Boeing 777 loses wing panel over Osaka
This is a panel with about 36 screw fasteners. It is not a quickly removable panel therefore not removed during line maintenance. What lies behind it I wonder.
Got to be maintenance error although I don't have any 777 familiarity, I do have a few other types in 36 years LAE.
Got to be maintenance error although I don't have any 777 familiarity, I do have a few other types in 36 years LAE.
Maybe if the bracket cracked through the screw holes? Or through some of them and then the rest of the screws broke or pulled out? I'm not really even convincing myself, though.
there is always the possibility that the screws were in place and unscrewed by themselves due to undamped vibrations stemming from another supporting bracket that failed.
but gee gosh why are we pursuing this in R&N ?
but gee gosh why are we pursuing this in R&N ?
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Unbelievable to see that some of you are stretching this discussion.
I told you what the reason was for the departing panel. If you don't believe this be my guest. But know this that it's complete nonsens to say it's a mx error.
KLM is not to blame.
Maybe a schock to ya'll but things can break on aircraft, It is not immediate human error.
I told you what the reason was for the departing panel. If you don't believe this be my guest. But know this that it's complete nonsens to say it's a mx error.
KLM is not to blame.
Maybe a schock to ya'll but things can break on aircraft, It is not immediate human error.
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I think we need to extend the discussion at least to the point where we understand your report.
So far, all you have said is that there is bracket that commonly fails. Presumably one that is holding this panel in place. If that is the only information you have, I would not conclude that a bracket failure was the immediate cause of the panel separation - because all of the screws are missing. Although I might guess that a bracket problem triggered the maintenance that left the panel with most or all of its screws missing.
But you seem to be convinced otherwise, and perhaps justly so. That would mean that you have other evidence that you have not shared. Perhaps you have seen other photos, or the bracket itself, or you know some other detail of the previous panel bracket issues.
Whatever it is, can you fill us in? At least in broad terms? Otherwise we are left with your assertion and the suspicion that you are misinterpreting whatever that additional evidence is.
So far, all you have said is that there is bracket that commonly fails. Presumably one that is holding this panel in place. If that is the only information you have, I would not conclude that a bracket failure was the immediate cause of the panel separation - because all of the screws are missing. Although I might guess that a bracket problem triggered the maintenance that left the panel with most or all of its screws missing.
But you seem to be convinced otherwise, and perhaps justly so. That would mean that you have other evidence that you have not shared. Perhaps you have seen other photos, or the bracket itself, or you know some other detail of the previous panel bracket issues.
Whatever it is, can you fill us in? At least in broad terms? Otherwise we are left with your assertion and the suspicion that you are misinterpreting whatever that additional evidence is.
Last edited by .Scott; 27th Sep 2017 at 13:01. Reason: quote was missing.
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@ErwinS - I have no cause to doubt what you say and think that it is said with the best intentions. But would like to add that the JTSB will most likely stretch a discussion like this into an independent Incident Report. It is not for the airline or maintenance organization, nor the manufacturer, to have the final say in what happened and why.
What surprises me and a number of others in this thread is, that on the photos that we have there is hardly any visible damage and the are no (bend or sheared) bolts or other tears or fragments. So what was the detachment sequence? Did the flight crew register it?
It put me on the track of thinking about what would be the difference in damage between hinged-panels (with failing latches) and non-hinged bolted-panels. In this case it looks like the panel popped or blew straight outward and did not hit the fuselage or any surfaces. Sounds special. And if it happened like that you could wonder if a pilot would be able to notice anything at all.
In another case of an 777, a hinged ADU-door of about 70lbs, detaching at 6,000ft, the pilots only felt a light shudder. And only investigated when the cabin crew reported something hitting the fuselage. They found the fuselage was penetrated and the plane dumped fuel and returned.
In that case the plane had only just left maintenance and was inspected a number of times, but the investigation concluded that only 1 of 13 latches had been closed properly. The probability of missing a countersunk bolthead is lower I guess than missing a latch.
So not stretching the discussion but interested in more facts.
What surprises me and a number of others in this thread is, that on the photos that we have there is hardly any visible damage and the are no (bend or sheared) bolts or other tears or fragments. So what was the detachment sequence? Did the flight crew register it?
It put me on the track of thinking about what would be the difference in damage between hinged-panels (with failing latches) and non-hinged bolted-panels. In this case it looks like the panel popped or blew straight outward and did not hit the fuselage or any surfaces. Sounds special. And if it happened like that you could wonder if a pilot would be able to notice anything at all.
In another case of an 777, a hinged ADU-door of about 70lbs, detaching at 6,000ft, the pilots only felt a light shudder. And only investigated when the cabin crew reported something hitting the fuselage. They found the fuselage was penetrated and the plane dumped fuel and returned.
In that case the plane had only just left maintenance and was inspected a number of times, but the investigation concluded that only 1 of 13 latches had been closed properly. The probability of missing a countersunk bolthead is lower I guess than missing a latch.
So not stretching the discussion but interested in more facts.
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The bracket failure will be that of the bracket that supported the screws box in the store room - thus leaving no screws to fit.
Or any other regular failure will be covered by a AD or SB by now or a grounding of type.
Or that is what happens in the real World.
Or any other regular failure will be covered by a AD or SB by now or a grounding of type.
Or that is what happens in the real World.
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okay Erwin, I couldnt find any images that showed the back fairing, but there is one of the front, so it is probably similar?
As many others have noted, the bracket seems like if it cracked or broke, at least some of the fasteners from either the bracket, or the attachment to the other panels, and even part of some bracket attached...it does seem very odd that there are no fasteners, no bracket, and really no evidence of any pulled through the fairing.
Since this failure did land in an urban area and cause damage, we are all going to find out anyways...
As many others have noted, the bracket seems like if it cracked or broke, at least some of the fasteners from either the bracket, or the attachment to the other panels, and even part of some bracket attached...it does seem very odd that there are no fasteners, no bracket, and really no evidence of any pulled through the fairing.
Since this failure did land in an urban area and cause damage, we are all going to find out anyways...
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Cant believe we have 3 pages about a lost panel..
The reason why this panel separates is that the support bracket design isn't rigid enough to stop the panel from vibrating and that leads to the screws migrating out. Its not unusual to see screws on a turnaround that have started to migrate out and this can be exacerbated by having worn anchor nuts or incorrect length screws - that being said I have seen this panel lost on a newish aircraft from Boeing that hadn't been through base maintenance and had never had that panel removed during airline service.
The reason why this panel separates is that the support bracket design isn't rigid enough to stop the panel from vibrating and that leads to the screws migrating out. Its not unusual to see screws on a turnaround that have started to migrate out and this can be exacerbated by having worn anchor nuts or incorrect length screws - that being said I have seen this panel lost on a newish aircraft from Boeing that hadn't been through base maintenance and had never had that panel removed during airline service.
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I don't know if this adds to the discussion at all; the incidents could be unrelated and I haven't found any news so far about investigation details but..
Earlier this month an ANA 767 based out of RJAA (If I remember right) lost a panel TWICE. I thought it was bad Chinese maintenance when I read about the 767 as it had been flying out of a Chinese airport, but now who knows. Of course it could just be a coincidence. Lost the panel on one flight, landed safely at destination, had panel replaced and then it came off again in flight. Both times landed without incident but I don't have details on what the butcher's bill was re: airframe damage.
Three panels, same airport (different companies) in the space of a month - could be unlucky coincidence but it is worth checking out the maintenance procedures as well as preflight procedures. Everyone be vigilant on your walkarounds. Hard to spot missing screws on the ground but do your best.. Maybe walkarounds with the 20something year old flight attendants with their eagle eyes would be a nice diversion from the normal
Earlier this month an ANA 767 based out of RJAA (If I remember right) lost a panel TWICE. I thought it was bad Chinese maintenance when I read about the 767 as it had been flying out of a Chinese airport, but now who knows. Of course it could just be a coincidence. Lost the panel on one flight, landed safely at destination, had panel replaced and then it came off again in flight. Both times landed without incident but I don't have details on what the butcher's bill was re: airframe damage.
Three panels, same airport (different companies) in the space of a month - could be unlucky coincidence but it is worth checking out the maintenance procedures as well as preflight procedures. Everyone be vigilant on your walkarounds. Hard to spot missing screws on the ground but do your best.. Maybe walkarounds with the 20something year old flight attendants with their eagle eyes would be a nice diversion from the normal
I've been working the 777 in line maintenance for almost 20 years. I've never seen or heard of an issue with that panel or that area. The hydraulic ADP access panel that came off a BA 777 some years ago is the only significant one that springs to mind.
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Cant believe we have 3 pages about a lost panel..
The reason why this panel separates is that the support bracket design isn't rigid enough to stop the panel from vibrating and that leads to the screws migrating out. Its not unusual to see screws on a turnaround that have started to migrate out and this can be exacerbated by having worn anchor nuts or incorrect length screws - that being said I have seen this panel lost on a newish aircraft from Boeing that hadn't been through base maintenance and had never had that panel removed during airline service.
The reason why this panel separates is that the support bracket design isn't rigid enough to stop the panel from vibrating and that leads to the screws migrating out. Its not unusual to see screws on a turnaround that have started to migrate out and this can be exacerbated by having worn anchor nuts or incorrect length screws - that being said I have seen this panel lost on a newish aircraft from Boeing that hadn't been through base maintenance and had never had that panel removed during airline service.
However, I wouldn't expect the conversation to end with everyone accepting the notion that a panel falling off a plane is to be expected.
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As I said, look it up on myboeingfleet - plenty of discussion there in the forum.
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Its not expected, just not unknown. I dont know what the rate of failure is but like everything else on an aeroplane below a certain percentage then the failure rate is acceptable. To re-engineer the brackets and make them more secure would involve putting the panel fasteners though the skin and then you get into yet another load of stress calculations and possible redesigns of the skin panels. Is all that cost worthwhile for an incident that maybe reoccurs once every 2 - 3 years?
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Everything in aviation is based on cost-benefit, would it be cheaper to re-engineer the aircraft or live with this pretty rare issue and try to mitigate it?.