Plastic Planes vs Traditional Metal Aircraft.
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This whole thread got of to a false start, Composites ARE NOT PLASTICS, they are as they say COMPOSITES, just like your chompers in your mouth, {but cheaper to maintain} Untill we sold our companies my wife and I operated over twenty "glass" aircraft and are both trained to repair them. Its true there is a shortage of qualified repair folks but the situation is improving. Dont ever call a composite aircraft plastic around Burt Rutan!
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A 'generic' term, if you like Mr 'C',
As distinct from 'wood and wire', or 'tin',.....for those amongst us who wish to know such things, it just refers colloquially to 'all things of composite, carbon fibre, glass', etc etc.
The water ingress - freezing to ice - expanding - problem seems to be acknowledged.
The problems of repairing 'impact' problems are not so well understood - by moi anyway - but then, that's not hard......
No emotions please - just the facts.....colloquially if you like....
Cheers
As distinct from 'wood and wire', or 'tin',.....for those amongst us who wish to know such things, it just refers colloquially to 'all things of composite, carbon fibre, glass', etc etc.
The water ingress - freezing to ice - expanding - problem seems to be acknowledged.
The problems of repairing 'impact' problems are not so well understood - by moi anyway - but then, that's not hard......
No emotions please - just the facts.....colloquially if you like....
Cheers
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As I said before I am not a fan of these composite structures, just something from experience with them.
This is what happened to an Airbus A310 one night at JFK when I was there, NOT the Airbus I was looking after thankfully.
It was grounded for some 7-8 months while people from Airbus fitted a complete new tail, unable to repair.
On that same tour of duty we operated an Airbus A300-600, same type as the American Airlines one that lost its tail, operating obviously also out of JFK and over very similar routes.
Every time we did an A check (or higher) at JFK we spent all night, and I mean all night, among other jobs draining water that had been trapped in the tail.
To this day I still think that it MAY have been part of the reason that the American A300 lost its tail out of JFK, however on a previous post o PPRuNe some years ago most of the Pilots blamed the Pilots.
This is what happened to an Airbus A310 one night at JFK when I was there, NOT the Airbus I was looking after thankfully.
It was grounded for some 7-8 months while people from Airbus fitted a complete new tail, unable to repair.
On that same tour of duty we operated an Airbus A300-600, same type as the American Airlines one that lost its tail, operating obviously also out of JFK and over very similar routes.
Every time we did an A check (or higher) at JFK we spent all night, and I mean all night, among other jobs draining water that had been trapped in the tail.
To this day I still think that it MAY have been part of the reason that the American A300 lost its tail out of JFK, however on a previous post o PPRuNe some years ago most of the Pilots blamed the Pilots.
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but what caused that damage? composite panels just don't disintegrate bythemselves, even if it was water damage, then thats a maintenance failure, impact damage on composite panels is usually inspected using tap tests to determine any delaminations, and a water tester to check for water contamination of the damage. (well at QF anyway when we still has jobs there)
judging by the pucture, it look like it has been hit by something, and possibly gone undetected for quite some time if that is a result of water/ice damage.. but if its damaged to a point to break the resin and fibres, then there should have also been evidence by a lot of paint damage/scuffing as well.
judging by the pucture, it look like it has been hit by something, and possibly gone undetected for quite some time if that is a result of water/ice damage.. but if its damaged to a point to break the resin and fibres, then there should have also been evidence by a lot of paint damage/scuffing as well.
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Maybe I didn't explain it very well, I thought I did.
The photo is of an Air Jamaica A310 that was damaged by contacting a hangar roof at JFK while under tow.
The trapped water to which I referred was in our A300-600 operating in and out of and serviced at JFK.
The photo is of an Air Jamaica A310 that was damaged by contacting a hangar roof at JFK while under tow.
The trapped water to which I referred was in our A300-600 operating in and out of and serviced at JFK.
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Hangar damage would have been just as bad with a metal aircraft, but dont forget, if it was a 767/747/ or most other Boeing products, the damage would have been the same, as their construction is similar with the exception that boeing use Metal Spar and attach points. all panels and rudder are still composite.
as for the water trapped, where was the water being drained from? behind the panels? or were holes drilled into the panels themselves to release water?
if its behind the panes, then some uneducated person might have mistakenly plugged the drain holes, or if within the panel, then someone needs to do an inspection of the panel to find its point of entry and repair it.
as for the water trapped, where was the water being drained from? behind the panels? or were holes drilled into the panels themselves to release water?
if its behind the panes, then some uneducated person might have mistakenly plugged the drain holes, or if within the panel, then someone needs to do an inspection of the panel to find its point of entry and repair it.
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True, most aircraft don't like hitting hangar roofs, I was not directly involved in the A310 incident (thank Godness) but was there and wanted some good photos. The ''experts'' that were there at the time all were of the opinion that it would have been a much easier repair had it been a Boeing, or any metal aircraft, as I said Airbus said there was no way to repair it and they eventually replaced the whole fin.
As for our A300-600 I don't know how else to explain it, when the aircraft was in the hangar overnight water drained/leaked/seeped whatever from the tail the whole night, either water that was trapped in there or more likely ice trapped in there melting.
Never thought much of it until the American A300-600 lost its tail out of JFK about 12 months or so later.
As for our A300-600 I don't know how else to explain it, when the aircraft was in the hangar overnight water drained/leaked/seeped whatever from the tail the whole night, either water that was trapped in there or more likely ice trapped in there melting.
Never thought much of it until the American A300-600 lost its tail out of JFK about 12 months or so later.
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FSO, yes I know all about "Generic" terms, the problem is that most airframe drivers are totally clueless when it comes to the difference between a Thermal Plastic and a Composite, one only has to read some of the threads on this web site to work that out, in fact one builder of glass aircraft had to go the legal route to silence one twit in the US who was causing problems with his uninformed writings {Hey he writes in a magazine, so he must be an expert!} So rather than Plastic, lets use another term to avoid confusion and misinformation. {Thats the job of our Government}
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I have been told that the composite aircraft coming on line now will suffer greater levels of damage in a catastrophic accident than the old "tin" aircraft thus making accident investigation somewhat more problematic (i.e. they will disintegrate) .
Any truth to this or just more illinformed nonsense?
Any truth to this or just more illinformed nonsense?
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C152 - Are you talking about light aircraft as in C172 versus Cirrus etc?
I've seen my fair share of crash outcomes of both and they seem to hold up similarly in terms of crash worthiness and survivability, but in terms of repair it would appear on the face of it that a fibreglass or carbon aircraft can be almost fully rebuilt whereas a tin job would be scrapped much sooner. It would be a hard call to determine the difference in terms of survivability to make any bold claims. I've seen both glass and tin hit powerlines with different results that can't really be compared due to the nature of the crash.
I've seen my fair share of crash outcomes of both and they seem to hold up similarly in terms of crash worthiness and survivability, but in terms of repair it would appear on the face of it that a fibreglass or carbon aircraft can be almost fully rebuilt whereas a tin job would be scrapped much sooner. It would be a hard call to determine the difference in terms of survivability to make any bold claims. I've seen both glass and tin hit powerlines with different results that can't really be compared due to the nature of the crash.
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Notmy, its more bloody nonsense, I have spent far too much of my life around smoking holes trying to work out what went wrong, if no fire the composite airframe is in most cases in large chunks, the metal airframe compressed into smaler chunks, the exception being is that if the composite burns there is very little left. {See pictures of Grob corporate aircraft crash} In one composite aircraft crash the cockpit was intact and both ocupants looked OK. the problem was that the" crash cage" was stronger than the internal organs of the human body, in the case of most metal airframe crashes with this kind of deceleration the whole cockpit tends to buckle as a result those inside dont look so good. Sorry to be so graphic but thats the way it is.
Last edited by clunckdriver; 30th May 2011 at 09:51.
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Thanks Clunc that was what I was after. XXX my question was aimed (although poorly worded) at the new Airliners such as 787 et al.
My illinformed source was of the view that they would turn to powder on impact. I have to admit I thought it sounded a reasonable proposition (not knowing how these things work of course).
I didn't think the smaller aircraft like the new Cessna's and LSA's would be travelling fast enough to suffer the same sort of high speed impact.
Clunc your answer does bring one question to mind though. Whenever there is a large aircraft coming into premature contact with the ground at a less than ideal descent profile there is usually flames attached to the result. So I guess that major catastrophies are going to be harder to investigate in future?
My illinformed source was of the view that they would turn to powder on impact. I have to admit I thought it sounded a reasonable proposition (not knowing how these things work of course).
I didn't think the smaller aircraft like the new Cessna's and LSA's would be travelling fast enough to suffer the same sort of high speed impact.
Clunc your answer does bring one question to mind though. Whenever there is a large aircraft coming into premature contact with the ground at a less than ideal descent profile there is usually flames attached to the result. So I guess that major catastrophies are going to be harder to investigate in future?
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Notmy, In the case of larger aircraft the CVR/FDR/Downloaded info should be able to let us know what went wrong, however you have a very valid point when it comes to light aircraft without such equipment, even in the case of metal aircraft I have seen the fire destruction so complete that we really couldnt come to any valid conclusion as to cause. In the case of a composite aircraft intense fire the destruction will render it even more difficult to work out the sequence of events leading up to the impact/fire.By the way, if you happen to have the misfortune to be at such a crash , try not to breath the smoke/fumes, nasty stuff!
