Turkish airliner crashes at Schiphol
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BOAC
What is missing for old farts like us is the rotary motion of the dial ASI which is a far better clue than scrolling numbers, sliding tapes or fancy green arrows.
I suspect this is manifestation of unfamiliarity and of oldfartedness however, and I expect the younger guys or at least those who still monitor their A/S when the AT is engaged, don't have a problem with it.
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AfricanSkies
Do I understand you correctly that you've been in "training" on this A/C for two months? Are you transitioning from another A/C? Are you doing this on your own or are you in an airline ground school? Just curious why you're asking questions on here.
Thank you.
BOAC - 2 months.
Thank you.
Per Ardua ad Astraeus
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Originally Posted by brandt
BOAC or whoever, can you please post the SOP for 73 and we'll be done with this
Which SOP?
this single RA causing the fully intact a/c to plow down the royal dutch farmland.
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The previous radalt faults were picked up, post accident. on the FDR. We do not,I believe, at this time know if they were ever recorded in the tech log or even if these previous occurrences were even noticed by the crews concerned. This crew may well have been, quite justifiably, unaware of these.
The crew were carrying out a cat 1 approach, during which the radalt is of little or no interest from a handling point of view.
So in effect, all the crew had to deal with was a misbehaving A/T and possibly, according to Boeing, the loss of one or both Flight Directors.
The crew were carrying out a cat 1 approach, during which the radalt is of little or no interest from a handling point of view.
So in effect, all the crew had to deal with was a misbehaving A/T and possibly, according to Boeing, the loss of one or both Flight Directors.
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btw
flight data recorder hit that radio altimeter (left one connected to AI) wrong reading (2x in 25 hours brutto flight time before accident)
there is no evidence that "someone" noticed beside or where and when (location) it ocurred, isnt it?
sorry for having same thought at a same time but due to delay took longer
there is no evidence that "someone" noticed beside or where and when (location) it ocurred, isnt it?
sorry for having same thought at a same time but due to delay took longer
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I've done a month's ground school and a month's sim and a month's line training so far. Transitioned from another aircraft, 3000hrs jet time.
I'm not a high-houred 737 pilot, so I ask questions and learn. And my questions here have not been answered, just hastily read, probably not understood and then ridiculed by some here.
I was taught there are two kinds of coupled approaches, a dual channel and a single channel.
Our SOPs say an autoland is only permitted from a dual channel approach. And the whole flare armed/ flare / retard thing only happens during an autoland, ie. a dual channel approach.
If we do a single-channel approach, SOP says we have to disengage the A/P and A/T by 50' agl, or 150' on some specific aircraft.
Never having been trained for single channel autoland, (as per my manual it is unavailable during a single channel approach), I ask if the A/T was left engaged during a single channel approach to touchdown what would happen?
1) assuming the A/P was also left engaged, would we get the flare/retard sequence? Given that the flare does not arm by 350' and is thus unavailable during normal 1-ch approaches I have previously done, I think not...
2) if not what target would the A/T go for, the MCP speed all the way to touchdown, and if you (incorrectly) did not disengage it, it would disengage 2 secs after touchdown, is this correct?
Thats all I asked.... now the big boys here either don't know, like BOAC admitted, or they are just here to ridicule the lesser experienced amongst us which is not a great attitude to have hey?
I'm not a high-houred 737 pilot, so I ask questions and learn. And my questions here have not been answered, just hastily read, probably not understood and then ridiculed by some here.
I was taught there are two kinds of coupled approaches, a dual channel and a single channel.
Our SOPs say an autoland is only permitted from a dual channel approach. And the whole flare armed/ flare / retard thing only happens during an autoland, ie. a dual channel approach.
If we do a single-channel approach, SOP says we have to disengage the A/P and A/T by 50' agl, or 150' on some specific aircraft.
Never having been trained for single channel autoland, (as per my manual it is unavailable during a single channel approach), I ask if the A/T was left engaged during a single channel approach to touchdown what would happen?
1) assuming the A/P was also left engaged, would we get the flare/retard sequence? Given that the flare does not arm by 350' and is thus unavailable during normal 1-ch approaches I have previously done, I think not...
2) if not what target would the A/T go for, the MCP speed all the way to touchdown, and if you (incorrectly) did not disengage it, it would disengage 2 secs after touchdown, is this correct?
Thats all I asked.... now the big boys here either don't know, like BOAC admitted, or they are just here to ridicule the lesser experienced amongst us which is not a great attitude to have hey?
Last edited by AfricanSkies; 5th Mar 2009 at 17:09.
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Boys/girls
Those too bogged down in technical minutae - forget it it was a slight aggravating factor.
Those simply blaming the crew be careful. We don't know all the facts, it easy to spout a n c call them muppets etc but not rewarding to future flight safety.
Those who blame culture within this airline tread very carefully. Not being pc here but this does not address the root cause. Don't believe me? An incident with amazingly similar detail happened to a uk operator recently the only difference was they recovered hence hardly got a mention.
I and indeed all slf should be interested in enhancing flight safety in future. This phenomenon is not 737 specific.
Please don't get too sidetracked.
Those too bogged down in technical minutae - forget it it was a slight aggravating factor.
Those simply blaming the crew be careful. We don't know all the facts, it easy to spout a n c call them muppets etc but not rewarding to future flight safety.
Those who blame culture within this airline tread very carefully. Not being pc here but this does not address the root cause. Don't believe me? An incident with amazingly similar detail happened to a uk operator recently the only difference was they recovered hence hardly got a mention.
I and indeed all slf should be interested in enhancing flight safety in future. This phenomenon is not 737 specific.
Please don't get too sidetracked.
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AfricanSkies
AfricanSkies
Thanks for that explaination. My only comment would be to get your answers from your instructors as they SHOULD know what pertains to the aircraft you will be flying. There's always the possibility that your aircraft will be different from other airlines, so the answers you get here might not apply. Not sure I'd EVER ask a Q like that on here not knowing the source of your answer. Better to get the info from your airline.
Thanks for that explaination. My only comment would be to get your answers from your instructors as they SHOULD know what pertains to the aircraft you will be flying. There's always the possibility that your aircraft will be different from other airlines, so the answers you get here might not apply. Not sure I'd EVER ask a Q like that on here not knowing the source of your answer. Better to get the info from your airline.
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1) assuming the A/P was also left engaged, would we get the flare/retard sequence? Given that the flare does not arm by 350' during normal 1-ch approaches I have previously done, I think not.
2) if not what target would the A/T go for, the MCP speed all the way to touchdown, and if you (incorrectly) did not disengage it, it would disengage 2 secs after touchdown, is this correct?
I would recommend you take further questions which are not really relevant to this thread elsewhere to avoid 'clutter' - and DC-ATE's advice is sound!
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Thank you all you wise old heads, and the 'aorta' crowd, its been interesting reading. However, I would dearly like to see the FMECA (Failure Mode Effect and Criticality Analysis) for the system! It was always stressed when I were a lad 'Take away one link in the chain and the accident doesnt happen', and this looks like just one such link that did not need to be there and caught the crew out.
Apologies to BOAC and other OFs from another OF!
I'll get my hat
Apologies to BOAC and other OFs from another OF!
I'll get my hat
Last edited by Biggles225; 5th Mar 2009 at 17:45. Reason: Forgot to explain the acronym
Something I notice more & more over the years, is the lack of instrument scan when the autopilot is engaged. At one end colleagues trying to read the broadsheets during the cruise with the instruments completely obscured. At the lower end flying approaches with autopilot engaged & basically trusting the autopilot to do as it is asked with apparent lack of a proper instrument scan. It doesn't matter if you are handflying or not you still keep ALL instruments in your scan.
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Rhett
the RA 1 fault looks to have been intermittent, so if it only happened away from base, detection may have been difficult. I understand THY said they repaired a RA (didnt say which one, but my moneys on no1) on 05 Feb. Wonder what they did? It could well have been on and off since.... the FDR suggests this. In my mind it should have been changed.
Accidents are usually a culmination of events
Accidents are usually a culmination of events
SoaringTheSkies;
Re your thoughtful response at #1315,
First, I appreciate "the engineer in you"! It's a partnership with the designers, of this there is no doubt.
I disagree. These two accidents bear only superficial similarities. I think it is beneficial to understand why. The main reason is, the similarity between the static/pitot sensors and a Radio Altimeter in terms of the nature of potential outcomes should one or the other fail, especially in the two accidents cited, is minimal.
An airplane with an unreliable Radio Altimeter can be flown without a problem - it is a non-event. I have seen it, flown it, seen such spikes/dropouts in flight data. I have also flown a B767 with serious pitot-static problems, (at night, over mountains) and know the potential for disorientation.
Because the crew can become quickly disoriented in an airplane with a faulty static port or pitot tube in IMC (Instrument Meteorogical Conditions- not sure you know the term, sorry, and both the Aero Peru and Birgenair flights were at nightm over water), the aircraft is at great risk without a very disciplined crew response. There is a very good reason why QRH's (Quick Reference Handbooks for Abnormals/Emergencies) now have detailed guidance for pitot-static system faults. There is an equally good reason why there is very little in the QRH regarding either subtle or obvious Radio Altimeter failure because it isn't an issue.
There may be engineering aspects to this but this isn't fundamentally an engineering issue. It is an airmanship, piloting issue.
When on approach, especially below 1000ft above ground, the pilot flying should have his/her hands on the thrust levers. The thrust reduction would have been felt as the thrust levers came back. Yes, that would be a natural response of the autothrust if the speed was high, (airplane capturing glideslope from above), but at some point the speed is going to bleed off as the glideslope is captured and maintained. If the thrust levers don't respond with more thrust, the pilot does his/her job and flies the airplane. A pilot NEVER waits for automation to do it's job if it isn't doing it's job. Once again, that isn't an engineering issue, it is a pilot issue.
I take your point, think it's an important one and am glad you're thinking this way as an engineer. However, there is no way "automation" could have been employed in either the Birgenair or Aeroperu accidents. No automation system can function on erroneous data - we have ample proof of that of course. The pilots had to intervene and hand fly and in an extremely short period of time, become test pilots in equally extremely demanding circumstances.
The kind of piloting intervention we are discussing here likely happens hundreds of thousands of times a day in almost every landing carried out by large and small transports alike. It is what we do - we fly an airplane and in a tragic moment of ?....this crew didn't. It really is no more complicated than that.
No system can be designed that can successfully and without creating collaterally-serious problems which didnt' exist before said design, to protect against human error. No automated system which is designed to tell the driver of a car that he should brake because the car in front is rapidly approaching, should be relied upon nor faulted for the rear-end collision....Nor, I will hastily add, do we have the right to expect that our accepted responsibilities, in this case professional ones, will be appropriated by engineering design solutions - they must, of necessity, always remain in the "assisting" role. Tricky, I would assume, but that is why this discourse is so important.
Again, thanks for your response.
Re your thoughtful response at #1315,
sorry, but the (non aviation) engineer in me sais differently:
As I said earlier, the systemic failure of this accident is terribly similar to the Birgenair 301 accident in 1996. In both cases, a faulty sensor was the single input to an automation system that subsequently flew the airplane into a stall.
An airplane with an unreliable Radio Altimeter can be flown without a problem - it is a non-event. I have seen it, flown it, seen such spikes/dropouts in flight data. I have also flown a B767 with serious pitot-static problems, (at night, over mountains) and know the potential for disorientation.
Because the crew can become quickly disoriented in an airplane with a faulty static port or pitot tube in IMC (Instrument Meteorogical Conditions- not sure you know the term, sorry, and both the Aero Peru and Birgenair flights were at nightm over water), the aircraft is at great risk without a very disciplined crew response. There is a very good reason why QRH's (Quick Reference Handbooks for Abnormals/Emergencies) now have detailed guidance for pitot-static system faults. There is an equally good reason why there is very little in the QRH regarding either subtle or obvious Radio Altimeter failure because it isn't an issue.
There may be engineering aspects to this but this isn't fundamentally an engineering issue. It is an airmanship, piloting issue.
When on approach, especially below 1000ft above ground, the pilot flying should have his/her hands on the thrust levers. The thrust reduction would have been felt as the thrust levers came back. Yes, that would be a natural response of the autothrust if the speed was high, (airplane capturing glideslope from above), but at some point the speed is going to bleed off as the glideslope is captured and maintained. If the thrust levers don't respond with more thrust, the pilot does his/her job and flies the airplane. A pilot NEVER waits for automation to do it's job if it isn't doing it's job. Once again, that isn't an engineering issue, it is a pilot issue.
But: both events shouldn't have developed to anything serious in the first place, because at least theoretically, all relevant information was available to the automation systems to make a decision to either continue in a coordinated, safe mode (A/T and A/P feeding off a known good data source) or to completely hand it off to those humans who, in ambiguous situations, should know better what to do than the engineer behind his desk.
The kind of piloting intervention we are discussing here likely happens hundreds of thousands of times a day in almost every landing carried out by large and small transports alike. It is what we do - we fly an airplane and in a tragic moment of ?....this crew didn't. It really is no more complicated than that.
No system can be designed that can successfully and without creating collaterally-serious problems which didnt' exist before said design, to protect against human error. No automated system which is designed to tell the driver of a car that he should brake because the car in front is rapidly approaching, should be relied upon nor faulted for the rear-end collision....Nor, I will hastily add, do we have the right to expect that our accepted responsibilities, in this case professional ones, will be appropriated by engineering design solutions - they must, of necessity, always remain in the "assisting" role. Tricky, I would assume, but that is why this discourse is so important.
Again, thanks for your response.
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I'm not a high-houred 737 pilot, so I ask questions and learn. And my questions here have not been answered, just hastily read, probably not understood and then ridiculed by some here.
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Just to put things in context for the non pilots here.
The autothrottle is just a tool, albeit a very nice one to have.
On the 737 it is not required to be operational for flight.
It is not even required to be operational for a Cat3 approach and autoland.
Autothrottles do throw wobblies every now and then, whether caused by a faulty radalt or anything else.
Autothrottles need monitoring and that means hands on throttles at critical stages of flight.
The autothrottle is just a tool, albeit a very nice one to have.
On the 737 it is not required to be operational for flight.
It is not even required to be operational for a Cat3 approach and autoland.
Autothrottles do throw wobblies every now and then, whether caused by a faulty radalt or anything else.
Autothrottles need monitoring and that means hands on throttles at critical stages of flight.
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Thanks BOAC.
I did not mean to get so off thread with that, the reason I asked that specific question was that I understood that during a single-channel approach (which the Turkish crew were doing) there was no chance that the A/T would go into RETARD below 27' radalt because no autoland was taking place.
So, why would it ever go into RETARD when it got the duff gen from the radalt?
But if what you say is correct and a RETARD will take place anyway even during a single channel approach, it makes sense.
I did not mean to get so off thread with that, the reason I asked that specific question was that I understood that during a single-channel approach (which the Turkish crew were doing) there was no chance that the A/T would go into RETARD below 27' radalt because no autoland was taking place.
So, why would it ever go into RETARD when it got the duff gen from the radalt?
But if what you say is correct and a RETARD will take place anyway even during a single channel approach, it makes sense.
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An apology if this has already been covered but 70+ pages are an awful lot to wade through. Has there been discussion about what the pilots did at 500 feet when they suddenly realised that they were about to stall? Yes I know they applied power, but did they push the nose down and gain speed at expense of height?
I write as a retired pilot (18,000 hrs) and a glider pilot. Gliders often fly very close to the stall and we know all about stall recovery. I never of course got into that situation experienced by the Turkish crew, but I have to wonder: Did they (in addition to applying TOGA power) push it down, if necessary descending almost to ground level if necessary in order to gain speed? From the reports that the tail impacted first, I would presume that they didn’t. I have indeed been in situations myself (military operations) when speed was essential at the expense of height.
More incipient stall recovery training needed perhaps?
I write as a retired pilot (18,000 hrs) and a glider pilot. Gliders often fly very close to the stall and we know all about stall recovery. I never of course got into that situation experienced by the Turkish crew, but I have to wonder: Did they (in addition to applying TOGA power) push it down, if necessary descending almost to ground level if necessary in order to gain speed? From the reports that the tail impacted first, I would presume that they didn’t. I have indeed been in situations myself (military operations) when speed was essential at the expense of height.
More incipient stall recovery training needed perhaps?
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Q*R*H
There is no design fault. The 737 autothrottle is designed to retard on a handflown approach (autothrottle in) as well as during an autoland. Admittedly the former is not recommended due to the marked pitch change with power reduction on this type. I flew the MD83 and it was normal to leave the autothrottle engaged to touchdown as there was no pitch change.
The fact remains that the autothrottle is far from essential and does not require endless fail safe devices. If it misbehaves, knock it off.
The fact remains that the autothrottle is far from essential and does not require endless fail safe devices. If it misbehaves, knock it off.