Turkish Airliner Crash

[iskyfly]

I'm just not sure why you feel it necessary to shoot down ideas in such a sarcastic way that other people share.

I don't feel it necessary.

[joeyb747]

I'm just not sure why you feel it necessary to shoot down ideas in such a sarcastic way that other people share.

I don't feel it necessary.

Seems that way...

[joeyb747]

They are now saying that both engines stalled shortly before the airplae fell to the ground. This counters early accounts of the passengers saying they heard the engines power up shortly before they hit. This article is dated Feb 27.

Has anyone heard for sure how much fuel was onboard?

Below is a link to the story...
 
http://www.timesonline.co.uk/tol/news/world/europe/article5811658.ece

[iskyfly]

They are now saying that both engines stalled shortly before the airplae fell to the ground. This counters early accounts of the passengers saying they heard the engines power up shortly before they hit. This article is dated Feb 27.

Has anyone heard for sure how much fuel was onboard?

Below is a link to the story...
 
http://www.timesonline.co.uk/tol/news/world/europe/article5811658.ece

pax and eyewitness descriptions of what they saw or heard are notoriously inaccurate.

I also don't put much stock in media reports that say the engines "stalled".

[joeyb747]

True about witness accounts. How offten do stories differ between people who were right next to each other?

And yea. I thought "stalled" was a strange word to use there...

[andreblt]

Both engines came to rest approx 100 ft in front of the fuselage. What made them do that??
My guess is they were running at high power at the moment of impact.

[joeyb747]

Both engines came to rest approx 100 ft in front of the fuselage. What made them do that??
My guess is they were running at high power at the moment of impact.

That would seem to suggest that, wouldn't it.

Or would momentum alone be enough to launch the powerplants foreward?

It's like we have black and white accounts of what happened. Some say the engines were dead, some say the were running at full power. 

Of course as iflysky and I were just discussing...You can't put all your eggs in the pax and witnesses basket!  "Notoriously inaccurate" is how iflysky put it...great wording!

[iskyfly]

My guess is they were running at high power at the moment of impact.

the pictures of the fan blades indicate low rpm at impact.

[tlsdk]

They are now saying that both engines stalled shortly before the airplae fell to the ground. This counters early accounts of the passengers saying they heard the engines power up shortly before they hit. This article is dated Feb 27.

Has anyone heard for sure how much fuel was onboard?

Below is a link to the story...
 
http://www.timesonline.co.uk/tol/news/world/europe/article5811658.ece

TTL fuel...12000kgs
trip fuel..8000kgs

[joeyb747]

They are now saying that both engines stalled shortly before the airplae fell to the ground. This counters early accounts of the passengers saying they heard the engines power up shortly before they hit. This article is dated Feb 27.

Has anyone heard for sure how much fuel was onboard?

Below is a link to the story...
 
http://www.timesonline.co.uk/tol/news/world/europe/article5811658.ece

TTL fuel...12000kgs
trip fuel..8000kgs

Was this fuel load at departure?

[joeyb747]

I worded that wrong...sorry. 

Does anyone know for sure how much fuel was onboard at the time of the crash?

[joeyb747]

My guess is they were running at high power at the moment of impact.

the pictures of the fan blades indicate low rpm at impact.

I agree iflysky.  From pics Ive seen, the engines are relatively intact, all be it missing cowling and casing. Here are two such pictures...in fact, in the head on view, the blades at the top of the powerplant look almost undamaged...like it was not running at time of impact...

http://commons.wikimedia.org/wiki/File:Crash_Turkish_Airlines_TK_1951_plane_engine.jpg
http://commons.wikimedia.org/wiki/File:Crash_Turkish_Airlines_TK_1951_plane_engine_2.jpg

[joeyb747]

http://commons.wikimedia.org/wiki/Category:Turkish_Airlines_Flight_1951

Lots of good pics on this page...

[tlsdk]

I worded that wrong...sorry. 

Does anyone know for sure how much fuel was onboard at the time of the crash?

about 4000kgs

[joeyb747]

I worded that wrong...sorry. 

Does anyone know for sure how much fuel was onboard at the time of the crash?

about 4000kgs

Ok. Thank you.

[iskyfly]

just the facts please....

http://www.flightglobal.com/blogs/unusual-attitude/2009/03/turkish-airlines-crash-evidenc.html

This morning the Dutch investigators are holding a press conference on the Turkish Airlines Boeing 737-800 crash at Amsterdam last week and I understand that later Boeing will release a safety bulletin. From a reliable source, the contents of the Boeing bulletin will include the points below. Regrettably they don't reflect well on the pilots, who are dead of course - but I'd caution that there is a long investigation still to come.


no evidence of fuel shortage, birdstrike, icing, windshear, wake turbulence, or engine, system or control malfunction
the first officer was initially flying the aircraft and was inexperienced in airline operations
autopilot and autothrottle were in use
the aircraft was initially high and fast on the approach and at about 2,000ft above ground the throttles were pulled to idle
the authrottle went to "retard" mode and the throttles then stayed at idle for about 100 seconds during which time the speed fell to 40kt below reference speed
the aircraft descended through the glideslope with the captain talking the first officer through the before landing checklist
the stick shaker activated at about 400ft above ground and the first officer increased power
the captain took control and as the first officer released the throttles they moved to idle due to being in "retard" mode
after six seconds the throttles were advanced but as the engines responded the aircraft hit the ground in a slightly nose-high attitude
throughout the episode the left-hand radio altimeter read negative seven feet altitude, but the right-hand radalt worked correctly
Boeing will warn crews about fundamentals like flying the aircraft, monitoring airspeed, monitoring altitude, and will give advice about radalt issues.

* Capt LH seat, (fully qualified) FO in RH seat, observer FO on jumpseat
* Normal approach, no changes, to 18R
* Descent on AP, normal procedure for TK
* At 1950 ft LH RadAlt indicated -8 ft and passed this info on the A/T
* From CVR: crew get aural landing-gear warning but not consider this a problem
* A/T pulled throttles closed (At 1950 ft. because A/P thinks aircraft is landing)
* stick shaker at 450 ft (Because no reaction by pilots on closing of throttles by A/P)
* From FDR: full power was then applied
* FDR stores 25 hours, in this case 8 flights, same problem had occured twice previously before previous landings.

[joeyb747]

Thanks for the great info iflysky!

So this is looking more like an autopilot error? Am I reading this correctly? The last line in your post says:
"* FDR stores 25 hours, in this case 8 flights, same problem had occured twice previously before previous landings."

And if my math is correct and if tlsdk is correct on the 4000KGS of fuel on board, that would mean, for us stuburn Americans , 4000KGS=8800LBS (2.2 LBS/KG), witch translates into roughly 1295 Gallons of fuel (One gallon of jet fuel weighs 6.8LBS).

Given that, I think its safe to say fuel starvation was not the case!

[andreblt]

So this is looking more like an autopilot error?

the authrottle went to "retard" mode and the throttles then stayed at idle for about 100 seconds during which time the speed fell to 40kt below reference speed

What is the first thing they teach at flying school?
This is basic flying stuff. Speed control!!
The pilot is there in case the automation fails.
There is always that danger of relying too much on automation.
Therefore in my company it is mandatory during the approach to keep one hand on the control column and one on the power levers. That way the pilot is perfectly " hooked up" to the aircraft and remains in touch with whatever the aircraft is or is not doing.
As in most cases this is a tragic combination of equipment and human failure!!
I hope the industry will take it's lessons from this.

[joeyb747]

"As in most cases this is a tragic combination of equipment and human failure!!"

Makes sense. Do you think the pilot were just not paying attention to what the airplane was doing? You would think they would notice 40kts below reference. You know, a "somthing dosn't seem right" kind of thing.

[iskyfly]

Thanks for the great info iflysky!

So this is looking more like an autopilot error? Am I reading this correctly? 

In a crash there is no one single cause. Redundancy / layers are designed into the system to prevent things like this from happening. The final report will probably look something like this;

-Crew error

[iskyfly]

Prelim report here;

http://www.onderzoeksraad.nl/docs/rapporten/Persverklaring_4_maart_GB.pdf

[joeyb747]

I agree...accidents are a culmination of many factors.

They reference the radio altimeter a lot in the report. I thought the autopilot based its altitude on the barometric altimeter...is that incorrect? The radio altimeter measures distance above ground, and fluctuates with terrain passing under the aircraft. The barometric altimeter measures altitude over sea level, and remains constant. Am I correct on that?

[iskyfly]

I agree...accidents are a culmination of many factors.

They reference the radio altimeter a lot in the report. I thought the autopilot based its altitude on the barometric altimeter...is that incorrect? The radio altimeter measures distance above ground, and fluctuates with terrain passing under the aircraft. The barometric altimeter measures altitude over sea level, and remains constant. Am I correct on that?

I am not familiar with AP's and how they work but I do believe that during an ILS approach the radio altimeter is used so that you get call outs in AGL. ie (100, 50, 40, 30 20).

[joeyb747]

Makes sense. I'm thinking it uses both systems in unison.

[toogd]

In the initial report there is this paragraph:

"The voice recorder has shown that the crew were notified that the left radio altimeter was not
working correctly (via the warning signal “landing gear must go down”).
Provisional data indicates that this signal was not regarded to be a problem."

I imagine there will be some discussion about whether the warning signal "landing gear must go down" is indeed an adequate warning in the case of what is a fatal autopilot malfunction. Would not something like "Autopilot Error! Disengage Autopilot!" be a more logical message to a sudden drastic change in altitude, like from 1950 to 8 ft in a fraction of  a second, as measured by one of the crucial inputs to the AP system?

Anyway, I just would not have believed it to be possible for an automatic landing system to actually stall the aircraft like this and allow it to drop from the sky a whole km short of the runway! It boggles the mind.