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AF447

Old 9th Jun 2009, 21:31
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curious.....do the A330s have AOA vanes?

If so, do they have AOA indicators on the pilot's instrumentation?

If so, does the data get interpreted by the ADC, and then transmitted/displayed on the indicator? or another means?

Thanks, KC135777

ps...sorry if this has been discussed already.....it's just too long to go through.
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Old 9th Jun 2009, 21:32
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Originally posted by sumi (reply 940)

Static dischargers are here to discharge static electricity, and when you get a lightning strike (can be anywhere on the fuselage, sometimes one or more "burn away", that's what they are installed for.
They are not installed for that purpose -

Airbus MM -
During flight the aircraft can become charged with static electricity. If the discharge of this static electricity is not controlled, it can cause interference in the communications and navigation systems. Static dischargers are installed on the aircraft to decrease the interference.

Boeing MM
Static dischargers are installed on the airplane to reduce radio receiver interference. This interference is caused by a corona discharge emitted from the airplane surfaces as a result of precipitation static and engine charging. Precipitation static results from an electric charge accumulated by the airplane striking charged air and moisture particles.

Static usually discharges at the wing and tail extremities and is coupled into the radio receiver antennas. The static dischargers are designed to discharge the static at points which are a critical length away from the wing and tail extremities where there is little or no coupling of the static into the radio receiver antennas.
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Old 9th Jun 2009, 21:35
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Vertical Stabilizer

Transition from air density at sea level to the density of salt water results in an increase of the mechanical leverage on the VS by a factor of 742.

Basic photographic evidence seen so far points to a clean parting from the airframe structure on the forward end of the VS and compression damage on the aft end, consistent with a high speed entry of the a/c.

mm43
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Old 9th Jun 2009, 21:59
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Interesting that the shot of the tail being hoisted from the ocean shows quite clearly 2 white box structures attached to the lugs. There should be three of these, but I can't tell from the photos if it's the fore or aft one that's missing.
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Old 9th Jun 2009, 22:07
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Originally Posted by capeverde2008
I feel that this thread may need a re-focus. Many of the comments seem to be bogged-down with minutiae....

Why would an experienced crew venture (with presumably expertise and w/x radar into a 'no-go' w/x storm CB soup such as this?).

I was trained to avoid this sort of weather by many miles. Experience taught me via various incidents that 20nm (min. trained) avoidance from CB tropical should actually be 100nm avoidance.....Full Stop! AAAC (Avoid at all costs).

If fuel is a worry; divert/turn back.

The weather indicated and discussed fully in all manner of prior posts was not; repeat NOT an area where any passenger aircraft should even have attempted to go anywhere near. Full Stop!

There is no proof that they went anywhere near a CB. Only speculation based on their planned route. They could have deviated a hundred miles around the nasty weather then crashed as they were returning to course.

Other crews transited that same area and there is no reason to expect that AF447 would have any trouble on the same route.

Be patient and deal with the known facts.
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Old 9th Jun 2009, 22:16
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Bighitdh

"There should be three of these, but I can't tell from the photos if it's the fore or aft one that's missing."
It is the fore part which is missing. The middle and aft lugs seem to be there and the bolts still in place.
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Old 9th Jun 2009, 22:18
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A detail of the "boxes" referenced earlier. Given access to the AMM, I suspect these are the middle and aft attach points for the vertical stabilizer. In fact, one can observe a hole where the front attach point would be - we have seen this kind of failure mode in the AA587 lugs.

These structures attached to the VS would be within the tail structure itself, further attached to the fuselage structure. The "ears" and "lugs" with which some are familiar here from the AA587 accident photographs can be clearly seen attached to these box structures, except the front one, I surmise.

The "ears" which form a part of the CFRP structure of the VS remain intact. Whatever separated the VS from the tail structure had to be strong enough to tear this entire structure away from the fuselage section itself. We still do not know whether the main loads were lateral or fore/aft.


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Old 9th Jun 2009, 22:21
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But why did the following IB aircraft divert 56kms to avoid the same storm?

Don't shoot the messenger, it's from the Spanish press three days ago,

Brgds
SB03
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Old 9th Jun 2009, 22:22
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TvB, PJ2,

Thanks for the clarification, that's what I suspected.

One would have to assume if the tail did part company with rest of the airframe while in flight, this would have created one hell of a hole.

As far as I am aware, all of these lugs are aft of the pressure bulkhead?
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Old 9th Jun 2009, 22:25
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Lugs and separation

BigHitDH!

affirm. they are aft the rear pressure bulkhead which - I believe with the new A330's is from composites too, such as the tailcone and tail section... Pls. correct me if I'm wrong.
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Old 9th Jun 2009, 22:28
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moderators, your call, don't know if this is acceptable info

The crewed submersible that will be used:
Nautile

The remotely operated vehicle that will be used:
Victor 6000

The researcher who answered some questions about this equipment, detection ranges, etc.
Air France 447 | Deep Sea News
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Old 9th Jun 2009, 22:28
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scarebus03
But why did the following IB aircraft divert 56kms to avoid the same storm?

BS! You don't know what information was available to the AF crew, or their circunstances!

Is good that IB avoided this WX, let's find out why AF didn't and whether this had an impact on the outcome.

Wait for the FDR\CVR , until them we should all pay respect to our colleagues who ended up in the ocean.
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Old 9th Jun 2009, 22:31
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Thanks TvB.

Scarebus,

But why did the following IB aircraft divert 56kms to avoid the same storm?

Don't shoot the messenger, it's from the Spanish press three days ago,
I'll avoid mentioning the loaded name...

There is no evidence to suggest that they didn't divert around weather. Their track may be vastly different from another aircraft 30 mins ahead/behind, the weather that night was clearly very dynamic and changing.
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Old 9th Jun 2009, 22:33
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BHD;
As far as I am aware, all of these lugs are aft of the pressure bulkhead?
Yes, well aft. This tells us nothing of the condition of the pressure bulkhead but permits some thought only, towards the rest of the structure ahead of the VS to the area overhead the pressure bulkhead. Because we cannot know about the rest of the structure, nor does this tell us nothing about the DFDR/CVR location or that it remained fastened to the structure.

What is on my mind I will now confess, is, what is the nature of the forces capable of doing this kind of damage? I find it difficult to accept that any rudder deflection in and of itself, could do this. Such forces may and will be calculated as a matter of engineering sleuthing as can the mode of failure through the aforementioned tell-tale marks, bent/torn metal, etc so we can know at least in terms of "foot-pounds" what it takes to uproot the VS thus.
this would have created one hell of a hole.
Yes - an examination of this area either by drawings or physical inspection of other 330's may tell us what else "left" with the VS, pulled by piping/cabling/wiring/ancilliary structure etc - pure conjecture but at least "reading" the trace.
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Old 9th Jun 2009, 22:40
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Força Aérea Brasileira is reporting a max distance of 85km between retrieved bodies. 46km radius (92km max distance) for 'large piece' debris.

I'm no expert in ocean currents...but that seems pretty far apart for an intact water entry...











(edited to add images)

Last edited by DorianB; 9th Jun 2009 at 22:51.
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Old 9th Jun 2009, 22:44
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this is probably a noise post.. but..

AF447 found itself in a certain space and time - and we need to understand the information and decisions that led to that space and time.. and what the conditions were at that space and time.

AF447, craft and crew, then had to deal with what they were dealt - and we need to understand what both did, what the results were, and why.

That's what needs to happen for the future of aviation and closure for the deceased. The rest is fluff.

Pilots don't intentionally do 'stupid' things, engineers don't intentionally design 'fragile' aircraft, and companies don't intentionally sell 'fragile' aircraft... The crew was experienced, the aircraft and the airline have good records. Let's back off on the character assassinations and pet theories and try to understand what clues we have.

As you were,
...tom
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Old 9th Jun 2009, 22:44
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Here's my thoughts on the photographic evidence. The forward mount of the VS appears to be missing and the aft mount appears to have torn away the supporting structure within the fuselage. The forward mount may have failed (either in controlled flight through turbulance or during the uncontrolled decent) tilting the VS rearwards (causing the damage to the lower part of the rudder on contact with the top of the APU bay). The VS would then be ripped from the aft mount area and rather like a sycamore seed falling from a tree, gently (reletively speaking) 'helecoptered' it's way to earth. This would account for the small amount of damage to the VS/rudder structure.
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Old 9th Jun 2009, 22:52
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We still do not know whether the main loads were lateral or fore/aft.
There is a major difference between this damage and AA587, all of the composite tabs on the vertical failed. Here, most of the attachment fittings, I would guess both sides, departed from the empennage, with some cross-over structure. And the crossover structure is sans empannage skin. Also, the rudder on AA587 was substantially damaged and removed from the vertical. Were the vertical attachment tabs redesigned to be stronger after the AA587 accident.

If the recovery ships rushed to the site of the first body recovery, then this would imply the vertical was in the same general area. (There are some maps on the Brazil site, but couldn't bring them up.)

Can visualize a case of inverted entry into the water where the vertical sliced through the surface, and the empennage structure was ripped away from the submerged vertical.

We need a structural engineer to chime in.
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Old 9th Jun 2009, 23:02
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PJ2

Fairly certain I see three attach/systems. the forward hole (missing the pin) is 'shading' a bulkhead cap similar to the most aft structure. All three towers seem present, though what would be the port side of the forward carriage is in darkness. The fairing at the emp/VS mate is gone, uncovering the primer in the shape of the fillet. (That may help some locate the assembly in the above picture of the a/c)

??

Last edited by Will Fraser; 9th Jun 2009 at 23:16.
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Old 9th Jun 2009, 23:03
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PJ2,

an examination of this area either by drawings or physical inspection of other 330's may tell us what else "left" with the VS, pulled by piping/cabling/wiring/ancilliary structure etc - pure conjecture but at least "reading" the trace.
Agreed. It would be a reasonable assumption that disruption of the airframe at this scale and location would have some impact on the structure of the THS also. In fact, could those white box structures be directly connected to the spar structure of the THS. Any A330/340 mechanics care to offer an opinion? PJ2, you appear to have access to the A330 AMM, is there any info in there?
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