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Turkish airliner crashes at Schiphol

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Turkish airliner crashes at Schiphol

Old 4th Mar 2009, 12:55
  #1021 (permalink)  
 
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No, it (AP) struggled to stay on the GS until stick shaker & stall. Max thrust then apllied to no avail at the low altitude. This is from the press conference just now.
That doesn't make any sense to me. On a dual channel the plane will go into flare at 50' and retard at 28' so why not here?

Not that it would have mattered really. Though the stall would have occured at higher altitude with more chance of recovery.
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Old 4th Mar 2009, 12:55
  #1022 (permalink)  
 
Join Date: Mar 2009
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Poor vision

Safety Board statement:
Error radio-alt: was 1950 but stated -8
A/T engaged put engines stationair. Because it acted as on ground.
Vision was poor, +/- 1000 ft
FDR readings: twice this error last 25 ours.

Did not gif any comments on handling of crew

This was only by readings of FDR.
Strong warning to Boeing to investicate Radio-alt connecting autopilot and/or A/T.
Dutch Safety board is leading investigator.
Participators:
Boeing
THY + Turkisch office transport
Englisch safety Board
French Flight safety
Frenche BEA
Not by the comma but pritty close.
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Old 4th Mar 2009, 12:58
  #1023 (permalink)  
 
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Birgenair DomRep 1996

sorry for injecting this, I'm usually wiser than to sepak up around you guys, but:

afair, the Birgenair 757 that crashed in the Dominican Republic in 1996 did so because of a clogged LHS pitot.
The A/P took it's speed reading from there and, as the static pressure decreased faster than the residual pressure inside the pitot, the indicated speed increased, causing the A/P to throttle back and pitch up to bleed off speed.
That's 13 years ago, and today we're seeing another accident, where the malfunction of one instance of a redundant instrument causes the A/T & A/P to fly the aircraft into a stall?
Should the systems not honor the redundancy and use the alternate system if one them signals a malfunction or at least the readings are wildly inconsistent?
There are probably more factors to consider than what I know, though.

Shortly after the Birgenair event, I got a chance to ride a 757 sim and the guys took me through the accident. There were multiple opportunities to save the day for the crew, had they interpreted the situation correctly and acted accordingly. I wonder if that wasn't true for this accident here.

But still: it seems that the system in both cases has failed and in doing so has not failed to safety.

and with that thought, I'll retract to silence again, leaving the discussion to those who know more than I.
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Old 4th Mar 2009, 12:59
  #1024 (permalink)  
 
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of course we know it was a dual coupled approach and so 'autoland' ready. If this was not the ' fact' the investigation board is undermining there own preliminary findings. If this crash has a relation with the RA's then it was a dual coupled approach.
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Old 4th Mar 2009, 13:03
  #1025 (permalink)  
 
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As I pointed out over a hundred posts ago in #921 you should be stabilised at 1000 feet in IMC. This means on glide, on speed and spooled up. If not it should be a mandatory go-around.

The crew seems to have got hot and high, and been way behind the aircraft. It seems amazing, but sadly all too likely, that they failed to notice the speed trend and of course the N1 values, never mind the Flight Mode Annunciation.

If this was meant to be an autoland then it also demonstrates the complacency that can be brought on by automation.

It just shows what is possible. But if this anything like what happened then it definitely goes on my '737 how not to do it' list.
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Old 4th Mar 2009, 13:07
  #1026 (permalink)  
 
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Unhappy

Sad to say it looks from the preliminary report that it was pilot error, no one was actually flying the airplane nor it would seem looking out of the windows.
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Old 4th Mar 2009, 13:09
  #1027 (permalink)  
 
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Did not gif any comments on handling of crew
Quite the contrary actually

Key factor according to press release:

Aircraft was on the GS and Loc. No deviations from that side. Auto throttle went to retard since it 'thinks' it's at 7ft RA and it's about to touch down. At the same time autopilot kept aircraft on GS --> airspeed reduced --> pitch up and so on....No corrective crew action taken...Stall and the rest we know.
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Old 4th Mar 2009, 13:09
  #1028 (permalink)  
 
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of course we know it was a dual coupled approach and so 'autoland' ready. If this was not the ' fact' the investigation board is undermining there own preliminary findings. If this crash has a relation with the RA's then it was a dual coupled approach.
If it was then a dual channel autoland, which would require 2 functioning Rad Alts, and one was obviously giving erroneous readings for the best part of 2000 feet, then the autoland should have be discontinued to a manual ILS (20/20 hindsight I appreciate, and there but for the grace, etc)
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Old 4th Mar 2009, 13:10
  #1029 (permalink)  
 
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press release OVV 4 March

http://www.nrc.nl/multimedia/archive...08_209243a.pdf

Here is the full preliminary 4 pages report of today in Dutch
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Old 4th Mar 2009, 13:12
  #1030 (permalink)  
 
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Inattentiveness with regards to airspeed control and FMA`s below 1000` on any approach is unacceptable . What is significant is WHY the crew was distracted from their primary task. The fact that it was a training flight will be a causal dynamic factor here. There comes a point when training should stop and doing the job safely becomes most important , leaving an opportunity for discussion on the ground safely after landing.
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Old 4th Mar 2009, 13:13
  #1031 (permalink)  
 
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At the risk of being shot down myself, the cloudbase couldn't have helped much in the situation that (allegedly) arose.
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Old 4th Mar 2009, 13:15
  #1032 (permalink)  
 
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first english newspaper comment (NRC dutch)

Bad altimeter a factor in plane crash
Published: 4 March 2009 14:37 | Changed: 4 March 2009 15:09
By the Associated Press
A faulty altimeter played an important role in a Turkish Airlines crash that killed 9 people in the Netherlands, according to Dutch investigators.

A forensic expert examines the wreckage of a Turkish Airlines passenger plane at Amsterdam Schiphol airport the day after the crash that killed nine people.
Photo Reuters
News - Five Turks and four Americans killed in Schiphol crash
Feature - White body bags on the brown clay at Schiphol
Background - Crash 'perfect' for technical investigation
Background - Twitter used as fast news service after plane crash
Pieter van Vollenhoven of the Dutch Safety Authority on Wednesday said the plane was landing on automatic pilot and the problem with the altimeter, a device that measures altitude, led to a loss of airspeed before the crash. At a nationally televised news conference in The Hague, Van Vollenhoven presented the agencies findings and issued a warning about the altimeter in the Boeing 737-800 that had experienced problems twice before.
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Old 4th Mar 2009, 13:17
  #1033 (permalink)  
 
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A very alarming aspect to this is:

FDR stores 25 hours, in this case 8 flights, same problem had occured twice previously before previous landings.
Is this within the MEL for the 738? Should something have been placarded as INOP?

The crew got themselves into a bad position with a KNOWN problem.
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Old 4th Mar 2009, 13:17
  #1034 (permalink)  
 
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From reading the last few posts I believe this was a simulated CATIII autoland, more than likely required for the new trainee so as to have the observer (possible safety pilot) released. Regardless, a failed RAD alt on one side should never end up with the aircraft falling out of the sky. I would be interested to see the companies SOP's for this type of approach. I fly the 738 myself and personally whenever the autopilot is going to land the aircraft I am very interested in the FMA both active modes and armed modes, so extreme vigilance is required by all pilots when carrying out these approaches, this was obviously lacking from this accident. Why was RETARD boxed in green right in front of the pilots eyes not picked up at almost 2000ft by any of the 3 crew. Very strange, I know our SOP's have the FO on instruments the whole way down until reaching taxi speed. Seems like a bit of automation complacency to me. On another note some posters above mentioned that the rad alt had done the same on previous landings. Off the top of my head i believe even 1 u/s rad alt downgrades the aircraft from CATIII.
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Old 4th Mar 2009, 13:17
  #1035 (permalink)  
 
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From Boeing

FROM: THE BOEING COMPANY
TO: MOM [MESSAGE NUMBER:MOM-MOM-09-0063-01B] 04-Mar-2009 05:29:01 AM US PACIFIC TIME
Multi Operator Message

This message is sent to all 737-100,-200,-300,-400,-500,-600,-700,-800,-900,-BBJ customers and to respective Boeing Field Service bases, Regional Directors, the Air Transport Association, International Air Transport Association, and Airline Resident Representatives.

SERVICE REQUEST ID: 1-1228079803
ACCOUNT: Boeing Correspondence (MOM)
DUE DATE: 10-Mar-2009
PRODUCT TYPE: Airplane
PRODUCT LINE: 737
PRODUCT: 737-100,-200,-300,-400,-500,-600,-700,-800,-900,-BBJ
ATA: 3400-00

SUBJECT: 737-800 TC-JGE Accident at Schiphol Airport, Amsterdam - 25 February 2009

REFERENCES:
/A/ 1-1222489391 Dated 25 February 2009

Reference /A/ provides Boeing's previous fleet communication on the subject event. The US NTSB, FAA, Boeing, the Turkish DGCA, the operator, the UK AAIB, and the French BEA continue to actively support the Dutch Safety Board's (DSB) investigation of this accident.

The DSB has released a statement on the progress of the investigation and has approved the release of the following information.

While the complex investigation is just beginning, certain facts have emerged from work completed thus far:

- To date, no evidence has been found of bird strike, engine or airframe icing, wake turbulence or windshear.
- There was adequate fuel on board the airplane during the entire flight.
- Both engines responded normally to throttle inputs during the entire flight.
- The airplane responded normally to flight control inputs throughout the flight.


The Digital Flight Data Recorder (DFDR) data indicates that the crew was using autopilot B and the autothrottle for an ILS (Instrument Landing System) approach to runway 18R at Amsterdam Schiphol airport. During the approach, the right Low Range Radio Altimeter (LRRA) was providing accurate data and the left LRRA was providing an erroneous reading of -7 to -8 feet. When descending through approximately 2000 feet the autothrottle, which uses the left radio altimeter data, transitioned to landing flare mode and retarded the throttles to the idle stop. The throttles remained at the idle stop for approximately 100 seconds during which time the airspeed decreased to approximately 40 knots below the selected approach speed.

The two LRRA systems provide height above ground readings to several aircraft systems including the instrument displays, autothrottle, autopilots and configuration/ground proximity warning. If one LRRA provides erroneous altitude readings, typical flight deck effects, which require flight crew intervention whether or not accompanied by an LRRA fault flag, include:

- Large differences between displayed radio altitudes, including radio altitude readings of -8 feet in flight.
- Inability to engage both autopilots in dual channel APP (Approach) mode
- Unexpected removal of the Flight Director Command Bars during approach
- Unexpected Configuration Warnings during approach, go-around and initial climb after takeoff
- Premature FMA (Flight Mode Annunciation) indicating autothrottle RETARD mode during approach phase with the airplane above 27 feet AGL. There will also be corresponding throttle movement towards the idle stop. Additionally, the FMA will continue to indicate RETARD after the throttles have reached the idle stop

Boeing Recommended Action
- Boeing recommends operators inform flight crews of the above investigation details and the DSB interim report when it is released. In addition, crews should be reminded to carefully monitor primary flight instruments (airspeed, attitude etc.) and the FMA for autoflight modes. More information can be found in the Boeing 737 Flight Crew Training Manual and Flight Crew Operations Manual.

Operators who experience any of the flight deck effects described above should consult the troubleshooting instructions contained in the 737 Airplane Maintenance Manual. Further, 737-NG operators may wish to review 737NG-FTD-34-09001 which provides information specific for the 737-NG installation. Initial investigations suggest that a similar sequence of events and flight deck indications are theoretically possible on the 737-100/-200/-300/-400/-500. Consequently the above recommendations also apply to earlier 737 models.
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Old 4th Mar 2009, 13:20
  #1036 (permalink)  
 
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?????

Post #1019 states:

Also, from the tech manual.

Two independent radio altimeters provide radio altitude to the related FCC. The Captainís radio altimeter provides radio altitude to the A/T. With a radio altimeter inoperative the autopilot will disconnect two seconds after LOC and GS capture, and the A/T will not retard at flare.

ALB

Something does not fit - in this case the autopilot did not disengage and the auto throttles did retard???!!

brgds
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Old 4th Mar 2009, 13:20
  #1037 (permalink)  
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To clear up a few points for non-737 folk.

Gear warning - probably 'too low gear' due to (faulty) low radalt reading with gear up at 1950'? (would normally be down at that height in my ops in that weather).

As far as I can see, we do NOT know it was a dual channel approach. In any case 'Flare' would not have been armed at the point of radalt fail on such.

A/P should NOT be used on the side with a failed radalt.

I think a radalt of 8ft would cause a retard of the throttles with A/T engaged but NB greb's post above - perhaps the RadAlt had not 'failed'? However, that should be instantly apparent with T/Ls that actually slam shut.

Based on the 'news' so far - I say Monitoring.................!!??? What a sad event. As lederhosen says, 1000' should have been the g/a point.
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Old 4th Mar 2009, 13:21
  #1038 (permalink)  

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SoaringtheSkies,

I'm not sure of the RA logic, but its always going to be problematic ascertaining which one is right if you've only got two isn't it? Redundancy isn't that simple but I'll leave that to the systems engineers...

My only other post on the thread suggested that this problem was somehow related to the operation (or lack thereof) of the AT...and it would appear that it is now heavily implicated.

However, for me, this accident demonstrates that we still don't have the man-machine interface sorted out yet.

From 1950-450ft I hazard a guess there was some confusion about what the automation was doing.

A salutary lesson to all of us and a reminder that, we are in control not vice versa.

Some will use this accident to defend, with renewed vigour, the elimination of pilots from the flightdeck.

We need to use it to justify our ongoing participation in commercial aviation.
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Old 4th Mar 2009, 13:21
  #1039 (permalink)  
 
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The crew seems to have got hot and high, and been way behind the aircraft. It seems amazing, but sadly all too likely, that they failed to notice the speed trend and of course the N1 values, never mind the Flight Mode Annunciation.

@ Lederhosen:
They were not hot and high. That was also stated after questioned by one of the reporters. The aircraft was ON the GS and ON the Loc witrh no excessive speed...
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Old 4th Mar 2009, 13:23
  #1040 (permalink)  
 
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I find it quite believable that any or all of the crew could have missed RETARD / FLARE or even WAKE-UP annunciated on the FMA as this is a very common omission even among highly experienced crew.
What I find unbelievable is that 3 pairs of eyes could have failed to notice a loss of 40kts speed from 1950 - 450 ft along with 3 pairs of ears failing to notice the reduction in airflow noise, along with 3 asses that didn't feel the change in body angle required to stay on the glidepath.
The final error "appears" to have been the other all too common fault of commencing a G/A but not pushing TOGA, therefore no useful F/D commands & no automatic movement towards & maintaining of G/A thrust. It appears that when the F/O relinquished control the Capt grabbed the controls with both hands but no-one was guarding the thrust levers.
Still, having said all this, I find it unbelievable that such an experienced crew could have allowed the situation to get this far. If this is true and there is nothing else nasty or dramatic involved, it really was a total loss of situational awareness on the part of 3 crew at a critical stage of flight.
Very strange & scary indeed.
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