LH A320 reportedly within 0.5m of crashing at FRA !!
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Just to make it clear where I stand, I enjoy flying the 320, but I have no intention of letting the same thing happen to me if I can help it.
Oilhead: AI SOPs call for the PF to move the controls and PNF to check deflections on the ECAM F/CTL page. My point is how do you know that what ECAM tells you is correct?
screwjack: Yes, AI's attitude is a problem. Mechanics doing visual checks at dispatch would be great, but I don't expect that to be implemented (cynic).
3 putt: Banter aside, before I get in. Our 320s are fairly old and the ailerons, elevator and rudder are almost always deflected from neutral when the jet is shut down. I have noticed that on the new jets being delivered the ailerons are almost always neutral at shut down (drat).
Its not perfect, but until AI or my company comes up with a better system, its all that I can do personally to make sure that I stay alive. Any better ideas wellcome.
Oilhead: AI SOPs call for the PF to move the controls and PNF to check deflections on the ECAM F/CTL page. My point is how do you know that what ECAM tells you is correct?
screwjack: Yes, AI's attitude is a problem. Mechanics doing visual checks at dispatch would be great, but I don't expect that to be implemented (cynic).
3 putt: Banter aside, before I get in. Our 320s are fairly old and the ailerons, elevator and rudder are almost always deflected from neutral when the jet is shut down. I have noticed that on the new jets being delivered the ailerons are almost always neutral at shut down (drat).
Its not perfect, but until AI or my company comes up with a better system, its all that I can do personally to make sure that I stay alive. Any better ideas wellcome.
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TvB
From what you say It would appear that the ECAM only shows the sidestick position and not the actual aileron position. If that is the case there is little point in doing a control check.
When I place the sidestick to the left I know that it is to the left! What I need to know is where the control surfaces are! I was always told not to look at the flap lever but to look at the ECAM because it used feedback from the flaps to show the actual position of the flaps. If what you say is true then the feedback to the ECAM is not from the control surfaces but just from the sidestick, which is of little use.
Edited for typos
[This message has been edited by Flap 5 (edited 24 May 2001).]
From what you say It would appear that the ECAM only shows the sidestick position and not the actual aileron position. If that is the case there is little point in doing a control check.
When I place the sidestick to the left I know that it is to the left! What I need to know is where the control surfaces are! I was always told not to look at the flap lever but to look at the ECAM because it used feedback from the flaps to show the actual position of the flaps. If what you say is true then the feedback to the ECAM is not from the control surfaces but just from the sidestick, which is of little use.
Edited for typos
[This message has been edited by Flap 5 (edited 24 May 2001).]
Guest
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TvB – my point is that if the flight controls are disturbed then a check is done with an outside observer watching the results. This is done if the sidestick was worked on as well as it is part of the flight controls. If the FCDC is swopped then the new unit is checked via the MCDU.
I am just surprised that there was no visual check requirement as there would have been in our airline. Was it not a requirement in LH?
I am just surprised that there was no visual check requirement as there would have been in our airline. Was it not a requirement in LH?
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Are we not talking about two different displays here? We look at two displays on taxi out on the bus. One for stick deflection, and one for surface deflection. You can see excactly what the ailerons are doing!
I can certainly see what the flight controls AND side stick are doing on the ground. In the air I can (electronically) see what the flight controls are doing too.
There is an ECAM Flight Controls Page which shows the position of the surfaces, not the sidestick. That page is either manually selected, or automatically appears on taxi out as you commence the full and free check. That page also shows ELAC and SEC status (FWIW).
Then there is the Primary Flight Display (artificial horizon in the old days, except this does a bit more) (PFD) Ground Display mode. After the first engine is started, a white box appears on the PFD. It shows the deflection of either sidestick, but not the resultant control deflection. It disappears after rotation. Then within the box there appears a little Maltese cross thingy. We call it the "side stick orders indication". It shows the combined displacement of Captain's and First Officer's side sticks. This way one can see the commanded side stick deflection during take off and landing roll.
Oilhead
[This message has been edited by Oilhead (edited 25 May 2001).]
I can certainly see what the flight controls AND side stick are doing on the ground. In the air I can (electronically) see what the flight controls are doing too.
There is an ECAM Flight Controls Page which shows the position of the surfaces, not the sidestick. That page is either manually selected, or automatically appears on taxi out as you commence the full and free check. That page also shows ELAC and SEC status (FWIW).
Then there is the Primary Flight Display (artificial horizon in the old days, except this does a bit more) (PFD) Ground Display mode. After the first engine is started, a white box appears on the PFD. It shows the deflection of either sidestick, but not the resultant control deflection. It disappears after rotation. Then within the box there appears a little Maltese cross thingy. We call it the "side stick orders indication". It shows the combined displacement of Captain's and First Officer's side sticks. This way one can see the commanded side stick deflection during take off and landing roll.
Oilhead
[This message has been edited by Oilhead (edited 25 May 2001).]
Guest
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Please excuse my lack of knowledge of civilian operating procedures, but I can't understand why a check of control surfaces was not done prior to take off. Are there reliable indications of stick movement in the cockpit? Or could a control check from the first officer have suggested the control surfaces worked correctly on the ground?
This check wasn't carried out in a hawk a few years ago (aileron cables not connected post maintenace) with tragic consequences.
This said, excellent effort by the FO and quick thinking no doubt saved countless lives.
This check wasn't carried out in a hawk a few years ago (aileron cables not connected post maintenace) with tragic consequences.
This said, excellent effort by the FO and quick thinking no doubt saved countless lives.
Guest
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TvB, are you sure the connector was at the sidestick and not the rack connector at the rear of the ELAC?
The sidestick wiring is relativeley simple with good access to work. Why would anybody rewire the capt's sidestick connector then move accross to the F/O's seat to check it out???
The pins on the rack connector are more susceptable to damage and more likely to be damaged troubleshootinfg an ELAC fault, the access is not as good, neither is the visibilty to seee what your doing so more likely venue for a f*** up.
The sidestick wiring is relativeley simple with good access to work. Why would anybody rewire the capt's sidestick connector then move accross to the F/O's seat to check it out???
The pins on the rack connector are more susceptable to damage and more likely to be damaged troubleshootinfg an ELAC fault, the access is not as good, neither is the visibilty to seee what your doing so more likely venue for a f*** up.
Guest
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bonajet, flap 5 and pengineer!
From what I got through the research of this incident:
It was the CM1 (cpt) sidestick connector, a 560 pin connector (4 segments with 140 pins each).
A flight control check on F/O's side was performed by the mechanic, but only inside the cockpit, using the ECAM indications.
A total of four wires (2 for the roll and 2 for the associated control channel for roll) were reversed in polarity. This apparently made the ELAC believe everything is okay and consistent. Indication on the screen would show proper movement of aileron according to desired actual input but actual movement would be opposite!?!
To my knowledge the AI logic and computers do not compare flight control input/output vs. actual aileron deflection (sensed at the aileron).
Lufthansa did not answer the FI request for comment. No addition information was therefore obtained in ref. to their specific procedures how to perform this flight control check after changing the connector.
But I believe they do it quite to the book, what ever the book says (they are Germans for Christ's sake!!!).
One source at LH told me that there is no requirement for a specific flight control check simultaneously inside/outside after this kind of repair. Could not get this confirmed as AI did not comment either. Possibly different company procedures might apply for different operators, but I really don't know.
Maybe those of you with access to "basis" are able to retrieve more information on this incident.
What some of you guys might find interesting though is what I got officially from Boeing in this regard (- of course I was curious how they have secured this important feature at their FBW B 777 -). Here is the answer from Seattle, WA:
"In the B 777 the EICAS will detect a single fault, as it was the case with the LH A 320. It (the computer-system) would have a problem to detect multiple faults (which is a common known problem with artificial intelligence systems).
The EICAS would generate an error message as it compares the pilots inputs verses the actual outputs. Each pilot input is translated into 3 independent signals. The computer also compares these 3 signals for plausibility and that they all agree.
Further it compares the ACTUAL surface deflection (left aileron up if control wheel input to the left, right aileron down and vice versa) to the desired control input.
Further: there is a specific mandatory maintenance task after performing ANY rewiring of ANY components. A special computerized test equipment is used to detect wiring faults along the line and they will be detected with this equipment.
Last there is a required visual check outside while somebody inside the cockpit performs the flight control check after repair to insure appropriate deflection an free travel of any control surface."
BTW: it took them (Boeing) 16 hours and 42 minutes to answer the questions, with a night in between!!!
Have a great weekend
TvB
(independent) editor aviation
www.aviationsafetyonline.com
[This message has been edited by TvB (edited 05 June 2001).]
From what I got through the research of this incident:
It was the CM1 (cpt) sidestick connector, a 560 pin connector (4 segments with 140 pins each).
A flight control check on F/O's side was performed by the mechanic, but only inside the cockpit, using the ECAM indications.
A total of four wires (2 for the roll and 2 for the associated control channel for roll) were reversed in polarity. This apparently made the ELAC believe everything is okay and consistent. Indication on the screen would show proper movement of aileron according to desired actual input but actual movement would be opposite!?!
To my knowledge the AI logic and computers do not compare flight control input/output vs. actual aileron deflection (sensed at the aileron).
Lufthansa did not answer the FI request for comment. No addition information was therefore obtained in ref. to their specific procedures how to perform this flight control check after changing the connector.
But I believe they do it quite to the book, what ever the book says (they are Germans for Christ's sake!!!).
One source at LH told me that there is no requirement for a specific flight control check simultaneously inside/outside after this kind of repair. Could not get this confirmed as AI did not comment either. Possibly different company procedures might apply for different operators, but I really don't know.
Maybe those of you with access to "basis" are able to retrieve more information on this incident.
What some of you guys might find interesting though is what I got officially from Boeing in this regard (- of course I was curious how they have secured this important feature at their FBW B 777 -). Here is the answer from Seattle, WA:
"In the B 777 the EICAS will detect a single fault, as it was the case with the LH A 320. It (the computer-system) would have a problem to detect multiple faults (which is a common known problem with artificial intelligence systems).
The EICAS would generate an error message as it compares the pilots inputs verses the actual outputs. Each pilot input is translated into 3 independent signals. The computer also compares these 3 signals for plausibility and that they all agree.
Further it compares the ACTUAL surface deflection (left aileron up if control wheel input to the left, right aileron down and vice versa) to the desired control input.
Further: there is a specific mandatory maintenance task after performing ANY rewiring of ANY components. A special computerized test equipment is used to detect wiring faults along the line and they will be detected with this equipment.
Last there is a required visual check outside while somebody inside the cockpit performs the flight control check after repair to insure appropriate deflection an free travel of any control surface."
BTW: it took them (Boeing) 16 hours and 42 minutes to answer the questions, with a night in between!!!
Have a great weekend
TvB
(independent) editor aviation
www.aviationsafetyonline.com
[This message has been edited by TvB (edited 05 June 2001).]
Guest
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I worked for QF for a while some years ago and their SOP was, before service, for the Flight Crew to visually check all the flight controls whenever any flight control system had been disturbed by maintenance.
This involved the F/E to take a headset (with a very long lead) and chat over the service interphone whilst the Pilots operated all the control surfaces.
We all thought this was a bit of a yawn in theory. I had to do it on a 747 S.P. on only one occasion. We discovered that the spoilers were not operating as advertised! (The most inboard spoiler was not doing it's thing, I've forgotten the detail, but it is different to a standard 100/200/300) By the way we only were doing this check because some other flight control had been disturbed. We relayed this info to maintenance who stated that it had probably left Boeing rigged in this manner! Nevertheless the A/C was dragged back into the hangar for investigation.
I hope QF still have this check as part of their SOP's, and it would certainly have done the trick in preventing LH's incident. Unfortunately my airline do not have this check requirement.
Well done to the Lufty crew.
Regards
Exeng
This involved the F/E to take a headset (with a very long lead) and chat over the service interphone whilst the Pilots operated all the control surfaces.
We all thought this was a bit of a yawn in theory. I had to do it on a 747 S.P. on only one occasion. We discovered that the spoilers were not operating as advertised! (The most inboard spoiler was not doing it's thing, I've forgotten the detail, but it is different to a standard 100/200/300) By the way we only were doing this check because some other flight control had been disturbed. We relayed this info to maintenance who stated that it had probably left Boeing rigged in this manner! Nevertheless the A/C was dragged back into the hangar for investigation.
I hope QF still have this check as part of their SOP's, and it would certainly have done the trick in preventing LH's incident. Unfortunately my airline do not have this check requirement.
Well done to the Lufty crew.
Regards
Exeng
Guest
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Kegworth - one engine on fire, other one thought to be and shut down. Subsequent proposals included CCTV to enable pilots to see what's happeneing behind them. Universally rubbished. How many dead was that?
A320 - pilots can't see control surfaces move for viusal check, airlines can't afford 6 minutes for an outside person to watch and confirm movement in desired sense. CCTV would do the trick, without time penalty, wouldn't it? How many have to have near misses like this one, and some die if the FO isn't as quick, before CCTV is though maybe to have some cost- and safety-benefits?
Just a thought from an amateur. (I was a motor industry beancounter - and no, I did not stop safety-related costs being incurred, I encouraged them because bad safety costs too much in the long run. And I fly gliders - visually check movement of control surfaces before every flight, with external helper if I can't see, and check very carefully after every maintenance episode - but then, what do I know?)
Chris N.
A320 - pilots can't see control surfaces move for viusal check, airlines can't afford 6 minutes for an outside person to watch and confirm movement in desired sense. CCTV would do the trick, without time penalty, wouldn't it? How many have to have near misses like this one, and some die if the FO isn't as quick, before CCTV is though maybe to have some cost- and safety-benefits?
Just a thought from an amateur. (I was a motor industry beancounter - and no, I did not stop safety-related costs being incurred, I encouraged them because bad safety costs too much in the long run. And I fly gliders - visually check movement of control surfaces before every flight, with external helper if I can't see, and check very carefully after every maintenance episode - but then, what do I know?)
Chris N.
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JJM: - Well that was true in the past but today this "partial remaining risk" is extensivly covered by insurance deals. The only looser might be the airline if it happens to be a small operator and not one of the big players. Did anybody go down or out of business recently because of a crash? Singapore? Egyptair? Air France? Swissair? American? I don't think so. Therefore I tend to believe that some egg heads really do take a fatality into account (only from time to time) when they do their budget cuttings. Let's hope that the "professionals" will stay smart, qualified and fast enough to jump into this gap when required and the manufacturers find ways to eliminate the rest.
Change? Well only if the "consumer" would demand it, and he really likes to be shuttled for as low as 250 bucks half around the world (and back)... so what?
[This message has been edited by screwjack (edited 27 May 2001).]
Change? Well only if the "consumer" would demand it, and he really likes to be shuttled for as low as 250 bucks half around the world (and back)... so what?
[This message has been edited by screwjack (edited 27 May 2001).]
Guest
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Oilhead is correct, and Doctor A300 and a few others are mistaken. The aileron position info (direction and amount of deflection) displayed on the flight controls ECAM page of course is that of the ailerons! Four position sensors called LVDTs look at the ailerons. This is quite independent of the sidestick positions. This display would not have been affected or reversed because of any miswiring of a sidestick. The additive positions of the sidesticks is displayed until rotation on the PFD.
I think Pelican put his finger on it. On control checks during taxi out the pilots saw spoiler movement and aileron movement in response to commands from each sidestick,correctly displayed on ECAM. It just happened to be in the wrong direction for one stick. Really quite easy to miss at a very busy time and so unexpected. Every pilot does control checks, thousands of times. It is always correct isn't it? Except for this oh so rare occasion.
I think Pelican put his finger on it. On control checks during taxi out the pilots saw spoiler movement and aileron movement in response to commands from each sidestick,correctly displayed on ECAM. It just happened to be in the wrong direction for one stick. Really quite easy to miss at a very busy time and so unexpected. Every pilot does control checks, thousands of times. It is always correct isn't it? Except for this oh so rare occasion.
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AVOMAN, STAGGER
I have to appologize, I wrote about the AIL. Indication, but mixed in the SIDE stick indication on the PFD.
AVOMAN, The Signal from the LVDT´s for the AIL. pass through first the SDAC´s and then the DMU´s. And as far as I can interpret the AMM the LVDT´s signal is converted to an 8 bit ARINC429 signal in the SDAC, the polarity (UP or DOWN) is derived from something else, which I have not been able to figure out yet.
But thanks for pointing out my mistake.
Brgds
Doc
I have to appologize, I wrote about the AIL. Indication, but mixed in the SIDE stick indication on the PFD.
AVOMAN, The Signal from the LVDT´s for the AIL. pass through first the SDAC´s and then the DMU´s. And as far as I can interpret the AMM the LVDT´s signal is converted to an 8 bit ARINC429 signal in the SDAC, the polarity (UP or DOWN) is derived from something else, which I have not been able to figure out yet.
But thanks for pointing out my mistake.
Brgds
Doc
Guest
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So just to reiterate then:
The sidestick order symbol would have been correct but the ailerons would have indicated reverse sense on the F/CTL page (exactly as most sensible people would believe)
If this is the case are we looking at a chain of human error insofar as an engineering procedures error was then followed by a crew error?
So now we can all stop wailing and moaning about the hidden agenda/conspiracy theory run from Toulouse and admit that the Airbus FBW series are darned good aircraft after all.
The sidestick order symbol would have been correct but the ailerons would have indicated reverse sense on the F/CTL page (exactly as most sensible people would believe)
If this is the case are we looking at a chain of human error insofar as an engineering procedures error was then followed by a crew error?
So now we can all stop wailing and moaning about the hidden agenda/conspiracy theory run from Toulouse and admit that the Airbus FBW series are darned good aircraft after all.
Guest
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DoctorA300, Don't the LVDT bits go through the FCDCs instead of the SDACs? I thought the FCDC sent their info straight through to the DMCs and then onto ECAM Flt Cntrls? Would seem more logical to me. I might be totaly wrong! Thanks for shedding some light on the mixup between the ECAM Flt Cntrls page and the sidestick position indicator on the PFD. You got me totaly confused there. M14P, Airbus great aircraft indeed, but different wiring orders for same connector on different aircraft of exactly the same type? Accident waiting to happen. AI has some explaining to do.
Guest
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Guys,
Not in the aviation industry, but the gist of what I saw here is that the sidestick was wired to a 320-200 specification, no A320-200 in particular, which turned out to be wrong. Had it ben wired to the specification of that particular aircraft, it would've been fine? Now, as for people saying this is a serious gaffe on AI's part, I have this to say. Do you honestly think every 737-400, A330-300, etc are identical in every technical detail? No, didn't think so. If airline maintenance has a proper document control system in place, these issues would be picked up. At the end of the day, the schematics used did not correlate to the serial number of the aircraft, this can happen anyone unless there are proper procedures in place. Any upgrades/changes by a manufacturer presumably go through numerous forums for an approval, and are then added to equipment configuration details. These equipment configuration details are captured in subsequent documentation, which is why it is so important to use the correct reference material for the exact aircraft being worked on. Is this even remotely the case, or am I miles off? Just curious, not trying to pi** off the professionals, but I'd like an insight into the workings of these issues...........
Not in the aviation industry, but the gist of what I saw here is that the sidestick was wired to a 320-200 specification, no A320-200 in particular, which turned out to be wrong. Had it ben wired to the specification of that particular aircraft, it would've been fine? Now, as for people saying this is a serious gaffe on AI's part, I have this to say. Do you honestly think every 737-400, A330-300, etc are identical in every technical detail? No, didn't think so. If airline maintenance has a proper document control system in place, these issues would be picked up. At the end of the day, the schematics used did not correlate to the serial number of the aircraft, this can happen anyone unless there are proper procedures in place. Any upgrades/changes by a manufacturer presumably go through numerous forums for an approval, and are then added to equipment configuration details. These equipment configuration details are captured in subsequent documentation, which is why it is so important to use the correct reference material for the exact aircraft being worked on. Is this even remotely the case, or am I miles off? Just curious, not trying to pi** off the professionals, but I'd like an insight into the workings of these issues...........