AF447, and call for more safety.

Frankreich: Piloten-Gewerkschaften kritisieren Air France | tagesschau.de (http://www.tagesschau.de/ausland/airfrance164.html)

Nach Flugzeugabsturz: Air-France-Führung gerät zunehmend unter Druck | ZEIT ONLINE (http://www.zeit.de/online/2009/31/air-france-kritik)

Idle Thrust

23rd Jul 2009, 11:44

Singpilot:

Best post in a long time here!

Porker1

23rd Jul 2009, 12:04

rgbrock1

23rd Jul 2009, 13:28

Porker1 wrote:
Pitot tube maintenance regime to be increased to every 6 months rather than every 18 months as is currently the case;

I'm somewhat baffled by this whole pitot tube maintenance issue. I'm sure one of you professionals will set me straight though.
If the pitot probes are that critical of a component, with several other systems relying
on the pitot system input/output, it would seem to me that even 6 months is pushing it.
I don't know where I read it but allegedly the pitot probes on some aircraft were discovered with a bee's nest in it. And I don't think it takes that much time for a bunch of bees to construct a nest.
Is it that difficult or time-consuming to, say, check the pitot system before each flight? Or is it just not that simple?
Thanks in advance

cwatters

23rd Jul 2009, 15:29

Wouldn't it be possible to build in a system that continuously checks for blockages? Perhaps by applying pulses of compressed air to each one in turn and looking at the way the pressure spikes up.

Hyperveloce

23rd Jul 2009, 16:14

I haven't the time to translate it all, but their key damands are:
- Re-organisation to create a new job of "Head of Flight Safety" reporting directly to the boss of AF;
- Pitot tube maintenance regime to be increased to every 6 months rather than every 18 months as is currently the case;
- Specific simulator sessions for pilots covering actions to take in the event of IAS failure.
Pretty clear what they think happened.....

Wow. This means that currently, there are no specific training session involving IAS failures ? Is it specific to Air France ? Haven't we had Pitots problems, corrupted IAS and confusing behaviours of the automated systems for several decenies now ? and several incidents/accidents due to these corrupted airspeeds ?
Jeff

singpilot

23rd Jul 2009, 16:44

Slight thread drift... A French Oceanographic Research Vessel has 'mapped' the Yemeni Airbus crash site, and 'pinpointed' (their words) the recorders. They were at a depth unreachable by divers. Another French Research Vessel with an ROV was enroute to retrieve the boxes.

OK, so I do know that there is a 'search' for the boxes in the Atlantic, there were no details about the depths in the Indian Ocean that were 'mapped', but this gives some small hope, despite the enormity of the search area scale differences.

HarryMann

23rd Jul 2009, 17:43

I think the depths are an order of magnitude greater, as is the search area...

Hyperveloce

23rd Jul 2009, 18:05

File:AF447SeaBottom.jpg - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/File:AF447SeaBottom.jpg)
from its deepest areas (~ -5200m) to the underwater relief peaks (~ -800m), this seabed can be seen as the Alps moutain chain (underwater): it would probably be an easier search if this seabed were an underwater Altiplano. so they have to do with this very difficult bathymetry.
Jeff
PS) Flight SA295's black boxes recovered at a 16 000 ft depth:
Blank Design page (http://www.strumpfer.com/Papers/HelderbergSearch.htm)
Extract Watts Book Re CVRs (http://www.scribd.com/doc/302040/Extract-Watts-Book-Re-CVRs)

PJ2

23rd Jul 2009, 18:25

Porker1;
- Re-organisation to create a new job of "Head of Flight Safety" reporting directly to the boss of AF;
This is a very revealing and important "demand".

Very often, and certainly in organizations which exhibit a high degree of structural and communications dysfunction, the Chief of Flight Safety, (generic title, indicating the boss of flight safety) of an airline reports only to the Chief of Flight Operations, (generic title, pointing to the boss of flight operations).

While it would seem logical for those not in the industry to have the safety guy reporting to the operations guy so he or she knows whats going on, the operations leaders' primary goal is cost control and running the business, not safety. Because of the conflict of interest between the safety guy and the operations guy's positions, the CEO or whoever is in charge then gets filtered safety information because safety costs and isn't a profit center for the corporation while controlling costs always gets atta-boys and banana-pellets from the CEO or whatever. So the guy in charge of the whole organization doesn't really know what's going on because "bad news" never travels up to the top in such an arrangement. Unless the leader is a safety guy him/herself and actually understands how to do safety and what it takes to do it right, ignorance, or, rather, plausible deniability, is bliss and it works, because most of the time "nothing" happens the operations people can rest on their "success", and point to the notion of "accident" (which mean "an occurrence that was not preventable and that happens once in a while") to excuse the organization.

This is very simplified I know but many of us have lived inside this kind of organizational dysfunction (which I would term "intentional" because these are not, by and large, stupid people who run the show), long enough to smell it when it's there. So the French pilots aren't off the mark in this.

rgbrock1

23rd Jul 2009, 18:45

PJ2. Interesting. As an outsider - SLF - I would never think that someone in charge of Safety would report to anyone having anything to do with Operations. I am appalled that this is not seemingly the case.
You say the two positions are mutually exclusive due, mainly, to the fact that Operations also has to control costs. But if safety takes a hit doesn't that eventually affect the "bottom line", costs and , indirectly, Operations?
It would seem to me anyway that all divisions of Safety within an airline organization should report directly to the CEO. Makes sense to me anyway. And eliminates the possibility of any filters being applied to safety reports.

Gary Brown

23rd Jul 2009, 19:06

Newspaper article in the french press today:

"AF 447 : The pilots demand safety measures"

"A letter addressed to the boss of Air France by four pilot unions demands an improvement in the safety of the company."

I haven't the time to translate it all, but their key damands are:

- Re-organisation to create a new job of "Head of Flight Safety" reporting directly to the boss of AF;
- Pitot tube maintenance regime to be increased to every 6 months rather than every 18 months as is currently the case;
- Specific simulator sessions for pilots covering actions to take in the event of IAS failure.

Pretty clear what they think happened.....

Le Figaro - France : AF 447*: les pilotes exigent des mesures pour la sécurité (http://www.lefigaro.fr/actualite-france/2009/07/22/01016-20090722ARTFIG00537-af-447-les-pilotes-exigent-des-mesures-pour-la-securite-.php)
Wow. This means that currently, there are no specific training session involving IAS failures ? Is it specific to Air France ? Haven't we had Pitots problems, corrupted IAS and confusing behaviours of the automated systems for several decenies now ? and several incidents/accidents due to these corrupted airspeeds ?
Jeff

Maybe worth looking again at the Air Caraibe internal incident analysis from 2008:

http://www.eurocockpit.com/docs/ACA.pdf

Here's an extract of the final section, on pp 12 and 13. Although it's talking about checklist contradictions and difficulties, I guess it would, by extension, apply to sim. training.

http://www.speakeasy.org/%7Edr_gary/Personal/Travel/caraibe1.jpg
http://www.speakeasy.org/%7Edr_gary/Personal/Travel/caraibe2.jpg

AGB

Hyperveloce

23rd Jul 2009, 19:24

AGBagb, During this meeting in Toulouse, it was agreed that Airbus would modify the check-lists/procedures about unreliable airspeeds situations, but nothing is said about the regular training sessions in simulators. By "by extension", you mean that these inconsistencies in the procedures of interest would never have been discovered in flight by the Air Caraïbe crew if these procedures had been simulated before on ground in any air transportation company ? Jeff

Gary Brown

23rd Jul 2009, 19:43

Jeff,
Never say never! You're right that there's no mention of relevant sim training (at all, in the whole doc.) and therefore one way of reading the report is that the crew were, to say the least, surprised at both the actual events in the cockpit, and the contradiction in the checklists: ie, sim training had never produced this particular sequence and alerted folks to the puzzle. On the other hand, earlier in the report (and alluded to in the last bit of the extract) is that the crew pretty much instantly knew that the STALL warning was wrong - which might suggest that the circumstance had been encountered in some form previously... Difficult to guess.

But I'm in danger of expressing views beyong my knowledge here (I'm no pilot.....). I do think that the Air Caraibe report makes for very interesting reading though, for something that came rapidly close to getting away from the flight crew (ie, if they had not rejected the STALL warnings...).

AGB

PJ2

23rd Jul 2009, 20:14

rgbrock1;
You say the two positions are mutually exclusive due, mainly, to the fact that Operations also has to control costs. But if safety takes a hit doesn't that eventually affect the "bottom line", costs and , indirectly, Operations?
It would seem to me anyway that all divisions of Safety within an airline organization should report directly to the CEO. Makes sense to me anyway. And eliminates the possibility of any filters being applied to safety reports.
Ops is concerned with daily costs and the longer-term operational priorities are driven by the bottom line, with an eye to safety but not a wholesale focus. The reporting structure described is the way many major carriers work and data and information "filtration" is a real factor in the knowledge base of the airline's executive leadership. I have seen this first-hand and know it to be true, even today, right now. Corporations are run on "good news" to keep the share price bolstered among many reasons, and bad news tends to contaminate the messenger who, after all, may have his/her own ambitions to rise in the bureaucracy.

These are largely latent factors in any organization and can be readily found and are as repeatable today as they were when the Challenger accident occurred in 1986. This is one area where organizational learning does not occur, simply because safety costs money and, but for rare instances, does not protect profit or shareprice.

The reliance is on the robustness of present systems which is not altogether a bad thing; such things as hiring policies, fuel and dispatch policies, enforcement of SOPs, dispatch flight watch/communications, an industry-standard safety reporting policy, (no discipline except in cases of negligence or egregious/intentional acts) and the use of collected safety information all contribute to a level of safety but two factors have been at work for some time now: the introduction of SMS, and the tremendous financial pressure all airlines are under, ostensibly since 2001 and certainly since October, 2008.

These factors will tend to compromise some systemic responses, will tend to atrophe communications on safety matters, will tend to cause "the safety message" to be suppressed because it is expensive and cannot in and of itself be "proven" to make an immediate, material difference, (so deferal is often the solution) and the CEO who is likely a non-aviation person from the outside or if from the industry will be a marketing specialist, etc is almost always fundamentally ignorant of flight safety work, what makes an airline safe or what programs can be of best long-term value and are worth supporting even if they point out the shortcomings of an operation.

There is a lot of ego involved in this and no one likes to show up at corporate safety board meetings and get his/her department pointed at with blunt data...so the "message" is suppressed, denied or ignored as "new fires" arise each day which need the time, attention and energy of a very thin management staff.

These are the principles in a nutshell. They are standard fare for anyone doing safety work and are the source of frustration to same because we can see where an accident is going to occur but we can't be specific as to when/how/why/what and that is the basis upon which safety work is dismissed.

The other reason is complexity - very, very few managers today are capable of dealing in complex understandings or systems outside of a narrow, highly-specialized area of knowledge or skill. Thus, the best attempts to communicate safety information must necessarily be dumbed down so much that the information is essentially useless for decision-making. The two curves (comprehension and data complexity) therefore never cross.

Enough drift. These are factors observable in many carriers. I do not say it applies to any specific one.

hetfield

23rd Jul 2009, 20:17

Wow. This means that currently, there are no specific training session involving IAS failures ? Is it specific to Air France ? Haven't we had Pitots problems, corrupted IAS and confusing behaviours of the automated systems for several decenies now ? and several incidents/accidents due to these corrupted airspeeds ?

Working for a major EU Carrier we do at least once a year

UNRELIABLE AIRSPEED

in SIM.

Hyperveloce

23rd Jul 2009, 20:35

Working for a major EU Carrier we do at least once a year
UNRELIABLE AIRSPEED
in SIM.
Thank you for this answer Hetfield. Do these unreliable airspeeds sims sound different stall (false) alarms at one point ? Do these sims implement "surprises" (different sequences of failures of the Pitots, static ports, whatever) or are they scenarii known in advance and prepared beforehand ?
Jeff

hetfield

23rd Jul 2009, 21:19

Do these unreliable airspeeds sims sound different stall (false) alarms at one point ? Do these sims implement "surprises" (different sequences of failures of the Pitots, static ports, whatever) or are they scenarii known in advance and prepared beforehand ?

1. Simulation of Stall Alarms are always to be considerd as "true" (reliable AOA Probe)
2. More or less the scenario is based on "surprises".

HazelNuts39

23rd Jul 2009, 21:42

RE: Hyperveloce (#3856)
During this meeting in Toulouse, it was agreed that Airbus would modify the check-lists/procedures about unreliable airspeeds situations,

Did they say that?

Hyperveloce

23rd Jul 2009, 22:26

Here is what H.H. the Air Caraïbe's Flight Security Officer says about this meeting at Airbus's Toulouse facilities (oct.2008):
"Despite these contradictory aspects (note of the translator: in the QRH), the PNT (pilots) of the FDF have had the appropriate reactions when the two false stall alarms sounded. Moreover, the Airbus engineers have fully taken the measure of the crew difficulties for a swift and efficient implementation of the UNRELIABLE SPEED INDICATION procedure. They agreed that our remarks are justified and will study a check-list modification. To be continued..."
Jeff
PS) Since words may be important (if you can read French), this is an attempt of translation of the very last page and paragraph of the Air Caraïbe report http://www.eurocockpit.com/docs/ACA.pdf (http://www.eurocockpit.com/docs/ACA.pdf)
PPS) Page 69 of the interim BEA report, I quote: for information, the “Memory Item” in the Airbus QRH relative to the same fault is shown below in the version in force on the date of the accident:
http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf

HazelNuts39

24th Jul 2009, 00:10

Hyperveloce,

I wasn't quite sure about the meaning of "recevabilité" and "réfléchissent". Thank you for helping out a non-french-speaking person.

regards,
HN39

Razoray

24th Jul 2009, 04:25

My instructions were that meal service was to end prior (giving the cabin crew 4-ish hours from T/O) to crossing the wx, and that we were not to be disturbed until we signaled that we were clear. I was always up front when I was junior, and learned that lesson when I got senior.. to be there as well. There would be plenty of time on the other side to rest, eat and deal with Dakar. The same for the reverse (southbound) leg.Singpilot,

excellent post,

The measures you would take as a pilot during the crossing were very prudent. But do all pilots and all carriers do the same. At this time should these types of measures be mandatory?

Some of the F/O's I flew with took this area as seriously as I did, and some did not. I know I'll read/hear about the ones that did not someday.

Drawing a parallel, when the Titanic sank in 1912, no one knew exactly what failed on the ship that caused it to sink...in fact we are finding out new information to this day about equipment failures that led to the ships sudden demise.......But after the accident mandatory safety measures were instituted that helped avoid a repeat occurrence: more life boats, 24 hr wireless, change in traditional routes, etc.....

So even if we do not know exactly what happened, shouldn't we accept that certain procedures should be in place when crossing such severe areas? Procedures that are followed by all carriers........

If anything, there would be less questions and mystery if standard procedures had been in place.....

mm43

24th Jul 2009, 05:52

Singpilot had it right.

In my opinion the most important part of the a/c to recover is the CVR. The FDR will only reveal the 'result' whereas the CVR will provide the 'why'.

As I have mentioned before, understanding what was happening in the cockpit after 0135z to around 0209z is far more important than the last 5 minutes. Loss of IAS, Q-corner stall/overspeed, ACARS etc. are all part of the 'result' and neither should have happened. So understanding the 'why' will be the most enlightening part of this whole sad event.

mm43

eswdev

24th Jul 2009, 06:27

The first ACARS message after 0210 was

2:10:10 - .1/WRN/WN0906010210 221002006AUTO FLT AP OFF

This indicates that the autopilot has been automatically switched off. I'm not a pilot, so I ask those who are familiar with standard procedures:

a) when the decision is taken to avoid potentially hazardous weather systems, is it necessary to switch the autopilot off?

b) same question regarding autothrust.

c) assuming that the answer to both these questions is YES, and given the final known position of the ill-fated flight (I understand that it was relatively close to an active weather system), is it surprising that both autopilot and autothrust were ON at 0210? That is, if they had been turned off temporarily to evade weather, is it likely that they would have been turned on again in relative proximity to the weather?

c) could the aircraft continue to fly more or less in a stable way for some time if there was no pilot control after the loss of autopilot and autothrust?

d) if a Mayday was sent, is it likely that it would have been received by other aircraft in the vicinity?

e) how much redundancy is there in systems to detect loss of cabin pressure on this model of aircraft?

My questions are partly motivated by discussion a while ago about the possibility of flight crew incapacitation. I thought it was significant that autopsies reportedly showed that the recovered victims did not die by drowning.

Robert

HarryMann

24th Jul 2009, 08:53

This indicates that the autopilot has been automatically switched offPerhaps answers your question?

Mayday
Yes, it would be expected, with some provisos

Drowning
When an a/c impacts very hard (and it seems likely it did) the cause of death would invariably be physical trauma of one sort or another. Thus it is not unexpected that drowning would not take place (in the majority of cases anyway).
NB. There could be more deductions to come with the full autopsy reports

Incapacitation
I also 'feel' that insufficient information is yet available to completely rule out some sort of crew incapacitation, but such suggestions will no doubt encourage (& have) dismissal or flak here...

The reason for this is it has to be said, with autopilot off, and no-one flying the a/c, it might be expected that from cruise altitude it would exceed speed/structural limits long before arriving at sea level - and - BEA (French accident investigation authority) and many here think that it was probably in one piece at the time of impact.

Recap:
The last ascertain(ed) crew action appears to have been at 2.01 hrs - a 3rd attempt to contact DAKAR control, approx 9 minutes before that A/P disconnect msg. I think we have it on good authority that this couldn't have been a pre-programmed action.

Speculation:
The a/c entered heavy turbulence (probably for the first time) between 2.01 and 2.10 hrs.

Additionally:
The a/c seems to have been apprpx. 3 nm West of expected track at 2.10 hrs. This could have been a deliberate action or the result of a prior disturbance

eswdev

24th Jul 2009, 09:27

I didn't make myself clear. I understand the point about automatic switch off. I'm suggesting that the crew were not responsive. First of all, they did not take evasive action before entering the weather system. Second, if your suggestion about turbulence is correct, surely the crew would have responded and the autopilot would have manually disconnected.

The turbulence theory could persuade me if some aerodynamic effect triggered the pitot errors that caused (?) the automatic disconnect. But isn't there some delay in the automated decision making, during which the crew would be taking action leading to manual disconnect?

Hyperveloce

24th Jul 2009, 14:26

So as to the A/THR (and A/P) settings & procedures about bad weather or turbulences, the Air Caraïbe crew applied the "weather deviation in oceanic controlled airspace" proc. altering their altitude to try to find better conditions ; then they applied the QRH 5.01, "severe turbulences" proc.: the crew disengaged the A/THR and fixed the N1 between 81 and 82% (for a mass of 206T and FL350). The A/P remained engaged untill its automatic disconnection (along with the ADR disagreement and the sequence of Pitots induced ECAM alarms). The AF 447 had probably not disengaged its A/THR: the AF 447 was probably not experiencing severe turbulences but only moderate ones then ? (at least before 02:10Z)
About a link between Pitots induced phenomenons & turbulences: even if the turbulences it experienced may not have been so severe, if the AF 447 had narrowed its upper aerodynamical margin (increasing its speed, due to stall alarms and maybe (?) a speed that had already been increased by the A/THR just before its disengagement), it may have been far more vulnerable to turbulences ? (even not so severe)
Jeff
PS) I have been said that if the A/THR was not disengaged, it should have been in managed speed mode ? If the measured airspeeds vary due to turbulences, the A/THR (maybe 3 or 4 sec. of reaction time) could also vary the engines regime trying to follow these sensed airspeed fluctuations as it could try to follow an airspeed rollback.
PPS) http://www.a330jam.com/documents/turbulence.pdf

PJ2

24th Jul 2009, 17:01

Robert;
a) when the decision is taken to avoid potentially hazardous weather systems, is it necessary to switch the autopilot off?
No. Weather avoidance is a routine flight operation requiring no special handling. The autoflight system on the A330, like all transport category aircraft, is designed to handle moderate turbulence should it be encountered. The autopilot almost always gives a better ride and less 'g' loads to the airframe.

In heavy turbulence which may be beyond the autopilot's design capabilities, the autopilot is disconnected to permit the aircraft to ride up or down encountered severe vertical drafts without the autopilot trying to maintain altitude. The autothrust is similarly disconnected. In such encounters the goal is to maintain the last settings before disconnection and ride the turbulence out without changing pitch or power, permitting small excursions of same to ease the load on the airframe.

Such conditions and responses are rare because avoidance techniques are so successful.

b) same question regarding autothrust.
Same answer, same reasons, essentially. If the autothrust chases the speed however, it is disconnected while the autopilot may or may not be left on. A situation where the autopilot is on and the autothrust is off means that the airspeed must be monitored very carefully. Too fast is far better than too slow, even overspeeding the airframe by as much as 20kts past VMO/MMO (Velocity Maximum Operating/Mach Maximum Operating)

c) assuming that the answer to both these questions is YES, and given the final known position of the ill-fated flight (I understand that it was relatively close to an active weather system), is it surprising that both autopilot and autothrust were ON at 0210? That is, if they had been turned off temporarily to evade weather, is it likely that they would have been turned on again in relative proximity to the weather?
The question is almost certainly immaterial as are the assumptions. There is the possibility that one or both were disconnected and the aircraft manually flown but there are no ACARS messages indicating this. A manual disconnection would generate such a message through the FIDS, (Fault Isolation and Detection System) and the CMC, Central Monitoring Computer and ACMS, Aircraft Condition and Monitoring System, which sends maintenance messages to the ACARS. The actual process of warning/message generation is far more complex than this as I'm sure you appreciate but that is the essence of it.

c) could the aircraft continue to fly more or less in a stable way for some time if there was no pilot control after the loss of autopilot and autothrust?
This is a highly speculative, hypothetical question and, necessarily, any response is the same. Keep in mind, the flight path is a result of all forces acting on the aircraft - smooth air, less forces, turbulent air, more forces, etc.

Hypothetically speaking, in smooth air where the dynamics are relatively undisturbed, because of the autoflight system fbw - fly-by-wire design, would remain fairly stable for some time, (no inputs mean no output - autoflight retains last set attitudes). Eventually however, without altitude hold (lost upon a/p disconnect), the flight path would tend to change with changes in temperature, (very slightly reduced/increased lift) and would also begin to lose speed stability. With other transport aircraft which are not fbw, loss of the flight path would occur much more rapidly without autothrust/autopilot connection.

In the kind of weather this aircraft was "in", loss of a stable flight path would occur more quickly only because of the vertical/lateral gusts associated with the surrounding (or entered) CB's.

In either case, with autopilot off and autothrust off (leaving the engines at the cruise power setting, the ultimate outcome of a "pilotless" transport is a very high-speed dive, possibly spiral dive. In other words, a flight path a very long way from the description offered in the BEA report. The wreckage pattern alone obviates any of this scenario.

d) if a Mayday was sent, is it likely that it would have been received by other aircraft in the vicinity?
Theoretically, yes. All aircraft monitor 121.5 and the common frequency. Even an open mike would have been "heard" by other aircraft and would be on their CVRs, (which would be a matter of routine investigation to check, I should expect). Almost certainly, (and this has been pointed out dozens of times by other pilots on this thread), the crew was likely very busy handling their aircraft in what seems to have been a rapidly degrading set of circumstances. They would not have had a moment to send out a distress call nor possibly to even key the mike to broadcasts "in the blind". The RMP, radio management panel, would be set to VHF 1 on #1 and VHF 2 on #2 but they were also in the process of contacting DAKAR (if I recall) and may have been on HF1 when trouble hit.

It may have been impossible to hang onto the sidestick to key the mike - the other switch is on the audio control panel and is tiny so placing it in the "transmit" position would be difficult - the trigger switch on the sidestick would be the more obvious choice. Neither occurred.

e) how much redundancy is there in systems to detect loss of cabin pressure on this model of aircraft?
You have to bear in mind that detection of this does rest with redundant systems but such systems rely upon their correct operation. As I have posted twice now, the schematic of systems which receive input from the ADRs, if an ADR is malfunctioning that may send false information to the two CPCs, cabin pressure controllers, which in turn may degrade and possibly send BITE - built-in-test-equipment, an internal self-test mode, messages to the CMC. In other words, as the BEA report states and as I stated around June 4th or so, on the first thread, the ACARS messages may not have occurred in the order that they appear in the now-infamous ACARS list of events. Also, in these circumstances, (rapidly degrading airplane due pitot/ADR/IRS issues), the actual cabin rate may or may not have exceeded the 1800fpm needed to trigger the message. For these reasons it is exceedingly important to avoid coming to conclusions, without extensive knowledge of the aircraft, using just the ACARS messages.

My questions are partly motivated by discussion a while ago about the possibility of flight crew incapacitation.
This notion has been posited a number of times throughout the thread. While it is acknowledged that "anything is possible", (bomb, meteor strike, EMF, terrorist intervention), other indications (the above discussion re loss of control with ap/at disconnected, condition of the recovered wreckage) do not support incapacitation theories. However, as singpilot as wisely stated, the CVR will help a great deal in winnowing all theories.

Hope this helps.

PJ2

rgbrock1

24th Jul 2009, 17:18

PJ2

What a fabulous technical discussion understandable by those not in the industry, like myself. Bravo.
Concerning the ACARS message sequencing. I know it might take some time to do so, and might not be worth the effort, but has anyone entertained the thought of taking the 12 (?) ACARS messages and re-sequencing them one after another to see if one particular sequence makes more sense than another, the output of which might lead to other causal factors being discovered? Or is that just not possible? Having said that, I would imagine some of those involved in the investigation might have already performed a similar task?

Richard

HarryMann

24th Jul 2009, 17:32

Is that 12 factorial or something :) A big number

I think BEA & others know pretty well how to group them into subgroups that helps though...

rgbrock1

24th Jul 2009, 17:40

12^12 = 8.91610045 × 10^12

WNcommuter

24th Jul 2009, 17:44

I've been wondering how likely it is that the pilots were distracted from monitoring the weather radar, e.g. by a mysterious series of failures in the avionics.

The other thing that I'm wondering is whether recovery of the CVR and FDR might fail to reveal all the causes of this accident. We like to believe that air travel is 100% safe, but this accident show us that there are still unknown unknowns.

4PW's

24th Jul 2009, 18:25

Is this thread still going, or am I dreaming?

LeandroSecundo

24th Jul 2009, 18:32

Hi,

Is this thread still going, or am I dreaming?

We are just on the begining :)

PJ2

It may have been impossible to hang onto the sidestick to key the mikeWhat force (G) may be deemed necessary to prevent pilot to move his arm at all ?

Bye.

Hyperveloce

24th Jul 2009, 19:40

Hi, What force (G) may be deemed necessary to prevent pilot to move his arm at all ?
Probably more than an A330 can withstand ? (but also depends on pilot's physical condition)
Jeff

HarryMann

24th Jul 2009, 19:54

What force (G) may be deemed necessary to prevent pilot to move his arm at all ?It's more hand than the arm, with a fashioned rest for the forearm, if we're talking sidestick?

mm43

24th Jul 2009, 20:16

For those wondering what is going on with the search, the following Radio Navigation Warning to shipping issued by the Brazilian Navy should be of interest..

CENTRO DE HIDROGRAFIA DA MARINHA

RADIO NAVIGATIONAL WARNINGS

NAVAREA V

1544/09 – NORTHWEST OF ARQUIPELAGO DE SAO PEDRO E SAO PAULO – CHART 10 (INT 216) - VESSEL POURQUOI PAS – CARRYING OUT OCEANOGRAPHIC RESEARCH IN CIRCULAR AREA WITH 70 NAUTICAL MILES RADIUS CENTERED IN POSITION: 03-00.00N 030-36.00W - UNDERWATER VEHICLE NEAR THE VESSEL - PERIOD: 26/JUL TO 16/AUG. BERTH REQUESTED. CANCEL THIS WARNING 170359Z/AUG/09.mm43

Hyperveloce

24th Jul 2009, 20:29

Has any investigation report been released about Austral Líneas Aéreas Flight 2553 ?
Jeff

JD-EE

24th Jul 2009, 20:46

Leonardo asks "What force (G) may be deemed necessary to prevent pilot to move his arm at all ?" That depends on the pilot and the layout of the stick. Fighter pilots manage through 9 G somehow.

On the other paw, however, consider holding a very full drink in one hand as you go over a speed bump a little too fast. Now imagine that in turbulence from a CB in three dimensions as you try to reach for the stick. The sidestick has a nice physical layout to ensure stability in turbulence. But you have to get there first and you have to be pretty tightly belted in to keep it stable, I'd bet.

I guess another way to look at it is to imagine you have some springs attached to your wrist exerting 3G accelerations (maybe 10 to 30 pounds force) in random directions every couple seconds as you try to put your hand onto a joystick attached to the arm of your chair. Of course, you desperately don't want to HIT that joystick knocking it full over by accident. Might even 1 G of such acceleration be enough to make it hard to get on the stick accurately and in a hurry?

JD-EE

HazelNuts39

24th Jul 2009, 21:01

RE: ACARS msg "TCAS FAULT (2:10)" not yet fully explained?

The exchange in posts #3872, #3873 and #3874 made me go back to BEA's Interim report on AF447 to count how many of these 24 ACARS messages have been marked as "not yet fully explained". I counted 4, and while going to the list it occurred to me how the TCAS FAULT can possibly be linked to pitot failure.

Others in this thread have explained that TCAS uses altitude and does not use airspeed. However, altitude is based on the pressure measured at a static port, which must be corrected for the position error of that port. The position error correction (PEC) is usually expressed as a pressure coefficient cp, which must be multiplied by the dynamic pressure measured at the pitot, to obtain the pressure correction. Some system must have 'reasoned' that since airspeed was unreliable, altitude was also unreliable, and hence TCAS would not be able to perform its intended function.

The PEC occurred to me while reading The Air Caraibe story, where it notes a sudden drop in altitude at the time that CAS and Mach drop, and the altitude steps up by about the same amount when airspeeds come back.

regards,
HN39

mm43

24th Jul 2009, 22:51

In December 2007 EuroControl issued a Safety Reminder Message regarding Low Altitude TCAS II RA's.

They also referred to Guidance for Operators of TCAS Training Programmes, and the initial part of the document is:-

JAA Administrative & Guidance Material
Section Four: Operations, Part Three: Temporary Guidance: Leaflets (JAR-OPS)
Section 4/Part 3 (JAR-OPS) 11-3 01.02.05
- Criteria: The flight crew member should demonstrate a knowledge and understanding of the ACAS limitations including:
(i) ACAS will neither track nor display non-transponder equipped aircraft, nor aircraft not responding to ACAS Mode C interrogations; and
(ii) ACAS will automatically fail if the input from the aircraft's barometric altimeter, radio altimeter or transponder is lost.

Note 1: In some installations, the loss of information from other on-board systems such as an inertial reference system (IRS) or attitude heading reference system (AHRS) may result in an ACAS failure. Individual operators should ensure their flight crews are aware of what types of failures will result in an ACAS failure.Clause (ii) gives 3 causes of failure, plus the IRS in Note 1.

Take your pick.

mm43

LeandroSecundo

24th Jul 2009, 23:00

Hi,

On the other paw, however, consider holding a very full drink in one hand as you go over a speed bump a little too fast. Now imagine that in turbulence from a CB in three dimensions as you try to reach for the stick. The sidestick has a nice physical layout to ensure stability in turbulence. But you have to get there first and you have to be pretty tightly belted in to keep it stable, I'd bet.

So .. seem's the stick is a handicap in this case and a conventional yoke will be more adapted for this kind of situation.
BTW I think a fighter pilot keep allway his hand on stick (assumption mode ON :) )

Bye.

PJ2

24th Jul 2009, 23:43

So .. seem's the stick is a handicap in this case and a conventional yoke will be more adapted for this kind of situation.
I don't wish to sound unkind, but when I posted my response I was wondering how long it would for someone to make this observation.

When something is over-analyzed, everything has a handicap that can be "pointed to" as a problem.

The difficulty here is, and I have taken great pains to be patient in explaining the aircraft and how we operate it and what it is like under ordinary and abnormal circumstances, is you just have to take it for granted that Airbus (and Boeing) have actually done some intelligent design work with the basics and believe me, that is really basic stuff that's been around for a very long time.

If I may offer some advise, please do some thinking beforehand and always assume that the people who conceive of, engineer and fly these aircraft know what they're doing and are very, very good at it. JD-EE's response to you was sufficient and well-placed for the layman to comprehend the issue. You're over-analyzing and second-guessing and it's noise, not progress. That's not the way to understand this or any accident or incident.

Just a word to the wise. Most pilots have long since left this thread.

Razoray

25th Jul 2009, 00:24

Ah! But not you PJ2.....

Please stick around to keep things real....

Thanks,
RP

:ok:

PJ2

25th Jul 2009, 00:35

Razoray;

At some point I think they are going to find the wreckage and the recorders. That will inevitably start a whole new round of speculation especially after preliminary readings are posted. Practically everyone, pent up with anticipation, will be suffering from premature release. A few very wise posters here have said that the recorders, if readable, may not provide all the answers either and so another round of tea-leaf reading will unfold. I think it is that moment at which all must keep their head and suspend judgement in favour of curiosity, (he said, knowing it won't happen). As I said in the first thread, we must be extremely circumspect in any new arrival of information and be very aware of the psychology behind "finding cause", the first factor of which is hindsight bias which, I know from personal experience here and in my own work will, (not may), blind one to new notions and original ways of seeing things.

A very long time ago in university, a psych prof said, "Eastern rats perform better for eastern psychologists". That lesson alone was worth the price of admission.

UNCTUOUS

25th Jul 2009, 00:43

Some further speculative commentary upon the BEA Interim Report is at:
.

this link (http://tinyurl.com/m6erww)
.
.

JD-EE

25th Jul 2009, 03:53

Well, UNCTUOUS, that flogs away at a different problem, which in this case would have made no practical difference. It points up a potential laxity on the part of the Brazilians and a serious laxity on the part of Dakar. (Note I said potential. I am willing to believe what we saw was a Brazilian presumption of professionality on the part of the Dakar operators who weren't very professional.)

Perhaps yet another fire needs to be lighted under the behinds of the Dakar operators. (Rumors I've heard indicate they are vastly improved from a decade ago or more. What you see is the improved Dakar. So imagine what it must have been then!)

However, in the case present the extra hours before SAR started would not have materially changed the overall results. Some bodies might have been noticed were the SAR aircraft able to get into the area and safely fly around looking at the surface of the ocean. But nobody was likely to be alive and the planes could not effectively search until the storm had abated. If I recall correctly reports from the first days of the aircraft based search included words about how difficult the conditions were due to the abating storm.

Now, there are some other things I draw from this part of the report that hit on my professional interest in RF communications. There are some techniques for RF communications that can ensure that if there is a frequency that can work the aircraft is aware of it and the ground is listening for it. It's a military technique called ALE, Automatic Link Establishment. But selling that technology to the aircraft industry will be difficult and cannot take place here.

I'm just pointing out that almost any part of the BEA report opens avenues for improvement of one kind or another. This is, again, probably not the place to flog these issues, dead horses or not. I could add some notes in private messages if somebody is really interested.

JD-EE

Graybeard

25th Jul 2009, 03:55

mm43: ...(i) ACAS will neither track nor display non-transponder equipped aircraft, nor aircraft not responding to ACAS Mode C interrogations; and
(ii) ACAS will automatically fail if the input from the aircraft's barometric altimeter, radio altimeter or transponder is lost.

Note 1: In some installations, the loss of information from other on-board systems such as an inertial reference system (IRS) or attitude heading reference system (AHRS) may result in an ACAS failure. Individual operators should ensure their flight crews are aware of what types of failures will result in an ACAS failure.
--------
mm43 statement:
Clause (ii) gives 3 causes of failure, plus the IRS in Note 1.

(i) This will not cause or result in TCAS Fail.

(ii) A sudden change in indicated altitude as experienced by Air Caraibe will not trigger TCAS Fail. There was no ACARS report of radio altimeter nor transponder Fail; hence, these do not account for the TCAS Fail. Moreover, there were no reports of ADR Altitude Fail.

1. IRU is inconsequential to Collins TCAS. IRU Fail might trigger Honeywell TCAS Fail. That, however, requires failure of both #1 and #3 IRU, as #3 is automatic backup. Does AF 330 fleet fly Collins TCAS, or Honeywell TCAS?

I agree with the BEA: TCAS Fail report remains unexplained/unrelated to the other Fail reports.

HN39 ...position error of that port. The position error correction (PEC) is usually expressed as a pressure coefficient cp, which must be multiplied by the dynamic pressure measured at the pitot, to obtain the pressure correction. Some system must have 'reasoned' that since airspeed was unreliable, altitude was also unreliable, and hence TCAS would not be able to perform its intended function.

The PEC occurred to me while reading The Air Caraibe story, where it notes a sudden drop in altitude at the time that CAS and Mach drop, and the altitude steps up by about the same amount when airspeeds come back.

If the measured altitude was good enough to display to the pilot, it was good enough to report to the transponder. From what little I've seen of airspeed correction tables in other aircraft, they are significant only at high angles of attack, and not at cruise.

Did Air Caraibe have a TCAS Fail during their event?

GB

BOAC

25th Jul 2009, 08:31

LeandroSecundo - I have never used a side-stick flight control but have used several 'side-stick system controls' in various fighting machines. Turbulence is your biggest problem and the decider is how 'sensitive' a particular control is to a random input. The 'control column' (yoke) is a very coarse control and turbulence does not create too much of a problem. If the AB side-stick is highly geared and hand support is not adequate you may have problems. Control stick damping is another design consideration. A little flying in a British 'Whirlwind' helicopter showed me that the 'stick' was not 'mass balanced' and if it fell over to one side when you let go the heli followed it:)

Moving a 'joystick' at 7g+ smoothly takes a lot of effort. However the 'g' we are looking at in this case are few.

HazelNuts39

25th Jul 2009, 16:09

RE: Greybeard (#3891)
Did Air Caraibe have a TCAS Fail during their event?No, the Air Caraibe Note does not mention TCAS FAULT. Good point, thank you for replying.

Nevertheless, the altitude steps remain puzzling. On page 2 of the ACA Note:

A 22H22 et 59S, on enregistre une diminution très rapide de la « CAS », du mach et de l'altitude (correction de mach). Ces paramètres passent respectivement de 273KT à 85KT, M0.80 à M0.26 et de 35000FT à 34700FT.(...)A 22H24 et 25S, la «CAS» augmente de 111KT à 275KT, le mach retrouve sa valeur initiale M0.80 et l'altitude augmente brutalement passant de 34200FT à 34500FT.On page 4:
NB1, seuils pour l'élimination d'une «ADR» : Altitude 3000FT pendant 1S, mach 0.05 pendant 10S, « CAS » 16KT pendant 10S, TAS 16KT pendant 10S, pression totale 20HPA pendant 10S, « AOA » 3.6° pendant 1S, pression statique 5HPA pendant 1S.

NB2, seuils pour l'élimination des deux « ADR » restantes : Altitude 3000FT pendant 1S, mach 0.05 pendant 1S, « CAS » 16KT pendant 1S, TAS 16KT pendant 1S, pression totale 20HPA pendant 18, « AOA » 3.6° pendant 1S, pression statique 5HPA pendant 1S. So the PRIM's don't fault the altitude, they fault first one, then all three ADR's
(F/CTL ADR DISAGREE), apparently because of faulty airspeed parameters.

Note however on page 9 of the ACA Note, that "le système <<AUTO FLIGHT>>" also monitors the ADR's, using different rejection criteria:
NB4, seuils pour le rejet d'une «ADR» : «CAS» 20KT pendant 0.45S, mach 0.04 pendant 0.45S, altitude 400FT pendant 0.45S.Would it be far-fetched to imagine that yet another system (for example TCAS) similarly monitors altitude, applying its own rejection criterion?

Finally, in the ACA case CAS dropped to 85 kt, what if it dropped to zero in the case of AF447?

regards,
HN39

PJ2

25th Jul 2009, 16:22

BOAC;
The AB sidestick fits the hand and the arm is supported by a very adjustable arm-wrest, (up-down, high/low angle) and the sidestick can be easily controlled from the wrist or even just the fingers if placed at the top of the stick. It is heavily damped. My point was, this is a very good control system which is natural and easy to get accustomed to and use even in heavy turbulence. If we are discussing severe/extreme turbulence or jet-upset conditons however, no aircraft is immune to high 'g' loads in terms of reaching/moving the controls, column/wheel or sidestick, especially with the likelihood of flight bags and everything else that's not tied down flying around the cockpit, (possibly in the dark)...

For background info, the sidestick does not move ailerons or elevators. The sidestick requests a roll-rate and a 'g' load. The FCPCs interpret the requests and provide the necessary commands to the servos, through the C* (fbw) laws which have been discussed. This is essentially the same as CWS - Control Wheel Steering - not sure the Boeing has it but the L1011 did.

The process is, for practical purposes, instantaneous - no lag between request and response. Also, the autoflight system, being fbw, keeps the aircraft in the last "known" attitude until another input is made, which, if one thinks about it, makes complete sense. One can "set" the attitude, leave the airplane with hand off the stick and the fbw autoflight system will "keep" the attitude until another input is made changing the attitude.

Even in heavy turbulence, the system (fbw, without the a/p engaged) will attempt to keep the aircraft at the last position established. You mention sensitivity levels - that's not so much an issue with the AB sidestick as understanding what's going on out on the wing - while the full-time fbw system is trying to maintain the last aircraft attitude, the FCPCs will also be interpreting the second-by-second sidestick manual "requests" by the flying pilot so will be busy satisfying both inputs.

For these reasons, the notion of "coarseness" is not so much applicable in understanding the system as is an understanding of what the ailerons are doing out there on the wing in response to all inputs, fbw & manual, and why. There are many cases in which over-controlling is an issue in the AB for exactly these reasons., (I note the thread on the Hamburg accident).

I have posted my biases lots of times - I am not a convinced Airbus pilot trying to "sell" the design or tout its benefits over other types. I'm describing the machine from one pilot's point of view. There are in my view some things that this design must answer for but with solid training, adherence to standards and continuous testing and recurrent training, handling the Airbus is a non-event. It was this level of appreciation for the design that I was making a point about. That said, your own experience re the stick in the Whirlwind, albeit a long way from the AB design, does cause one to sit back a moment.

BOAC

25th Jul 2009, 16:30

That said, your own experience re the stick in the Whirlwind, albeit a long way from the AB design, does cause one to sit back a moment. - yes, but not for too long:).

Apologies if you have misinterpreted my post - I was trying to give a general answer to LS with just a 'dash' of AB, not to invoke any criticism.I have, as I said, never used it.

Hyperveloce

25th Jul 2009, 16:35

The two Air Caraïbe A330, the AF 908, the NW planes did not experience any TCAS problem during the corrupted airspeeds events (slight altitude bias, a few 100 ft, -300 ft in the Air Caraïbe case). In the AF 447 case, it could be that the Pitot-static duo was compromised more severely/time than in the other cases ? Or the TCAS problem has nothing to do with the Pitot phenomenology (not my view).
-In the last evening TV news, there was some news about the analysis beginning at the CEAT: Journaux télévisés en vidéo - France 2 (http://jt.france2.fr/player/20h/index-fr.php?jt=20090724&timeStamp=663) at ~12:40, you get a close up on a map of the plane showing colored seats that were occupied by the passengers who were recovered.
-Thank you Unctuous for the interesting scenario: BEA interim report* *Extract (http://www.iasa-intl.com/folders/belfast/Interim_BEA-Report/AF447_InterimReport.htm)
This is speculation, but if the flight data are not recovered, the BEA will also be left to speculate :bored: Speculating is not bad, as long as it also provides the means to be tested at one point (speculating is probably the most creative part in science, and... nice etymology).
It is speculated/hypothetized that:
_____________
e. Disorientation (normally following flight instrument failure)
f. Thunderstorm encounter
g. Stalling or Mach Crit encounters near coffin corner (probably induced by an incorrect manual response to a warning alert - and involving a Flight Law mode change degradation).
The last two instances are the two likely scenarios for AF447. The history of Thales pitots and the similarity of the recorded fault sequences transmitted by ACARS is pointing relentlessly at scenario g.
_____________
It is also speculated that the A/THR had possibly already narrowed the upper aerodynamic margin just before it was auto-disengaged along with the A/P when the cascade of ECAM alerts began. Then the pilots may have further reduced their margin (by reacting in an opposite manner to the Air Caraïbe crew) and got very vulnerable to the turbulences (that may have increased as they were approaching the main Cb cell within the mesocluster). Their stress was probably increased by a sudden & unusual event (a cascade of aural/visual alerts), their attention was split between failure analysis & solving, procedures/check lists impossible (frustration) to apply due to time constraints & very confusing about stall alarms (see Air Caraïbe), manual flight, monitoring met conditions,... At night, in the absence of outside visual clues, an increased workload with the eyes scanning rapidly varied parts of the cockpit and attention split, spatial disorientation may have played a role as suggested ? No pilot should be placed in such a situation (intrumental & procedural ambiguities) and at worst, if this can't be avoided, they should be trained for that:
-As automation grows within the cockpit, the failures get more complex, potentially confusing, and pilots have also to become flight engineers. I don't know about how they are trained for complex system failures analysis (all the ways for otto to get crazy) but don't you think that ground simulation training should also implement false alarms ? I haven't be able to find any pilot whose regular training in ground simulations involves unreliable airspeeds and associated false alarms :\ Hope this is because pilots have flown away from here. Sorry for not being concise.
Jeff

hetfield

25th Jul 2009, 17:03

As automation grows within the cockpit, the failures get more complex, potentially confusing, and pilots have also to become flight engineers.

Fully agree!

This is a very sad example of "industrial evolution" .

Money, Profit, Money, Profit.......

FrequentSLF

25th Jul 2009, 17:21

Fully agree!

This is a very sad example of "industrial evolution" .

Money, Profit, Money, Profit.......

Hmm...i would qualify this as a SLF post. No added value to the discussion...

FSLF

hetfield

25th Jul 2009, 17:38

@fslf

Feel free to qualify my post to whatever you want.

I'm sorry if it wasn't clear enough.

The price for highly automatic/sophisticated FD isn't zero. I was refering to Hyperveloce's post in respect to very basic FD like 727/747 classic versus very complex FD like AB fly by wire.

Kind regards

hetfield

727/A300/A340/A320

And yes, sometimes SLF;)

Hyperveloce

25th Jul 2009, 18:06

...if you have lost a major indicator like airspeeds and if you are at high altitude with a little aerodynamic margin (GPS ground speed insufficient) and no visibility ?

would the pich & thrust interplay do it ? a few days ago, a pilot asked to the other pilots: flying without airspeeds at FL350 with an AoA~4°, your pich/altitude remain well under control, would you think you are approaching a stall ? (as far as I understand). would such a behaviour (evolution) of the pich/altitude (given the thrust, AoA & altitude) be a non ambiguous indication of a sufficient airspeed ?

if you have more time (assuming you are not subjected to multiple stall alarms), can you assess your aerodynamical authority by inducing a smooooooth vertical manoeuver ? (loosing a bit of altitude and stabilizing it with a slight attempt to regain altitude to assess the airframe authority).

Would you see means to appreciate (swiftly) whether a stall alarm is justified or not ? How will you do if it happens to you ?
Jeff

PS) Automation is not bad (simply you can't rely on it and you have to know it intimately as it is a critical part of your plane) and sometimes, men & automata (Alpha prot.) collaborate for the best:
http://www.ntsb.gov/events/2009/Weehawken-NJ/13-Lutz-presentation.pdf (http://www.ntsb.gov/events/2009/Weehawken-NJ/13-Lutz-presentation.pdf) (I know, this is an Airbus presentation, but...)
PPS) today is Bleriot's 100th anniversary, a man not bothered by autmated systems: Le 25 juillet 1909 (http://bleriot.2009.free.fr/page2.html) .The same flight was performed today

PJ2

25th Jul 2009, 18:45

No worries BOAC - it was an opportunity to clarify, which is always a welcome and needed thing when discussing this complex machine!

Rog' on the not-sitting-back-for-too-long...the image made my morning :)

daved123

25th Jul 2009, 20:27

PJ2
I think BOAC's reactions in those days omitted the requisite question, "what's it doing now ? " !
DaveD

BOAC

25th Jul 2009, 20:34

Actually there were extra words between 'what' and 'it':) My QHI had a gentle titter.

sevenfive

25th Jul 2009, 20:55

At some point I think they are going to find the wreckage and the recorders.

Maybe they dont want to find the recorders...

AnthonyGA

25th Jul 2009, 21:19

That has occurred to me as well. Ever since Habsheim.

PJ2

25th Jul 2009, 21:21

sevenfive;
Maybe they dont want to find the recorders...
In any fatal accident, there are always interested parties for whom the existence of data is "inconvenient" and perhaps even harmful to their interests. Safety investigations go where they must of course, regardless of "harm".

I certainly am not alone in experiencing this kind of ostrich-like corporate behaviour when confronted with data that paints an ugly operational picture. Denial's a powerful thing.

However, it is the nature of the process under ICAO Annex 13 that a thorough investigative process will, notwithstanding the capacity and abilities of the investigators in charge under the leadership of the IIC, unfold in a way that will at least ensure that reasonable outcome which is non-conspiratorial in nature and goes where it will regardless of who or what it harms, will obtain.

I am well aware that such outcomes are somewhat ideal and that investigators can "get it wrong" in parts. There are plenty of dissenting views and assessments which go to this point. But that is different than "hoping the recorders won't be found", which I think, while it is not an unrealistic statement, goes to unethical and dangerous thinking.

I was wondering when "Habsheim" would arise in this thread again...:ugh:

Smilin_Ed

25th Jul 2009, 22:41

I'm not a widebody pilot, and in fact I've never had my hands on anything bigger than a B-47, (steam gauges and steam powered controls) so I'm asking this in all innocence: Are ABs routinely being flown too close to the coffin corner? If so, is it for reasons of cost? Do they need to change their cruise procedures to avoid perilous circumstances?

wes_wall

25th Jul 2009, 23:03

From what I saw in the French TV news, I assume the highlighted seat chart indicated seat assignments of paxs recovered. It would appear they were random locations, but mostly the right side of the airplane, beginning in FRCL and progressing rearward. Is there a more detailed visual of the seating chart.

PJ2

25th Jul 2009, 23:39

Smilin',
Are ABs routinely being flown too close to the coffin corner? If so, is it for reasons of cost?
No, they're not flown too close to "coffin corner", precisely because of the high cost in fuel flow. That said, one takes what altitude one can get on the ocean crossing. Taking a high altitude early protects one's position while taking one too low may not permit one to climb later, depending upon traffic. Westbound, er, no, eastb..n...yeah, eastbound out of Hong Kong/Beijing etc across Japan to N.A. can be a problem. I think out of Hong Kong with the 340's hair dryers we always had to cross ELATO (if I recall the name correctly) at 290 because of weight and even that was a stretch. Three hours into the flight however, reduces the weight and improves the MAX ALT and Optimum Alt substantially.

FWIW, I don't think, (never did) that "coffin corner" had anything to do with this accident. The airplane's flight planning package, (fuel flow, weights, temps) and digital presentations (the actual lowest and highest speeds available are presented right on the Primary Flight Display) and the cost of fuel all mitigate against climbing too early in the flight notwithstanding all the above - FL350 is not an extraordinary altitude for the 330 at that point in the flight - pretty normal stuff, really. The stall speed and the Mach buffet speed at that altitude would be, guessing, about 100 kts apart perhaps slightly less, say 190ks to 290kts IAS, (the stall charts in the AOM only go to FL200 and there is no Max Dive speed indicated but maintenance isn't even interested in overspeeds until they're 20kts above the VMO).

Smilin_Ed

25th Jul 2009, 23:57

The stall speed and the Mach buffet speed at that altitude would be, guessing, about 100 kts apart perhaps slightly less, say 190ks to 290kts IAS,

This being the case, why do I get the feeling that many on this thread are concerned about either stalling or entering mach buffet and experiencing a loss of control? With a 100 knot difference, I wonder why a spurious stall warning wouldn't be easily recognized. I get the feeling from many here that flying under these conditions is like trying to balance on a bowling ball.

JD-EE

26th Jul 2009, 00:52

PJ2, with regards to "maybe not wanting to find the recorders" perhaps we should start a real live rumor that there was secretly about $30,000,000 in gold aboard the plane.
:D

JD-EE (Did *I* say that? I deny everything!)

PJ2

26th Jul 2009, 00:53

Smilin'
This being the case, why do I get the feeling that many on this thread are concerned about either stalling or entering mach buffet and experiencing a loss of control?
I don't know. My AOM, (not for a 330 with center tanks), shows an optimum weight for a 4000ft climb from 310 to 350 for a M0.80 cruise as 237k kg's. I believe they were about 205k kgs if I recall so there is lots of room between stall and Mach buffet speeds - Mach buffet isn't an issue here nor is a stall between 0200 and 0214Z. We cannot say what happened after.
With a 100 knot difference, I wonder why a spurious stall warning wouldn't be easily recognized.
My "100kts" is an educated guess and not from the books, so it's in quotes. It could be 70 to 90 kts but it isn't 30 to 40kts. A spurious stall warning would likely be recognized because of the absence of buffet and air noise, (if the warning was false) but there was no stall warning in the time frame we have information for.
I get the feeling from many here that flying under these conditions is like trying to balance on a bowling ball.
In my view that feeling is unfounded. A 205k kg A330 at 350 even in heavy turbulence is a stable platform with lots of headroom. Been there.

Smilin_Ed

26th Jul 2009, 01:02

A spurious stall warning would likely be recognized because of the absence of buffet and air noise, (if the warning was false)......

That's what I would have thought but so many here seem to be afraid of improper reaction to a stall warning, spurious or otherwise. Seems pretty straight forward to me, but I've never flown an AB.

HarryMann

26th Jul 2009, 03:05

It is also speculated that the A/THR had possibly already narrowed the upper aerodynamic margin just before it was auto-disengaged along with the A/P when the cascade of ECAM alerts began.If that proves to have been the case, we would be back again discussing similar issues to Turkish/Schipol - in an opposite sense though, both in height & speed. Namely - unnoticed degrading margins due to automatic functions, albeit in AF447, the aircraft would have been at fault.
However, if this is a credible scenario, how would the a/c gain speed? More thrust - that's where any crew monitoring function would/should have (been able to) pick it up?

1) How would you see that increasing Mach as displayed thrust change - or would you the steady rise against varying thr. levels (assuming some turbulence) ?
2) Is there any reporting of discrepancy between Inertial and ASI rates of change (at least in the longitudinal axis) - e.g. unaccountable apparent accelerations

===== On the general drift of inherent dangers at cruise at M .8/.82 @35k & 205 tonne). ===

PJ2 paints a very different picture than the linked (& somewhat scary) analyis from UNCTUOUS. The incipient speed-rise situation above might explain it, as perhaps would extreme turbulence. It does sound like it would have to have been a combination of turbulence + poor speed control, from his judgement on the matter?

PJ2

26th Jul 2009, 03:15

Ed; found some M0.82 cruise numbers:

Some reasonable but hypothetical speeds:

At FL350, with an MAC of 37% at 205k kgs, the IAS is 279kts, 271kts for M0.80.

Green dot, high and low speed buffet onset - A330, no center tanks:

Best lift/drag ratio speed is "Green dot", named for its symbol on the Primary Flight Display airspeed tape for 205k kgs at 350 would be 245kts, 26kts below cruise speed.

VLS, (lowest selectable speed) known as "the hook" because of the shape of the symbol, is 1.23 VS in the clean config and would be approximately 236kts or 35kts below cruise speed.

For a M0.82 buffet onset it would take a bank angle of 54deg (in a coordinated turn) to produce a 1.75g load factor for a 330 weighing 200k kg with a 40% CG

The buffet onset charts indicate that at 1g, mach buffet is well above MMO at about M0.87 perhaps a bit less, for an IAS of about 296kts or about 25kts above cruise speed.

The low speed buffet would be M0.58 at 1g, (level flight) or an IAS of about 192kts at FL350 or about 80kts below cruise speed.

...or about 100kts or so between the two buffet boundaries.

singpilot made a salient comment the other day - "trying to get into the cockpit" or something to imagine what was going on. I think a lot are trying. I'm trying to imagine what circumstances would cause the loss of 80kts or so. From 272kts, (roughly) to 192kts, (roughly), it would take a very long time even with engine thrust at idle, maybe a knot every second or two, or about a minute and a half to slow from 272 to 190.

Speed reduction occurs much more quickly with speed brakes out. With the boards up, both the VLS and stall speeds go up with speed brake use. In my experience, I have seen VLS increase by 30kts when the boards are at their maximum deflection, (usually in descent - they are rarely used if ever, in cruise unless one needs to slow the airplane down very quickly - it's not an issue, it's just rare). There is a slight pitch-up with use of speed brakes and a corresponding pitch down when they are stowed. The rate of deployment and retraction are computer-controlled and quite slow, (3-5" for up, 5-8" for down), giving lots of time to adjust pitch attitude.

While the speed calculations are from the AOM and are not unreasonable, what was done with them is entirely speculative and not knowable at present.

HarryMann;
The incipient speed-rise situation above might explain it, as perhaps would extreme turbulence. It does sound like it would have to have been a combination of turbulence + poor speed control, from his judgement on the matter?
In the article to which "UNCTIOUS" supplied the link, I saw no direct analysis of the A330 performance numbers or direct references to speeds. While I think the article is correct in its statements about "mach crit" and other notions the statements which are generic, do not bear a solid (causal) relationship to the A330 or this accident. A 100kt "distance" between the two buffet boundaries bears this assessment out. I think the statement contained in the article about "surprise" is a reasonable statement, perhaps understatement, but that alone does not account for the loss of control.

The article does make some statements that cannot be verified and are pure conjecture,

"It's becoming apparent that whichever pilot was PF in AF447 misinterpreted the ADIRS symptoms as an aerodynamic stall and added power (possibly also increasing AoA) - with a resultant coffin corner encounter with Mach crit (which rapidly leads to uncontrollable roll and pitch excursions - see definitions below in next box)."

and that, and the absence of any analysis as it relates to the performance numbers of an A330 regarding high and low speed buffet boundaries leads one to suspect other "conclusions".

Nor am I "arguing a case"! I'm just trying to use the best numbers and a bit of thinking to see "what fits" and what isn't reasonable.

threemiles

26th Jul 2009, 06:20

There are many cases in which over-controlling is an issue in the AB for exactly these reasons., (I note the thread on the Hamburg accident).

The opposite is true for Hamburg, which was an incident. The A320 entered ground mode after one leg touched the ground briefly and did not revert to air mode for more than three seconds, during which roll authority was limited, so the gust could not be countered by manual input.

Ed; found some M0.82 cruise numbers:

Pointless numbers unless you know what the actual ISA deviation was. Can be very very significant in a tropical storm, maybe ISA+40 and then?

PJ2

26th Jul 2009, 07:30

threemiles;
Pointless numbers unless you know what the actual ISA deviation was. Can be very very significant in a tropical storm, maybe ISA+40 and then?
Well, for a given SAT rise and a maintained Mach and CAS, only the TAS increases. ISA+40 would yield about a 39kt TAS increase but the Mach remains at M0.82, the CAS at 279kts.

ISA+40 is pretty rare and it would seem you're not likely going to be staying at 350 at ISA+40. The Environmental Limitations (ATA90) doesn't list a maximum TAT but the graph shows 350 and a SAT of -20 as right on the FL350 line. The AOM doesn't have cruise performance charts for anything other than ISA and the Optimum weight for 4000ft step climb has ISA+10 and ISA+20. ISA+20 @ M0.82 shows a climb from 310 to 350 at an optimum weight of 226k kg's however. So ISA+40 may not present the serious issues we might have first thought. You were thinking of a column of much warmer air, as per the earlier conversation in re Tim Vasquez' work could possible stall the aircraft? Otherwise, not sure what you're thinking.

Your notion brings to mind an accident that occurred on the Vancouver coast - Fraser river delta, when a heavily-laden fishboat sank, costing five lives, if I recall. The ship was in salt water and when it entered the less bouyant fresh water of the Fraser's outpouring, it became unstable.

HazelNuts39

26th Jul 2009, 07:40

Some reflections to invite comment:

- An airplane stalls when it exceeds a critical angle of attack, regardless of airspeed.
- Stall warning is an important protection against stalling, especially when airspeed is unreliable.
- Pilots should be able to rely on stall warning and should respect it when it occurs.
- Stall warning should be based on angle of attack and should not be corrupted by false airspeed information.
- If there is a need for an additional warning based on airspeed to cater for unreliable AoA, that warning should say something like "SPEED SPEED SPEED" rather than "STALL STALL STALL".

That being said, a stall is normally not catastrophic as long as there is sufficient height available to recover from it. 35000 ft should normally be sufficient.

regards,
HN39

BOAC

26th Jul 2009, 07:58

The AOM doesn't have cruise performance charts for anything other than ISA and the Optimum weight for 4000ft step climb has ISA+10 and ISA+20. - somewhere in the dark dungeons of this thread someone posted a graphic carpet graph with ISA deviation for a 330. Don't have tiime to search for it at the moment. I seem to recall that I later posted "ISA+17" as a possible problem area at that weight. Whether it was the 'step climb' carpet or not I cannot remember.

HarryMann

26th Jul 2009, 11:48

ISA +40

Think I'm right in saying that if you suddenly ran into +40, then your MCrit margin would in short term increase, thrust decrease, and stall margin decreases (?)

... until A/P A/T restabilises at cruise Mach.Which would take some time.

Hyperveloce

26th Jul 2009, 13:11

I have just colored each seats on an A330 plan from the stills. With a thought for each of these. I only numbered 33 individuals. Available in private.
Jeff
- about the CVR/FDR, if they are located in the tail of the aircraft (probably thought to be the safest place in most cases ?), in this case they may have been in the area absorbing most of the impact energy. The flight data are armored but the ULB/pinger (little cylinder on the armored box) does not seem very hardenned: could it be that these ULB were damaged at the impact and have never pinged at all ?
- about the false stall alarm recognition : is it easy to discriminate between the pre-stall buffeting and the effects of turbulence ?
can a rapid loss of 300 ft (like in the Air Caraïbe case) reinforce the idea of an on going stall ?
- about the ACARS not transmitting possible stall alarms : we cannot be certain that these have occurred, but they did in several past cases involving Pitot freezing (with little delay after the A/P & A/THR off), and we know that they could be a natural consequence of corrupted airspeeds (using AoA and airspeeds to generate the stall alarm in alternate law 2). If the "stall - stall - stall" was generated in a similar manner to the other cases, then this may have occured as early as 02:10 or 02:11Z, and the overspeed may have been initiated as early as 02:10Z through the A/THR chasing airspeeds that were roling back (increased/max thrust from 02:10Z).
- about the colored seats: after correction, there are 38 colored seats on the BEA map (38 passengers + the 2 crew members)

PJ2

26th Jul 2009, 17:02

HarryMann;

Yes, you would be correct in that statement - warmer air, fewer molecules. If the air suddenly warms up, until things stabilize, Mach decreases, (speed of sound decreases, so relative to that, aircraft Mach decreases), engine power is reduced, low-speed buffet onset speed increases.

But I would offer that in and of itself, such a change, (while rare) would not cause loss of control. Engine thrust would increase immediately as per design and as you say, the mass would take some moments to increase velocity. In taking a look on the Jepp CR2, a 20C temperature change makes about a 15 to 20kt change in TAS, (the Jepp assumes "steady state" of course so a sudden "rise" in OAT shows a 20kt increase in TAS but in fact, until things stabilize at the new "equation", there would be an airspeed deficit), and pitch attitude would decrease very slightly first as "CRZ ALT" mode is a "soft" altitude with a 100' window to wander 50' up and 50' down to correct minor speed variations without changing engine thrust.

BOAC;
A 17C increase in OAT under the conditions AF447 was in wouldn't make a dramatic difference in and of itself. The airplane was a long way from the so-called coffin corner everyone is on about. I haven't seen any data to the contrary, proving otherwise. Here's the chart you're referring to, I think. Below this one, here is a graph of the environmental envelope for a 330, (no center tanks):

The following caveat/caution will be familiar to most in aviation. It applies to all readers and is necessary to ensure clear understanding as to intent and use:
The following information is for education, demonstration and discussion only and is not valid for flight planning. These graphs are not associated with any specific airline or model of A330. Do not use these graphs for planning or flight operations purposes.

ISA vs Altitude, M0.80 & M0.82 Cruise:

http://i277.photobucket.com/albums/kk76/batcave777/A330_ISAvsAltChart_2009-07-26_09065.jpg

http://i277.photobucket.com/albums/kk76/batcave777/A330_EnvironmentalEnvelope2009-0-2.jpg

Here is a buffet boundary graph for an A330:

http://i277.photobucket.com/albums/kk76/batcave777/A330BuffetBoundaries_2009-06-07_-1.jpg

BOAC

26th Jul 2009, 17:10

PJ - thanks for all those graphs - the one I recall put it closer to the line, but did not specify the margin. I have spent some time looking back for this graph (posted pre 3/Jul) but I think it got 'moderated'out of existence. Yours certainly closes the case for 'too high'.

robertbartsch

26th Jul 2009, 17:20

What evidence is there to support a conclusion that this ship bellyflopped whole into the Atlantic? The autopsies don't support this; right?

Hyperveloce

26th Jul 2009, 17:47

...before the fault detection schemes switch it off (A/THR & A/P).

Beyond the A/THR chasing declining airspeeds and reducing the upper aerodynamic margin before being switched off, could it be that the A330 alpha protection laws had also reduced the plane's AoA reacting to the same declining airspeeds ? An Airbus in approach (AP off, A/THR on in managed speed) with substained high surface winds was surprised by a sudden wind drop (-20 kts in a few sec on the airspeed) and began to sink, the pilot tried to abort the approach/landing and to initiate a go-around but the AoA laws prevented it (reacting to the airspeed drop), by inducing a nose down that the pilot could not overrule. What about a button on the stick for the pilots to overule any automation, primary reflexes of the A330, protection laws included ? full authority (like on Airbuses operating flight tests at the limits of the envelope ?)
Jeff

PJ2

26th Jul 2009, 18:24

Jeff;
An Airbus in approach (AP off, A/THR on in managed speed) with substained high surface winds was surprised by a sudden wind drop (-20 kts in a few sec on the airspeed) and began to sink, the pilot tried to abort the approach/landing and to initiate a go-around but the AoA laws prevented it, by inducing a nose down that the pilot could not overrule.
Hm, can you provide a link to the report or to the quote, Jeff? On the surface of it, this doesn't sound correct so I wouldn't mind verifying what happened just out of curiosity, thanks.

Hyperveloce

26th Jul 2009, 18:39

PJ2, you are right, I am mixing up two cases:
- the Cayenne incident (A340 A/THR increasing thrust reacting to a wind drop):
http://www.bea-fr.org/docspa/2001/f-zc010525/pdf/f-zc010525.pdf
- the interrupted go-around (A320 AoA laws reacting to turbulence and updrafts):
http://www.pn.ewi.tudelft.nl/education/et4-138/notes/loc.pdf
so I was wrong in saying that the AoA protection law was triggered by declining airspeeds (due to a wind drop) in this case, this was the result of up/down wind gusts.
Jeff

AirRabbit

26th Jul 2009, 18:40

At the risk of setting off some very personalized feelings, can someone with some specific knowledge confirm something that continues to come up in the circles in which I find myself.

There is a rather large international operator of Airbus aircraft whose very experienced instructor cadre are absolutely convinced that the pilot on board this aircraft was also on board the aircraft that landed and skidded off the runway at Toronto in 2005. :hmm:

Can anyone confirm this or is this just another one of the "I'll-bet-I-know" rumors that get started? I reaffirm, this one organization is apparently absolutely sure of their position.

VFR Only Please

26th Jul 2009, 18:46

It IS odd that while we've seen details of the experience on the A330 and on this stretch of the Atlantic of AF447's crew, I've seen no names published.

PJ2

26th Jul 2009, 19:14

Thanks Jeff, that makes sense.

Hyperveloce

26th Jul 2009, 19:19

There is a rather large international operator of Airbus aircraft whose very experienced instructor cadre are absolutely convinced that the pilot on board this aircraft was also on board the aircraft that landed and skidded off the runway at Toronto in 2005. :hmm:

:sad: Even if it was true, what would it prove ?
It was an A340 that skidded off the runway in 2005 and we can read in the BEA report that Marc (the AF 447 captain) qualified to fly A340 in 2007: "Qualification de type Airbus A340 obtenue le 9 août 2007" (p. 15). Hence it was not the AF 447 captain. The 37 yrs old AF 447 copilot whose name is not known was certified on A340 in 2002 (he had many more flights on A330/A340 than the CPT) but he is obviously not the F-GLZQ captain who had first flown on his own on a glider on the 1st dec. 1963 (Toronto report), nor the F-GLZQ copilot who joined Air France in 1985 (should also be well over 40 yrs in 2009)
Jeff
sources:
Le Bureau de la sécurité des transports du Canada - RAPPORTS AVIATION - 2005 - A05H0002 (http://www.tsb.gc.ca/fra/rapports-reports/aviation/2005/a05h0002/a05h0002_index.asp)
http://www.bea.aero/docspa/2009/f-cp090601e1/pdf/f-cp090601e1.pdf

PJ2

26th Jul 2009, 20:06

Nice sleuthing work Jeff. Such work should have been done by the "very experienced instructor cadre [who] are absolutely convinced".

edga23

26th Jul 2009, 20:09

I think the co-pilot of the Toronto plane was a women, and she was PF during that landing. All three pilots in AF447 were males.

AirRabbit

26th Jul 2009, 20:22

You might want to recall that it was the F/O of the Toronto accident aircraft in 2005 who was at the controls initially - and, if the accident information is correct, that would make the Toronto F/O a male, not female. The Canadian's don't release the names of pilots involved in accidents they are investigating. If the AF447 Captain (Marc, leaving last name blank) was first type rated on the A330 in October 2006 and type rated on the A340 in August 2007 - does anyone know what his assignment was in 2005?

I'm not making accusations ... I'm asking for anyone who may KNOW the facts.

kilomikedelta

26th Jul 2009, 20:24

The Transport Safety Board report indicates that the flight deck crew were all male. Transportation Safety Board of Canada - AVIATION REPORTS - 2005 - A05H0002 (http://tsb.gc.ca/eng/rapports-reports/aviation/2005/a05h0002/a05h0002.asp)

edga23

26th Jul 2009, 20:29

I am sorry. I checked the facts, and the female co-pilot was on a plane during an incident in french Guyana. I mixed-up the two incidences.

Hyperveloce

26th Jul 2009, 20:40

You might want to recall that it was the F/O of the Toronto accident aircraft in 2005 who was at the controls initially - and, if the information is correct, that would make the Toronto F/O a male, not female. I'm not making accusations ... I'm asking for anyone who may KNOW the facts.

I read in the Toronto report:
"Le commandant de bord a été désigné pilote aux commandes (PF) pour le décollage et la première moitié du vol. Le copilote devait être le PF pendant la seconde moitié du vol, y compris pendant l'approche et l'atterrissage à CYYZ. Les tâches de PF/PNF (pilote non aux commandes) avaient été interverties afin de permettre au commandant de bord d'effectuer un décollage au cours de ce vol. Les tâches ont été échangées à 16 h 17, et l'équipage est passé du pilote automatique no 1 au pilote automatique no 2."
(the CPT was the PF who took off the plane and flew the 1st half of the flight, the copilot being scheduled to be the PF for the 2nd half, approach and landing)
"À 16 h 17, les membres d'équipage ont échangé leurs tâches de PF et de PNF, ce qui s'est traduit par un passage du pilote automatique no 1 au pilote automatique no 2. À partir de ce moment-là, c'est le copilote qui a été le PF"
(at 16:17, the copilot becomes the PF and he is the one who will land the plane at 20:01)
source: Le Bureau de la sécurité des transports du Canada - RAPPORTS AVIATION - 2005 - A05H0002 (http://www.tsb.gc.ca/fra/rapports-reports/aviation/2005/a05h0002/a05h0002_sec1.asp)

...and the Toronto copilot joined AF in 1985 (over 40 yrs in 2009): he is not the AF 447 captain (not qualified for A340 in 2005) nor the copilots (too young). So the facts seem to oppose to the possibility that either the Toronto CPT (now probably retired) or the copilot/PF for landing may have been in the AF 447 cockpit, don't you agree ?
Jeff

SaturnV

26th Jul 2009, 20:51

Hyperveloce, Brazil said several days ago it has identified 49 of the 50 bodies recovered. Was the matching of recovered bodies to assigned seats against 33 bodies, or some higher number? (As I recall, at least three of the bodies recovered are those of the crew.)

And without being specific to individuals, is wes wall's characterization correct that the recovered bodies came from all sections of the aircraft, with somewhat more bodies from the right side than the left?

Hyperveloce

26th Jul 2009, 21:16

SaturnV, it appears to me that the distribution of colored seats is much more dense at the rear of the plane. There are indeed colored seats in every parts of the plane, but how to be sure that all colored seats were occupied at the impact ?

AirRabbit

26th Jul 2009, 21:28

...and the Toronto copilot joined AF in 1985 (over 40 yrs in 2009): he is not the AF 447 captain (not qualified for A340 in 2005) nor the copilots (too young). So the facts seem to oppose to the possibility that either the Toronto CPT (now probably retired) or the copilot/PF for landing may have been in the AF 447 cockpit, don't you agree ?
I'm afraid you have the advange of me, Jeff, as I don't read French very well. However, if you say that the pilot of AF447 was not assigned to and did not fly the A340 as a copilot in 2005 - I agree with your conclusion. But if the Toronto copilot joined Air France some 24 years ago and the AF447 pilot was rated in the A330 in 2006 and rated in the A340 in 2007, these facts do not indicate any reason why they cannot apply to a single person. Certainly, the AF447 pilot was flying something for Air France in 2005, but I don't know what - and, as I understand the reports, the AF447 captain was younger than his copilot(s) on that flight. Is this not true?

I'm only interested because of the absolute certainty with which I am told these two pilots are one in the same and, if true (notice, I said IF true) that would speak volumes about whether or not Air France takes seriously the fact that their pilots operate with a really good sense of situational awareness regarding things like weather.

Hyperveloce

26th Jul 2009, 21:49

The AF 447 CPT was 58 in 2009 (I think close to the retirement), and not qualified for A340 in 2005. The 37 yrs AF 447 copilot could have flown an A340 in 2005 but the ages do not match: the Toronto copilot joined AF in 1985 (and followed a pilot training course in th U.S. the following year). Let's assume he had at least 18 yrs in 1985, it would give at least 18+(2009-1985)=42 yrs in 2009, which exceeds the ages (32 and 37 yrs) of bth the AF 447 copilots. The Toronto CPT would be over 60 in 2009. Jeff
PS) next time this rumor will come up again in the circles in which you find yourself, kill it if you agree with the above.

AirRabbit

26th Jul 2009, 22:20

OK - last time. You said "The AF 447 CPT was 58 (I think close to the retirement), and not qualified for A340 in 2005." Does "not qualified for A340 in 2005" mean he had not been trained on the A340 in 2005 or does it mean that he was not type rated on the A340 in 2005? Sometimes the same terms have different meanings in different languages - as I am sure you are aware. In the US "not qualified" means the pilot had not been trained on the aircraft for either pilot position. However, a pilot can be qualified on an airplane and not be "type rated" on that airplane. If the Captain on AF447 was "not qualifed" (meaning that he had not been trained as a F/O) on the A340 in 2005, then I agree, there is little chance that these seasoned veterans at this international airline are correct and they are all mistaken. But, if that pilot was not type rated on the A340 in 2005, does that allow for the possibility that he may have been operating as a F/O in the A340 in 2005? Of course, I'll accept your conclusion.

Hyperveloce

26th Jul 2009, 22:39

In the English version of the BEA report, about the AF 447 CPT:

• Airbus A340 type rating obtained on 9 August 2007
• Line oriented flight training on 7 September 2007
(in 2009, he had cumulated 654 hours on Airbus A340)

The Toronto report states about the copilot, who was the PF at the landing:
"Il a été copilote sur Airbus A319/A320/A321 pendant trois ans et demi avant de recevoir sa qualification de type sur A340 le 11 septembre 2001".

the Toronto copilot obtained his Airbus A340 type rating on the 11th of september 2001: he cant' be the AF 447 CPT.
Jeff

AirRabbit

26th Jul 2009, 22:48

Thanks Jeff, I'll be able to refute those ill-advised accusations.

HarryMann

27th Jul 2009, 02:53

Here is a buffet boundary graph for an A330:

That's a nomogram.. very clever things nomograms. Reading them can sometimes be, er... 'less than obvious'. Drawing them up, even more so... :ugh:

===
I can see the good sense in the alt.hold being 'soft' and Mach being 'harder' presumably - but there might be questions coming on auto-flight presumptions, philosophy & man/machine interface in general, for AF447, as well as two others currently under investigation.

Aware that you may well not sign up to that, even as pure speculation at this stage.

PJ2

27th Jul 2009, 04:26

HarryMan;
That's a nomogram.. very clever things nomograms. Reading them can sometimes be, er... 'less than obvious'. Drawing them up, even more so... :ugh:
Oh, so that's why I couldn't read it... It is REALLY confusing - arrows going in different directions etc - I followed one data point to get the high speed buffet at 205k kgs, (> M0.87) and gave up.
Aware that you may well not sign up to that, even as pure speculation at this stage.
Well, I'm not a convinced Airbus believer and not a convinced automation user. I understand it, can use it and recover from screw-ups but two things, (obvious to all, now) mitigate full enthusiasm: Automation robs situational awareness through absence of physical/sensory cues of flying the machine and as a result atrophes flying and thinking skills, and when automation degrades it can overwhelm even a highly competent, well-trained crew. Other than that, automation, used as intended, (not an airplane babysitter but tool for accuracy, predictability and timeliness of action), I am enthusiastic because it is a flight safety enhancement.

Machinbird

27th Jul 2009, 04:58

Hi Gentlemen,
I'm an old used military jet type with only steam gage experience, but there was something that I did not see in the BEA report that should probably have been in there at this point.
The size of the recovered wreckage fragments from AF447 appears to be relatively large and this implies a relatively low speed impact with the water (albeit with a large downward vector). I think some of the other old hands have sensed this as well, but it hasn't been explicitly stated.
Having participated in a few accident investigations over the years, I've seen what happens when an aircraft hits the water at medium speeds and at high speeds. Kinetic energy goes up as the square of the velocity. This energy converts the aircraft into a churning mass of fragments which then beat on each other until their energy is dissipated. The higher the energy, the smaller the fragments.
There are approximately 5 minutes of ACARS messages which were coming in at a good clip and probably would continue to come in if the aircraft were still airborne and under electric power. As I understand it, ACARS requires generator power from the engines to be operational.
It would probably require at least 1 minute for the aircraft to decelerate from cruise to stall speed if that is what it did. To then descend from FL350 to the surface in the remaining 4 minutes would take a descent rate of almost 9000 ft min which implies a very deep stall or that the aircraft had some unpowered flight time.
I would imagine Airbus has already worked out the numbers whether 9000 fpm is even possible in a deep stall. If this type of scenario seems reasonable, we can look backwards and see what might have precipitated it. Thoughts?
Sid

d747

27th Jul 2009, 07:28

Good Morning,
Is there any news on the FDR and CVR recovery? If not, How much more time and money will be allocated to finding them?

Kind Regards

D747

Hyperveloce

27th Jul 2009, 15:58

Hello d747
Hi there. It was said here in France that the "Pourquoi pas ?" should begin a "2nd phase" (the 1st was the search of the ULB/pingers) of underwater searches using a multibeam high resolution sonar (the SAR: Système Acoustique Remorqué, or Towed Acoustic System, used to locate the Titanic) for 4 to 6 weeks. Merging full res SAR lateral images with the AF 447 pieces of fuselage shows that there should be very good chances to detect the wreck, it could look like this (not a SAR simulation)
http://img124.imageshack.us/img124/3917/sarimages.jpg
Search parameters: operational speed at which the SAR must be operated (as a function of the desired resolution), Reference value in the report ~2 NM per hour (full res), search area of 16 000 km² (or a 70 NM square), the width of two lateral images is 512 pixels or 128 meters at full resolution (footprint), which will not be practicable on the entire search area. But with a medium resolution (the middle SAR image), the search area could be scanned in ~50 days (more at sea!). Search strategies could vary the SAR resolution as a function of an a priori probability to find the wreck in a given area. But the very difficult bathymetry will probably slow the operations.
Jeff
Source: http://www.ifremer.fr/flotte/systemes_sm/images/sar/07_043%20Guide%20exploitation%20du%20SAR-1.pdf

rgbrock1

27th Jul 2009, 16:03

PJ2

27th Jul 2009, 16:32

Thanks Jeff, very interesting information on the technical aspect of the search. PJ2

Dani

27th Jul 2009, 16:47

I guess the other question regarding the possibility of the wreckage being found is:
is an attempt made to hoist the wreckage (would seem near impossible to me dependent on depth) or simply map and film it?

When wreckage is found, they send the robot submarine down and look for the recorders. They try to lift them to the surface. If data are recovered, that might solve the mistery. If not, they might look for further evidence on the wreckage.

Dani

Hyperveloce

27th Jul 2009, 17:18

Thank you PJ2.

When we look to the means deployed in the impact area and the multiple partners:
-the French Navy ships: Ventôse Frigate, Emeraude nuclear submarine, Mistral support ship, Aircraft from the fleet air arm and the air force
-the civilian ships chartered by the BEA: the IFREMER ship, the « Pourquoi Pas? », two tugs from Louis-Dreyfus Armateurs (Fairmount Expedition, Fairmount Glacier)
-Two Remotely Operated Vehicle: the ROV Victor and the Nautile submarine
-BEA investigators, AAIB investigator (UK), advisors from Air France, Airbus, advisers from CEPHISMER, SHOM, US Navy, IFREMER, GENAVIR,...
Can the French authorities or the multiple partners be suspected not to do their utmost to recover the black boxes, or to hide things ? Some people really like conspirations. This 2nd phase is scheduled for 4 to 6 weeks, I hope and I think that it should be sufficient, but I am also convinced that the efforts can be prolongated if needed. Wait and see. Also a (very) small hope from the CEAT, was the left wing spoiler torn away from its wing at the impact or by the aerodynamical efforts ? are there clues in the debris about the loss of control and not only the impact ? We never know.
Jeff

SaturnV

27th Jul 2009, 18:04

They are about one week into the sonar scan, and assuming they started where they think the plane most likely impacted, that would be an area scanned of 3,000 - 4,000 sq km. Unless Jeff has heard unpublished news that they have found, or think they have found, parts of the plane, a negative scan result would be disappointing. There was a report in the French press late last week that the search area had been localized (if I translated correctly), but without being more specific, and a 16,000 sq km area could be localized in the larger order of things.
__________________________
I think this is the video mentioned by wes wall.

France 24 | Investigators piece together wreckage from doomed Air France jet | France 24 (http://www.france24.com/en/20090724-investigators-piecing-together-wreckage-af-flight-447-accident-france-rio-paris)

There is an English voiceover on several remarks spoken en Francais, but one of the investigators apparently said there are burn marks on parts of the wreckage.

Squawk_ident

27th Jul 2009, 19:44

SaturnV
There is an English voiceover on several remarks spoken en Francais, but one of the investigators apparently said there are burn marks on parts of the wreckage.

No no no please.
This is a translation of the last Friday France2 report . This Gendarme did not say that there was burn marks found at any moments. He simply said that the inquiry will try to find any clues including burn marks or traces or cut, rupture or anything pertaining to the debris found. At no moment he said that burn traces were found.

lomapaseo

27th Jul 2009, 19:51

I guess the other question regarding the possibility of the wreckage being found is:
is an attempt made to hoist the wreckage (would seem near impossible to me dependent on depth) or simply map and film it? The latter would, of course, preclude
recovery of the CVR and FDR.

A lot can be done with pics relative to structural questions. There's a whole science and experience bank with this. However, if the larger issues are performamce issues of the airplane or crew then the black boxes are a high priority for recovery.

The submersibles have some capability for extraction and lift, is it enough??

Lacking the lift capability (black box emeshed in something too heavy) then some more difficult attempts may be made with flotation devices.

But first things first :) lets get the pics and see what the experts recommend after that.

mm43

27th Jul 2009, 20:11

The "Pourquoi pas ?" is a sophisticated oceanographic / hydrographic research vessel built in 2004 as a joint venture between the French ministries of Defence and Research. Full Specifications (http://www.ifremer.fr/fleet/navires/hauturiers/pourquoipas/descriptif.htm) of its equipment etc. can be found on this (English version) page which has been updated today.

A Navarea V Radio Navigation Warning to shipping is currently effective for the "Pourquoi pas ?" underwater operations -

1544/09 – NORTHWEST OF ARQUIPELAGO DE SAO PEDRO E SAO PAULO – CHART 10 (INT 216) - VESSEL POURQUOI PAS – CARRYING OUT OCEANOGRAPHIC RESEARCH IN CIRCULAR AREA WITH 70 NAUTICAL MILES RADIUS CENTERED IN POSITION: 03-00.00N 030-36.00W - UNDERWATER VEHICLE NEAR THE VESSEL - PERIOD: 26/JUL TO 16/AUG. BERTH REQUESTED. CANCEL THIS WARNING 170359Z/AUG/09.mm43

Hyperveloce

27th Jul 2009, 20:30

Nautile (http://www.ifremer.fr/fleet/systemes_sm/engins/nautile.htm)
(100 daN for each 6 dof arms, propulsion 300 daN, where 1daN~1kg)
http://www.ifremer.fr/flotte/systemes_sm/images/nautile/-%20Guide%20d'exploitation%20du%20Syst%8Ame%20Nautile.pdf

VICTOR 6000 (http://www.ifremer.fr/fleet/systemes_sm/engins/victor.htm)

Loerie

27th Jul 2009, 20:57

I have read the report mentioned and listened to the video and,according to the way the report is written it states that Lt Col.Mulot is 'expecting a lot from the study.....debris......broken and traces of burns'......that`s what it says in type,for what it`s worth,in that press report. Have no idea what they mean and just repeating what is written...

BOAC

27th Jul 2009, 21:08

According to Lieutenant-Colonel Xavier Mulot, chief investigator for AF flight 447, "We're expecting a lot from this study because, thanks to the way the debris was broken and traces of burns, it'll eventually allow us to understand what happened."

What do you make of that, Squawk?

SaturnV

27th Jul 2009, 21:08

Squawk Ident, I defer to your hearing the original.

For what its worth, here is the English-language text of what he said on the France24 site.

According to Lieutenant-Colonel Xavier Mulot, chief investigator for AF flight 447, "We're expecting a lot from this study because, thanks to the way the debris was broken and traces of burns, it'll eventually allow us to understand what happened."

Most speakers with English as their mother tongue would say that he described the recovered wreckage as having traces of burns.

Hyperveloce

27th Jul 2009, 21:26

Squawk is right. Lieutenant-Colonel Xavier Mulot did not say that trace of burn were actually observed, he was merely exploring possibilities and... expecting a lot from this study. Another BEA technical expert was interviewed (on other TV channels) and much more cautious about this study given the available data. Jeff

ArthurBorges

27th Jul 2009, 21:36

I cannot make out at all how exactly Col. Mulot expressed himself in French in the video: the voiceover masked it entirely.

The accompanying transcript says:

According to Lieutenant-Colonel Xavier Mulot, chief investigator for AF flight 447, "We're expecting a lot from this study because, thanks to the way the debris was broken and traces of burns, it'll eventually allow us to understand what happened."

mm43

27th Jul 2009, 21:56

ArthurBorges -

The link as originally posted by Hyperveloce is:-

Journaux télévisés en vidéo - France 2 (http://jt.france2.fr/player/20h/index-fr.php?jt=20090724&timeStamp=663)

mm43

Squawk_ident

27th Jul 2009, 22:04

I will try to translate as precisely as I can what this man said.
Eventually is a "false friend". In English or in French.

You may listen (while it is still possible) to the original broadcast here:
Journaux télévisés en vidéo - France 2 (http://jt.france2.fr/player/20h/index-fr.php?jt=20090724)

and go to +12'

"We are expecting a lot from this study because it will allow us to understand by the shape of the debris, by the cuts and possibly marks of burn what happened."

In this context "éventuellement " may be translated by "perhaps".

The France3 network also covered the same event on the same day and interviewed the very same person. And he said almost exactly the same thing:

Journaux télévisés en vidéo - France 3 (http://jt.france3.fr/player/soir3/index-fr.php?jt=20090724)

and go to +15'45''

Will Fraser

27th Jul 2009, 22:05

Awaiting a French translation, I did hear the word from the official, brulure. 'Burns'. I have no context, obviously my French is lousy.

The airfoil surface featured in both videos looks most definitely like Elevator. Found floating (obviously) as was the VS with Rudder. Who can determine where each was recovered ?

ArthurBorges

27th Jul 2009, 23:35

His statement to A2 was:

"We're expecting alot from the investigation because it will enable us to understand what happened from the shape of the debris, how debris was cut up, and any traces of burning.

As noted, Col. Mulot was interviewed by FR3 as well, where he mentions "éventuellement des brûlures" = "any burn marks (we might find)".

My reading of both statements is that the good colonel is NOT saying he's seen any evidence of fire but simply allowing fire as a reasonable-to-remote possibility.

As I understand it, a second shipload of wreckage has yet to arrive and I speculate the colonel has in mind early reports of orange fires on the surface of the water or at least is speaking from general experience of a/c accident investigation.

End of story.

(Note, for pedantry's sake, that I have rejuggled his word order.)

The only weird thing is that footage showed several hydraulic jacks: I didn't know they floated.

JD-EE

28th Jul 2009, 00:27

The only weird thing is that footage showed several hydraulic jacks: I didn't know they floated.

Um, if they were really air cylinder actuators they might have floated, especially if they had been still attached to something like the rudder or the elevator that were recovered.

JD-EE

Hyperveloce

28th Jul 2009, 01:39

Another companion case, the AF 908 (FGNIH) between Paris and Antanarivo, very similar to the two Air Caraïbes events, and to the AF 447 seen through the ACARS, available at:
Eurocockpit - Archives (http://www.eurocockpit.com/archives/indiv/E009479.php)

Quick translation:

FL370, on the AWY UB612 (OFFSET 1R), between the OBD and MLK waypoints, in contact with Khartoum, above the cloud layer, light turbulence, crepuscular lighting.

-at 15h10TU: Pitot 1 & 2, 2 & 3 et 1 & 3 FLT
AUTO FLIGHT AP OFF, REAC W/S DET FAULT, IAS DISCREPENCY , NAV ADR DISAGREE, ALTN LAW PROT LOST
it is noted that the turbulence strength had increased just before (at 15:09) this event when they entered the cloud layer, with a burnt smell in the cockpit, speed was reduced to Mach 0.80 (just above green dot), cabin crew warned, no ICE DETECTION alarm.
a few sec. later, the speed indication on the copilot PFD plunged from 280 Kts to 100 Kts in the red band during numerous sec. In the same time, on the CPT PFD, the airspeed rolled back 15 kts under the green dot (& displayed a speed trend of -50kts).
immediately followed by a Stall, Stall, Stall alarm... without the cricket sound, triggering a TOGA LK indication.
-at 15H11 : amber alarm F/CTL RUD TRV LIM FAULT
Since the speed trend was still of -50kts, the hand flying CPT initiated a slight descent and turn (to depart from the AWY route). A MAYDAY is issued by the copilot. The airspeed recovered at FL340, the A/THR was disengaged (to exit the TOGA LK state). The altitude being stabilized, the "unreliable airspeed" procedure was implemented. Anti ICE ENG & WING, PACKS FLOW set on HIGH and cross-checking between the airspeeds / altitude and the GPS ground speed / altitude + the winds data from OCTAVE. AP1 & A/THR reengaged. Descent at FL330 and MAYDAY cancelled. The crew joined the maintenance by satcom for a more throughout failure analysis and a PRIM/SEC reset was decided without results. An incoherence is found about the flap configuration between the QRH and the status (?).
Like in the other cases, the Pitot freezing & corrupted airspeeds event lasted between 3 and 5 mn. The crew set the weather radar on max sensibility for the rest of the flight (it was on CAL and did not detect anything suspect before the Pitot freezing).
Jeff
PS) -One of the differences between the AF 447 and all these cases with Pitot problems is the A/THR settings when the fault sequence began (engaged in the AF 447 case, off and N1 fixed for the turbulence penetration in the other cases). The visual clues: the Air Caraïbe case was in daylight, the AF 447 was a night flight (all in poor met conditions). I don't see any pilot refering the pre-stall buffeting indication in their in flight/post flight analyze of the stall alarm event in the safety reports.
The reasons why the Air Caraïbe crew is convinced that the stall aalrms are not justified are not explicitely stated in the report. Maybe it is linked to a question asked by a pilot to other pilots here.
-The speed trend on which the pilot based his decision about the stall alarm is completely artefactual/spurious: why this speed trend is still computed & displayed on the PFD during a corrupted airspeed event ? (Pitots FLR+ADR disagree). He probably also had in mind that they were just above the green dot just before the sudden sequence of FLRs.
-And in the same manner, why is the stall alarm still generated during a corrupted airspeed event ? Is it mandatory for the manufacturers that their planes have a functionnal stall/overspeed alarms in all circumstances ? (Airbus knows the risks and displays it on the ECAM "risks of undue stall warnings). An alarm plagued by false alarms is no more a valuable alarm, it is a danger. This danger can be further increased by the applicable procedures.
- we may have slightly different sequences of Pitot-static gradual failures, different timings for the different phases (before the fault isolation/detection by the automation, revertion to degraded modes, phase before the stall/overspeed alarms, after). Some will enable the crew to implement a part of the "unreliable airspeeds" proc. before the stall alarms may occur, other will not (AF 908). According to the sequence, the crew attention may be allocated differently on the failure analysis, procedures/check lists implementation, hand flight, cabin crew warning, etc...). I feel it would very useful to have a short-list of the indicators that may enable a crew to discriminate between a false and a justified stall alarms. How much time the cross-checking implemented by the AF 908 crew using OCTAVE can take ? Are there faster ways ? (when the fligh security is impacted). On the contrary, being able to know the "false friends" that you must avoid to rely on in such a case of unreliable airspeeds, seems equally interesting.

HazelNuts39

28th Jul 2009, 13:57

RE: Hyperveloce (#3969 p.199)
Is it mandatory for the manufacturers that their planes have a functionnal stall/overspeed alarms in all circumstances ? Systems whose functioning is required by the applicable regulations are subject to a safety analysis during the certification process. (See for example FAR 25.1309). The general principle is that there must be an acceptable relation between the calculated probability that a certain failure occurs and the effect of that failure on the safe continuation of flight.
regards,
HN39

Hyperveloce

28th Jul 2009, 15:19

RE: Hyperveloce (#3969 p.199)
The general principle is that there must be an acceptable relation between the calculated probability that a certain failure occurs and the effect of that failure on the safe continuation of flight.
I see. But we have:
1) an intrument or a device (can be a Pitot-Static system, a plane)
2) a signal/indicator monitoring the performance of 1)
3) relevant procedures when 2) is activated
4) crew training/reactions to 2), given 3) and their observation of 1)
and it seems that all the 4 contribute to the flight safety ? If the regulations only specify the first 2, are they sufficient to ensure a probability on the safe continuation of flight ? (How is the "acceptable relation" between 1)-2) & 3)-4) & the overall flight safety impact defined or evaluated ?). Are there specifications about false alarms rates in normal/degraded modes ?
Jeff

Mad (Flt) Scientist

28th Jul 2009, 16:21

I see. But we have:
1) an intrument or a device (can be a Pitot-Static system, a plane)
2) a signal/indicator monitoring the performance of 1)
3) relevant procedures when 2) is activated
4) crew training/reactions to 2), given 3) and their observation of 1)
and it seems that all the 4 contribute to the flight safety ? If the regulations only specify the first 2, are they sufficient to ensure a probability on the safe continuation of flight ? (How is the "acceptable relation" between 1)-2) & 3)-4) & the overall flight safety impact defined or evaluated ?). Are there specifications about false alarms rates in normal/degraded modes ?
Jeff
The regulations go a bit further than just requiring failure rates to be commensurate with the hazard.

The failure rate of systems (including their warning systems0 is as noted previously, covered by 25.1309, and specifically 25.1309(b)(1)and(2).

The provision of appropriate procedures is required per 25.1585(a)(2)and (3) for abnormal and emergency cases.

That the procedures provide "continued safe flight and landing" for the various failure cases is determined in accordance with various handling requirements (for example) with various precedents and guidance material concerning, say, degraded handling acceptable for such cases.

I suspect that, certainly at initial cert, the basic probability of total loss of the air data system was already so low that compliance was achieved without worrying about the procedures, and any procedure provided was above and beyond the basic cert requirements.

To answer the question about false alarms, a false warning is in itself a system failure and would be assessed like any other for its consequences versus the probability.

lomapaseo

28th Jul 2009, 16:37

I suspect that, certainly at initial cert, the basic probability of total loss of the air data system was already so low that compliance was achieved without worrying about the procedures, and any procedure provided was above and beyond the basic cert requirements.

That suspicion is worth examining in more detail

If true, it puts the aircraft outside of its presumed airworthiness standards under continued airworthiness and suggests that a product change to a more reliable system or a major change to other mitigation means is needed to continue safe operations in that fleet.

I was under the impression (could be wrong :) that the original design did presume a higher level of all-air-data system failures and as such adequate mitigation was presumed at the flight deck level.

Let's take another look at this.

edited due to dyslexia

Squawk_ident

28th Jul 2009, 21:30

Seats marked in orange on the seat map shown by the France2 coverage would be from what I could determine:

J/CL 2AJK 3K 4AK 7JK TTL 8
Y/CL 19F 20AJ 22D 24D 26BK 28BK || 29F 30D 31DF 32GK 33BJK 34AFGK 35BJ 36K 38DK 39F 40F 41D TTL 30
TTL 38
The last row in Y/CL is 42 (ABJK) on this aircraft/configuration.

Strangely the Gendarmerie considers that the registration number of the doomed aircraft was "FGZPC" i/o FGZCP. This mistake is repeated on all the covers visible in the TV report.

DrGitfinger

28th Jul 2009, 21:38

Apologies if this has already been covered:

Le Figaro - France : Sonde Pitot : un nouvel incident chez Air France (http://www.lefigaro.fr/actualite-france/2009/07/28/01016-20090728ARTFIG00440-sonde-pitot-un-nouvel-incident-chez-air-france-.php)

Le Figaro is reporting a pitot failure incident on an Air France A320 (flight 1905) on July 13 this year. It was equipped with the new Thales BA pitots which are meant to be more reliable. Incident only lasted a minute or so.
SNPL pilots' union may ask for the new Thales pitots to be replaced by Goodrich versions.

SaturnV

28th Jul 2009, 22:13

Of the 38 matches, these represent 6 of the 16 passengers in First, 11 of 61 passengers sitting over the wings between rows 7 and 28, and 21 in rows 29 back, predominately on the right side. With three crew members recovered, that leaves 9 or 10 passenger matches remaining. (The matches presume that every passenger was in his or her assigned seat.)

JD-EE

29th Jul 2009, 00:47

Hyper, you do realize that diagram is a really good argument for the plane hitting mostly flat and pretty much shattering tossing bits and pieces all over the place, don't you?

If it broke up in the air and spewed people from where it broke you'd see a different distribution, I believe. The broken fuselage with px still belted in probably would not hit hard enough to crack it again like an egg shell. And there'd likely be more px from either near the crack (both sides) or from where it finally broke up if it did. A fairly even distribution would not likely happen.

Yes, there are more from from the rear than from the front. And over the wings is somewhat lightly represented. The px from the front and rear argue for a complete breakup on inpact as the BEA suggested with the wing area being partially protected by the mass of the wings themselves.

If the px in those seats suffered compressed spines then the issue of how the plane came apart is "close" to settled. It had to have experienced a REALLY violent stop from a rather fast vertical fall. If the px had "flail" injuries but few if any spinal compressions from at least one area of the plane then it may have broken up at altitude.

Alas, none of this tells is WHY it got there. It is more data to fold in with "found here on date and time such and such, water currents, and 02:10:34 position report" data to find out what happened. Why and how are very likely FDR and CVR related questions. (I suspect both are needed to pin down precise reasons and sequences of events. CVR is probably more help than FDR.)

JD-EE

gfmb

29th Jul 2009, 06:19

This report suggests a short time similarity - except for the tragic outcome -with AF447:

Incident: Air France A320 enroute on Jul 13th 2009, unreliable airspeed for one minute (http://avherald.com/h?article=41d651ac&opt=256)

Referring to the last sentence in the report; does anybody know anything about the difference/s between Thales and Goodrich pitot sensors? And - are they of the same basic construction for A320 and A330?

/gfmb

Squawk_ident

29th Jul 2009, 07:43

"Lefigaro.fr" is reporting a new incident with A320 FCO-CDG as AF1905
( F-GFKJ?). This aircraft was equipped with Thalès pitot -BA serie (new model).
Crew experienced a loss of speed indication for about one minute.

AF management gas confirmed the incident.

Le Figaro - France : Sonde Pitot*: un nouvel incident chez Air France (http://www.lefigaro.fr/actualite-france/2009/07/28/01016-20090728ARTFIG00440-sonde-pitot-un-nouvel-incident-chez-air-france-.php)

..."And the report of the crew accessible on the Sentinel software from the company states again "a brutal loss of the indications speed and then a disappearance of anemometric information”. In other words, the pilot had no more informations on the speed of the plane and had to change to manual mode"...
In the same article it is reported that The SNPL (Syndicat National des Pilotes de Ligne) might call for a replacement of the entire AF Airbus fleet with Goodrich tubes.

plb1964

29th Jul 2009, 07:51

An Air France Airbus A320-200, registration F-GFKJ performing flight AF1905 from Rome Fiumicino (Italy) to Paris Charles de Gaulle (France), was enroute when all airspeed information as well other air data related indications were lost in the cockpit, autopilot and autothrust systems dropped offline. The crew continued manually until the indications returned about one minute later. The flight continued without further incident and landed safely at the Charles de Gaulle Airport at 20:35 local (18:35Z).

Weather satellite images show a well developed frontal system overhead France at 18:00Z.

Air France said, the airplane was already equipped with the modified pitot tubes (Thales BA type instead of the standard AA type). The maintenance ACARS messages received by Air France are similiar to those, that were received from flight AF-447 on June 1st, that crashed into the Atlantic Ocean. An investigation is underway.

The NTSB is investigating two similiar incidents, see Incident: Northwest A333 over East China Sea on Jun 23rd 2009, unreliable airspeed and Incident: TAM A332 enroute on May 21st 2009, unreliable airspeed and altimeter.

French pilot unions are querying similiarities between the crash, these incidents and this new incident and state, that if similiarities do exist, the pitot sensors must be changed to the rival products of Goodrich rather than Thales.

Metars:
LFPG 131930Z 20009KT 170V270 CAVOK 21/15 Q1011 NOSIG
LFPG 131900Z 19009KT CAVOK 21/15 Q1011 NOSIG
LFPG 131830Z VRB09G20KT 9999 FEW040 BKN066 BKN100 22/15 Q1010 NOSIG
LFPG 131800Z 20009KT 9999 FEW040 BKN066 22/14 Q1010 NOSIG
LFPG 131730Z 19011KT 170V260 9999 FEW040 BKN066 22/14 Q1011 NOSIG
LFPG 131700Z 19011KT 9999 FEW040 BKN066 BKN100 23/14 Q1010 NOSIG
LFPG 131630Z 20013KT 9999 FEW040 BKN066 BKN100 23/14 Q1011 NOSIG
LFPG 131600Z 18012KT 9999 FEW040 BKN066 BKN083 23/14 Q1011 NOSIG

wilyflier

29th Jul 2009, 09:02

post23.40 squawk ident july29 #3798......photos

I suppose the jacks all were attached to floating flying surfaces,but did this
recovery of the undercarriage indicate that a pretty large piece of wing or centresection survived in one piece?Can an isolated gear leg float by itself?

HazelNuts39

29th Jul 2009, 09:48

RE: Hyperveloce (#3971)

(How is the "acceptable relation" between 1)-2) & 3)-4) & the overall flight safety impact defined or evaluated ?).How it's done? Read Appendix A in this document (see for example page 86):

NTSB safety report no. SR-06/02
Safety Report on the Treatment of Safety-Critical Systems in Transport Airplanes

http://www.ntsb.gov/publictn/2006/SR0602.pdf

(Link originally provided by SPA83 in his post #3841 on page 193 (23-07-09), thank you SPA83)

Two quotes from the "Executive Summary":
The Safety Board recognizes that the findings in this report are presented during one of the safest periods in commercial aviation history and acknowledges that FAA’s certification process has contributed significantly to that level of safety. However, the Board notes that there is room for improvement. The report includes three recommendations in two areas.The second area focuses on the ongoing assessment of safety-critical systems throughout the life of the airplane. The Board concluded that a program must be in place, once the type certification process is completed, to ensure the ongoing assessment of risks to safety-critical systems. Such a program must recognize that ongoing decisions about design, operations, maintenance, and continued airworthiness must be done in light of operational data, service history, lessons learned, and new knowledge, for designs that are derivatives of previously certificated airplanes.regards,
HN39

Graybeard

29th Jul 2009, 11:22

A/B said quite some time ago (probably in this thread) that the BA probes were not offered as a solution to the icing of the AA probes. It was assumed by some that this was a weasel way of fixing the problem without warranty cost, and operators like AF proceeded to replace the AA probes with BA at their own expense.

Now, we see that A/B was honest: the BA probes are not the cure. It must be an aging or corrosion problem with Thales probes.

GB

Porker1

29th Jul 2009, 11:52

Subsequently it seems that the union representing the majority of the AF pilots have now definitively demanded that all Thales pitots in the AF fleet are replaced with the Goodrich ones that, and I quote, "have never been implicated in any reported incident".

Air France: les pilotes répudient les sondes Pitot fabriquées par Thales - Libération (http://www.liberation.fr/economie/0101582523-air-france-les-pilotes-repudient-les-sondes-pitot-fabriquees-par-thales)

The lawyers preparing the compensation claims for the AF447 accident must be rubbing their hands at all this technical prejudice.....

Hyperveloce

29th Jul 2009, 12:28

Yes GB, I also remember that the Pitot probe manufacturer warned that his new probe was not designed to withstand increased specifications about icing conditions. I also remember that the regulatory bodies said that the replacement of the Pitot probes was not mandatory precisely because they had not the guarantee that the new probes would solve the problem. I would understand this reasonning if there was only a unique Pitot manufacturer, but it appears that there is another brand of new Pitot probes which does not fail so frequently.

...and continued airworthiness must be done in light of operational data, service history, lessons learned, and new knowledge, for designs that are derivatives of previously certificated airplanes.

Ok HN39, this might be this part that was not fully implemented: the regulatory bodies state that Pitot problems do not impact the overall flight safety (hence the not mandatory replacement). The AF 447 flight may enable to reevaluate this statement about the safety impact, but given the previous two Air Caraïbe incidents, considering that a total airspeed deprievation, alternate law 2 & prot lost, false stall alarms, unsatisfactory "unreliable airspeeds" proc. poses no problem of flight safety sounds really weird.
Jeff
PS) It seems that Cathay Pacific's large Airbus fleet has not experienced any Pitot problem with their new Goodrich probes (designed to improve anti-icing performance).
PPS) some FDR/CVR specs (requirements of ED-56A)
- Impact Shock 3400g’s, 6.5 msec. duration (half-sine)
-Deep water immersion at a depth of 20000 feet for a period of 30 days (it took 2 month to locate the wreck and more than one year to recover the CVR for the flight SA 295, in the Indian ocean at 4900 m of depth )
http://www51.honeywell.com/aero/common/documents/Voice,_Data_-_Combined_Recording_Systems.pdf (http://www51.honeywell.com/aero/common/documents/Voice,_Data_-_Combined_Recording_Systems.pdf)

rgbrock1

29th Jul 2009, 12:50

I've searched this thread before posting and have not seen the following issue with the CVR and FDR addressed.
Is there a "crush depth" for both of these recorders? It is likely, but not certain, that the CVR and FDR are both lying on the ocean floor perhaps at a very great depth. Do the recorders have specifications as to a crush depth? And even if they were both "crushed" do to ocean depth pressure would that preclude being able to read the contents thereof?

SaturnV

29th Jul 2009, 13:39

rgbrock1, the recorders are supposed to survive submerged to a depth of 20,000 feet.

wes_wall

29th Jul 2009, 13:58

Le Figaro is reporting a pitot failure incident on an Air France A320 (flight 1905) on July 13 this year. It was equipped with the new Thales BA pitots

Another bit of luck? Lets hope that it continues, and that if any further events that they occur in daylight.

overthewing

29th Jul 2009, 14:23

Presumably other airlines use Thales probes? I wonder if any correlation has been made between Thales vs other makes and these temporary failures?

UNCTUOUS

29th Jul 2009, 17:43

So was it the air pressure transducers all along??

--------------------------------------------------------------------------------

Air France Pilots Report Speed Sensor Problems
July 28, 2009
An Air France flight from Rome to Paris earlier this month briefly lost its speed readings due to faulty sensors, pilots said on Tuesday, in the latest safety scare involving speed sensors.

Several problems with speed sensors, or pitot tubes, made by Thales have been reported since 2008, and investigators are looking to see if they played a role in last month's fatal crash of an Air France A330.

A spokesman for France's SNPL national pilot union, Erick Derivry, said the union would ask Air France to see whether the latest incident was similar to those previously reported.

If it was, the union would ask the airline to replace its Thales sensors on its Airbus fleet with models manufactured by Goodrich.

Air France replaced an earlier Thales model on its planes with a more recent version following the June crash of one of its Airbus A330s. All 228 people aboard died when the Rio de Janeiro to Paris flight crashed into the sea.

But the latest incident on July 13 occurred with a new model, the company said.

"This incident was caused by new sensors. It lasted a few seconds, with no consequence for the passengers, and an analysis is under way in cooperation with the manufacturers and investigators," an Air France spokeswoman said.

The SNPL spokesman said a calculator that converts pressure into a speed reading (transducer) might also have to be replaced.

In June, under pressure from another pilots' union after the crash, Air France changed all pitot tubes on its A330 and A340 planes, having already changed them on its A320s.

(Reuters)

JD-EE

29th Jul 2009, 18:28

Hyperveloce

I would understand this reasonning if there was only a unique Pitot manufacturer, but it appears that there is another brand of new Pitot probes which does not fail so frequently.

Numbers - I want to see real solid numbers with regards to flights in the same conditions that SEEM to nail the Thales probes. I'm prepared to believe they are a problem. I just want real, solid, numbers on which to base it.

JD-EE

JD-EE

29th Jul 2009, 18:33

UNCTUOUS

The SNPL spokesman said a calculator that converts pressure into a speed reading (transducer) might also have to be replaced.

It seems reasonable that different probe designs would have different calibration curves. It seems unreasonable, to me, that the probes do not include their own calibration function as they generate their digital output. This IS the 21st century now.

On the other paw, we are talking about a late 80s aircraft.

JD-EE

cwatters

29th Jul 2009, 19:10

Scientists are still learning a lot about water ice. It now seem that very small ice particles can melt at temperatures as low as -180C. Presumably therefore they can fuse together and refreeze.

How to make ice melt at -180 °C - physics-math - 24 July 2009 - New Scientist (http://www.newscientist.com/article/mg20327184.900-how-ice-can-melt-at-180-c.html)

Will Fraser

29th Jul 2009, 19:11

"It lasted a few seconds, with no consequence for the passengers...."

AF spokesperson

Both Thales are now involved, several carriers, and one Manufacturer.

By all means, take your time.

Will Fraser

29th Jul 2009, 19:14

cwatters

Your post could just as easily have appeared on the BA038 thread. It is also possible to freeze water at 500C. Not on this Planet, not outside the laboratory.

pax2908

30th Jul 2009, 07:11

kiwiandrew

30th Jul 2009, 07:47

Airbus to fund extra search for Air France black box | World | Reuters (http://in.reuters.com/article/worldNews/idINIndia-41421520090730)

PARIS (Reuters) - Airbus will help fund an extended search for flight recorders and debris of an Air France airliner that crashed into the Atlantic last month, a newspaper said on Thursday.

I wonder what the conspiracy theorists who have posted that Airbus doesnt want the recorders found have to say to this ? Let me guess , "Airbus knows exactly where the recorders are and will pay for someone to search somewhere else for 3 months at considerable expense so that it looks as though they want them found " ?

barrymah

30th Jul 2009, 08:22

"I won't repubilsh their article here as I don't have permission."

As someone who makes part of my living from publishing I applaud this attitude. The availability of the Internet is not an invitation to re-publish without acknowldgement or permission.

Bye, Barry

vapilot2004

30th Jul 2009, 08:24

Airbus Industries has every reason to find the data recorder and CVR. The causes of this crash if at all aircraft/design related must be discovered with haste. A willy-nilly approach to avoidance is but an invitation to future losses if we do not know the point(s) of failure that led to it.

Air France on the other hand faces the ambiguities of whether their crew acted imperfectly, if perhaps weather and the aircraft systems conspired together in an unwinding tapestry of fate with an undefined X-factor, typical in certain crashes of late, that will almost always be applied in the direction of the crew when it comes to blame.

ArthurBorges

30th Jul 2009, 08:27

TRANSLATION

"We undertake to support extension of search operatioins with substantial funding," says Airbus President Thomas Enders to La Tribune.

La Tribune says funding will be € 12 to 20 million to extend the blackbox search by three months. It will cover two or three surface vessels and one mini-submarine.

ORIGINAL

"Nous nous engageons à soutenir l'extension des recherches en apportant une contribution importante", déclare au quotidien le président du constructeur, Thomas Enders.
Cette contribution, selon La Tribune, oscille entre 12 et 20 millions d'euros pour des recherches prolongées de trois mois. Cela permettra de maintenir deux ou trois bateaux et un sous-marin de poche sur la zone du sinistre, précise le journal

This is a pickup by Reuters.

Pasted from <Airbus prêt à financer la recherche des boîtes noires de l'AF447 - Yahoo! Actualités (http://fr.news.yahoo.com/4/20090730/tts-france-bresil-airbus-ca02f96.html)>

syseng68k

30th Jul 2009, 09:07

Unreliable airspeed occurrences: does it happen more often now (e.g. past year), or merely the problem it is now getting more attention? If it does happen more often, why? Is it because some component(s) (Pt probe, transducer, etc) have degraded? Or can it be due to software changes? I mentioned this several weeks ago, suggesting that increased frequency of severe weather conditions may be taking the probes beyond their original time of certification design limits.

The system design should ensure that no set of redundant components can degrade to a single point of failure, yet this is exactly what appears to be happening in the case of the probes. For a function that is so critical in terms of other systems that depend on it's data, why has this problem not been fixed ?. An engineering design issue that needs only the will and resources to find a solution. ie: If there's not enough probe heat at limit, redesign with more effective heating, perhaps with better insulation on the outer surfaces to prevent heat loss. If the probes are corroding due to excessive heat on the ground, redesign the probe heat controller to prevent this. If the drain holes are blocking, redesign. If there is a need to make the drain holes bigger, correct for this in the adc lookup tables etc.

The crew may recover in most cases, but should never be placed in a situation where they need to if the problem can be engineered out. After reading this thread for several weeks now and getting a feel for the status quo, the apparent industry complacency about this issue just beggars belief, imnsho… :ugh:

Chris