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Turkish airliner crashes at Schiphol

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Turkish airliner crashes at Schiphol

Old 6th Mar 2009, 16:33
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Last edited by Rainboe; 17th May 2009 at 22:50.
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Old 6th Mar 2009, 16:34
  #1542 (permalink)  
 
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@rainboe

My answers in red beneath your words:

And you young man can't see the simple fact that an aeroplane is just a basic flying machine. It has things to help it fly and make life easier for the pilot. Those things are not important to the basic requirement to fly the aeroplane. When one of those aids fails, and an aeroplane crashes, one has to look dispassionately and thing 'did the aeroplane crash because of the failure, or did it crash because of the incompetence of the pilots?'

I already admitted the responsibility of the pilots earlier. It's nonsense to bring this up.


The failure of a totally unimportant item did lead to a crash because totally incompetent pilots could not handle the failure of this totally unimportant item and fly the aeroplane! I used to fly without a RA at all! It is an aid to your flying, not a vital piece of equipment. Remember that. Don't get tied up in the technicalities- it is an aid to flying only.

We are discussing aviation design. If it's so unimportant why do you even need it? I have to repeat that it's not the RA failure that caused the crash. The aircraft can sure fly with a broken RA we know that. The main problem is that the A/T is fed by a single RA whatsoever, even in a sudden 1958 feet variance and an absurd negative -8 reading at 1900 feet. The fact that pilots are responsible, doesn't change the fact that Boeing has a faulty flight computer design. If the design was OK, they wouldn't accept that and release the recent memo after the crash.

So is there a trend causing crashes. Er.....how many RA failures in the history of the millions of take-offs and landings of 737s, 747s have caused the plane to flop out of the sky? None. There is no trend. We have an incident caused by a completely out of tune crew, for whatever reasons. What is the answer? Blame Boeing for ONE crew unable to fly a plane, or maybe Turkish needs to look at its training, its checking, where it sources crew from, how it trains them. Turkey must not try and pass the blame onto the manufacturer for its bizarrely incompetent crew in this incident.

First if the system was the same as the 747's. Boeing statement would include 747's as well. It's just the 737 family, its just the left and main RA, it's not the right one never. Boeing apparently figured out that the faulty RA indirectly caused A/T to shut off just after the crash. Otherwise they would have issued the recent statement on Feb 11. Boeing had a design flaw making the flight computer insecure. They didn't figure it out up until the accident and they didn't fix it before (not the RA, the system design). Second, as far as I read, many 737 pilots have had the same (-8) RA reading but at altitudes higher than 2.000. So no A/T problem. The fact that this happened on TK 1951 is a coincidence to happen just before landing, A/T engaged. Yes the pilots, should have solved it in 100 seconds, for gods sake. But still the design is faulty.

I don't like anonymous new posters coming here and discussing like you have. Why should I listen to you? Say please what your expertise and aviation experience is if you are going to make statements like you have. I don't know if you are a schoolboy or a pilot.

You assume that I'm a young boy from Istanbul, trying to save my country's ass and reputation and blame it on Boeing. I am as anonymous as you are. You are prejudiced. My experience in aviation is irrelevant. I stated that I'm a non pilot, just a tech savvy guy. I can make serious simple reasoning without aviation or avionics experience whatsoever and still get credit from forum members and you are angry at this.

Remember this: Bad design kills, as well as incompetent staff does. There is no difference with a bunch of incompetent Boeing engineers and 3 incompetent stress paralyzed pilots. They all are human like you are and I am, and helped fly or crash this aircraft. So cut the arrogance, and do not listen to me if you do not want to. By answering me irrelevantly me like this in front of everyone you are giving me credit and discrediting yourself. Realize this.
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Old 6th Mar 2009, 16:34
  #1543 (permalink)  
 
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BOAC

From the MOM

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
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Old 6th Mar 2009, 16:35
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Rainboe,

I must admit, I fully agree with your last post.
This accident has happened primarily due to the crew not flying the aircraft.
Boeing is not the big culprit here, although I learned new issues with the autoflight system while following this topic which I have never seen written in any Boeing-manual.

The Turks need to face the fact and ADMIT that in this case, their crew is largely to blame for the accident. Lessons must be learned by all, including you and me and our operation will hence become hopefully that more safe.

If the Turkish people will refuse to take a large part of the responsibility on their shoulders, then they show that they have a looong way to go before any chance in joining the EU, and full EASA member for that matter.
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Old 6th Mar 2009, 16:38
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OK, these are things that can/may happen with faulty RA2. Is it known if in this crash F/D got disconnected too?
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Old 6th Mar 2009, 16:39
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An automation system that doesn't validate input?

A decision was made by the system based on invalid input from RA#1.
It should have detected a sudden change from +1950 to -8 ft as invalid.
It should have compared with the available backup RA#2
If it wasn't designed in such a way, there is only one
conclusion and that is: a basic design failure!
The system should have detected:
-1- the impossible change in value
-2- huge difference between values from 2 inputs for the same parameter.
and at least alerted the crew for such a situation and/or
handled it properly by not using the invalid input!!!
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Old 6th Mar 2009, 16:42
  #1547 (permalink)  
 
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Oz Aviation Safety Investigation Report - Final.
Airbus A330-341, PK-GPC. 27 August 2001

200104399

The loss of valid radio altimeter signals did not result in the automatic switching from flight mode to flare mode when the autopilots disengaged. That was due to the water ingress into the radio altimeter antennas, and which resulted in the radio altimeter signals being interpreted as out of range signals, rather than as a failure of the radio altimeters.
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Old 6th Mar 2009, 16:45
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OK, these are things that can/may happen with faulty RA2. Is it known if in this crash F/D got disconnected too?
No... the crew plus the jumpseat got disconnected from their aircraft.
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Old 6th Mar 2009, 16:46
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bobcat4: >"Why is it possible to program a Boing 737NG to stall????"

Because it's possible to program a Boing 737NG to land.

The problem is to detect the [possible] non-landing context. The RA enhancement I suggested above is one of the ways, an analogous enhancement in the AT would be another (possibly a better one). Each would result in incorrect behaviour for a short period (as BOAC says, on landing AT RETARD comes before weight on wheels) but after that the program would end with an error message - AT disconnect and a significant alert.

Each would follow the software principle "I am not artificially intelligent, thus if I detect a state I have not been designed for, stop with an error message ."

BTW, I realise that this was never an autoland scenario, but one in which AP and AT would remain coupled to near landing.

Last edited by Gegenbeispiel; 6th Mar 2009 at 17:06.
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Old 6th Mar 2009, 16:47
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@hsxnl: Right on, why did the computer not issue a warning when a value goes from 1950 to -8 instantly. Surely the computer knows it is an airplane which can not do that in a few millisecs. The computer must also know that being on ground the value should be -2 so any value beyond -2 is BS. -8 is just plain a hardware fault.

Faulty system design leading to confusing the crew or in this case not notifying the crew clearly. You can debate if it was system and/or crew failure but if automation is to support and not cause death in this case I clearly go for system design fault.
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Old 6th Mar 2009, 16:47
  #1551 (permalink)  
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Thumbs down


Last edited by Rainboe; 17th May 2009 at 22:50.
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Old 6th Mar 2009, 16:52
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(...)and at least alerted the crew for such a situation and/or
handled it properly by not using the invalid input!!!
But the instruments are not telling lies either (not every single one, at least)... a simple cross check would reveal the odd value, IF the PM does the M part.

It would be conspicuous even if all the FO's instruments went bananas, you still can compare your RA with your pressure ALT to see anything strange (never mind seeing a red bar along side the speed tape and the speed arrow trend pointing down)

Last edited by GearDown&Locked; 6th Mar 2009 at 17:05. Reason: first sentence not clear enough
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Old 6th Mar 2009, 16:54
  #1553 (permalink)  
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foresight - my apologies - I forgot that. I am, however, even more confused now that a TC would not have noticed this from 2000' and think it may have been in the 'possible' symptoms list from Boeing - I suspect it would refer to the 'in-use' A/P rather than the slave?

RB - no. -8 is not a 'valid reading'
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Old 6th Mar 2009, 16:54
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@rainbow: You're defending Boeings system design.

Add a few lines of code to detect a value change in sensor greater then x in y (milli)seconds. If that happens, issue warning that something is fishy. Repeat at each value change. After that switch over to next available device. If none available inform crew and disconnect all dependant systems.
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Old 6th Mar 2009, 16:55
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Can someone tell me if an RA responds to tall buildings passing underneath?
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Old 6th Mar 2009, 16:56
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Yes, and aeroplanes (hopefully not at -8......).
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Old 6th Mar 2009, 17:00
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Yes its a RADAR altimeter where D is down and R is to the nearest reflecting object
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Old 6th Mar 2009, 17:00
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Ok.. (are you paying attention Rainbow? ), I'm not a 737 driver.. nor in fact a driver of anything! - i'm a computer consultant involved with safety critical software within the aviation sector (Radar and air traffic management).

I'd firstly like to pay my respects to all those who have lost their lives in this incident and hope that the industry can learn from the mistakes and reduce the possibilty of the same incident ocurring again.

Now for my two penneth...
From the information provided (gleaned from this forum and from the statements from Boeing) and from my knowledge of designing safety critical systems - how is it possible for a flight management system to not cross check systems?
It is all very well to say that the pilots "should be flying the aircraft", but if you overload any operator with conflicting information, it is VERY easy for them to become so distracted that they forget to do their primary function - IMHO the blame sits firmly with Boeing, they should not have released a system that allows the system to effectively ignore conflicting information WITHOUT warning the crew that there may be an issue - if I were designing such a system, i'd either introduce a third RA as a control (and then treat matching RA values as valid) - or I'd prevent the crew from selecting a suspect RA for use without first informing them that it is suspect.

Automation is good.. but it is only as good as the information you provide it... "garbage in.. garbage out"
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Old 6th Mar 2009, 17:00
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System design fault: If -8 is documented being officially a 'non-valid' reading then the warning given is clearly misleading (gear down ).

Instead there should be a warning: RA1 fault, A/T disabled - you're on your own now. With that the crew would have instantly have understood the situation.
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Old 6th Mar 2009, 17:01
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1- Who is to say it's impossible?
If the altitude changes from 1,950 to -8 within a few seconds what is the implied vertical speed? And what would happen to the plane if it really fell that fast?
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