In 2000, several drop tests of 737 fuselage sections were conducted at the FAA William J. Hughes Technical Center.

30-ft/s vertical velocity (1800 fpm) onto solid wood base, with no lateral, longitudinal, or rotational velocity components.

Max accelerations recorded varied from 11 to 36 g's depending on what/where the measurement was being made and differences in nearby structure.

http://i337.photobucket.com/albums/n...g/737drop1.jpg

http://i337.photobucket.com/albums/n...g/737drop2.jpg

You need to slow down and look at the data mate. This position is about 250 meters north of the resting place of the wreck. The aircraft is still airborne. Now put this into a picture of an aircraft attempting a stall recovery. As it continues the vertical speed reduces but not enough to prevent impact. The actual vs just prior to impact could be rather different.

PS. 4000ft/min is about 20 m/s

Dani and Rainboe,
The survivability of a crash depends on g forces...and the way these forces are spread at the instant of the crash.
You both concentrate - rightfully - on the stopping distance, but it's only one aspect of what happened.
My opinion - and it's just my opinion - is that the distribution of the deceleration forces played a significant role :
The way I see it
1/ They hit the groung tail first, beginning a structural absorption of said forces (the energy is spent partially in bending the tail and shearing the stabilizer).
2/ With some of the kinetic energy already spent, some is further absorbed by the mud and shearing the landing gears off.
3/ When they hit the ground after a fuselage rotation around the gear struts, the inertia of the different parts of the fuselage, especially those ( the parts of the cabin on both sides of the wing root ) in a cantilever state. The shearing/compressing energy involved broke the fuselage into the three pieces we can see.
4/ the farthest point away from the de-rotation would be the cockpit, also with the greatest deceleration. The part that was subjected to the second most important decel will be the one just abreast of the landing gear...
In other words, the structure deformation/failure absorbed most of the crash energy, which apparently wasn't very important (that's relative...),considering the slow speeds involved.

autothrottle issue?
 

the issue with the autothrottle seems plausible -
fully configured at 3nm in approx. 1000ft with F30 and being distracted by heavy training on the flight deck on final approach, speed starts dropping and nobody realises that the A/T is off. aircraft gets upset and descends below glide directly into the wake of the preceding 757 (observed by the pax as turbulence), which could make a recovery well below 500ft impossible...

jupilair
 

You state "sadly" that in the Turkish culture a go-around is not an option.
Is this forum a place where we can talk almost anything about people, countries, their culture etc.? It is interesting that you think you have the right to blame a country's culture with careless phrases. But no! You do not have the right!
Aviation in Turkey is being conducted (like in all other western countries) under strict rules. An indication for a go around in New York is not different form an indication for a go around in Trabzon!
A go around IS an option in our culture if the conditions warrant it. Please be careful when talking about people and their cultures. And you better do not talk about anything you are not familiar with.
As you see, I haven't commented on your (IMHO very nonsense) explanation of the tragic accident. But I would suggest that all posters try to concentrate on facts and do not try to blame someone or a whole land without any objective evidence.

You're right, he never said the engines stalled. He said something like that the engines probably weren't working otherwise the passengers would have heard them after which the interviewer concluded they were not working.
He said it in the NOVA interview
It more and more seems to be a stupid remark for an "accident investigator".

two repairs at the crashed a/c in the last 2 months
 

A Turkish newsletter reports, that there have been two repairs (out of regular maintenance) at the crashed A/C in the last 2 months.

But no word about of what kind this "repairs" were ... ???

Maybe a typical newsletter "catch-line" or a new hint ...

Repairs
 

Details of the repairs (including Master Caution Light) are provided in press release 3 by Turkish Airlines on their website. It's been badly translated but I guess it will mean something to you guys. Here is the link:

http://www.thy.com/DarkSiteEN/press.aspx

(I've read through all posts)
Some comments:
Seems to me like the foward fuselage failure (break apart) is due to buckling. If you see the foward part of the break up area is also turned inwards, and it's more visible on the left side pictures. Even more in the front close to the cockpit there are buckled sections.
If you see the inside of the fuselage (the inside window frames) are also moved foward (caompare the outter frame with the inner frames).
I think the nose plunged down in the mud and 'stopped' puting huge loads that failed the fuselage by buckling. I think the worst place to be in that plane would be front rows, infront of the front break up.
The break up of the tail may not be that severe, things that are allowed to break apart, take their energy withthem and don't develop high g loads.

The things protruding out behind the cockpit are also strange and I think indicate huge forces on the front part of the aircraft. Would be good to know if cabin crew that sits in the front facing the back, straped, have survived...

In general I agree with Dani BUT I think that what killed the pilots was the muddy field. I think the front part broke at the last moments before stoping, due to the nose plunging into the mud stoping it abruptly and the fusalege failed due to buckling infront of the wing. If the nose had broken earlier (shear loads - vertical forces) from hiting the ground it wouldn't have been there.

Another note.. I doubt the forces where 2g. Things in aircraft cabins are designed not to be seperated at 9g vertical 7-9g horizontal and 3-4g sideways (as far as I remember). A318 hard landing in LCY recently was 3g nothing broke apart (aircraft has to be checked I guess).
Someone said sth like more than 2g on A/C and the A/C is damaged. No way!!! Nothing will break apart at 2-3-4g... BUT there will be cracks created and the life of the aircraft is seriously reduced. It has to do with the magnitude of the alternating load in fatigue. An aircraft at 1.5g may have a life of 30,000h at 2g it can be cut at half.

There is diffirence in what 'damage' is for an engineer and what damage is for a passanger. If passangers knew how many 'damaged' parts are in a plane they would go by boat (whoever flames back at this obviously has little depth in aviation safety issues).

Strangely I believe this was a good emergency landing (deliberate or not I don't care), defenitely sth was VERRYYY wrong before.

The thierd person in the cockpit may have been another pilot or stuff of turkish airlines, flying for free. Don't tell me it doesn't happen or that they would mention it.

P.S: There is way to much spam in this forum guys... Why are you reposting newsagencies data... We all read this...

Sorry for the long post.

ADS-B Track of this flight on OpenATC.com
 

All,

here are the links to the Google Maps and (more interestingly) Google Earth tracks for this flight from OpenATC.com. Make sure you select the "Black Box" Mode for the Google Earth view:

Google Earth (requires Google Earth installed):
openATC Google Earth

Google Maps:
openATC Google Maps

Looks like the last three transmissions are hinting at the pilot trading speed vs. altitude until, at 83kts ground speed, gravity won and the vertical rate was up to more than 4000fpm (20m/s). Quite an impact!

Important notes for those not familiar with ADS-B:

- The speed is GPS derived, i.e. ground speed, NOT IAS!
- The altitude as well as vertical speed are pressure derived, NOT GPS! However, the altitudes are always expressed in flight levels, i.e. in reference to 1013 hPa pressure, standard sea level pressure. Hence you see the -200ft.

Turkish Airlines Bulletin
 

Hopefully the bulletin is only referring to press comments about a couple of defects. 2 Tech Log defects in the timescale they are talking about seems mighty few to me.

Overhead Panel (P5)
 

Can't remember if this is hinged at fwd or aft but I remember it has a latch which catches it from dropping after you release the fasteners. It's very heavy. Anyone tell me where the hinge is?

What Dimitris has said is interesting for sure. I noticed it earlier whilst looking over photos. It looks to me that the aircraft would of continued to slide further, but the front of the aircraft has dug in, hence the front seperation of the plane. It would also explain why the middle of the aircraft is somewhat overlapping the front part of the fuselage (much like what would happen in a train crash, with the front carriage stopping and the rest of the train still in movement.)

What's bothering me are these conflicting reports. I've now read several where people have said the engines sounded like they were requesting more thrust, yet the engines seem somewhat undamaged. It just seems odd to me? Either they are completely wrong or something is not quite right here. What I was trying to piece together was if this was a chain of events rather than one overall failure. One of the engines seems almost perfect whilst the other is damaged but not as much as expected. Could if be that they lost one engine, whilst the other was particially responding? Regarding fire, as I already posted there were one or two reports of one of the engines being on fire briefly after detaching, but soon exinguished itself?

I think our theories could go on forever. Whatever the outcome it seems puzzling what has led to the incident. No Distress call which suggests something happened very quickly, both engines failing at the same time due to starvation? very unlikely is it not? It just seems like an unfortunate chain of events and possibly failures have lead to this. Looking at the posts it seems that even the professionals are stumped to what could be the cause.

I look forward to reading more information from you guys soon.

Ps. I think another evil twist of fate is that the people who could directly assist with the investigation (Flight crew and the Boeing staff) all lost their lives.

Has there been any announcements as to why the Boeing staff were on the plane out of interest? I was just wondering if they were in anyway related to the aircraft in question or just normal passengers.

dimitris - I believe the guesstimate 2G acceleration mentioned was in regard to the moment acting to swing the nose towards the ground after the tail contact, rather than the deceleration of the nose upon impact.

Yes. Transponders send altitude code in mode C referenced to 1013,25 / 29.92, technically it is Flight level and not altitude. The sent data give no reference to acual selected altimeter baro setting. (I have no idea if perhaps it may be available through mode S coding).

Also one other information I found possibly confusing in the thread is that there would be no terrain warining in landing configuration via GPWS. That is correct, GPWS would only have (loud enough) "GlideSlope" alert. On the other hand, Enhanced GPWS which I believe had been made mandatory for the likes of this 738 operated from Turkey, does have a mode called Terrain Clearance Floor which could have been activated. One way or another, the situation probably triggered several warnings; whichever took priority I cannot guess with my limited tech knowldege but CVR will surely reveal. Niether do I suggest that once the crew is made aware more warnings are automatically better help to solve the situation.

FD (the un-real)

P5 Overhead panel
 

Answered my own question from The Overhead Panel
so what probably encroached on the cockpit from behind the crew was the circuit breaker panels. I was considering that it might have been the overhead panel.

As a SLF only; I have been thinking about this accident and there is one strain of thought that concerns me; so I wanted to run it passed the professionals to see your views.

If an aircraft is flying along at high altitude on 1013mb and is then landing at an airfield with a higher pressure setting of 1027mb (for instance) but for some reason the altimeter is not set to the airfield setting; wouldn't the aircraft then be 420' (14 x 30') lower than the pilots thought it was?

In the Turkish airlines crash; I've read that the aircraft should have been at about 355' altitude at the crash site if it were on a normal approach.

So.... IF the aircraft were 420' lower than it should have been and then the pilots became visual with the ground after breaking cloud, and the picture wasn't what they expected, wouldn't they initiate a go-around? I've also been reading that the B737-800 can be a bit tricky in a go-around with pitch and thrust; so isn't this a good precursor for a stall? If the go-around were initiated from 420' below the normal flight path (that would be about 2-3km back from normal?) wouldn't a failed go-around and stall then put them about at the crash site?

Food for thought or just talking out my A**e?

From the plot on Google Earth, the rate of descent and speed are fairly normal for an ILS in a B737 until the point when they are passing the golf course to the east. From that point, the speed is decaying steadily but the vertical speed remains constant until they cross over the motorway, where the vertical speed increases rapidly as the wing stalls. Yes Dani, I said it stalled. For me, this points to a lack of thrust and an attempt to avoid striking the motorway, followed by a loss of control when the stall occurred.

Rainboe

Would it not require deliberate fuel system adjustment not to drain fuel from the centre tank first? I thought all Boeing designs have higher pump output pressure from the centre tank?

snoozer ...
 

Nope - t'other way I think .......

On previous accident threads, about 98% of the accident cause & sequence theories put forward on PPRuNe were made obsolete by FDR and CVR data.

I bet it will be the same here.

Having looked at the ADS-B Google Earth track in more detail I start to think the -200ft altitude value reported at the crash site can be an instrument error caused by the impact. The QNH at the time was 1027 which implies about 370 ft height difference to the track's readings which are referenced to QNH 1013. This is an excellent fit with the airplane's level-out altitude reported at 1625 ft, which applying the 370 ft correction fits exactly with the 2000 ft indicated on the approach chart.

Still, for some reason, after the FAF, 6.2 miles out (EH621) the track shows that the airplane descended with up to 1300 fpm instead of the about 600-700 fpm indicated on the approach chart.


Another thought is that the crew apparently believed they had engine power available. Otherwise, if they had been aware of a total power loss, a natural option would have been to turn slightly left where there was a much larger and more open field and no roads increasing the hazards.

Well.. speculation... FDR will tell.

Nothing ominous, but the 757 is normally classified as a Heavy, despite it being under the 136,000kg limit.

Here's the excerpt from the Australian AIP:

The folks at OpenATC.com have now put screenshots up from various viewing angles: OpenATC.com recording of THY1951 crash

snoozer -

As an 'SLF' as you put it, may I suggest you continue to read what's posted here by those that are more familiar with possible reasons for this accident. I know it's hard to determine who's "more familiar", but you admit that you're an SLF.

Regarding your remarks about go-around capabilities for this aircraft, or any aircraft for that matter, it is not a difficult maneuver for professional pilots as they perform that in the simulator countless times before they ever set foot in a real airplane. And then, they have no doubt done a few there as well.

For those that do not know Mr van Vollenhoven:

The "Mr" is not a generic gender title. In Dutch, this signifies a Masters degree in Law. He also happens to be a University Professor (in Risk Management and independent investigation into Government Policy) but that part of his title is normally not mentioned. He's not a dumb fellow. Not by a fair margin.

He's been busy with transport safety since at least the last 25 years and it is through his efforts that the Netherlands has a completely independent board of investigation for transport accidents - the Onderzoeksraad voor Veiligheid (OVV), which is the successor of the Raad voor Transportveiligheid (RvTV). This board is, by law, tasked with investigating airline accidents for the sole purpose of making air transport safer. The results of these investigations may not be, under any circumstances, used for criminal/civil lawsuits and the like. That's why you see the Attorney General starting its own, independent investigation right now.

The OVV can be thought of as the US NTSB but where the NTSB is limited to investigating transport accidents, the scope of the OVV is far wider. They can basically investigate any accident as and when they please, although by law they have to investigate certain types of accidents, including airline accidents. And their conclusions are not ignored. For example, an earlier investigation by the Raad, into the fire in the asylum seekers cell complex at Schiphol, where 11 people died, led to the resignation of two cabinet ministers.

To dismiss his role as head of the board as honorary because he happens to be a Royal Family member and enjoys being in the spotlight is NOT appropriate. He earned that position.

Although I do question some of the statements he made. After visiting the accident site, at least 24 hours after the crash, he did not even know the distance from the site to the threshold.

Oh yes, and he happens to be married to the sister of the Queen. Is that relevant? Probably not anymore, although in the past it might have given him easier access to the higher levels of government.

snoozer,

With all respect sir,
Your calculations regarding the air pressure are upside down, and you must not use 30' but 27' in the calculation.
Please feel free to read these pages, but may I ask you kindly to refrain from actively participating if you do not posses a commercial Pilot licence?

Airspeed fade during approach
 

To FA10....you bring up some good issues about distractions during final approach and a gradual and unnoticed loss of airspeed leading to a stall...

One is reminded of the C-5 crash at Dover recently...apparently they ran out of airspeed while distracted by a serious engine thrust issue....Aviate...Communicate...navigate ! (my error: Aviate/Navigate/ communicate !). Thx to Flight Detent for pointing this out.

Hi averow....

I always thought it was "Aviate...navigate....communicate"

plus...

with A/T ARM selected, engaged or not, there is minimum speed protection in the B737NG.

Cheers...FD...:)

Rainboe

Re: Your post #518. Sometimes its hard to get through to those poor souls who lack experience isn't it!!

It's certainly occurred to me that distraction might have played a part... (there are usually 3 fairly discrete errors (human or mechanical) that make an accident happen)

Without one of them, sometimes the situation is not even recognised as '..an accident opportunity'.

I think someone earlier wondered whether any stats had been produced on 'non-standard cockpit crew complements' contributing to aircraft accidents / incidents?

===========================================

I would agree with Dani, that this was a short hard landing... in 'his' terms, though not with everything he has said.

The a/c was descending at 'nominal' descent rates and flying slow, certainly not fully stalled, but mushing along short of thrust to arrest the descent rate...
The muddy field possibly helped some sections to remain intact and minimise instantaneous vertical 'G' but contributed to very high longitudinal decelerations.

As far as survivability theory goes, we don't yet know for sure where the Boeing personnel where, or the distribution of serious injury cases throughout the cabin

ADS-B plot
 

Hi
Total noob here sorry...

In the comms log it says:
"OK for ILS 1-8 right", which the news report says is an instruction to intercept an electronic beam to guide it to the runway.

Is it possible there was a problem after this hookup was complete/incomplete, and is what put it off course?

Sorry if this is a dumb question.

Thanks in advance
Steve

Aircraft hit wake turbulence every day. They don't fall out of the sky because of it. If you are following behind, wake turbulence causes an airliner to roll to the left or right. That didn't happen here. If you cross it at angle, you get a momentary bump or jolt and continue on..... No big deal.

These are the facts as I see them:

1) Passengers reported turbulence just before landing. This suggests the aircraft experienced a stall buffet or pre-stall buffet close to the ground. This means the airspeed was too slow. We don't know why, but there are lots of reasons it could happen. Believe it or not, engine failure is not a reason to loose airspeed. It is every pilot's duty to monitor airspeed at all times, and if necessary, maintain airspeed by lowering the nose. You don't need power to maintain airspeed. Power certainly helps if you also want to maintain altitude.

2) Passengers said the aircraft suddenly dropped. Some of them then surmise that the aircraft must have run out of fuel. This is because, in their limited knowledge, nothing else could have caused the aircraft to drop. (Of course everyone, and their dog, runs with this idea, even though there were no calls to ATC regarding a fuel problem)

3) Other, more astute passengers, gave conflicting information. They say the aircraft dropped, but they also heard increased engine noises. This was probably the pilots adding power in reaction to the initial stall warnings.

4) Witnesses on the ground describe nose high attitude, followed by a dive to the ground.

5) The aircraft hit the ground tail first in a high rate of descent with low forward speed. This is obvious from the photos of the crash scene.

When the FDR and CVR information is released, I expect that it will confirm a low altitude stall, or approach to stall, with an incorrect or incomplete stall recovery.

http://i2.photobucket.com/albums/y17...ine/Crash4.jpg

On the 757 "rumour":
Track Flight Status for (NW) Northwest Airlines 60

The source for the rumour is either the mass of folks parked at AMS with ample time to study their surroundings, or the LiveATC scanner, where NW60 is the last aircraft handed off to tower before the flight in question.

Oh, and forgetting to set the altimeter? We're not talking about the Thunderbirds here.

The pushing button TOGA instead of button AT/OFF is reason for confusion on low altitude. Sometimes it happens on 737. May be it was source for event?

Info in pictures
 

I'm surprised nobody has done this yet, but here goes. I can eliminate some of the huffing and puffing and speculating over distances with a couple of maps I drew together in Google Earth and some pointers to photos with landmarks. The maps are plan view (0° tilt) and I checked them against some known landmarks(independently verified to 0.001 minute GPS precision) for heading and distance.

TC-JGE Crash Overview Orientation is South UP (180°) How do I know this is where? It's on the front page of Schiphol's website. "...along the A9 motorway near the Rottepolderplein in the village of Haarlemmerliede." Rottepolderplein is the name of the motorway junction of A9/A200/N205. At the top is the apron of 18R with a 747 on short final providing scale. At the bottom, a red aircraft labeled "Nose" representing the crash site. The line is coming from the row of trees lining the edge of the field and is approx. 220m long. The crash site is 1950m from the top of the piano keys.

TC-JGE Crash site. Orientation is runway heading (183°) Important landmarks: Berm in middle of field, Barn/house just North of East, House to SE, A9/A220 junction to NW with road signs, Zwanenburgdijk crossing at South, Same line.

Other measurements: Trees to berm 235m, Across field to storage site with a bunch of (shipping containers?) 455m, To next set of trees 560m. With the exception of the last, these only get longer if he's on a heading to encroach on 18C, otherwise they're shorter.

The Fire Brigade at Schiphol has the best set of pictures on the ground. Good for determining the position of the aircraft in the field.

Also important to this is the video available on YouTube, the police helicopter video. It's not as good as the original from nos.nl, but the mods deleted the post with that link. The eye catches the movement of regular features like the divot the tail carved in the mud. Looks like about 2 1/2 plane lengths to stop. Screenshots Oblique and full views show that foreshortening via telephoto isn't much of an issue for guesing relative distance.Far view from other side shows relationship to road where trees are and berm with helos for additional scale.

With this large image of engines with route signs in background and this pic which shows the port engine (the one with the trashed cowling) with the SE house in the background we can sort of triangulate where they ended up.

BTW Here's the pic where the rescue squad got into the cockpit. It doesn't look like the roof is hacked any more than it was with the piece of support popping out. It does look like the cockpit and first class acted like a ground anchor. That's what, 5 feet of crush and 10 feet out of alignment?

Roger that... Lost_in _Saigon

Except that the LP Fans don't look like they were under much power so I wonder if extra power was applied or if some passengers who experienced a nose up attitude assumed this was connected with application of thrust ? People's minds play tricks.

I found a reference that the crashed aircraft was grounded on Feb 23 after the crew detected a problem with the "Master Caution Light" just before take off.

Crash jet was grounded for repairs-27 February, 2009

What was that about ?

DC-ATE;

The "non-moving thrust levers" seem to be a problem for you and yet the DC8-40 series did not have moving throttles. If I recall (been a long time but I have the manuals somewhere), no DC8 had moving throttles except when they were engaged in a "quasi" speed mode during an "auto" approach, which, I think you'll agree, was a very ropey experience at best especially on the short '8's. Not sure of the 707 but someone here will know and can tell us. I flew it on the Atlantic for a number of years and we were always, always tweaking the EPRs in response to mild speed excursions, (wave action, temperature changes and of course, weight changes).

The non-moving thrust levers on the bus are a non-issue. Those who are most vocal about it haven't flown the airplane or if they have, not for long. It just isn't an issue for experienced crews and neither is the fbw.

Habsheim isn't relevant and the many conspiracy theories are nonsense. You yourself know what acceleration capability to expect of a turbine engine at idle thrust and an angle of attack of 15deg with energy rapidly reducing and the airplane at 30ft above ground. It wasn't computers, fbw or a nefarious cabal of Airbus executives and designers that "explain" Habsheim - it is Newton, in 1687.

Also, the steam gauges on the early '8's and 727's such as the three-pointer altimeter killed a lot of people before they realized that design could be easily misread. A CFIT accident today is almost always human error, SOPs, training or culture.

I loved the DC8 - beautiful airplane which rewarded a fine hand (and equally rewarded a poor hand!), but I'll take the 320/340 series any day - it's simply a far, far better design, and the next one, (787?) will be that much better.

As for pilots losing flying ability and SA? That's a cockpit discipline, experience and a training issue, (and perhaps a hiring and safety culture issue), not an ergonomic/human factors issue. I would even suggest that it is a professional matter if one is uncomfortable hand-flying an airplane but does nothing about it.

If the airplane was as difficult or obscure to fly and operate as you and others claim, the accident rate would reflect it.

I've read all the posts and I tend to believe there is an autothrottle issue here coupled with a high-workload cockpit but I remain open to fuel issues. As for how it hit the ground, its absolutely immaterial and discussion/argument about how it did is irrelevant bordering at times on the morbid, and a diversion for those too impatient to wait for the recorders to be read.