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AF447 wreckage found

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AF447 wreckage found

Old 1st Jun 2011, 22:38
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spatial disorientation after a stall

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]Conclusions (Wikipedia) AF358

After the autopilot had been disengaged, the pilot flying increased engine thrust in reaction to a decrease in airspeed and a perception that the aircraft was sinking (spatial disorientation).
Very interesting your mention of the "spatial disorientation"

PS : But for your "AF bashing" it is not necessary ; AF has not to prove it knows how to operate planes since the 1930' ; and the Paris - Rio route is one of the oldest !
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Old 1st Jun 2011, 22:58
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Flight Plan

The AF447 flight plan on the Vasquez site clearly states destination is Charles De Gaul (LFPG). So we can debunk the Toulouse destination theory if that is a reliable facsimile.

Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data
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Old 1st Jun 2011, 23:37
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Barnyard Logic II

Lonewolf50
For Graybeard and about AoA Probes and indications
Graybeard, in re "better" AoA indicators. I'll suggest to you that the US Navy has been using one "better" (actually, I doubt it's any better) from before I started flying which functions reilably at airspeeds below 60 knots. (There is one on the T-34C Trainer that works as you describe ... a weather vane in the horizontal plane. See also AoA probes on various Navy jets).

I don't think it's the probe that's the issue, but a software decision on signal processing. You could do what you need to (no stall chirp on the ground) with a WoW switch (already have one on the bird, yes?) without artificially clipping the AoA signal when in flight.

Your comments, sir?
The real measure of AOA is degrees, not knots, of course, although everybody has been shouting for a Stall Warning below 60 knots, not a specific AOA.

I don't have the numbers, but it appears that onset of stall of the A330 at that MAC and flap is less than 20 degrees. The report shows AF447 achieved AOA in excess of 40 degrees, double the onset of stall. How much AOA does it need to measure, 90 degrees, 120 degrees? What's the point?

You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system. In fact there was no doubt a point in the zoom climb to stall that airspeed was near zero, and the AOA vanes would fall with gravity, probably showing a negative AOA.

Last edited by Graybeard; 1st Jun 2011 at 23:38. Reason: typo
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Old 2nd Jun 2011, 00:24
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Saturn,
The recent BEA note indicates that the PF briefed the PNF who had arrived at the cockpit that at some time before 1 h 59 min 32 s that logon with DAKAR had failed. (At least 21 minutes before estimated changeover from ATLANTICO to OCEANIC DAKAR which was at 2 h 20 at the TASIL waypoint.) LH507 (believed to be the flight with AMDAR) monitored 121.5 the entire flight and never heard any communication from AF447.

So CVR transcripts of any conversation on what they were seeing on their radar displays will be interesting.

I'll leave it to others to comment on jumping ahead on a frequency change 21+ minutes before one arrives at the boundaries of the FIR.
SaturnV,
The notification from ATLANTICO to DAKAR, (contrary to what happens now), was not automatically done from one ATC to the other at that time, once the CPDLC/ADS FANS system was not fully operational at that time. According to FANS procedures, one should try to notify/(log-on) between 10 to 40 minutes before reaching the boundary. Further, there are normally two HF radios on A330's. Therefore, it was common practice to call DAKAR, at least 10 minutes before reaching the boundary on HF2, while maintaining a SELCAL watch with ATLANTICO on HF1.

But I'm with you. I'm very curious on what CVR transcripts may bring to light.
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Old 2nd Jun 2011, 00:31
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Greybeard reminds us:

The AOA sensor is just a high priced vertical weathervane,
...but like the weathervane, shouldn't it too be statically balanced? And if so, why would it be unreliable below 60kt?

The balance weight would not need to be out in the airstream; it could be internal, behind the aircraft skin.

Just askin'.
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Old 2nd Jun 2011, 00:52
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Static Balance

Every AOA sensor I've seen on ground has been full stop down (neg AOA), which indicates no static balance. Don't believe I've ever seen one in flight.

I don't know a lot about AOA vanes, which I why I asked for someone really knowledgeable to speak up. You can peruse pix on airliners.net to get a good sample.
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Old 2nd Jun 2011, 01:23
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TheShadow:

Your prescience is unparalleled on this thread. We have only been provided with a sou-son of data but I believe you have nailed it. The THS situation was, I also believe, the lethal factor.

I thank you for your insights. As a current 330 pilot I will now be paying a lot more attention to its position. Especially if things ever get convoluted!

I wondered who you were. I see from a basic search you may be an ex-Viet chopper guy. How do you know about all this Airbus stuff? And especially in such detail? Please tell us more?

Your erudition is also commendable.

Please keep up this extraordinary work.
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Old 2nd Jun 2011, 02:03
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The aviation industry may have just found their spokesperson. Notice his emphasis on proper training and having AoA displayed . We should all be grateful he landed that plane safely on the Hudson and became a hero. It seems his time has come....

Sully: Training is key to avoiding air accidents - CBS News Video
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Old 2nd Jun 2011, 02:15
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You have to balance Stall Warnings in extremely rare events with far more common nuisance stall warnings, in order to maintain confidence in the system.
True. But where that balance point is located is a matter of opinion (i.e, professional judgement). People can and do disagree. We tend to fixate on the needs of the moment and forget there is two sides to the story. Then it just becomes a game of ping-pong where we respond to one crisis by going too far to the left and another crisis by going too far to the right. It seems to me that the better course of action over the long haul is to pick a point of balance, any point, and then train around it.

I'm not sympathetic to the cacophony that wants to tweak software systems in response to every accident. The human being with their hand on the stick has to bear some responsibility, as does the entire safety systems in the corporation. Who trained this crew? Who gave them their line checks? Who oversaw the sim sessions and designed the syllabuses.

Edit:

The aviation industry may have just found their spokesperson. Notice his emphasis on proper training and having AoA displayed . We should all be grateful he landed that plane safely on the Hudson and became a hero. It seems his time has come....
I think his time has been and gone. Everything he says sounds good in theory but he fails to mention the critical factor of money. Sims are not cheap, sim sessions are not cheap, practice lessons in the plane are not cheap. How much money is a society supposed to spend in order to save 200-300 lives. Naturally, if it's your life at stake you want them to spend a lot of money. But when it's the other guy, maybe not so much. Whether it is explicit or implicit there is always a cost/benefit analysis going on. Always.

Last edited by MountainBear; 2nd Jun 2011 at 02:29.
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Old 2nd Jun 2011, 02:16
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Gents,
a question - without intending to minimise the difficulty of dealing with a situation like this - espec when the EFIS appears to have been giving very confusing readings, in strong turbulence and a confused flight deck environment - and without intending to insult anyone's intelligence.
Does this model of Airbus have a standby analog artificial horizon on or near the centre of the panel as I have seen in some airliners?
In what would appear to have been a jetupset situation like this, could any experienced airline pilots viewing this thread comment on how feasible it would have been to simply set cruise power and then maintain a wings level, nose level attitude using an analog AH alone?
I know it's aviaition 101 if you go IMC in a light aircraft, but perhaps not in a heavy jet...
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Old 2nd Jun 2011, 02:29
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Artificial Horizon is an available selection, at extra cost, and was not optioned by AF for this a/c, as I understand it. I think it occupies the LHS of panel, top and left in P1's scan.
 
Old 2nd Jun 2011, 03:54
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AVIATE

Razoray,

Part of AVIATE means don't fly through CBs when you are close to the "coffin corner". Had they deviated, all this talk of this law and that law and how to handle a stall would not be taking place. That's the real cause of this crash, nothing else. If they were already close to the CC at 35,00 ft, think of what would happen when they went to 38,000 ft.
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Old 2nd Jun 2011, 04:11
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Fuel stop

Soaring the Skies,

The embarrassment of making a fuel stop should never get in the way of safety. Divert if necessary then stop somewhere for fuel. That's the Captains prerogative. The Captain is totally responsible for the safety of the aircraft and it's contents. They could have stopped in the Canaries or Lisbon for fuel.
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Old 2nd Jun 2011, 04:11
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Tartare

The pressure side of the EFIS was giving erroneous information the ATTITUDE part of the PFD was still working so they had a large Artificial Horizon to enable attitude to be flown.

Bearfoil

They had a standby AH it is called the ISIS, basically a smaller version of the PFD.
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Old 2nd Jun 2011, 04:43
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So - a hypothetical question - Bearing in mind the idiosyncrasies of swept wing aircraft in stalls... if such a jet is in a fully developed stall, applying power and then using the AH/EFIS to obtain a wings level, nose level attitude would arrest the stall?
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Old 2nd Jun 2011, 05:24
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So - a hypothetical question - Bearing in mind the idiosyncrasies of swept wing aircraft in stalls... if such a jet is in a fully developed stall, applying power and then using the AH/EFIS to obtain a wings level, nose level attitude would arrest the stall?
Not without a big afterburner.

Too much induced drag. Reduce AOA first, accelerate, and fly happily ever after.

Try to power out of it and everyone will be shaking their head at your airmanship as they attend the funeral.
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Old 2nd Jun 2011, 05:29
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Alternate destinations

xcitation:

The BEA Interim Report stated:

1.17.1.3 Preparation of flight AF447 on 31 May 2009
Preparation of the flight by the central flight study service
The flight was prepared between 15 h 28 and 18 h 59. Paris Orly was given as the alternate airport at destination. Given the estimated load of 37.8 t, the dossier included a main flight plan at a standard Mach of M 0.82 with an ETF at Bordeaux Mérignac with alternate at Toulouse Blagnac as well as two additional direct flight plans, one at Mach 0.82 and the other at a "slower Mach", i.e. M 0.81. A summary table of the loads offered enabled the crew to make the choice of the definitive flight plan from among these three options.

The full report is at http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf
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Old 2nd Jun 2011, 05:55
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Lack of Stall Warning

To have a design where blockage of the pitots not only loses airspeed data but also (because it now shows speed is less than 60kts regardless of the truth) disables the stall warning strikes me as unwise.
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Old 2nd Jun 2011, 05:59
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Flight Plan

xcitation:

The BEA Interim Report stated:

1.17.1.3 Preparation of flight AF447 on 31 May 2009
Preparation of the flight by the central flight study service
The flight was prepared between 15 h 28 and 18 h 59. Paris Orly was given as the alternate airport at destination. Given the estimated load of 37.8 t, the dossier included a main flight plan at a standard Mach of M 0.82 with an ETF at Bordeaux Mérignac with alternate at Toulouse Blagnac as well as two additional direct flight plans, one at Mach 0.82 and the other at a "slower Mach", i.e. M 0.81. A summary table of the loads offered enabled the crew to make the choice of the definitive flight plan from among these three options.

The report is available at: http://www.bea.aero/docspa/2009/f-cp...90601e1.en.pdf
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Old 2nd Jun 2011, 06:30
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Two questions I could not find the answer to in this thread (bear with me if I overlooked them):

1. auto-trim moved the THS to up 13° while the PF was pulling up -- was the auto-trim movement a consequence of the PF's pulling up?

2. would a full down sidestick have had the authority to overcome the full up THS later on?
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