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Turkish Airliner Crash in Amsterdam (Read 1198 times)
Feb 25th, 2009 at 5:41am

ShaneG   Offline
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Just seen a breaking news report, it's 5:30am here, so anyone in Europe got any more info?

All they know here is that it crashed on landing at Schipol and broke into 2 or 3 major pieces, but no fire thank goodness.  Oh, wait, they just showed a picture, looks like it was somewhat survivable. Undecided

 
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Reply #1 - Feb 25th, 2009 at 6:03am

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official statement that no one has died. so good news.
 
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Reply #2 - Feb 25th, 2009 at 6:24am

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close to my favorite spottersplaces, the news here is that there are no fatal injuries.... quite miraculous!
 

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Reply #3 - Feb 25th, 2009 at 6:26am

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Glad to hear that! Smiley Details here are still pretty sketchy and they just keep repeating the same stuff.

 
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Reply #4 - Feb 25th, 2009 at 6:37am

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I found some pictures but also shows medical personell working on victims so I don't know if the links are suitable for anyone, there's no blood or gore or anything like that but it shows the aircraft really well
 

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Reply #5 - Feb 25th, 2009 at 6:47am

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Unfortunately, Dutch media is now reporting a possible 4 or 5 casualties, press conference in 20 mins I'll keep you updated in case cnn doesnt
 

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Reply #6 - Feb 25th, 2009 at 7:11am

ShaneG   Offline
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They're showing the footage of the rescue workers now, but still reporting everyone Ok.  They haven't said what kind of plane yet either. A little hard to tell from the pics I'm seeing.
 
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Reply #7 - Feb 25th, 2009 at 7:48am

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Unfortunately the mayor of Haarlemmermeer reported 9 confirmed fatalities with over 50 wounded of which 25 seriously. The next press conference is at 16:00 local time ( in about 2 hours)

The plane was a 737-800
 

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Reply #8 - Feb 25th, 2009 at 9:01am

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Well, at least it did not break earlier. It looks like it broke apart near where it stopped. No fire, very lucky. 9 is still too many people to go... Cry
 
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Reply #9 - Feb 25th, 2009 at 9:51am

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Most of the information flow seems to have stopped now. Here's the information I could gather so far. Please note that not all of the information is officially confirmed yet and a lot of it could be based on speculation and/or rumours alone.

The website of Schiphol (http://www.schiphol.nl/index_uk.html) reports that at 10.31 this morning flight TK 1951 of Turkish Airlines, coming from Istanbul went down just north of the Polderbaan runway. The Boeing 737-800 was carrying 127 passengers and 8 crew members. Upon impact, the plane broke down into three main pieces.

During the press conference it was confirmed that 9 people were killed in the crash and over 50 were wounded, including 25 heavily wounded.

An information hotline is available for passengers’ family and friends: +31 235676543

Eyewitnesses reported that the plane was coming in extremely low and was flying very slow. The plane seemed to wiggle from left to right and then the tail dropped down. It flew like this for a moment and then the nose dropped down violently. It is unclear what happened in the moments between the nose dropping down and the impact. A man who was aboard the plane reported that the aircraft began to shake and then after about 10 seconds it crashed.

There are some unclarities about the way the plane crashed into the ground. It crashed into a muddy field that had just been plowed. Some people say it just fell straight down to the ground. Others report a 100 - 150 meter sliding distance before coming to a halt. This seems to be confirmed by the fact that one of the engines is lying about 100 meters behind the plane. The engines are designed to snap off quite easily in case of a crash. Peolpe living in the vicinity of the crash site felt the ground shake during the impact.

The plane broke into three large pieces (photos here: NOS News). There is a crack between the tailplane and the fuselage and another crack between the wings and the cockpit. Luckily, there was no fire, although there are some reports of one of the engines burning for a short while after the crash.

People crawled/ran out of the plane right after the crash. Some people went back into the plane to help others who were still stuck inside. There were also some locals on the ground who went in to help. Professional emergency help started arriving in about 15 minutes.

The weather conditions at the time of the crash were fairly normal for this location and time of year. It was was raining slightly and a little bit hazy.

Judging from all the images I've managed to estimate the location of the crash site:

Estimated crash site

Crash site overview

Schiphol airport overview

(all images from Google Earth)

The Polderbaan runway is a long distance from the main terminal area (about 7 kilometers).

Air traffic from and to Schiphol is still going, but of course there are much delays and cancellations. Some traffic is rerouted to Rotterdam Airport. Both the Polderbaan and Zwanenburgbaan runways have been closed.

According to the Turkish authorities the plane was constructed in 2002 and last inspected in december 2008.

I saw a Turkish press conference. I think the president of Turkish Airlines was speaking, although I'm not sure. Apparantly the plane was piloted by Hassan Tarcin. They started having problems at 500 meters altitude (about 1500 feet). It was also reported that all crew members survived, although Dutch sources report that some of the crew members were injured.

There is much speculation going on about the possible causes of the crash. There is much talk about a lack of fuel. This is supported by the absence of a fire after the crash. No official statements about the cause of the accident have been made so far. However, it seems clear that there was a sudden lack of power on the last part of the approach.

My thoughts are with all the people who are involved in this crash in any way. A condealance register has been opened here: http://www.condoleance.nl/registers/register_11104.html
 
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Reply #10 - Feb 25th, 2009 at 10:00am

ShaneG   Offline
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Thanks for the very in-depth report and the maps and links. This could have been so much worse than what it appears to be so far.

Still a tragic loss of life though. Sad

The running out of fuel certainly raises a lot of questions. Undecided
 
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Reply #11 - Feb 25th, 2009 at 10:23am

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ShaneG wrote on Feb 25th, 2009 at 10:00am:
Thanks for the very in-depth report and the maps and links. This could have been so much worse than what it appears to be so far.

Still a tragic loss of life though. Sad

The running out of fuel certainly raises a lot of questions. Undecided


You're welcome, but again, please note that the running out of fuel is only speculation.

The next press conference has been delayed for half an hour (16.30 European time).
 
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Reply #12 - Feb 25th, 2009 at 11:47am

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New information from the press conference:

134 passengers were aboard the plane
9 confirmed fatalities, including 3 crew who are still in the cockpit.
6 critically wounded.
25 heavily wounded
24 lightly wounded
31 people with injuries that need to be examined further.

84 people were taken to 11 different hospitals. Rescue operations included 60 ambulances and 150 personnel. There were also some trauma helicopters and special vehicles with tracks to get the injured out of the muddy field.

The "black boxes" (I guess they are talking about the flight data recorder and the cockpit voice recorder) have been found.

A special flight with family and friends has departed from Istanbul. The Turkish government thanked the Dutch government for making an exception on visa regulations.

The next press conference will be at 19.15, European time. I don't think there will be news about the cause of the crash though.

Apparantly flight TK1951 didn't dump fuel over the ocean before landing, as it was supposed to. This might point to a lack of fuel. However, these are all still rumours.

Video of the crash site here: http://www.rtl.nl/components/actueel/rtlnieuws/miMedia/2009/week09/wo_1545_vlieg...
 
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Reply #13 - Feb 25th, 2009 at 1:22pm

Ivan   Offline
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9 dead at time of writing...

Probably full of holiday returnees.

Media is already starting a THY bashing session. Turkish airlines have a bad reputation here.

But they were lucky... it could have ended much worse... on the highway or crashing into the road dike
 

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Reply #14 - Feb 25th, 2009 at 7:54pm

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What could happpend? No Fire? a Boeing 737-
800
? this is weird  Undecided
 
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Reply #15 - Feb 25th, 2009 at 11:26pm
Sir Crashalot   Ex Member

 
Apperently that video in the link Syste provided doesn't work so here is another one: http://www.nuvideo.nl/algemeen/24055/helikopterbeeld-vliegcrash-bij-schiphol.htm...

 
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Reply #16 - Feb 26th, 2009 at 4:36am

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I see that no fire and fuel is being questioned quite a bit on the various bloggs, well one thing does point to it, though there could be other reasons.

Notice any similarities in the two pictures.........no rotational damage to the fan blades?
However, like everyone else, I am speculating

Matt

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Reply #17 - Feb 26th, 2009 at 7:34am

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Our head of the NTSB also indicated yesterday that there may have been a problem with the engines.

CFM has sent a delegation to check, Boeing has done likewise
 

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Reply #18 - Feb 26th, 2009 at 7:49am

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the spoilers were down,see the lead edge
 
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Reply #19 - Feb 26th, 2009 at 2:31pm

Ivan   Offline
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Nose gear allegedly went through the cockpit floor...

Most people are already released from the hospital...

More info tomorrow from the FDR.
Radio comms dont have any suspicuous communications from passing the border until transfer to tower
 

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Reply #20 - Feb 28th, 2009 at 6:54am
Sir Crashalot   Ex Member

 
There is a video released made by one of the passengers right after the crash. Emergency services still have to arrive.

http://www.hartvannederland.nl/item/19565/Eerste_beelden_van_net_na_de_crash

 
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Reply #21 - Feb 28th, 2009 at 7:11am

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Quote:
There is a video released made by one of the passengers right after the crash. Emergency services still have to arrive.

http://www.hartvannederland.nl/item/19565/Eerste_beelden_van_net_na_de_crash



A reflection of todays society, time to take a video, but not help/try to help other passengers, sit with and or comfort the trapped especially when the emergency services have not even arrived. Maybe I am a bit old fashioned Huh

Aside from that, any word of FDR/cockpit recorder data in the Dutch press Crash? The UK are reporting that the Turkish Airline Pilots Association are saying it was caused be wake turbulence from a 757 that was two minutes further up the flight path. The fact that the crash damage to the engines show otherwise, well certain nationalities do let national pride get in the way of rational thought and Turkey is very high up on that list. Not a racist remark, but an observation, being in Germany one is able to witness this almost on a daily basis Undecided

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Reply #22 - Feb 28th, 2009 at 7:20am
Sir Crashalot   Ex Member

 
No news on the FDR/CR for as far as I know. They were sent to France to be examined. Speculations here are ranging from lack of fuel to that wake theory you mentioned.
 
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Reply #23 - Feb 28th, 2009 at 7:43am

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expat wrote on Feb 28th, 2009 at 7:11am:
Quote:
There is a video released made by one of the passengers right after the crash. Emergency services still have to arrive.

http://www.hartvannederland.nl/item/19565/Eerste_beelden_van_net_na_de_crash



A reflection of todays society, time to take a video, but not help/try to help other passengers, sit with and or comfort the trapped especially when the emergency services have not even arrived. Maybe I am a bit old fashioned Huh

Glad I'm not the only one to notice that.
 

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Reply #24 - Mar 4th, 2009 at 9:14am

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Hagar wrote on Feb 28th, 2009 at 7:43am:
expat wrote on Feb 28th, 2009 at 7:11am:
Quote:
There is a video released made by one of the passengers right after the crash. Emergency services still have to arrive.

http://www.hartvannederland.nl/item/19565/Eerste_beelden_van_net_na_de_crash



A reflection of todays society, time to take a video, but not help/try to help other passengers, sit with and or comfort the trapped especially when the emergency services have not even arrived. Maybe I am a bit old fashioned Huh

Glad I'm not the only one to notice that.


Yes! Let's all jump straight to conclusions based on vague video material! After all, we all know how easy it is to keep thinking straight after being in an aircraft crash!

Roll Eyes


Anyway, there has just been a press conference with the first reports about the cause(s) of the crash.

The left radio altitude indicator was malfunctioning. It read -8 ft instead of 1950 ft. The right radio altitude indicator was working properly. The crew was using the auto pilot to land. The malfunction in the altitude reading caused the auto-throttle system to "think" it was right above the runway, so the power to the engines was reduced to idle. Because the plane was already very close to the runway, the pilots didn't respond to this as being a problem (throttle to idle is normal in the last stages of the approach). Only when the plane was beginning to stall did the crew react, but then it already was too late.

The plane hit the ground at 170 km/h and slid for 150 meters. The gear and engines snapped off, like they are designed to do in case of a crash landing. There were 127 passengers and 7 crew members on board. 4 American crew members and 5 Turkish passengers were killed in the crash. 28 people are still in hospital, one of them still in critical condition.

According to the data in the flight data recorder, the plane had trouble with the left radio altitude indicator before on two occasions. No further information about this is available at the moment.

A warning has been sent to Boeing about a section in the 737-800 manual, concerning the radio altitude indicators.
« Last Edit: Mar 4th, 2009 at 3:56pm by Sytse »  
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Reply #25 - Mar 4th, 2009 at 1:00pm

expat   Offline
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Sytse wrote on Mar 4th, 2009 at 9:14am:
Hagar wrote on Feb 28th, 2009 at 7:43am:
expat wrote on Feb 28th, 2009 at 7:11am:
Quote:
There is a video released made by one of the passengers right after the crash. Emergency services still have to arrive.

http://www.hartvannederland.nl/item/19565/Eerste_beelden_van_net_na_de_crash



A reflection of todays society, time to take a video, but not help/try to help other passengers, sit with and or comfort the trapped especially when the emergency services have not even arrived. Maybe I am a bit old fashioned Huh

Glad I'm not the only one to notice that.


Yes! Let's all jump straight to conclusions based on vague video material! After all, we all know how easy it is to keep thinking straight after being in an aircraft crash!

Roll Eyes


Anyway, there has just been a press conference with the first reports about the cause(s) of the crash.

The left radio altitude indicator was malfunctioning. It read -7 ft instead of 1950 ft. The right radio altitude indicator was working properly. The crew was using the auto pilot to land. The malfunction in the altitude reading caused the auto-throttle system to "think" it was right above the runway, so the power to the engines was reduced to idle. Because the plane was already very close to the runway, the pilots didn't respond to this as being a problem (throttle to idle is normal in the last stages of the approach). Only when the plane was beginning to stall did the crew react, but then it already was too late.

The plane hit the ground at 170 km/h and slid for 150 meters. The gear and engines snapped off, like they are designed to do in case of a crash landing. There were 127 passengers and 7 crew members on board. 4 American crew members and 5 Turkish passengers were killed in the crash. 28 people are still in hospital, one of them still in critical condition.

According to the data in the flight data recorder, the plane had trouble with the left radio altitude indicator before on two occasions. No further information about this is available at the moment.

A warning has been sent to Boeing about a section in the 737-800 manual, concerning the radio altitude indicators.



Well it would appear that the crew messed up in a big way then. The 737-800 (like most aircraft) have four altimeters, two baro and two rad alt. Firstly, they should have been cross referencing (when ever I have flown in the jump seat this is done shortly after take off and before landing). If an RA has failed then the autopilot is then degraded. If RA 1 had failed, then autopilot "A" should not be used for approach, if RA 2 has failed, then autopilot "B" should not be used for approach. If they noticed it and ignored it, well they should have known better. If they missed it, there were three other altimeters to reference too. It was reported that at the time it was misty and reduced visibility, possible CATII. For anything above CATII approach both RA's are mandatory.

From the MEL
Radio altimeter indicator or receiver/transmitter.
2 indicators must be operative for CAT II, CAT II Autoland and CAT IIIA
2 receiver/transmitters must be operative for CAT II, CAT II Autoland and CAT IIIA
Both indicators may be inop provided associated receiver/transmitters operates normally and approach minimals do not require its use.  
Do not use the autopilot and autothrottle for approach if the associated RA is inop.

Obviously more information has to come out before a full picture is made possible, but it would appear a lack of system monitoring and ignoring three altimeters against one did not help the situation Undecided

Matt
 

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Reply #26 - Mar 4th, 2009 at 1:28pm

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Sounds like a go-around as soon as the problem appeared may have been a prudent option. Time will tell, and from the comfort of an arm chair it is easy to say - the heat of the moment, far harder.
 
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Reply #27 - Mar 4th, 2009 at 3:54pm

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expat wrote on Mar 4th, 2009 at 1:00pm:
Well it would appear that the crew messed up in a big way then. The 737-800 (like most aircraft) have four altimeters, two baro and two rad alt. Firstly, they should have been cross referencing (when ever I have flown in the jump seat this is done shortly after take off and before landing). If an RA has failed then the autopilot is then degraded. If RA 1 had failed, then autopilot "A" should not be used for approach, if RA 2 has failed, then autopilot "B" should not be used for approach. If they noticed it and ignored it, well they should have known better. If they missed it, there were three other altimeters to reference too. It was reported that at the time it was misty and reduced visibility, possible CATII. For anything above CATII approach both RA's are mandatory.

From the MEL
Radio altimeter indicator or receiver/transmitter.
2 indicators must be operative for CAT II, CAT II Autoland and CAT IIIA
2 receiver/transmitters must be operative for CAT II, CAT II Autoland and CAT IIIA
Both indicators may be inop provided associated receiver/transmitters operates normally and approach minimals do not require its use.  
Do not use the autopilot and autothrottle for approach if the associated RA is inop.

Obviously more information has to come out before a full picture is made possible, but it would appear a lack of system monitoring and ignoring three altimeters against one did not help the situation Undecided

Matt


Thanks for the aditional information, Matt. This is the stuff I was wondering about, but they don't tell you on TV. Some questions for you (or others who know the answer):

Are there two autopilots (A & B) because there are two radio altimeters?

What is CAT II mist?

At what altitude is the gear usually lowered in an airliner?

How exactly does the autopilot work on landing? I figure it will fly the ILS and then flare for touchdown at 29 feet altitude? I didn't even know planes could land solely on the autopilot...

Why is it possible for the autopilot to put the aircraft into a stall. Shouldn't there be a precautionary system that prevents this from happening?



Some more info I could gather:

The pilots should have known the left RA was malfunctioning even before taking off, because it had malfunctioned two times before in the last 8 flights. This was found in the examination of the flight data recorder, which records the last 25 hours of flight data. However, I don't know what the exact maintenance procedure is for detecting and reporting this kind of malfunctions.

The crew now noticed the RA was malfunctioning after hearing the "gear down" warning. They did not think of it as a problem at the time.

Between the malfunction of the RA and the stall warning were 100 seconds (not an official fact) and an altitude difference of 1500 ft (1950 - 450).

The First Officer on the flight was in training. The 3rd crew member in the cockpit was an extra First Officer.

Use of the autopilot on landing is usual on Turkish Airlines flights. This is not an exceptional procedure.

At the start of the descent (it is not clear here whether they mean the start of the approach or the the start of the sudden descent) the runway was not yet visible to the pilots.

For the press conference (in Dutch) and an animation of the crash (based on interpretation) go to http://www.nos.nl/nosjournaal/artikelen/2009/3/4/040309_persconferentie.html

Also, a small correction of what I typed earlier. The malfunctioning RA indicated -8 ft, in stead of -7 ft. The plane's actual altitude was 1950 ft.
 
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Reply #28 - Mar 4th, 2009 at 5:54pm

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Sytse wrote on Mar 4th, 2009 at 3:54pm:
expat wrote on Mar 4th, 2009 at 1:00pm:
Well it would appear that the crew messed up in a big way then. The 737-800 (like most aircraft) have four altimeters, two baro and two rad alt. Firstly, they should have been cross referencing (when ever I have flown in the jump seat this is done shortly after take off and before landing). If an RA has failed then the autopilot is then degraded. If RA 1 had failed, then autopilot "A" should not be used for approach, if RA 2 has failed, then autopilot "B" should not be used for approach. If they noticed it and ignored it, well they should have known better. If they missed it, there were three other altimeters to reference too. It was reported that at the time it was misty and reduced visibility, possible CATII. For anything above CATII approach both RA's are mandatory.

From the MEL
Radio altimeter indicator or receiver/transmitter.
2 indicators must be operative for CAT II, CAT II Autoland and CAT IIIA
2 receiver/transmitters must be operative for CAT II, CAT II Autoland and CAT IIIA
Both indicators may be inop provided associated receiver/transmitters operates normally and approach minimals do not require its use.  
Do not use the autopilot and autothrottle for approach if the associated RA is inop.

Obviously more information has to come out before a full picture is made possible, but it would appear a lack of system monitoring and ignoring three altimeters against one did not help the situation Undecided

Matt


Thanks for the aditional information, Matt. This is the stuff I was wondering about, but they don't tell you on TV. Some questions for you (or others who know the answer):

Are there two autopilots (A & B) because there are two radio altimeters?

What is CAT II mist?

At what altitude is the gear usually lowered in an airliner?

How exactly does the autopilot work on landing? I figure it will fly the ILS and then flare for touchdown at 29 feet altitude? I didn't even know planes could land solely on the autopilot...

Why is it possible for the autopilot to put the aircraft into a stall. Shouldn't there be a precautionary system that prevents this from happening?



Some more info I could gather:

The pilots should have known the left RA was malfunctioning even before taking off, because it had malfunctioned two times before in the last 8 flights. This was found in the examination of the flight data recorder, which records the last 25 hours of flight data. However, I don't know what the exact maintenance procedure is for detecting and reporting this kind of malfunctions.

The crew now noticed the RA was malfunctioning after hearing the "gear down" warning. They did not think of it as a problem at the time.

Between the malfunction of the RA and the stall warning were 100 seconds (not an official fact) and an altitude difference of 1500 ft (1950 - 450).

The First Officer on the flight was in training. The 3rd crew member in the cockpit was an extra First Officer.

Use of the autopilot on landing is usual on Turkish Airlines flights. This is not an exceptional procedure.

At the start of the descent (it is not clear here whether they mean the start of the approach or the the start of the sudden descent) the runway was not yet visible to the pilots.

For the press conference (in Dutch) and an animation of the crash (based on interpretation) go to http://www.nos.nl/nosjournaal/artikelen/2009/3/4/040309_persconferentie.html

Also, a small correction of what I typed earlier. The malfunctioning RA indicated -8 ft, in stead of -7 ft. The plane's actual altitude was 1950 ft.


To answer some of your questions;

There are two autopilots A&B. This has has nothing to do with the number of rad alts. The quick answer ,there are legal requirements laid down for autopilots and autoland. One of these requirements is two fully functional autopilots. They monitor each other along with several other functions.

The CAT's I,II,IIIA and IIIB&C are standards of ILS and visibility. I believe that the day in question was CAT II (requiring both RA's for autopilot approach).
Category I - A precision instrument approach and landing with a decision height not lower than 200 feet (61 m) above touchdown zone elevation and with either a visibility not less than 800 meters (2,625 ft) or a runway visual range not less than 550 meters (1,804 ft).
Category II - Category II operation: A precision instrument approach and landing with a decision height lower than 200 feet (61 m) above touchdown zone elevation but not lower than 100 feet (30 m), and a runway visual range not less than 300 meters (984 ft).
Category III is further subdivided
Category III A - A precision instrument approach and landing with:
a decision height lower than 100 feet (30 m) above touchdown zone elevation, or no decision height; and
a runway visual range not less than 200 meters (656 ft).
Category III B - A precision instrument approach and landing with:
a decision height lower than 50 feet (15 m) above touchdown zone elevation, or no decision height; and
a runway visual range less than 200 meters (656 ft) but not less than 50 meters (164 ft).
Category III C - A precision instrument approach and landing with no decision height and no runway visual range limitations. A Category III C system is capable of using an aircraft's autopilot to land the aircraft and can also provide guidance along the runway surface.
(Cut from Wiki)

The autopilot on landing follows the ILS path. These are standard frequencies that are "beamed" out from the runway to show the aircraft the ideal glide slope to follow (the localiser and the glide slope) The autopilot takes these signals and follows them down to the runway........that was the simple answer. As for your flair question, only if the aircraft has autoland, otherwise the system will fly the aircraft without flair into the ground. Pilots don't like as a rule giving this bit of control away and go manual shortly before touch down. However in this case, if the crew were flying an autoland approach and an RA is inop, then certain autoland options are also inop, throttle retard on touch down for example.

Why the autopilot put the aircraft into a stall, we don't have enough information about that, but I would guess that the crew did it in the last seconds. Noticed what was going on, fire walled the engines and then pulled back, but did not have enough hight to arrest the sink rate, but just a guess on that one.

The gear question, maybe Charlie will be able to answer that one.

As for the crew noticing that the RA no longer functioned when the gear was put down, they should have known that the autopilot was degraded at that point and that they should not make a CATII autopilot approach, as Charlie said earlier, a go around would have been a good idea and then work on the problem, that however is 20/20 hindsight on our part.

If as you say the runway was not visible (at any stage), a CATII autopilot approach with duff RA, big no no. They should have flow manual on the needles until decision hight and called it.

Flying the approach on autopilot is a company decision. The last company I worked for, an autopilot approach was company policy. The present company I work for the pilot has to manaully fly the needles once established or at the latest when the VASI's are seen.

Lastly, it would sound as if they where flying an approach with only one autopilot engaged because the system will be monitoring itself and would disengage if it found a large error.I hate to go on, but if that was the case, another no no under CAT II autopilot approach.

OK, now the disclaimer...........I am speculating a bit, we do not have all the facts outside of the regulations that I know and have to work with. Maybe other members who are air side can chip in too.  All information therefor is subject to amendment and correction as more facts are released about the accident.

Matt

 

PETA ... People Eating Tasty Animals.

B1 Boeing 737-800 and Dash8 Q-400
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Reply #29 - Mar 4th, 2009 at 7:37pm

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expat wrote on Mar 4th, 2009 at 5:54pm:
The gear question, maybe Charlie will be able to answer that one.


I can only of course speak for one type, albeit similar sized. W put our gear down before intercepting the localiser/runway extended centreline, and hence before the glidepath (ie, the final approach). Normally about 12nm out. If anything it helps control the speed at a reasonable level without taking more than 20 flap, particularly if doing a low noise approach, where further flap is only taken at about 4nm.

Quote:
Flying the approach on autopilot is a company decision. The last company I worked for, an autopilot approach was company policy. The present company I work for the pilot has to manaully fly the needles once established or at the latest when the VASI's are seen.



Thankfully my employer is more flexible. I'd say that of every 5 ILS's I'll do, I do 3 or 4 manually, and 1 or 2 using our autopilot, mainly to keep my hand in at the switchery and mouth-music required. Having said that, ours is an old and temperamental AP, so occasionally they become manual anyway. We're also only Cat I.
 
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Reply #30 - Mar 4th, 2009 at 8:45pm

Sytse   Offline
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Thanks for all the info huys. this really helps make a clearer picture.

Quote:
The autopilot on landing follows the ILS path. These are standard frequencies that are "beamed" out from the runway to show the aircraft the ideal glide slope to follow (the localiser and the glide slope) The autopilot takes these signals and follows them down to the runway........that was the simple answer. As for your flair question, only if the aircraft has autoland, otherwise the system will fly the aircraft without flair into the ground. Pilots don't like as a rule giving this bit of control away and go manual shortly before touch down. However in this case, if the crew were flying an autoland approach and an RA is inop, then certain autoland options are also inop, throttle retard on touch down for example.


The RA was not inoperative, but malfunctioning. So, the throttle retard is exatcly what happened, but the plane was still high in the air, in stead of touching down.

I don't know about the visibility, but it didn't seem very hazy on TV, only a little. People driving on the highway could see the plane in the air, just before it crashed. The clouds were very low though.

Charley, at what altitude (above ground level) are you flying when lowering the gear?
 
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Reply #31 - Mar 5th, 2009 at 5:03am

expat   Offline
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Sytse wrote on Mar 4th, 2009 at 8:45pm:
Thanks for all the info huys. this really helps make a clearer picture.

Quote:
The autopilot on landing follows the ILS path. These are standard frequencies that are "beamed" out from the runway to show the aircraft the ideal glide slope to follow (the localiser and the glide slope) The autopilot takes these signals and follows them down to the runway........that was the simple answer. As for your flair question, only if the aircraft has autoland, otherwise the system will fly the aircraft without flair into the ground. Pilots don't like as a rule giving this bit of control away and go manual shortly before touch down. However in this case, if the crew were flying an autoland approach and an RA is inop, then certain autoland options are also inop, throttle retard on touch down for example.


The RA was not inoperative, but malfunctioning. So, the throttle retard is exatcly what happened, but the plane was still high in the air, in stead of touching down.

I don't know about the visibility, but it didn't seem very hazy on TV, only a little. People driving on the highway could see the plane in the air, just before it crashed. The clouds were very low though.

Charley, at what altitude (above ground level) are you flying when lowering the gear?


The point here is the crew noticed that the rad alt was malfunctioning and did nothing about it and ignored three perfectly working altimeters. So if they noticed it, it should have been regarded as inop. Add to that if they could not clearly see the runway with the naked eye, they should not have been flying an approach on a single autopilot. Without wiring diagrams (I am at home), I cannot say what influence a malfunctioning RA would have had on the autothrottle, but the autothrottle has minimum speed protection when on the glideslope (other times too, but they are not in question). Also, autothrottle retard is at 27 feet RA, so the crew would be flaring to land some three to four seconds later. When in this time scale you have not touched down, well we will just keep faring, the runway must be somewhere under us???

Matt
 

PETA ... People Eating Tasty Animals.

B1 Boeing 737-800 and Dash8 Q-400
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Reply #32 - Mar 5th, 2009 at 9:05am

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Sytse wrote on Mar 4th, 2009 at 8:45pm:
Charley, at what altitude (above ground level) are you flying when lowering the gear?


Normally around 2000ft AGL, depending on the approach in question. Not many approaches are any lower.
 
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