Turkish airliner crashes at Schiphol
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Thanks Juud - impressive linguistics as always
Is that all of the quote - looking to see where transoratia gets that bit from?
NB - I prefer not to comment on AEI..................
Is that all of the quote - looking to see where transoratia gets that bit from?NB - I prefer not to comment on AEI..................
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Oops again, missed the first paragraph of the following three. Must be the Monday phenomenon 
"The preliminary investigation by DSB has already established that this altimeter sent an erroneous signal to the autopilot, which steered the aircraft towards the runway, while the two pilots were engaged in a conversation".
"The erroneous signal appeared while the aircraft was still at 700 metres altitude, and said that the aircraft suddenly was 1.3 metres above ground. This caused the autopilot to reduce thrust to idle, even if the aircraft was too high to land".
"During the following precious seconds, as the pilots were inattentive, the speed of the aircraft reduced until it reached stall speed, and fell down. The pilots were able to notice that the situation was critical, and commanded maximum thrust, but too late".
You can make your own conclusions. My conclusion is that there is nothing new regarding the accident flight, which was not known before. The only new information is regarding the previous flights.
"The preliminary investigation by DSB has already established that this altimeter sent an erroneous signal to the autopilot, which steered the aircraft towards the runway, while the two pilots were engaged in a conversation".
"The erroneous signal appeared while the aircraft was still at 700 metres altitude, and said that the aircraft suddenly was 1.3 metres above ground. This caused the autopilot to reduce thrust to idle, even if the aircraft was too high to land".
"During the following precious seconds, as the pilots were inattentive, the speed of the aircraft reduced until it reached stall speed, and fell down. The pilots were able to notice that the situation was critical, and commanded maximum thrust, but too late".
You can make your own conclusions. My conclusion is that there is nothing new regarding the accident flight, which was not known before. The only new information is regarding the previous flights.
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Thanks SNF
TRANSORATIA - if you are on frequency - can you tidy this up? Where was that bit? You have put a slightly different interpretation on the article.
TRANSORATIA - if you are on frequency - can you tidy this up? Where was that bit? You have put a slightly different interpretation on the article.
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Rainboe:
So a minor element of an uncertified configuration of the automation malfunctioned triggering an uncommanded mode the crew were not made aware of - given the TL's were probably at idle anyway in the early part of the descent on G/S, except by a subtle change in mode annunciation that could be easily missed.
I don't excuse the crews apparent inattention to airspeed, thrust setting or mode annunciation during the approach. But neither should we excuse the triggering effect caused by the malfunction of a relatively minor piece of equipment, nor its effect on recovery from the ensuing stall. All as a result of the way Boeing chose to wire the equipment to provide an undocumented and uncertified configuration of the automation. A configuration which crews are not normally trained on and judging by many of the comments from NG qualified pilots on this thread, were until this accident largely unaware of.
I doubt the investigative or regulatory agencies will either.
It (the autoland function) is a default. Except you are not allowed to do this (on one autopilot).
I don't excuse the crews apparent inattention to airspeed, thrust setting or mode annunciation during the approach. But neither should we excuse the triggering effect caused by the malfunction of a relatively minor piece of equipment, nor its effect on recovery from the ensuing stall. All as a result of the way Boeing chose to wire the equipment to provide an undocumented and uncertified configuration of the automation. A configuration which crews are not normally trained on and judging by many of the comments from NG qualified pilots on this thread, were until this accident largely unaware of.
I doubt the investigative or regulatory agencies will either.
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undocumented and uncertified configuration of the automation
.)
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I'm not quite sure what was uncertified here. The crew was flying an approach with an autopilot and the autothrottle engaged. If things had gone properly, I am sure that the pilot would have disconnected the autopilot at some point and finished the landing. That would be quite normal and certainly legal.
I am not sure what some of the people here are talking about with a single autopilot autoland. On the Classic B747, the rad alt would trip the autopilot off at 150ft. RA. On the -400s, the autopilot can fly the aircraft down to 5ft. RA before it trips off. If left alone, I am quite sure the aircraft would fly itself into the ground but surely you can't call this autoland.
It also has to be remembered that the logic on the aircraft has to cover many other possible conditions, not just the setup they had that day. Personally, I think if anyone was to study the systems thoroughly, they would be quite satisfied with the design in place.
I am not sure what some of the people here are talking about with a single autopilot autoland. On the Classic B747, the rad alt would trip the autopilot off at 150ft. RA. On the -400s, the autopilot can fly the aircraft down to 5ft. RA before it trips off. If left alone, I am quite sure the aircraft would fly itself into the ground but surely you can't call this autoland.
It also has to be remembered that the logic on the aircraft has to cover many other possible conditions, not just the setup they had that day. Personally, I think if anyone was to study the systems thoroughly, they would be quite satisfied with the design in place.
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engaged in conversation
I recall a plane crash in which the cvr showed the pilots were discussing swimming pools in the backyards of the houses below...they stalled this particular transport jet...it didn't have autothrottles.
so, let's drop the autothrottles and at least consider inattention to basic flying skills as the cause of the crash???????
so, let's drop the autothrottles and at least consider inattention to basic flying skills as the cause of the crash???????
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I was a little hesitant a few days ago saying that they would look at what the previous crews had entered in the tech log.
Apparently it was not written in the tech log.
Still the basic airman ship and allowing the airspeed to go 40 knots below VREF is
the root problem here.
This R/A was a simple failure, monitoring the airspeed was a major malfunction.
Apparently it was not written in the tech log.
Still the basic airman ship and allowing the airspeed to go 40 knots below VREF is
the root problem here.
This R/A was a simple failure, monitoring the airspeed was a major malfunction.
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The article can be read by anyone. I have no interest to make something up SnowFalcon2.
In the article, there is a lot written that has already been hashed and rehashed here. I am too lazy to repeat all that.
I have just picked out of the article what I believed was new information (and I have read all 2000 posts).
The sentence "Det er allerede fastslået ved den hollandske havarikommisions indledende undersøgelser, at denne højdemåler sendte et forkert signal til autopiloten, som selv styrede flyet ned mod landingsbanen, mens de to piloter var optaget af en samtale." translates to:
"It has already been established by the Dutch accident commission's (DSB) initial investigations that this altimeter has sent a wrong signal to the autopilot (!) which steered the plane down towards the runway while the pilots were busy with a conversation."
I take that to be the interpretation of the journalist and not necessarily the exact situation on the flight deck.
However, I take exception to the statement that I am making things up or translate incorrectly.
Link: Groft sjusk med fly-logbøger var årsag til flystyrt i Amsterdam | Ingeniøren
In the article, there is a lot written that has already been hashed and rehashed here. I am too lazy to repeat all that.
I have just picked out of the article what I believed was new information (and I have read all 2000 posts).
The sentence "Det er allerede fastslået ved den hollandske havarikommisions indledende undersøgelser, at denne højdemåler sendte et forkert signal til autopiloten, som selv styrede flyet ned mod landingsbanen, mens de to piloter var optaget af en samtale." translates to:
"It has already been established by the Dutch accident commission's (DSB) initial investigations that this altimeter has sent a wrong signal to the autopilot (!) which steered the plane down towards the runway while the pilots were busy with a conversation."
I take that to be the interpretation of the journalist and not necessarily the exact situation on the flight deck.
However, I take exception to the statement that I am making things up or translate incorrectly.
Link: Groft sjusk med fly-logbøger var årsag til flystyrt i Amsterdam | Ingeniøren
Last edited by transoratia; 9th Mar 2009 at 20:34. Reason: added link
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The non reporting of the previous radalt faults may also have a partial contribution to this crash
The fault on previous flights (and this) was only seen after the FDR was analysed.
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If the quoted part re. conversation in the article is true, why is this comment not in the official initial press release document? As it is not there, where did this journo pick this info up?
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Thanks to all the Danish translators - I think we can put this aspect to bed now. (On the other hand, a few could disagree and take this on another hundred or so posts) Reading between the lines it would appear that round about the time the false signal first arrived from RA1 the crew were 'chatting' about something - possibly even that - who knows? It does not appear to suggest they were similarly 'chatting' as it approached the stall.
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Thats the way it usually happens, don't write the tech log item, it will ground the aircraft etc.
When in reality it always bites the next crew on the back side..
Turkish airlines has no excuse for this, they have backup aircraft not like some charter ones there that are banned in the EU and have to fly or go broke.
But its still not correct no matter how you look at it.
This airplane had a simple fault, something caused these pilots to stall the airplane, and it was not a simple R/A failure.
When in reality it always bites the next crew on the back side..
Turkish airlines has no excuse for this, they have backup aircraft not like some charter ones there that are banned in the EU and have to fly or go broke.
But its still not correct no matter how you look at it.
This airplane had a simple fault, something caused these pilots to stall the airplane, and it was not a simple R/A failure.
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MU300A (#2009)
Let me write it once more, hopefully for the last time.
The RETARD function serves a purpose even when not on a Dual Channel approach:
The crew is on a Single Channel approach at some stage PF disengages the A/P but not the A/T. Instead PF deselects the speed mode with the A/T engaged.
Because Boeing doesn't want Min Speed Reversion to pop up during the flare and ruin the landing, the A/T are designed to RETARD at 24/27 feet (chose the right one)
Any questions?
Let me write it once more, hopefully for the last time.
The RETARD function serves a purpose even when not on a Dual Channel approach:
The crew is on a Single Channel approach at some stage PF disengages the A/P but not the A/T. Instead PF deselects the speed mode with the A/T engaged.
Because Boeing doesn't want Min Speed Reversion to pop up during the flare and ruin the landing, the A/T are designed to RETARD at 24/27 feet (chose the right one)
Any questions?
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The nose pitches further and further up as the trimmer clacks away....the airspeed drops to Vref -40 and not one of three pilots notices something strange?
What was happening in the cockpit that three pilots did not notice this?
It must have been something pretty damn engrossing.
No matter what happened with the RA and the A/T and all that happened before, bottom line is that these boys were distracted very badly by something at a critical time.
What was it?
What was happening in the cockpit that three pilots did not notice this?
It must have been something pretty damn engrossing.
No matter what happened with the RA and the A/T and all that happened before, bottom line is that these boys were distracted very badly by something at a critical time.
What was it?
Warning Toxic!
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Well done ant. Said it like it is. It does serve a purpose. Proper operation of the system depends on proper piloting. You cannot have such a system that will work for ANY poor pilot. It's amazing there are people who cannot understand the system, yet feel they are knowledgeable enough to castigate the designer!
Nicholas49- way out. Nonsense. Nobody has suggested it, you have absolutely no evidence for mad airspeed theories!
JG1, thank you, take a ticket and stand in the corner- you are the 47th. person to post that and the 547th not to have read the thread history!
We really have reached the limit of what can be discussed based on what evidence has been released. It's a zoo, with every shade of opinion and experience (and inexperience) posting the same queries and remarks, and EVERYBODY knows how to design an autoflight system better than Boeing! I'm impressed (not).
Nicholas49- way out. Nonsense. Nobody has suggested it, you have absolutely no evidence for mad airspeed theories!
JG1, thank you, take a ticket and stand in the corner- you are the 47th. person to post that and the 547th not to have read the thread history!
We really have reached the limit of what can be discussed based on what evidence has been released. It's a zoo, with every shade of opinion and experience (and inexperience) posting the same queries and remarks, and EVERYBODY knows how to design an autoflight system better than Boeing! I'm impressed (not).
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ant1
Thanks for the explanation.
A question.
How many pilots would normally be relying on the RETARD function to close the throttles on this type of approach? In other words, in 99.9% of approaches of the type flown by the accident crew, wouldn't the throttles already be closed by the time the RETARD function initiates? Just not at 2000' as in this case, but over the runway threshold?
Thanks for the explanation.
A question.
How many pilots would normally be relying on the RETARD function to close the throttles on this type of approach? In other words, in 99.9% of approaches of the type flown by the accident crew, wouldn't the throttles already be closed by the time the RETARD function initiates? Just not at 2000' as in this case, but over the runway threshold?
Warning Toxic!
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You're not following the thread. You would disconnect a single channel approach when visual hundreds of feet up- it would not have happened. You then either turn OFF the A/T (and lose automatic G/A thrust capability) or put A/T to standby ('Speed Off') so if you hit the TOGA switches, the A/T will reactivate and give you G/A thrust! Depending on your airline SOP. If you are not visual by Cat1 limit, you would GA. Well above 27'!
It's flogged to death now!
It's flogged to death now!
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I don't use the speed off method but if someone does then he either:
- Disengages the A/T and retard manually or
- Lets the A/T retard by themselves (maybe with a little help if needed)
So if you go speed off till touchdown then the A/T have to retard otherwise even if the PF retarded them they might go back forward.
And regarding the RA, I've already said I'd be happier with a RA comparator that could disable the retard feature or even disengage the A/T altogether, specially if the single RA dependence is proved to be a factor in this one.
- Disengages the A/T and retard manually or
- Lets the A/T retard by themselves (maybe with a little help if needed)
So if you go speed off till touchdown then the A/T have to retard otherwise even if the PF retarded them they might go back forward.
And regarding the RA, I've already said I'd be happier with a RA comparator that could disable the retard feature or even disengage the A/T altogether, specially if the single RA dependence is proved to be a factor in this one.
Last edited by ant1; 10th Mar 2009 at 00:07.