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AF447

Old 3rd Jul 2009, 23:19
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In the absence of information another possibility? It is easier to assess the things that data suggest, especially when the alternative would be to impugn or call into question the skill of the crew, and that without data.

It is why I wanted there to be no Horizon on the panel, with it, one assumes there was a way out. I have been borne by winds that treated me and the a/c as if I was a feather, and landed white as a sheet. I resist the thought the crew may have entered a bad one, I know the feeling. Hope this isn't histrionic.

Will
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Old 3rd Jul 2009, 23:55
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good question..

marsk

The technology is clearly there so if cost is not an issue, what is preventing airline flight crews from having access to these data?
fresh sat charts in the cockpit ...

well, honestly have no idea??

you would not even need any big expensive "certified" installations, just take your lap top in the cockpit, most modern airliners have high speed data internet access via satcom, here you go...

beats me why it's obviously not yet the norm..??

but I am sure, nobody will leave home without it a couple of years from now..
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Old 4th Jul 2009, 00:17
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Using the Best Wx Radar Would Help

The newest Wx radars from Collins and Honeywell do automatic tilt and scan, and can see when the plane is headed into dangerous Wx. All the designers would have to do is to engage the Windshear Warning light when storm entry is imminent, to be sure the pilot has not turned down the intensity on his display to where he can't see what's coming, as related by ekLawyer in a prior post here.

Info on these radars is in Techlog.

Unfortunately, airlines have the frugal habit of buying only systems that have been mandated, and so 40-50 year old radars are still flying in revenue service.

It would be nice to know what system AF is flying on their A3xx fleets. They might be flying transceivers that are only 25-30 year old technology, as those meet the minimum requirement, and hence are basic fit on new planes.

GB
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Old 4th Jul 2009, 01:30
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Graybeard, from the report

Air France Airbus A330 aircraft are equipped with the Collins WXR700X radar. The radar image is presented on the NDs superimposed on the other information. It can detect precipitations in liquid form greater than 1 mm/h as well as wet hail. Thus, cloud systems made up of drops of water starting from a certain size can be observed but the radar cannot detect dry particles of ice, hail or snow with a diameter less than three centimetres.

In use, the radar beam has a narrow aperture angle of 3.4, which means that it is necessary to adjust the TILT (angle between the horizontal and the middle of the beam) accurately, in particular according to the maximum range selected at the ND (RANGE): 160 NM for look ahead, 80 NM for avoidance.
The GAIN adjustment (amplification of the return signal) is normally "calibrated" (in the CAL position) to prevent saturation. However, a manual selection can be made.

A turbulence detection function (for the zones of precipitations in liquid form) is available (in the WX+T or TURB position) in a radius of 40 NM, whatever the RANGE chosen at the ND.

When cruising above 20,000 ft, a slightly downwards adjustment of the TILT is recommended so that the ground echoes only appear on the ND at the limits of the furthest range markers.
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Old 4th Jul 2009, 01:34
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p51guy, one co-pilot had 4,500 hours on type, >3x more hours on type than the captain. The other co-pilot had 800 hours on type. Hours are approximate.
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Old 4th Jul 2009, 02:46
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CB scenario

I am following this thread like the first A447 Thread from the very beginning. I am amazed how this speculation of entering a "monster CB" is beeing posted in a nearly constant frequence. Untill now there is no evidence for this.

I have seen other maps showing A447 as already outside the weather at 0214UTC. As far as I have seen no mention to entering a CB has been written in the BEA report.

With a difference of about 20 minutes LH507 did fly the same AWY and only diverted by 10NM, if I remember well. Many of you were claiming, that this 'monster CB' would have to be avoided by a lot more.

I do belive only the DFDR could tell us that part of the story.


I personally saw what hapened to the horizontal stabilizer. I can imagine that the airbus 330 might not be quite as robust.

I really do have a problem with statements like this. I would not think we are comparing planes here. Are you aerospace engineer to have such a strong oppinion about the structural strenght of the A330's tailplane?

You may delete this, but I had to write this.......
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Old 4th Jul 2009, 05:08
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Flyinheavy CB scenario

--------------------------------------------------------------------------------
I am following this thread like the first A447 Thread from the very beginning. I am amazed how this speculation of entering a "monster CB" is beeing posted in a nearly constant frequence. Untill now there is no evidence for this.

I have seen other maps showing A447 as already outside the weather at 0214UTC. As far as I have seen no mention to entering a CB has been written in the BEA report.

With a difference of about 20 minutes LH507 did fly the same AWY and only diverted by 10NM, if I remember well. Many of you were claiming, that this 'monster CB' would have to be avoided by a lot more.

I do belive only the DFDR could tell us that part of the story.
What are you talking about? Who says it would have to be a "Monster CB" to cause a jet upset for a high and heavy aircraft? 35000' is barely chest-high on an average CB, and moderate to severe turbulence can and does exist 5000' above a developing one, well in the clear of any visible cloud water vapor, and therefore even further above tops calculated by radar returns.

Every CB is a "monster" when it comes to potentially wreaking havoc with aerodynamics and air data. A 10-mile diversion is still a diversion. With developing CBs commonly having growth rates between 5'000 and 10,000 fpm (as measured by water droplets, which lag) a 20 minute difference in a convective, dynamic area can mean the difference betweeen safely transiting the area and having absolutely nowhere to go.

Furthermore, you don't have to be inside the contouring returns shown on airborne radar to experience localized areas of moderate to severe turbulence due to not only vertical, but also horizontal shearing in such a dynamic area, and anyone flying around them enough knows this. Developing cells, which often produce the worse updraft/turbulence, frequently offer little radar return at all compared to mature or dissipating cells nearby and have the fewest visual cues (like frequency of lightning) if its night or when the cells are obscured/imbedded.

The same goes for sudden and transitory temp increases aloft in these areas with such convective activity. Put the wrong combination of turbulence and temp together when you're high and heavy with narrow buffet margins/low performance/degraded maneuvering ability as limited by load factor, and the can of worms can quickly be well-opened.

Like someone else wrote..Occam's Razor. You can say there's "no evidence" for this yet jet upset is a very real thing with very real incidents and/or accidents, and the heightened potential for a high and heavy aircraft in an area of severe weather experiencing it is the 1,000 pound gorilla hanging over this event.

Otherwise, you accept that a sudden instrument or mechanical failure just happened to occur at that place and time (in the area of convective activity), was of a type that went around all engineering redundancies, and so sudden and catastrophic that the crew couldn't even transmit a Mayday. To believe that you have to ignore the 1,000 pound gorilla outside the window, and even though nobody makes mystery movies or CSI episodes about the obvious, it's still the high probablity reality compared to some obscure, one-in-a-zillion chance failure.

Last edited by AMF; 4th Jul 2009 at 06:54.
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Old 4th Jul 2009, 05:23
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Flyinheavy wrote:
I am following this thread like the first A447 Thread from the very beginning. I am amazed how this speculation of entering a "monster CB" is beeing posted in a nearly constant frequence. Untill now there is no evidence for this.

I have seen other maps showing A447 as already outside the weather at 0214UTC. As far as I have seen no mention to entering a CB has been written in the BEA report.

...
I would be careful with using "other maps" - or in fact any maps at all - when you try to pinpoint exactly where the plane was with respect to the weather.

The time resolution of the imagery from the two primary satellites covering this area is 15 minutes for one of them (Meteosat-9), 30 minutes for the other (GOES-E). However, the nominal time for the images needs to be taken with a grain of salt. The reason is that satellite imagers are not snapshot cameras but actually use almost the whole 15 (or 30) minute period to acquire their images. I won't go into the details of all the possible scan patterns here, but the point is that the instrument looks at different regions within the overall image region at different instants during the image acquisition period.

So unless you have intimate knowledge of the file naming convention and the data acquisition pattern of the particular imager, you won't know exactly at what time the pixels you see near the last reported position of AF447 in for instance the 2:00 UTC image were really obtained. The offset between the time given on the "map" and the time of the A/C report could in the worst case be up to 15 (or 30) minutes. In terms of horizontal travel distance I'm guessing this could be anywhere in the vicinity of 100 to 120 NM depending on wind speed and direction - and even half of that could make a big difference with respect to being outside the weather or not.
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Old 4th Jul 2009, 05:42
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marsk

I agree and it isn't possible to 'shade' the last position relative to the red. Emphasizing or minimizing weather makes no sense. For me the flight and some very bad wx were in the same place at the 'same' time. "Having gotten through the worst" can mean absolutely anything. 'In what condition?' 'Is the position and the perimeter of the wx 'accurate'? 'Weather related' is absolutely the least value one might claim here.

Robert

I do think BEA have an attitude. I also think it is to be expected. The history says authorities put their heads together and share. The autopsy prohibition was harsh, to be honest. When the exact position of debris and pathologies are in, I believe BEA will backtrack, but they have a built in fallback, they weren't privy to all information. Ever CYA.
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Old 4th Jul 2009, 07:56
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the plane may have even flatly spun
An airliner can not spin flatly. Even a normal spin is very unlikely. It's more of a spiral.
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Old 4th Jul 2009, 09:58
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Just a thought from a retired Boeing pilot.

If the pitot tubes were blocked what is the effect on the actuation of the rudder, in particular if the ASI was indicating too low a speed would the rudder accept higher rudder pedal inputs than would otherwise be the case?
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Old 4th Jul 2009, 11:18
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>I do believe the French are trying to spin this,
quite probable
>and the US media is falling for it.
Possibly.

The interim report suggests some deep stall/flat spin situation that was entered due to some combination of weather, weight and balance, erroneous speed information. This slammed onto the water with high vertical velocity but little if any forward motion is said to be supported by the concave failure of the fuselage and the compressive failure of vertical structural members.

Are you able to list the counter-vailing indications and then list whether these indications are based on unsupported news reports or are more factually supported by direct observations.

Failure to inflate a life vest can be attributed to a high velocity vertical impact, a horizontal impact, disorientation due to stress, a conscious desire due to clear-headed decision, etc. Multiple failures to inflate a life vest are consistent with the interim report's views, but hardly substantial evidence of anything.
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Old 4th Jul 2009, 11:20
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Robert Campbell,

I'm having a hard time accepting the BEA report considering the forensic evidence. No clothing, Pink/magenta coloring of teeth, and other information from the Brazilians.
The BEA did not use any forensic evidence, as it seems they did not have them.

Last edited by JuggleDan; 15th Jul 2009 at 07:32.
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Old 4th Jul 2009, 12:01
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Dani

An airliner can not spin flatly. Even a normal spin is very unlikely. It's more of a spiral.
Upon what evidence do you base that statement?
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Old 4th Jul 2009, 12:55
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.. and despite of all this theory the flight crew sat back and said utterly nothing to anyone for some minutes, oh what a tangled web the authorities weave ..... Windy
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Old 4th Jul 2009, 13:02
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Wx deviations ?

Precise calculations using the last ACARS position message coordinates (as reported by BEA) show that the crosstrack error (XTK) was 2.95 nm left of UN873 centerline.

Examination of the messages reception times and precedence, assuming equal transmission times, exclude the possibility that the a/c was on track and on course when the AP disconnected.

This can neither be explained by assuming they were using a tactical route offset since these offsets are only allowed right of track.

Hence, I tend to believe there is a strong clue that weather deviations had been in progress when the first cockpit alarms occured.
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Old 4th Jul 2009, 13:43
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A good question 320 Driver, especially as an inadvertantly entered flat spin is about the only thing that could bring the aircraft to where it ended up at the minimal rate of descent required to produce the evidence found to date.

In other words, a flat spin is the simplest answer that fits the evidence as we know it.

I don't doubt that modern aircraft are supposed to be spin resistant and have all sorts of ways to prevent getting to a stall, but we all know strange things happen in the vertical and horizontal movements in CB buildups and it is not difficult to imaging how a storm could take over and induce a high angle of attack, perhaps yaw, the crew lose control and a flat spin result.

I wonder if either of the crew on duty had any spin recovery training at all? It used to be a requirement for a Private Pilot license, but I hear that is no longer so, perhaps because a spin is an out of control manoeuvre and training is all about control. Equally, who would have recognized a flat spin anyway - would the instruments tell you? How would today's AHRS electronic instrument sensors translate the forces of a spin? It used to be that the only dependable clues were the slip indicator and the rate of turn indicator (turn & bank) and airspeed...

I should add that a flat spin produces an extreme rate of yaw as opposed to a "normal" spin which might make one wonder about the Vertical Stabilizer and that in a spin, at least one wing is stalled, and the two wings are operating at very different angles of attack.

I could go on, but would not want to be distracting by throwing too much aerodynamic fact into the frey.
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Old 4th Jul 2009, 13:44
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One of the Satellite plots I saw here showed them flying through the last bit of the storm in what could be interpreted as a hook, the classic signature of a tornado.

I thought also one of the other flights around that time had flown a left offset. Not so?

GB

Last edited by Graybeard; 4th Jul 2009 at 14:09. Reason: Substitute Satellite for Radar
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Old 4th Jul 2009, 13:48
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GB

at least they saw something they did not like and sought to avoid it?
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Old 4th Jul 2009, 13:53
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Originally Posted by Graybeard
One of the radar plots I saw here showed them flying through the last bit of the storm i
- let's get this straight one more time! You have NOT seen ANY 'radar plots' becuase there was no 'radar'. You have seen the last ACARS reported position superimposed on satellite images of upper cloud structure and GUESTIMATED flight path from then on. No one, including BEA, knows whether they were avoiding weather or not.
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