Turkish airliner crashes at Schiphol

[funfly]

I've followed this thread and am surprised by the people who are convinced that when stalled the aircraft is in vertical descent therefore any forward movement indicates a non stalled situation!
Incipient stall - massive rate of descent but still some forward movement.

Seems though that the passengers did not notice any 'switchback' feeling before the incident which rules out a desision made to 'stretch' a problem to avoid the roadway

[Rainboe]

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

[FA10]

stall + wake turbulence

Coming back to the wake turbulence:
I agree that there is generally no problem with wake encounters for a 737 when following other traffic - even behind a 757 on a reduced separation.
But was the ill fated flight on an ILS G/P? Probably not, as they hit the ground about 1,5km short of the runway.
As wake vortices are gradually descending, the struggling crew - as Belgique has perfectly described - may have been hitten by another problem, which made the recovery from a suspected low-level stall impossible.
Double trouble: Stall, extreme pitch and wake encounter.
Maybe no encounter that gave them a huge roll moment, just one enough to spoil the last bit of lift they still had...

[deSitter]

De Telegraaf is now reporting wake turbulence as a possible cause:

'Ander toestel mogelijk oorzaak crash' - Binnenland - Telegraaf.nl [24 uur actueel, ook mobiel] [binnenland]

My Dutch is probably horrible here as it's derived from German, but to approximately translate the headline

"The crash of a Turkish passenger plane at Schipol was possibly caused by another plane that landed at the airport shortly before. The short distance between the airplanes unfortunately meant extra turbulence for the Turkish aircraft, so reports the Turkish pilot's union TALPA on Friday."

Hope that was close.

-drl

[fyrefli]

You'll find the De Telegraaf article largely the same as the English one that was posted earlier in this instance - the starting point for both is the TALPA statement, as opposed to Dutch information that has then been translated (c/w misunderstandings) into English as was the case yesterday. When the original links were posted to the English version of the wake turbulence story and the nu.nl one, I read the latter with the intention of translating it for the benefit of non-Dutch speakers but there was so little difference it wasn't worth it.

[DC-ATE]

There's been much discussion on the fact that there were 3 people in the cockpit. I think we'll have to wait and see exactly what each one was 'assigned' to before ANY assumptions can be made. After the report comes out, then you all can go ahead and speculate all you want.

As an aside, the airline I was with required 25 (as I recall) hours observer time before you touched anything. THEN you went on a line check with a Flight Manager. THEN you were turned loose. Of course every airline is different.

[HundredPercentPlease]

Rainboe,

That's how it's always done in the sim. But in reality the "autothrottle-off / AP-on + distraction" stall and recovery is somewhat different, and this event has occurred a few times for real recently.

[jonny dangerous]

Regarding NG A/T and A/S control, generally:

When I was a newish pilot on the NG, the following happened on two separate occasions, with two separate pilots, while I was PNF:

We were descending in LVL CHG (A/T in ARM mode) below 10000 feet while on vectors for the approach. For some reason the A/P was disengaged, and then the PF began manoeuvring for a visual approach (we were high on profile on one occasion). I remember the cockpit getting busy, and there being momentary confusion on the part of the two PFs as they looked down and saw the speed dropping (perhaps in response to call of mine, or not; too long ago to remember) below target.

They had not immediately realized that they were now MANUALLY controlling the T/L's, and were definitely caught off guard.

From those occasions, it reinforced a previous Airbus operation SOP about not using LVL CHG below 3000' AGL, IIRC. If using V/S at the time, and A/P is disengaged, the A/T will remain in MCP SPD mode.

Of course if APPROACH (for an ILS) mode is armed, upon G/S interception (Post LOC capture) the A/T will be back in MCP SPD regardless of A/P status.

[redskin-blue]

Speculation nr 1001

Hasn't this accident written "Bangalore" all over it? Remember the early A320 days where an Indian A320 crashed short of the Bangalore runway due to, apart from some other factors, a lack of understanding of the flight guidance system/ AT system?
Subsequently, in my former airline, the use of the "open descent" feature (Boeing: "FLCH") was forbidden below initial approach altitude.
Thesis Nr 1001:
Descending in FLCH declutches the AT i.e. AT mode annunciates: "hold" (Airbus: "clamp").
The FMA reads, from left to right:
HOLD (!!!)-LOC-FLCH SPD (yes, I'm making assumptions that the 777 flight guidance system isn't that different from a 737-800's system)
Normally , a capture of the G/S and/or a capture of a set altitude (has of course to be set LOWER than the a/c's actual altitude), changes the AT "HOLD" mode to "SPEED" mode i.e. engages(!!) the AT.
All it needs is the omission of the setting of a lower altitude and the arming of the G/S.
Seeing the glide slope indicator come upwards, while intercepting from above, makes one adjust the pitch upward, the FD will point downward (ordering speed thru pitch down adjustment): confusion!
This confusion and crucially, realising the speed drop too late and not immediately, manually adjusting the power sets the scene.

[Giolla]

Something must have been commented by the flight attendants and the surviving people of Boeing if they had any practical knowledge about piloting.

@deSitter - your translation was correct

This captain's exclamation: oi oi oi etc. - mentioned in one of the replies as one of the passengers made, how do they know it was the captain who said that and how did this person came to hear of it?

[IO540]

I have been given this by a colleague living in The Netherlands who asks me to post it here:

Witness (Dutch) on Dutch TV about Turkish Airways crash:

The approach was very smooth. Suddenly the plane dropped a lot. I
became light in my chair. I then heard full power being applied, but
it was too late. The plane pitched up but hit the ground with the tail.

What is new is that he claims he could feel the sudden drop before the
engines spooled up.

Amazingly the man experienced less than a week before a taxying
accident at Istanbul when taxying out for a flight to Iraq

[Tashdo]

Another point and questions...

One of the witnesses from the motorway saw the crash and came by the 738. Also another survivor aggrees that; co-pilot Murat Sezer was alive for app. 40 mins but stuck in there. Both say they saw him from the glareshield and heared, then warned people afterwards but no one from first-aid moved to rescue him...just for criminal purposes! I probably wouldnt care air-law at that time but is it possible to leave him die like that ? Or does the law say dont touch anything in the cockpit, nor a switch or the crew...I couldnt see any human approach in there !!!

[HarryMann]

Originally Posted by Atreyu

Besides no-one can be sure of what the crews actions were before impact, the only clues we have are the physical evidence of the wreckage, which do suggest a Staines-esque IMPACT, note the word impact people, I'm not suggesting the same causes at force here, but the tail seperating from the main wreckage and lack of fire along with a relatively small debris field SUGGEST a stalled condition on impact, as in the Staines disaster.

I'd say that a stretch far too far, for you and so many to keep using the tail-separation as some sort of evidence of a fully stalled condition with commensurate rates of descent ... two of us (at least) here keep saying... this aircraft did not have a particularly high rate of descent at impact - everyone would be dead!

Originally Posted by deSitter

At the right speed and attack angle a partial stall can occur, without buffeting, where the flow is still more or less laminar but there is a great reduction of lift - a sort of "flying squirrel" regime of flight which is really more like an air-cushioned fall.

Laminar flow is a misuse of the term, it is a boundary layer condition (laminar/turbulent) and so often confused with separation and stalling it drives aerodynamicists nuts!
Leaving that out, I agree, but a few pages back called it 'waffling along' I believe in a partially stalled high drag regime. Which points us back to Atreyu's post above... gross lifting ability is NOT lost, but forward speed is steadily if not rapidly decaying unless sufficient thrust is available, taking us into the serious lift-loss regime.
These are 1g, unaccelerated stalls, and few wings today exhibit what so many seem to think they see when looking at traditional 2D Cl~Alpha curve. For one, the sweep and AR ameliorates the (classic sharp stall) condition, let alone the profile with flaps and slats too...

[AN2 Driver]

Tashdo,

co-pilot Murat Sezer was alive for app. 40 mins but stuck in there. Both say they saw him from the glareshield and heared, then warned people afterwards but no one from first-aid moved to rescue him...just for criminal purposes! I probably wouldnt care air-law at that time but is it possible to leave him die like that ? Or does the law say dont touch anything in the cockpit, nor a switch or the crew...I couldnt see any human approach in there !!!

I find that VERY hard to believe. I have seen rescue teams in action, granted not in AMS but elsewhere, I was a fireman for a while myself, but if they are pointed so someone badly hurt or critically injured by ANYONE, bystanders, whoever, they'll move hell and high water to get them out. Unless there was a real misunderstanding between them and the witnesses, and particularly with regard of the time frame you mention, I regard this account as highly questionable.

All: I heard on the news that Dutch officials confirmed that according to FDR both engines had failed before the crash. Can anyone confirm this?

Best regards
AN2 driver

[electricdeathjet]

Just out of interest, how well does the CFM-56 cope with a large thrust demand from idle, at low speed, and in a stalled condition? Does the intake buffet have any effect in such a situation? I dont believe there is an auto-ignition function on the FADEC of the 737.

[xetroV]

Originally Posted by AN2 Driver

All: I heard on the news that Dutch officials confirmed that according to FDR both engines had failed before the crash. Can anyone confirm this?

The FDR is currently being analysed in France and no information about the FDR data has been released yet.

[flyburg]

Quote from tashdo:

One of the witnesses from the motorway saw the crash and came by the 738. Also another survivor aggrees that; co-pilot Murat Sezer was alive for app. 40 mins but stuck in there. Both say they saw him from the glareshield and heared, then warned people afterwards but no one from first-aid moved to rescue him...just for criminal purposes! I probably wouldnt care air-law at that time but is it possible to leave him die like that ? Or does the law say dont touch anything in the cockpit, nor a switch or the crew...I couldnt see any human approach in there !!!

Tashdo, I'm sorry for the loss of life from your country men, but that is complete B.S. The rescue workers have but one goal/purpose...to rescue people. To suggest that they didn't rescue Murat Sezer so as not to interfere with the criminal investigation is ridiculous and would be considered criminal neglicense on the part of the rescuers!!!! Their only job is to rescue people, they don't care how much they f@ck up the scene for the consequent investigation.

Once again, I feel for your country men, but don't come on this bourd spouting some incredibly stupid conspiracy theory. By doing so you are basically insulting all the rescue workers who, by all standards, have done a exceptional job.

[GlueBall]

Rainboe . . .

I was practising 737 stalls in November. It is very very hard and takes tremendous stick force to hold a 737 right into a stall. You cannot maintain altitude and it takes diabolical pressure to keep the nose up. Near the stall with buffet occuring, a high ROD regime naturally occurs. The warnings, tactile, sensual and visual are manifest. You cannot do this inadvertently, not on a straight descent!

Be mindful of the fact that the non aviation crowd would not presume that you're doing this . . . in the simulator! And besides that, be careful with those exact comparisons as no 6-axis sim has true fidelity, especially not with the "sensual and visual" parts, with emphasis on inertia.

[InSoMnIaC]

To me it sounds like a line training flight gone wrong? Maybe an inexperience 737 pilot at the controls disconnecting Automatics (A/P and A/T) to make a manual landing then becoming so overwhelmed with the situation that they inadvertantly enter a stall due low speed/insufficuent thrust.

The reason why i suspect training flight is because of the storys of there being 3 pilots in the cockpit (maybe 1 was a safety pilot)

If this was the case it would re enforce the importance of leaving the A/T in arm as opposed to off during manual flight.. at least then you would have underspeed protection.

[telster]

I used to be an ambulance paramedic and at times covered both Luton and Stansted airports and so potentially could have been sent to a similar incident to this had it happened in the UK.

There certainly isn't any instruction to leave the treatment of the crew either to after the passengers have been cared for or for any accident investigation reasons.

Similarly that pilots on this forum shouldn't second guess what the flight crew involved in this accident did or didn't do, I can't comment on the actions of the rescue teams that attended this crash, but either the unfortunate co-pilot wasn't treated because he wasn't accessable or his injuries were so severe that other casualties that stood a better chance of survival took priority. Almost certainly in this case that rescuers just couldn't get to him.

In any mass-casualty situation the idea is to do the most good for the most people. That does mean that sometimes someone who is very severly injured with little chance of survival is passed over for those with lesser injuries. There is no point rescue personnel concentrating on one very badly injured person while five others with slightly less serious injuries slip away.

Certainly, whether a casualty is a crew member or passenger wouldn't enter into the the decision process.