Turkish Airlines Boeing 737-800 crashed @ AMS

[Hakan 2]

according as report, aircraft was making approach and then Autopilot (aircraft) thought reach the flare altitude and gets the aircraft in flare position before the runway and wrong alitude due wrong altitude indicator value! also with so many suspicious claims.

 

firstly;

 

there are 3 pilots in the cockpit, if Captain saide altirude shows erroneus altitude value, how they passed crosscheck altitudes! final approach phase is the most important part of a flight, so all pilots (at least PF and PNF) should be in aware whats going on, how they missed N1,Throttle iddle position for a long time, dropping speed (on speed tape).

if was it so, how they didn't see DH,MDA, DME compare when aircraft gets flare position! and they didn't make during 100second?

 

Secondly;

according as report, F/O in PIC(PF) at that moment, wrong altitude indicator was left side, so captain's. Autopilot B was ON position and approach was DUALMODE. Autopilot gets the altitude information from captain's side even be F/O flies or AP B in active! this is very critical design faiulure for a 70million dollars airplane!

 

there are too much things to say about details of report.

[Ashmil Abd Ghani 0]

METAR: EHAM 251025Z 22011KT 3500 -DZ BR OVC007 05/04 Q1027 TEMPO 2500

 

Hello good day to all,

 

Sorry ask a question been posted long time here..I really appreciate if someone can explain what the METAR reading about..What it mean for each reading??

 

Sorry to ask because I not a sim player and have little knowledge of flight deck instrument..

 

Thanks in advance.. :)

Edited March 15, 2009 by Ashmil Abd Ghani

[Mohd. Afiq A. 0]

Secondly;

according as report, F/O in PIC(PF) at that moment, wrong altitude indicator was left side, so captain's. Autopilot B was ON position and approach was DUALMODE. Autopilot gets the altitude information from captain's side even be F/O flies or AP B in active! this is very critical design faiulure for a 70million dollars airplane!

 

Many systems in the aircraft are designed that way, it's the same for Airbus too. When AP2 is selected and we select Dual channel for approach, it swaps to AP1 automatically, and thus will take the readings based on Capt's instruments. Not really a design failure if you ask me, more like a safety reason. In this case, it was just so unfortunate this happened. Maybe the Capt was teaching the F/O things on approach, and was not monitoring the instruments. It's always and definitely easier to say things from our point of view. But if we're in their shoes, it would be a different story. Just my two cents

 

Btw, if RA 1 is giving erroneous reading and it's a defect that has been deferred, would the procedure call for them not to use dual channel on approach? I can't quite remember myself. Maybe Capt Radzi could clarify this.

 

Ashmil, METAR decoded for you

EHAM=airport identifier, 25=date of issue, 1025Z=time the METAR is issued UTC time, 220 =wind direction, 11KT=wind speed in Knots. 3500=visibility in meters. -DZ=slight drizzle BR=Mist. OVC007=Overcast clouds at 700feet. 05/04=Temperature is 5 degrees Celsius and the dew point is 4 degrees Celsius. Q1027=QNH 1027. TEMPO 2500=Temporary change of visibility to 2500 meters

[Ashmil Abd Ghani 0]

Ashmil, METAR decoded for you

EHAM=airport identifier, 25=date of issue, 1025Z=time the METAR is issued UTC time, 220 =wind direction, 11KT=wind speed in Knots. 3500=visibility in meters. -DZ=slight drizzle BR=Mist. OVC007=Overcast clouds at 700feet. 05/04=Temperature is 5 degrees Celsius and the dew point is 4 degrees Celsius. Q1027=QNH 1027. TEMPO 2500=Temporary change of visibility to 2500 meters

 

Thank You Capt/FO (??) Afiq... :good: Just add some valuable knowledge to me..I appreciate that..

 

"..It is been a pleasure having you onboard and we are looking forward to serving you again soon.."

[Hakan 2]

Afiq,

 

according as your opinion, autoland systems can be get altitude information from captain side RA, that is normal even there are 2 radio altimeters besides captain sides.

 

-Is this a design mistakes of autopilot structure? becouse pilots would be thinks about "we have spare systems if one of them malfunction"

-Why Boeing engineer/system engineers didn't made any alternative way to if dropps LRA INOP and why system verified with other Radio altimeters for continue approach because if you are in the middle of CATIII approach you would like to trust to works as well radio altimeters and probably your expects, working RA would be provide systems.

 

-Has Boeing capability of any warning about LRA INOP/ if LRA INOP, is there any warning message or sound about while you are attempting in dual/single channel autoapproach/autoland?

[Pieter C. 5]

The sad remains of TC-JGE, being 'stored' in the Hangar 4, for further investigations...

 

 

(as you can see, all windows are sealed-off)...

[Pieter C. 5]

Turkish 737 altimeter fault occurred on several flights prior to crash

 

Dutch accident investigators have determined that the radio-altimeter fault that is the focus of their probe into the fatal loss of a THY Turkish Airlines Boeing 737-800 at Amsterdam Schiphol had occurred on several of the nine previous flights by the aircraft.

 

On two of the flights, which were retained on the digital flight data recorder (DFDR), the fault caused the autothrottle to enter retard mode and the throttles to close as they did on the accident flight.

 

The investigators note that Boeing guidance is that the autopilot and autothrottle should not be used on approach, as they were on the accident flight, if the radio altimeter malfunctioned on the previous flight. It is not stated whether a malfunction was in fact identified on the previous flight.

 

In their preliminary report they also describe how the aircraft entered the glidepath from above rather than below, and only decelerated to the correct approach speed of 144kt at an altitude of 770ft. With the throttles at idle, the aircraft's speed subsequently fell to 110kt at 420ft and a last-ditch attempt by the crew to recover was unsuccessful.

 

The report relates how, in daytime and good weather on 25 February, the aircraft (TC-JGE), which was otherwise found to be fault-free, was flown from Istanbul to Amsterdam by the crew consisting of a line-training captain, a first officer performing a "line flight under supervision (LFUS)", and another first officer in the jump seat required as a safety pilot during a LFUS. All three died, as well as a flight attendant and five passengers.

 

The left-hand radio altimeter, which feeds the autopilot and autothrottle, recorded its maximum permissible altitude of 8,191ft until the aircraft descended to an actual altitude of about 1,950ft when the recorded value "suddenly changed to -8ft and remained at that value up until shortly before impact".

 

Cockpit voice recorder data shows that "several aural landing configuration warnings" - for flaps and landing-gear - sounded at altitude and then again while on the approach, when they were triggered by the low radio-altitude reading. The warnings and the crew's reaction are still being examined.

 

The investigators say the standard procedure for runway 18R at Amsterdam is for air traffic control to line up aircraft at 8nm and 2,000ft altitude, but a line-up of 5-8nm may be offered. The Turkish flight lined up at 6nm and 2,000ft and descended to onto the glidepath from above, the crew selecting vertical-speed mode to attain the glidepath at 1,330ft. They reduced speed from their initial 165kt to the correct 144kt by 770ft, selecting 40° flap at 900ft.

 

At the same time the autothrottle "entered the retard mode" normally engaged during the landing flare and the thrust levers went to idle. The speed continued to decay and the autopilot steadily commanded nose-up to try to maintain the glideslope.

 

Eventually the stick-shaker, warning of an imminent stall, triggered at about 460ft. The report says the thrust levers were immediately advanced but "moved back to idle" and the autothrottle disengaged, either by the crew or automatically. Speed by then was 110kt, the aircraft 11° nose-up, and the angle of attack at about 20°.

 

At 420ft the crew disengaged the autopilot and attempted to recover, reaching 8° nose-down at 310ft with full-power then generating a slight climb, but it eventually reached a 22° nose-up attiude with 10° left bank before crashing 1.5km from the threshold. The fuselage broke in two places and the cockpit and cabin were severely damaged. Eighty-six occupants were injured, in addition to the nine fatalities.

 

The report states: "The door between the cabin and the cockpit was found partly opened."

 

It concludes: "The Dutch Safety Board has issued a warning to Boeing in which extra attention is asked for a part of one of the manuals (737 dispatch deviations guide) of the Boeing 737. In this guide it is stated that if, [during the] preceding flight, the radio altimeters are malfunctioning, the associated automatic pilots and autothrottle systems cannot be used for approach and landing. The board has given Boeing into consideration to investigate if these procedures should also be valid during all phases of a flight.

 

"Boeing has issued a multi-operator message the same day concerning malfunction of the radio altimeters."

 

[Gavin Andrew David 6]

 

 

On February 25, 2009, a Turkish Airlines Boeing 737-800 (Turkish Airlines Flight 1951) crashed about a mile (1500m) short of the runway at Amsterdam Schiphol Airport. The Dutch Safety Boardpublished preliminary findings only one week after the crash,suggesting the autoland played a key role in downing the plane.According to the Flight Data Recorder, the airplane was on a full autoland approach at a height of 1950 ft / 595 m when the left Radio Altimetersuddenly misreported a height of -8 ft. The autoland system respondedaccordingly and configured the plane for touchdown, idling the engines.This made the plane lose speed and stall.When the flight crew received stall-warnings, they were already too lowand too slow to pull up again. As a secondary factor, the Safety Boardsuggested the crew did not have a visual ground reference because offoggy conditions.

 

At this point it is unclear how failure of one radio altimeter couldcause a crash during an autoland approach. The autoland system hasobviously been designed to be fail-safe and the airplane was equippedwith more than one radio altimeter.

 

The final investigation report will be published later this year.

 

 

Always imagined this as redundant with the autoland disconnecting as soon as something wasn't right .

 

Quite a scary thought

 

 

 

[Hakan 2]

At this point it is unclear how failure of one radio altimeter couldcause a crash during an autoland approach. The autoland system hasobviously been designed to be fail-safe and the airplane was equippedwith more than one radio altimeter.

 

Yes , we are curious how could it to be? becouse CMD2 is active on F/O side but autopilot/autolanding still works by "only" captain side RA!. Crew tried to full open throttle but levers comes back to iddle. Captain supposes open full throttle and takes his hands from levers thatswhy no one realize throttle levers back. When realized throttle came back iddle, they lost very precious a few seconds. I couldn't read any report,crew pushed TOGA button or not. Also there is no clear points about; did they do -disengage A/P- or not, if yes when? that 5-8 seconds are really mind confused.

 

According me, there is a system problem between RA+autopilot/autoland. This is nt seems very big problem but if some unexpected situations gets side by side, it causing accident. Another point that I'm curious, as far as I know, if you push/pull control yoke with an overlimit forces or sudden movement on control yoke, CWS is becomes active. I think it means control changes to pilot from autopilot. Why auto throttle throttle did not disengage when pilot applyed forced to open full throttle? TOGA button is a certain necessary for disengage without switch off A/T?

If Boeing engineers has been add a commands on flight controls onto throttle like as CWS maybe pilots would have a chance.

 

Honestly, I don't expect Boeing's engineers forgets this possibility. But I belive , something goes wrong in there.

[Pieter C. 5]

Here's is final report of the Dutch Safety Board:

 

The Feb. 25, 2009, crash of a Turkish Airlines 737-800 on approach to Amsterdam Schiphol was caused by a malfunctioning radio altimeter, a non-stabilized approach, poor reactions from the pilots and insufficient directions from air traffic control, the Dutch Safety Board concluded in its final report released yesterday.

 

Nine persons were killed and a further 120 injured after the aircraft crashed short of the runway during final approach. "That the accident could happen was the result of a convergence of circumstances," the board said. "These circumstances could only have resulted in the accident happening because of their mutual interaction."

 

While executing the approach by means of the ILS with right autopilot engaged, the 737's left radio altimeter showed an incorrect height of minus 8 ft. on the left primary flight display. This resulted in activation of the autothrottle's "retard flare" mode whereby the thrust of both engines was reduced to a minimal value (approach idle) in preparation for the last phase of the landing. Owing to the approach heading and altitude provided to the crew by ATC, the localizer signal was intercepted 5.5 nm. from the runway threshold rather than at least 6.2 nm., with the result that the glideslope had to be intercepted from above.

 

"This obscured the fact that the autothrottle had entered the retard flare mode. In addition, it increased the crew's workload," investigators noted. When the aircraft descended to 1,000 ft., the approach was not stabilized "so the crew should have initiated a go-around," the board said. The right autopilot (using data from the right radio altimeter) followed the glideslope signal. As the airspeed continued to drop, the aircraft's pitch attitude kept increasing. "The crew failed to recognize the airspeed decay and the pitch increase until the moment the stick shaker was activated," according to the report. "Subsequently the approach to stall recovery procedure was not executed properly, causing the aircraft to stall and crash."

 

The board said its investigation did not uncover a reason for the altimeter malfunction but stated that "the failure of radio altimeter systems in 737-800 aircraft has a long history." Boeing "reasonably" could have realized that the problem, particularly the effect on the autothrottle, could have had an impact on safety, it said. It is recommending that the manufacturer improve the reliability of the radio altimeter system and that it review its "approach to stall" procedures with regard to the use of autopilot and autothrottle.

 

The report also was critical of AMS controllers, who "must observe the procedures as they are described in the rules" and not engage in individual interpretation. "The given heading instructions did not enable the aircraft to be in level flight on the final approach track before intercepting the glidepath from below," the board said. "This is not in line with the ICAO guidelines for this type of approach."

 

THY said it disagrees with "certain aspects" in the DSB report, in particular two conclusions: "Approach stabilization is not a factor in the causation of this accident and it is claimed by the report that the crew could have recovered the aircraft after the stall warning was received. However, even though the crew promptly reacted, autothrottle kicked back unexpectedly. The second attempt by the crew, after disengaging the autothrottle, to advance thrust levers was successful but too late."

 

-----------------------------------------------------------

 

This is the Reuters press-report:

 

Altimeter, Pilot Error Led To Schiphol Crash

 

May 6, 2010

 

A faulty altimeter and pilot error led to the Turkish Airlines crash at Amsterdam last year, Dutch investigators said on Thursday, urging the industry to improve training and reporting of technical glitches.

 

Nine people were killed when flight TK 1951 from Istanbul crashed on approach to Schiphol Airport on February 25, 2009. Investigators had earlier said a faulty altimeter had shut down the engine of the Boeing 737-800 before it crashed.

 

But the Dutch Safety Board said in its final report that a combination of the altimeter problems, bad reactions from the Turkish Airlines pilots, as well as a loss of speed and insufficient directions from air traffic control, led to the crash.

 

The board said that due to the failing of the altimeter, the airliner automatically lost speed, dropping below the minimum velocity needed to avoid the risk of engines stalling.

 

The pilots failed to intervene adequately at several crucial moments of the descent, said safety board director Pieter van Vollenhoven, who called for better international pilot training to deal with emergencies.

 

Boeing had said in response to the initial findings last year that it was "issuing a reminder to all 737 operators to carefully monitor primary flight instruments during critical phases of flight".

 

Officials at Boeing were not available for comment on the final findings. Turkish Airlines also had no immediate comment.

 

Dutch law firm AKD Prinsen Van Wijmen (AKD) has since said that survivors of the crash have agreed to its advice to ask Clifford Law Offices to start compensation proceedings in the United States against Boeing.

 

Safety board chief Van Vollenhoven said at a news conference that via "an exceptionally unfortunate combination of circumstances" the flight crew received directions from air traffic control to approach the runway in the usual manner.

 

Van Vollenhoven added Boeing and many airlines were aware of problems with the radio altimeter system, but that this had been considered a technical rather than safety issue. Also, in most cases, pilots did not report problems with the altimeter system.

 

"If Boeing had received more reports, the manufacturer might have reached the conclusion sooner that a new analysis was necessary," the safety board said in its finding.

 

Frans Vreede at law firm AKD said he was most concerned by findings that an altimeter comparator was not installed in the plane to ensure the right-hand altimeter, which was operating correctly, overrode the left-hand altimeter and alerted pilots.

 

Evert van Zwol, chairman of the Dutch pilots association VNV, said he welcomed recommendations for improved training, noting how the pilots appeared to have been distracted while running through the landing checklist.

 

"Training does happen, but it must happen more often. It should be repeated every year or once every two years or so," he told public broadcaster NOS.

 

(Reuters)

[Hakan 2]

Reuters and Dutch safety board still accuse to pilot insistently!

 

this is crash report which was released a few days ago;

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

 

also this is animation of crash about how was happend

http://link.brightcove.com/services/player/bcpid3138436001?bclid=1481460921&bctid=83635223001

 

Pilots hs responsible of crash only this point; they should be awarn when speed drops below Vref and throttle was not move on to get taken approach speed. But according reports,at that time , so when plane established G/S and reach down to Vref speed, crew was performing landing checklist. Theese are very important seconds between live and crashed.If they finished checklist few seconds before, they should be realize plane slowing down to below Vref before stall warning.

 

Also crash report says %80 Boeing is responsible of this accident.However Reuters won't be write down this very important system failure in whole news.

 

When I read the pre-report of accident I said that "there is a serious-critical software or system design failure on RA+Autoapproach system+Autothrottle mechanism.

BEcouse;

1- Autolanding or autoapproach system can not to be connect only on RA source!This is very important features of an aircraft and there are 3 source of getting RA value; captain,F/O and standby! there should be alternate options.Or system should be compare reliable values with three systems. If the system connected only captain side RA, when system shows errenous value, there is no chance to realize it!

This is really big mistake while making desing of an airplane autoland systems!

 

2- Second critical problem, throttle should have "also" disengage options when you push forward suddenly besides A/T disconnect buttons on throttle levers. Captain pushed to full throttle but , levers came back becouse system still thinking "flare" mode. For the safety reasons, go around shouldn't be apply push to disconnect A/T and A/P etc etc. Pilots should be only one action to get airplane controls if they needs. At this point, Boeing must be think all variations about pilots shall have emergency situations in 40000feet or 1000ft!If throttle did not back in first attempt, they have find a chance to recovery.

 

Interesting point of Turkish Airlines technic's reports to Boeing on their corporate discussion forums before years ago. THY technics has been informed to Boeing about this captain side RA failures also opens discussion forum pages of Boeing about getting other reports who they using the same model plane. Boeing did not react about this problem and did not publish bulletin until accident. But interesting, 2 years ago, Boeing modified the RA system on new produced Ng types! never need to inform to Boeing users!!!

 

This is not a USERS FAILURE, thatswhy bills would be really expensive for Boeing Company becouse of Boeing couldn't be get responsible of producers mistake while US economic crisis, when orders cancels or drops down in that period since 2000s!.

 

As result,

 

accident caused by %80 Boeing/%20 pilot+EHAM ATC. According me,%95Boeing is guilty and I give %5 pilots and EHAM ATC.

[Ian Parker 0]

Just came across this AlJazeera English article on a possible cover up by Boeing on problems on the 737 NG. Dunno if it has validity or jusr fear mongering. Interesting to watch anyways. Quite long.