Storminnorm

Rings a bell but I am not too sure why. Perhaps it was an issue on the Originals or the early Classics. There used to be an issue with the autopilot trimming the aircraft into an out of trim situation and then promptly giving up, but I think that was only an issue on the Originals.

The obvious one with the runaway situations were the ruder hard-overs. Doubt that was an issue here (but who can ever be 100% sure, except the investigators (sometimes)), but this aircraft was not fitted with a Spery autopilot from the Originals so the likelyhood of an out of trim is far removed from those early days when you had to disconnect the AP every once in a while during cruise just to see if the damn thing was still in trim. I am not sure if there is now a form of protection agains a runaway situation on the NGs (I have not done the differences - no one will let me anywhere near anything that new). Anyone shed any light?

RIX

captplaystation

so you think it was a double eng flame-out due to bird strike and in short final the Crew wasn't able to land on the rwy or at least as smooth as possible on a field?

RIX, you're right, it was with the early classics, but I believe
the stab trim system is still pretty similar on the NG's.
Or perhaps not?

it seams like the 737 has low frw speed!

Turkish 737 had 'low forward speed' before Amsterdam crash

stab trim on the 737 is one of the most annoying devices ever...a huge wheel always flipping around right next to your right knee...you can't miss its movement...intended by design of course.

video of an actual landing on 18R
 

video taken from cockpit of an actual landing on 18R can be found here

protectthehornet -

Couldn't've said it better!!

There are some more good quality photos to look at now like these...

http://cdn-www.!!!!!!!!!!!!!!/aviatio.../2/1489234.jpg
Photos: Boeing 737-8F2 Aircraft Pictures | !!!!!!!!!!!!!!

With a view now of both engines it can be seen that neither first stage fan shows evidence of radial distortion indicating very low/no rotation at impact. In fact one of the fans looks in such good condition that it may actually have been at rest at impact.

Several hypotheses have been expounded about the probable cause.....

- Birdstrike ? Serious bird damage tends to come in two varieties, big flocks of small ones (Ryanair CIA) or small/medium flocks of large ones (those damn Canadians!). There is absolutely no evidence of mass bird impact on any of the forward surfaces, nor any isolated damage by larger birds to the first stage fans of either engine. Simultaneous engine loss caused by birdstrike would not seem to be on the agenda.

- Inadvertent stall by loss of SA (subtle A/T loss or whatever) ? The first reaction of any pilot to a stall warning, (stick shaker in the 737), is to apply TOGA power. Whilst the 737 is an absolute pig to recover in the approach config due to the trim change and drag, the initial reaction is always the same - apply TOGA power. These engines did not impact with TOGA power applied.

- Mishandling of SEF on finals? This is not an easy exercise on the 737 and involves continuing down the glide whilst increasing power and selecting a lower flap setting, when a safe speed is reached you decide whether to continue to land or go around. If this situation was mishandled the subsequent evidence would reveal TOGA power on the live engine at impact. It is also highly improbable that a mishandled SEF would result in a ground impact with the aircraft wings level.

I am at a loss to imagine a situation that the crew would not share with ATC, that evidences a stalled impact on short finals with both engines at very low/no N1. The crew clearly experienced a total power loss below 1000' which they were unable to translate into a successful off-field landing. I wonder whether both engines were running prior to 1000' or perhaps one had already been lost, the other failing around 600-800'.

Fuel exhaustion or starvation is now looking much more probable.

For the record.... I have an extreme distrust of any airline management that is capable of reporting 'No Casualties' from the comfort of their Turkish Office only minutes after an aircraft accident a thousand miles away. Furthermore, to then announce later that the technical records held at base bear witness to a perfectly serviceable accident aircraft takes a moron of extreme proportions.

Am I the only one to conclude that Turkish Airlines have an corporate safety culture that would be more at home in the depths of Africa?

Magplug:
 

what about if the engines detached before the full weight of the aircraft structure hit them?

I'm thinking of tail strikes the ground causing rapid nose down pitching, then main gear hits causing high g load which detaches both engines before the fuse hits the ground.

If they came off their pylons with a high fan speed but bounced allong to a stop would the type of blade damage we see be possible?

I'm more inclined to go with mishandling the approach leading to a stall in the landing configuration than fuel starvation.

Hawker Siddeley Trident - auto-landing since 1962....

Nothing wrong with automation if it helps ease the workload DC-ATE...


Doh - where'd his post go?!

Storminnorm -
You might be thinking about the rudder power control unit.

magplug

What is meant by radial distortion?

Yes the two engines look different, but then again where are any pictures showing the same views of the fan blades outer airfoils?

Impact has two meanings. Most associate it with the aircraft which in this case seems to be the tail section before the engines.

However the damage to the fan blades has possible timings

1) in the air preceeding the initial ground impact?

2) at the time that the nose comes down hard?

3) One engine wing low takes the brunt of the impact?

4) an engine torn loose from the wing rolling along the ground?

Unless you are willing to connect the damage condition of the fan blades to one of the above then a conclusion is not possible.

Anyway, what does the turbine look like since it may have taken the brunt of the impact?

This is the airline's 22nd hull loss. As airlines of similar size go is this a high or low number?

Yes, you're right DC ATE. Rudder!!!!!

BlackWater01,

I think there exists a possibility yes. In this case the aircraft in a very draggy landing configuration is unlikely to make the Runway. The Ryanair accident is a little different as they had commenced a go-around which probably gave them a little extra height/energy before the second engine failed.
It would be a fairly difficult manouvere to convert a normal approach into a glide in landing configuration from say 200-300ft, and with landing flap the judgement of the flare/landing off a glide approach would not be so easy to do accurately, and could certainly be expected to result in a less than optimal "arrival" on a soft unprepared surface.

Not sure about runaway stab trim but there have been many issues with hard over rudder. Lots of corosion in A/P servo for rudder syst. I probably should not be speculating on this. leave that for the investigators etc..

"Two pilots and an apprentice pilot"
 

I find this phrase, being used by the media, a bit unusual. I believe it came from the Dutch Safety Board.

Does anyone, especially a dutch speaker, know whether "apprentice" is intended to mean something different from "trainee".

Apprentice is not a Dutch word. Not even close to a Dutch word. So before putting this into context, consider that a Dutch word was first translated into English, leading to the word Apprentice. Trying to translate this back into Dutch and then attaching meaning to it, without context, isn't going to help a lot.

Where did you find this quote? We may be able to find the original Dutch text and put it into perspective for you.

But my guess is that they would indeed mean "trainee", or at least somebody who was not fully qualified yet.

> [...] ...who was not fully qualified yet. => on that Aircraft type.

For the rest, I couldn't add anything to your precise linguistic explanation (& much else).

All the best,
vonbag

***edited after my Dutch wife returned at home:
"leerling op dat vliegtuig type" [?]
I did not have a chance and listen to that broadcast myself.
Het beste --

Look at these pictures of the BA777 crash at LHR.
www.flightglobal.com

As you can see from the first picture the first stage turbine blades are sheared off at around half of the length of their radius. This was because they were rotating at some speed when the impact occurred. The engine nacelle was forced onto the rotating blades causing almost identical damage to all the blades as they turned and they have all fractured at a similar radial length. The engine therefore must have been rotating and producing at least some thrust on impact.

Look now at the second image of the other engine and you will see that the turbine blades are all intact even though the nacelle has hit the ground quite hard and scooped in a lot of dirt in the process. This engine was not rotating at impact and therefore could not have been producing any thrust.

As is also witnessed by the BA incident, a total loss of thrust below 1000' can be brought so a safe outcome given favourable terrain.

Witness/passenger reports taken from sky news.

Jihad Alariachi said there was no warning to brace for landing before the ground loomed up through the mist.
"We braked really hard, but that's normal in a landing. And then the nose went up. And then we bounced ... with the nose aloft," she said.
Passenger Kerem Uzel said the jet's tail made contact with the ground first.
"We were at an altitude of 600 metres (2,000ft) when we heard the announcement that we were landing," he said.
"We suddenly descended a great distance as if the plane fell into turbulence. The plane's tail hit the ground ... It slid from the side of the motorway into the field."

As I recall, both engines were operating, but they did not produce commanded thrust.

The article you linked to is very old and appears to be in error.

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

Has anyone else ever dispatched with the autothrottle unservicable on a B737. I did - it was memorable in that my F/O and myself both forgot it as we levelled off in the holding pattern prior to approach. Fortunately we noticed the speed decay in time. The A/T system is normally so reliable that it is taken for granted.

Goinggrey, yes the 737 incident at BOH I think was also an Autothrottle or lack of problem I believe

Rainboe
Like you I am old enough to remeber Papa India all too clealry-I was in Staines that very day and my friend and I heard it hit the ground though we did not know what it actually was at the time.

As you say the aircraft looked virtually intact and the wreckage pattern engines aside of course for obvious reasons looks remarkably similar to the TK 737 with the fuselage spliting in a couple of places the tail detached and the nose sort of pointing downward. As I recall the cockpit area suffered rather more severe damage than the 73 did but PI stalled at about 1300 feet as I recall and presumeably had more vertical speed when it hit.

I won't specualte but will just underline that observation that the wreckage looks very similar to the ill fated Trident all those years ago.
PB

goinggrey -
I sure don't like to hear an attitude like that from a 'professional' pilot.

Everything seems to be 'automatic' these days. Doesn't anyone know how to fly an airplane any more?!

What do you think?
 

Boeing recommends on the 737NG that if the autopilot is disengaged the auto throttle should be disengaged for manual flying (either full automation or no automation), If the speed is not carefully monitored the aircraft can quickly degenerate into a low energy state and high rate of descent and I think the aircraft was too close to the ground to recover. Just speculating what do you guys think?

apprentice
 

"leerling" is normally a student, but my Dutch/English dictionary also gives as an alternative "apprentice", which in turn is described as a trainee.

Turbine blades?

And another one
 

Regarding the link about THY accidents from "in my last airline", they also had a fatal 737-400 accident in about 2001, when the aircraft was ferrying with full crew from (I believe) Diyarbikir to Jeddah. It flew into a thunderstorm and lost control, causing a crater 5 metres deep on impact about 15 minutes after take-off.

"Leren" is to learn, so the most direct translation of "leerling" is simply "learner".

Rainboe, I strongly reject your comment that my posts are missleading. Indeed yours are!

If this 737 would have been in a very high or even normal high rate of descent (ROD), there wouldn't have been any survivers. Stall at an altitude above a few meters is not survivable. Modern airliners are very efficient and Boeings are rigid and strong, but a fuselage with high ROD would desintegrate immediatly. G forces would be so strong to kill everyone on board. I assume that the ROD must have been less than 1000 ft/min, most probably less than 500. (normal sink rate at touchdown 100-300). The ground track was not short but indeed very long under these circumstances. Remember how fast the "Hudson Airbus" stopped on the water (seen by the CCTV)? Remember other accidents like the AUA F70 or the SAS MD80?

You may call it luck but I say that this was a near perfect landing on a soft field. (that doesn't imply that the crew didn't do mistakes before).

Dani

Looks more like a 20G "landing" to me..:sad:

engine stop after tailstrike?
 

Re comparing engines -- would the tail breaking off cause the engines to shut down such that the blades would have stopped moving before the engines hit the ground)?

That's assuming the engines _were_ running when the tail broke off.

I favour Rainboe's theory. I higly doubt this aircraft landed in a controlled state at near normal speed.

I consider it to be an uncontrolled crash following a stall.

Early remarks from the investigators also supprt this scenario. Turkish 737 had 'low forward speed' before Amsterdam crash

Interesting to note on the 18R approach video where the landing checks were being done, half mile or so before the impact point. Selection of flap 30, followed by landing checks and distraction therefore not applying power to counter extra drag of flap 30? The auto-throttle disarm light, although flashing red and in the immediate field of vision of the FO is surprisingly easy to miss. There is no master caution or aural alert. As i said back on page 3 or so,Im still guessing that the a/c was allowed to get slow on the GS, without the crew noticing.

Busz (737-800 jockey).........And waiting to be proved wrong

care to explain the why the tailplane is so far behind the rest of the wreckage?

Apprentice
 

Thanks for the replies. The word has been copy-pasted all over the media, including Flight magazine's website.

I was curious as to whether this "apprentice" status would permit him to sit in the RH seat for landing. I originally assumed he was in the jumpseat.

However since all of that is already known to the Dutch authorities, my two cents worth is just a distraction.

No, the tail breaking off would not cause the engines to stop.

There are even some examples where the engines continue to run after an accident has occurred.