LH3431 B737 lightning strike?
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ok
1. What could have happened if not the part that was causing the shaking was thorn away? I have to say that it had to be very hard to control the aircraft in such a turbulence. How long could the aircraft stand such turbulence before it affected other parts/instruments?
I'm not current on 737 but most airliners are certified for 0/+2.0 g with flaps extended. They can withstand more.
2. How bad was it for you expert that has seen the pictures? Are they trying to make this better then it was? Or am I just to "close" the incident to see things clear?
There is always a backup system in commercial airliners. If the elevator would fail completely, the aeroplane can be controlled by the trimmable horizontal stabiliser.
3. How crusual are the part that was hit and how difficult is it to fly without it?
See above.
4. Shouldnt this be more official than it is?
Didn't get this one.
1. What could have happened if not the part that was causing the shaking was thorn away? I have to say that it had to be very hard to control the aircraft in such a turbulence. How long could the aircraft stand such turbulence before it affected other parts/instruments?
I'm not current on 737 but most airliners are certified for 0/+2.0 g with flaps extended. They can withstand more.
2. How bad was it for you expert that has seen the pictures? Are they trying to make this better then it was? Or am I just to "close" the incident to see things clear?
There is always a backup system in commercial airliners. If the elevator would fail completely, the aeroplane can be controlled by the trimmable horizontal stabiliser.
3. How crusual are the part that was hit and how difficult is it to fly without it?
See above.
4. Shouldnt this be more official than it is?
Didn't get this one.
Last edited by hetfield; 9th Apr 2008 at 06:46.
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Passanger
So... briefly one can say that this was no danger? 
Well... I can say that I have no problems if it wasnt and nothing would be more good than that. I just dont want LH to try to "smothen" things up if it was more bad...
I just can say that the 5 minutes with the shaking was terrible and i had plenty of time to think bad thoughts...
I am not sure if it helps to know that things really was under control or not. The 5 minutes I really felt that I should die. I dont think it is really possible for someone that has not been in a similiar situation to really know what its like. Well.... it gets better and better. I just think i need to speak to some professionals to prevent any after-damage
Thank you for your replies and understanding.
Well... I can say that I have no problems if it wasnt and nothing would be more good than that. I just dont want LH to try to "smothen" things up if it was more bad...
I just can say that the 5 minutes with the shaking was terrible and i had plenty of time to think bad thoughts...
I am not sure if it helps to know that things really was under control or not. The 5 minutes I really felt that I should die. I dont think it is really possible for someone that has not been in a similiar situation to really know what its like. Well.... it gets better and better. I just think i need to speak to some professionals to prevent any after-damage
Thank you for your replies and understanding.
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Swede
In normal hydraulic control this tab is locked and in line with the elevator. With no hydraulics in manual control, it is unlocked and works as a trim tab.
The "trim" of the tab is mechanically set and fixed by the two burnt control rods you can see in the photos and is critical to longitudinal trim control in a loss of hydraulic power situation.
It's late and I'm on my third wine so apologies if not quite correct.
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An interesting piece on similar incidents...
To quote from a TSB of Canada report (A95P0272 ) on a trim-tab induced flutter on a 737-200, in which a 24-inch section of the right elevator trim tab separated from the aircraft in flight: "The failure of the right trim tab did not endanger the aircraft from the standpoint of a loss of control; control surface flutter, however, can lead to further aircraft structural damage. The outboard section of the tab was attached to the elevator without any restriction to its movement, and it oscillated uncontrollably. This in turn caused the elevator to oscillate, which resulted in the severe airframe vibration felt by the crew."
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What should have happend:
All parts of the aeroplane structure should be bonded (connected) either via direct metal to metal contact at joints or via bonding jumper leads to connect moving parts such as tabs. This should allow any electrical current from a strike to travel through the structure, harmlessly, and find an exit path via the line of least resistance to one or more of the static wicks" at the a/c extremities; wing tips; ailerons; elevator and rudder etc. and discharge to atmosphere due to the potential differece.
I there is a breakdown or even complete abscence of this bonding for any reason then the current will attempt to jump this gap and arcing/burning can or will occur and can be severe in some cases causing physical damage.
In this case if the tab end is damaged and no longer aerodyamically clean then airflow breakdown will occur with ensuing vibration and possibly flutter as described earlier and perhaps being apparent through the whole airframe. Probably the vibration was such that the damaged portion eventually broke free allowing reasonably clean airflow once more.
Composite structures such as the tab and elevator in this case often have some metal embedded into them to assist with this very point. I confess to being fairly ignorant for now about this achieved on the very modern and very large composite structures.
New aeroplanes are at design stage subject to enormous electrical discharges to prove their viability and there are some amazing photos of this somewhere.
apologies to any granny readers.
All parts of the aeroplane structure should be bonded (connected) either via direct metal to metal contact at joints or via bonding jumper leads to connect moving parts such as tabs. This should allow any electrical current from a strike to travel through the structure, harmlessly, and find an exit path via the line of least resistance to one or more of the static wicks" at the a/c extremities; wing tips; ailerons; elevator and rudder etc. and discharge to atmosphere due to the potential differece.
I there is a breakdown or even complete abscence of this bonding for any reason then the current will attempt to jump this gap and arcing/burning can or will occur and can be severe in some cases causing physical damage.
In this case if the tab end is damaged and no longer aerodyamically clean then airflow breakdown will occur with ensuing vibration and possibly flutter as described earlier and perhaps being apparent through the whole airframe. Probably the vibration was such that the damaged portion eventually broke free allowing reasonably clean airflow once more.
Composite structures such as the tab and elevator in this case often have some metal embedded into them to assist with this very point. I confess to being fairly ignorant for now about this achieved on the very modern and very large composite structures.
New aeroplanes are at design stage subject to enormous electrical discharges to prove their viability and there are some amazing photos of this somewhere.
apologies to any granny readers.
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Another Passenger Perspective
We were also passengers on the flight out of Sofia on Saturday evening and would like to tell how we experienced the events of that evening.
While still in the departure lounge we observed a line of cloud approaching - which appeared to be a front sufficiently active to be worthy of comment. When we were on the aircraft the rain had started and it increased as we taxied to the runway.
We were sitting in seats next to the over-wing exits on the starboard side. About 5 minutes after take off, in cloud, we were struck by lightning. I was reading but saw a flash of lightning from my right followed immediately by a loud bang and sparks or flashes across the upper wing surface. We did not witness any flames.
Immediately this happened there was vibration. This increased in severity in a stepped manner at about 4 minutes after the strike and again after a further minute. The vibration was severe enough to cause the cabin windows to be moving in and out approximately 10 – 12mms. It was frightening for all on board and particularly so for those with children.
The sensation and type of vibration in the aircraft, and the photographs published since, suggest that a similar situation has arisen as has been described by The Bartender. The inboard trim tab has been destroyed and disconnected from the control system. In this configuration any loose panel or debris will cause oscillation of the trim tab and set up violent vibration.
The plane was flown very gently back to Sofia, so much so that we were hardly aware we were descending until we broke cloud – and not at all aware we had completed a circuit. We truly thought we were landing straight ahead and wondered where that might be. It was a surprise to be back at Sofia.
At no point during this very unpleasant experience were there any announcements from either flight crew or cabin crew, although many people on board were obviously distraught. While we fully appreciate the pilots were likely to be occupied, we are surprised that the cabin crew did nothing to calm the situation since this is their job - and we completely understand the fears expressed by Steelfo. We were probably a little less inclined to panic than some on board because we have some knowledge of aircraft but we were still scared, so to suggest this experience was either exaggerated or the result of some ‘rogue activity’ is disingenuous.
The lack of information and communication was really appalling. Some people on the aircraft were approaching hysterical, others were tearful and yet more were quietly anxious but all would have welcomed – and expected – some explanation and reassurance.
We are also interested to discover from Steelfo that Lufthansa has issued a statement. It hasn’t reached us.
Collmac and Chris
While still in the departure lounge we observed a line of cloud approaching - which appeared to be a front sufficiently active to be worthy of comment. When we were on the aircraft the rain had started and it increased as we taxied to the runway.
We were sitting in seats next to the over-wing exits on the starboard side. About 5 minutes after take off, in cloud, we were struck by lightning. I was reading but saw a flash of lightning from my right followed immediately by a loud bang and sparks or flashes across the upper wing surface. We did not witness any flames.
Immediately this happened there was vibration. This increased in severity in a stepped manner at about 4 minutes after the strike and again after a further minute. The vibration was severe enough to cause the cabin windows to be moving in and out approximately 10 – 12mms. It was frightening for all on board and particularly so for those with children.
The sensation and type of vibration in the aircraft, and the photographs published since, suggest that a similar situation has arisen as has been described by The Bartender. The inboard trim tab has been destroyed and disconnected from the control system. In this configuration any loose panel or debris will cause oscillation of the trim tab and set up violent vibration.
The plane was flown very gently back to Sofia, so much so that we were hardly aware we were descending until we broke cloud – and not at all aware we had completed a circuit. We truly thought we were landing straight ahead and wondered where that might be. It was a surprise to be back at Sofia.
At no point during this very unpleasant experience were there any announcements from either flight crew or cabin crew, although many people on board were obviously distraught. While we fully appreciate the pilots were likely to be occupied, we are surprised that the cabin crew did nothing to calm the situation since this is their job - and we completely understand the fears expressed by Steelfo. We were probably a little less inclined to panic than some on board because we have some knowledge of aircraft but we were still scared, so to suggest this experience was either exaggerated or the result of some ‘rogue activity’ is disingenuous.
The lack of information and communication was really appalling. Some people on the aircraft were approaching hysterical, others were tearful and yet more were quietly anxious but all would have welcomed – and expected – some explanation and reassurance.
We are also interested to discover from Steelfo that Lufthansa has issued a statement. It hasn’t reached us.
Collmac and Chris
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Don't think there is any "mistery" (sic).
Took off into sh@t weather got hit by a bolt from Big G, knackered the tail due to Boeing inability to bond the A/C ( thought that was only an 800 prob, obviously not ) came back landed.
As stated by my fellow Jock, a reassuring P.A. might have been a good idea, but, I guess if tail was trying to shake itself loose they maybe needed some reassurance themselves.
Took off into sh@t weather got hit by a bolt from Big G, knackered the tail due to Boeing inability to bond the A/C ( thought that was only an 800 prob, obviously not ) came back landed.
As stated by my fellow Jock, a reassuring P.A. might have been a good idea, but, I guess if tail was trying to shake itself loose they maybe needed some reassurance themselves.
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It may be the cabin crews 'job' to calm and reasure but keep in mind they may never have had this happen to them before.
I am not saying you are wrong, and i know what i am talking about, have been through a similar situation, and i dont mind admitting that i was scared s
less!!!
I am not saying you are wrong, and i know what i am talking about, have been through a similar situation, and i dont mind admitting that i was scared s
less!!!
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Can anybody provide METARs and TAFs for that hour of departure in Sofia.
LBSF 051800Z 09001MPS 7000 -RA OVC036 08/06 Q1005 NOSIG
LBSF 051830Z 13002MPS 100V170 4500 RA OVC017 08/06 Q1005 NOSIG
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Lufthansa
Hi Collmac and Chris.
Thank you for your description of the situation. It is good to hear another statement that this was an horrible experience. We were a group of 18 so of course it could have been the possibility to "scare" up each other, but as I read your story it is similar of what we experienced.
The statement from Lufthansa we got from the country manager of Norway. Probably and surely because the story ended up in one of Norways largest newspapers. It was a letter that didnt calm me, but just a very brief explanation of the incident. I was a little pissed because I felt it didnt say anything about what really happened. Thats why I seeked more information in among others this excellent forum.
Lufthansa did not at any time appologized either the lack of information on board or after. I surely understand the lack of time the pilots had and the fearfull experience of the other working on board. But if the captain had so much control and if the situation was not as bad as Lufthansa say I find it strange that we did not get more information.
Well anyway.... I now have much more information about this and how serious it was. Much thanks to this forum. So I feel calm about the physical situation. I am more concerned about the phsycical reaction the situation caused. Much of that could after my opinion been reduced by more information both on board and at least after.
Best regards
Steelfo
Thank you for your description of the situation. It is good to hear another statement that this was an horrible experience. We were a group of 18 so of course it could have been the possibility to "scare" up each other, but as I read your story it is similar of what we experienced.
The statement from Lufthansa we got from the country manager of Norway. Probably and surely because the story ended up in one of Norways largest newspapers. It was a letter that didnt calm me, but just a very brief explanation of the incident. I was a little pissed because I felt it didnt say anything about what really happened. Thats why I seeked more information in among others this excellent forum.
Lufthansa did not at any time appologized either the lack of information on board or after. I surely understand the lack of time the pilots had and the fearfull experience of the other working on board. But if the captain had so much control and if the situation was not as bad as Lufthansa say I find it strange that we did not get more information.
Well anyway.... I now have much more information about this and how serious it was. Much thanks to this forum. So I feel calm about the physical situation. I am more concerned about the phsycical reaction the situation caused. Much of that could after my opinion been reduced by more information both on board and at least after.
Best regards
Steelfo
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Lightning Strikes?
Well thank you to all the information on the so-calles Bonding of all surfaces - there is no way to prevent damage caused by a direct strike of lightning on anything.
The damage may be limited by all sorts of precautions like bonding etc . . . .
However the only way to prevent damage is to stay away from CB's and other sources of imbalance in static electrical charge -
If there are indications of static on the stormscope go left or right to avoid - If you can't you are in grave danger - It becomes not if but when you are going to be struck - being a foreign object with a different electrical charge than the surrounds and lots of static activity.
So my opinion is the pilot took a calculated risk to take off with the weather as reported - but we all do as schedules require etc . . .
Maybe a better monitoring of the cockpit instruments (Radar & Stormscope) and alternative routing requested from ATC could have prevented the terrible experience.
This is one of the last issues that the aviation world have not really had an answer for - Lightning!
VG300
The damage may be limited by all sorts of precautions like bonding etc . . . .
However the only way to prevent damage is to stay away from CB's and other sources of imbalance in static electrical charge -
If there are indications of static on the stormscope go left or right to avoid - If you can't you are in grave danger - It becomes not if but when you are going to be struck - being a foreign object with a different electrical charge than the surrounds and lots of static activity.
So my opinion is the pilot took a calculated risk to take off with the weather as reported - but we all do as schedules require etc . . .
Maybe a better monitoring of the cockpit instruments (Radar & Stormscope) and alternative routing requested from ATC could have prevented the terrible experience.
This is one of the last issues that the aviation world have not really had an answer for - Lightning!
VG300
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Vortex Gen said:
Surely that is a very misleading not to say inaccurate posting and alarmist to boot.
Of course there is protection.
It is true that scientists and meteorology experts are still discovering new phenomena about such events. It doesn't seem all that long ago that it was discovered that lightning can and does strike upwards from cloud to aircraft.
But an enormous amount of work is done at the certification stage including placing a full size production aircraft into what is effectively a wire cage and then subjecting the aircraft to electical discharges of at least the same magnitude as measured or calculated from actual lightning. I have as alluded to earlier seen some excellent photos of this process at one of Boeing's facilities, I believe, and it would, I am sure allay lots of people's fears or misunderstanding to see such a picture or even better a video of this. Link anyone?
But nothing is perfect or remains perfect as the aeroplane gets older and goes through a variety of maintenance checks and suffers general wear and tera which may reduce some of this protection.
And isn't every lightning strike a "direct strike"?
there is no way to prevent damage caused by a direct strike of lightning on anything.
The damage may be limited by all sorts of precautions like bonding etc . . . .However the only way to prevent damage is to stay away from CB's and other sources of imbalance in static electrical charge -
The damage may be limited by all sorts of precautions like bonding etc . . . .However the only way to prevent damage is to stay away from CB's and other sources of imbalance in static electrical charge -
Of course there is protection.
It is true that scientists and meteorology experts are still discovering new phenomena about such events. It doesn't seem all that long ago that it was discovered that lightning can and does strike upwards from cloud to aircraft.
But an enormous amount of work is done at the certification stage including placing a full size production aircraft into what is effectively a wire cage and then subjecting the aircraft to electical discharges of at least the same magnitude as measured or calculated from actual lightning. I have as alluded to earlier seen some excellent photos of this process at one of Boeing's facilities, I believe, and it would, I am sure allay lots of people's fears or misunderstanding to see such a picture or even better a video of this. Link anyone?
But nothing is perfect or remains perfect as the aeroplane gets older and goes through a variety of maintenance checks and suffers general wear and tera which may reduce some of this protection.
And isn't every lightning strike a "direct strike"?
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Starbear
Take note, not all lightning strikes are direct, some are strays, and let me just qualify something, most things in this world if hit by lightning areed, wheteher it be a small hit or large hit.
Commercial airliners are one of the few things on the planet that survive most with little or no damage. Note the word "most" as in not all.
Bloody lucky that it was a modern B737 (even a classic is modern) compare to many other earlier a/c.
J
Take note, not all lightning strikes are direct, some are strays, and let me just qualify something, most things in this world if hit by lightning are
ed, wheteher it be a small hit or large hit.Commercial airliners are one of the few things on the planet that survive most with little or no damage. Note the word "most" as in not all.
Bloody lucky that it was a modern B737 (even a classic is modern) compare to many other earlier a/c.
J
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My sympathy for all the people who have experienced such an distressing event.
Will you fly again?. After my lightening strike, when I check there´s a storm in my route, I cancel my flight. It wasn´t such dramatic, but I do understand you quite well.
And of course I share your feelings.
Will you fly again?. After my lightening strike, when I check there´s a storm in my route, I cancel my flight. It wasn´t such dramatic, but I do understand you quite well.
And of course I share your feelings.
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Flying Again
Thank you for asking.
Firstly we had to fly on the day following the incident, first to Frankfurt and then on to Edinburgh and, as fairly frequent flyers with our work as well as for pleasure, we really don't have much choice in the matter. However, we are both quite accepting of it being just one of those things and will have no trouble flying again.
Chris flew to London on Monday; I am off to the islands next week. Alternative transport is not convenient for us and cancellation is not usually an option but we'll not be losing sleep over it.
Collmac
Firstly we had to fly on the day following the incident, first to Frankfurt and then on to Edinburgh and, as fairly frequent flyers with our work as well as for pleasure, we really don't have much choice in the matter. However, we are both quite accepting of it being just one of those things and will have no trouble flying again.
Chris flew to London on Monday; I am off to the islands next week. Alternative transport is not convenient for us and cancellation is not usually an option but we'll not be losing sleep over it.
Collmac
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Well done. I suppose this is like the lottery. One never gets the price again for the second time.
I am surprised at the lack of information given by the crew.
I am surprised at the lack of information given by the crew.
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Vortex-gen300 is not misleading or being alarmist, bonding is only a protective measure and the only way to be totally safe from lightning is total avoidance. It is not common but quite possible to see bonding leads and strips blown apart or off by severe lightning overload. When this happens the lightning will find another path. Composite structure often has copper mesh laid into the subsurface layers. If it does not the lightning will track through the water content of the composite and cause severe damage as it vapourises.
Certification tests on aircraft structure are with simulated lightning. I have considerable experience of dealing with real world results and can tell you that there is no such thing as a standard lightning strike. Every aircraft can expect to be struck a few or maybe several times a year depending where it is operated. The vast majority of strikes leave no damage apart from a tiny pitting mark where they enter and possibly some very minor burning at the exit point. The crew may well be unaware they have been struck in some cases and in most events even experienced engineers may have difficulty in finding the entry & exit points.
My point is lightning is like waves at sea, in the vast majority of cases no big deal but like the sea with rogue waves there are rogue bolts of lightning that will render all certification testing pointless. Aircraft undergo bonding testing during maintenance to ensure the integrity of the bonding path but in some very rare cases a lightning strike will overwhelm this and cause damage.
Anyway if I could reassure Steelfo by stating that every commercial aircraft flying has or will be struck by lightning at some point. It is [U]very[U] rare for that damage to be severe enough to loss of control or a crash. In fact I can think of only 1 case off the top of my head and this involved small commuter aircraft.
http://www.airdisaster.com/photos/ln-hta/photo.shtml
Certification tests on aircraft structure are with simulated lightning. I have considerable experience of dealing with real world results and can tell you that there is no such thing as a standard lightning strike. Every aircraft can expect to be struck a few or maybe several times a year depending where it is operated. The vast majority of strikes leave no damage apart from a tiny pitting mark where they enter and possibly some very minor burning at the exit point. The crew may well be unaware they have been struck in some cases and in most events even experienced engineers may have difficulty in finding the entry & exit points.
My point is lightning is like waves at sea, in the vast majority of cases no big deal but like the sea with rogue waves there are rogue bolts of lightning that will render all certification testing pointless. Aircraft undergo bonding testing during maintenance to ensure the integrity of the bonding path but in some very rare cases a lightning strike will overwhelm this and cause damage.
Anyway if I could reassure Steelfo by stating that every commercial aircraft flying has or will be struck by lightning at some point. It is [U]very[U] rare for that damage to be severe enough to loss of control or a crash. In fact I can think of only 1 case off the top of my head and this involved small commuter aircraft.
http://www.airdisaster.com/photos/ln-hta/photo.shtml
Last edited by BeeBopp; 15th Apr 2008 at 16:10.
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My Lightning Story
Not terribly exciting - I was flying back from LGW to MSP on a Northwest DC10 a couple of years ago (Mid April).
The approach to MSP was a little rough through low cloud. I was seated by the left wing and was looking out the window when the wing was struck near the tip. Other than being closer to a lightning strike that at any other time in my life it was basically uneventful - just a big spark and a loud bang.
Nobody said a word until we touched down then everybody was like "Did you see that !!!".
I couldn't even see a mark on the wing from where I was sitting.
The approach to MSP was a little rough through low cloud. I was seated by the left wing and was looking out the window when the wing was struck near the tip. Other than being closer to a lightning strike that at any other time in my life it was basically uneventful - just a big spark and a loud bang.
Nobody said a word until we touched down then everybody was like "Did you see that !!!".
I couldn't even see a mark on the wing from where I was sitting.