Dfdr & Cvr...
 

Dani
The assertiveness of your statements regarding this accident seem to imply that at this stage of the investigations you have a certain background knowledge and/or other AAIB related skills and experience. E.g. elaborating on the deceleration behavior of “an object”, e.g. “an aircraft”, on water compared to wet/humid soil should incorporate knowledge about Newtonian liquids, i.e. water, compared to the viscous behavior of wet/humid soil with a potential non-linear behavior. While studying your public profile, your non-tech skills seem to be excellent but it lacks of hard core tech skills.
Now an airline pilot, having spent myself 9 years at university before, earning mechanical engineering degrees with specialization in structural and aerospace engineering plus 10 years of experience in said industries do not put myself into the position to issue such statements based on pictures, youtube videos and other media. Media items are certainly an intrinsic part of an AAIB investigation but the hard facts are on those disks and they will tell us the true story. This is a professional pilots network and not a newspaper.
FI

Hot-and-high, thank you so much for your informative post. I agree with you completly. When you talk about a stalled aircraft then it implies that the aircraft as a whole stalled, not only parts of the wing or a stabilizer. That's why I say it's completly nonsense to talk of a stalled plane. You can stall an aircraft in any speed (even at cruising speed).

So we are coming to the point of "high ROD". Of course it must have been higher than normal (so the passenger tell us). But it cannot be really high, otherwise there wouldn't be any passenger left to explain us. I stay with the version that this was a relative soft landing.

Rainboe, the tail hit the ground at a relatively early stage of the crash landing. Granted. That doesn't mean that it was a "tail strike" landing and it's associated low speed. It could also stem from the fact that during touchdown, the main gears where burrying themselves into the soft ground. btw we don't even know if the gear was out (although they most probably where). Good pilots also know that during certification flights, aircraft have to touch the ground with the tail and still able to fly (minimum unstick speed tests). And last but not least: The spot where the tailplane lies is most probably not the point of first impact into the ground, the traces must have started before - the landing "roll" was even longer than appears from the wreackage location.

I'm not here to discuss the reason for the accident. We simple cannot discuss it here because we have no clue. I just started to take part in the thread because some obvious facts are disregarded.

Flare-idle, my knowledge comes from the intensive lecture of accident bulletins and visits of actual crash sites. It is relatively easy to tell the ROD by watching the wreckage. Please compare similar accidents and look at aircraft that really were "falling from the skies", stalled or flew into terrain. Good luck.

So, please, I'm still accepting bets...

Fuel temperature a problem after 3 hours flight?????

Rubbish.

I know that the engines don't show as much as damage as they could, but I find interesting that at least the right engine stoped in a very similar orientation as the plane. With the wide opening to the front. Maybe its is only coincidence, but I think it is odd after travellling dozens of meters (there is some picture taken from the highway, depicting apparently the engine going forwards and leaving a dust trace), through soft ground. Could it be due to the gyroscopic effect?, then the blades may have beeing turning.

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Nick14 22/10/08
 

SaysFour months ago nick you were a wannabee.

My guess is that you have at least 400 hrs in your log book now.

Do us a favour and just read the posts rather than giving it the experienced 738 pilot routine.

The the length of a complete 737-800 is about 39 meters long. What do you estimate the stopping distance to be?

I say 60 meters....

http://i2.photobucket.com/albums/y17...ine/Crash3.jpg

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I would like to put the Investigation Board's chairman Mr van Vollenhoven's remarks into perspective.

He is NOT an investigator nor an aviation professional.
He is a member of the royal family (married to the Queen's sister) and somehow it seems to be a honorary job.
It also seems to me that he enjoys being in the spotlight.
Nevertheless he has done it for quite some time and is not much criticized.

Still I think his remarks are premature and more born from a desire to answer questions then from known facts.


Another thing today mentioned on interviews with survivors on dutch TV: they are already contacted by American (sic!) lawyers to be "represented".:yuk::yuk::yuk::yuk:

Correct! We cannot discuss the cause of the accident because we don't have the evidence.

I just want some posters to stop ludicrous assumptions and allegations that clearly are disproved by the pictures.

Dani

Dani, agreed your point about a “stalled plane” – I now understand what you were saying - sorry if I was a bit micky-mouse in my post but I guess it explains it for anyone who may be interested! :\

Fireflybob,

Fully agreed - for a wing of constant profile across the span! And, after the Critical Angle is reached, the reduction in Cl (or Lift) is rapid. Apologies for the nurdish aerodynamics coming up. All I was trying to explain was that the angle of incidence of the wing root is designed to be greater than the angle of incidence at the wingtips. This is to force a stall to develop (ie Critical Angle to be reached) at the wing roots first as the Pitch Angle of the aircraft progressively increases. For a given Pitch Angle, AOA will progressively reduce towards the wingtips. Therefore, simplistically, half way to a fully stalled wing, the tips will be probably be unstalled, mid span will be partially stalled, and the wing roots, fully stalled. The net result is a partially stalled wing! This was to explain why Dani’s implied on/off stall description does not hold water - but I now understand what he was getting at! :O

Obviously, the rate of Washout determines the rate of progress of the stall outboard as Pitch Angle increases – and, of course, I use Pitch Angle loosely as, clearly, with washout, AOA varies across the wingspan for any given Pitch Angle. While PA and AOA are not the same, if you include Relative Air Flow, they are linked. As I said, once the CA is reached, the reduction in lift is very rapid while drag continues to increase, but CA is reached at the wing root first and then spreads outboard as Pitch Angle increases (assuming constant RAF!!!)

Do I qualify for a Nerd Award? Fireflybob, I hope that clarifies(!!!) what I was trying to say – clearly, rather badly in my last post!

H ‘n’ H

Lost in Saigon, lost the Plot??? 60meters? Even the first debries lie more than double away from the wreckage than the whole plane length! Take into account that also the debries have an inertia and continue to move forward. You don't see the traces on the ground from that distance, and the traces have to start before the first debrie.

Ah, I forgot, you think that the aircraft had no forward speed... :rolleyes:

like the ludicrous assumption that mode s transmits averaged data.

Hot 'n' High, not at all - I feel we are singing from the same hymn sheet!

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Mode S data is not averaged. The transponder has multiple inputs, fed from sources such as air data computer, FMS, etc. These arrive at the transponder concurrently and are emitted together. There will be some time skew but not significant in this context.

Come on guys, be serious, Fuel icing is not an issue here.
Anyone trying to sell that one doesn't fly commercially.

Wing icing due to cold fuel on ground, yes, especially on the NG, but that is irrelevant to this accident.

yeah but when the last data burst goes out during touchdown it clearly doesn't transmit the last air speed... Most probably the cockpit was the last part of the aircraft that stayed intact and thus could still send data while the aircraft had "landed" already!

Dani -
Ah...but that's done on take-off, not landing.

BTW, you have a PM.

I estimate the stopping distance to be where the tail first contacted the ground, to where the tail would have been had it still been properly attached to the aircraft.

About 60 meters...

http://i2.photobucket.com/albums/y17...ine/Crash3.jpg

Agreed, though if one had the previous packets it should be apparent which ones were transmitted while sliding along - the altitude value will be constant. How much data did this spotter record?

Rainboe
 

Landing gear parts

http://www.pprune.org/rumours-news/3...ml#post4748767

and what about the white dots behind your red arrows? Are they cows? Are they tulips? And the touchdown happened most probably before the first debrie.

btw this footage is shot by a zoom. Objects further away from the lense appear to be smaller...

wing tank fuel used first
 

Rainboe,

interesting theory of highly non-standard procedure to use wing tank fuel first, which brings you completely out of the certified envelope for the 738.
However - using this procedure will not lead to fuel starvation, because after the wing tanks are half empty the fuel in the center tank will automatically be drained into the main tank #1 (left wing tank), which gradually will lead to a nasty imbalance.
Therefore your proposed procedure does not make a lot of sense.

If it is really necessary to get cold fuel out of the wings (to avoid icing on ground) there is an approved procedure to transfer fuel from the wings INTO the center tank when you are on ground - so you are able to refuel the wing tanks with warm fuel.
The procedure takes a while, but you stay within approved area!

..............

737-800 length
 

737-800 Exact dimensions from Boeing Doc. D6-58325-6

Overall length: 129 ft 6 in (39.47 m)
Fuselage length: 124 ft 9 in (38.02 m)

737-900 dimensions from same doc.

Overall length: 138 ft 2 in (42.11 m)
Fuselage length: 133 ft 5 in (40.67 m)

That also would explain only the first hint of the plane trying to turn itself into an accordian behind the cockpit.

magplug
 

in your post, you seem to indicate that the LHR777 pictures show damage to the turbine blades...but I only see fan or compressor blades...are you confusing turbine with fan?????????????

Fragments and wreckage are going to be scattered in every direction when an aircraft hits hard.

Dani, How far do you estimate the stopping distance to be?

....................

Not disputing your subsequent points but where have you actually seen/read him say that? I watched RTL Nieuws and read several articles earlier and couldn't find any evidence he'd actually said that. The closest I could get was the piece I translated earlier where he quite clearly said he thought the aircraft had stalled.

To make my reasoning more understandable (for the doubtfuls):

This is a wreckage where pasengers can walk away (if they are lucky):

Atlasjet 4203

btw noone survived...

This is the wreckage where there is no big chance of survival:

Kegworth

btw 47 survived the crash.

Basically the chance of survival of a crash is a function of g forces. There is also the question if there are evacuation possibilites and fire or smoke.

If your G forces are too high, your body will be destroyed. So now compare these two pictures with the wreckage in AMS, and you can clearly see that primary structures were relatively intact, that the passenger floor with it's seats stayed in place and that there where a lot of survivers.

So this should be a clear evidence that this aircraft didn't fly below stalling speed, that the ROD wasn't very high. Compare post Post 445 for information of the very similar SAS accident (everybody survived).

Dani

Rainboe,

All I can say is that your company has an interesting fuel policy if your wing tanks will top-off with 1500kgs on a turnaround!!!!

Also why would -25C be a problem, do you have any idea what the minimum fuel temperatures are???

By the way. Congratulations on all of your experience. Some people have 20000 hours experience and others have 100 hours experience 200 times over.

Like I said, fuel icing, rubbish.

Over and out.

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Grrrrh, still don't get it?
We can only speculate on things we know. The only thing we know is what is on the pictures. Everything else we cannot find out.

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Callsign Type Registration Code LAT LON ALT VSP GSP TRK
THY1951 B738 TC-JGE 3554 N 52° 22.7' E 4° 42.8' -200ft -4096ft/min 83kts 181°


This is the last mode-s data from the flight.

ALT -200ft the QNH was 1027 so that would indicate 190 ft AGL.


DANI do you really believe this ac didn't stall on finals??????

FEHoppy, yes I do! If this aircraft would have landed with 4000ft/min there wouldn't be anything left except powder! btw 83kts is most probably ground speed. The fact that this aircraft couldn't impact with 4000ft/min is a sign that these transponder data are not correct.

Rainboe:
Well, the only interesting are the last 100'. Because all accident happen there! But I understand your wish to know more about the causes. OK. We will never have the chance to find out except when the investigation is finished.

My motivation here is to hint to certain thinking mistakes which are easily to falsifie when you look at the pictures. So that you can rule out 99% of all posts here and elsewhere.

My last post here, good night, happy landings, live long and sound,
Dani

I'll try a last time. There is nothing interesting in the actual crash apart from looking at the surviveability aspect for future safety proofing. All that matters is what caused the Baby Boeing to descend below 100' at that position! That's where the discussion should be centred. Goodnight Good Sir!

And here is a thought. If the Dutch had filled Holland in properly instead of leaving it a giant hole and the ground at -10', the aeroplane wouldn't have fallen so far. So it's their fault. But the French own KLM, so can we pin any blame on the French? We always blame them.

-200 ft (as in minus)? This is presumably the 1013 value?