Nimrod Information
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The only reference to Kapton wiring my addled brain can come up with - ISTR an incident involving a Harrier accident in which a Kapton wiring fire may have been involved. I don't have any details and I don't have access to mil docs any more.
It's a vague memory, I'm afraid, but it did lead to controversy at the time about the use of this cabling in other [commercial] aircraft, maybe even to the extent of replacing it fleetwide...
It's a vague memory, I'm afraid, but it did lead to controversy at the time about the use of this cabling in other [commercial] aircraft, maybe even to the extent of replacing it fleetwide...
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I believe the Tornado was (is?) still full of the stuff, due mainly to it weighing less and being less bulky than just about any other type of insulation then available. I remember attending an early Q course were the carbon arc tracking video was shown. I am sure several losses were attributed to this. The footage looked to be quite old even then.
Has kapton got anything to do with Nimrod? I don't know, but I'm fairly certain that civil fleets spent a lot of effort in getting the stuff removed.
Has kapton got anything to do with Nimrod? I don't know, but I'm fairly certain that civil fleets spent a lot of effort in getting the stuff removed.
I don't own this space under my name. I should have leased it while I still could
DV from what I read, the Kapton sheath acts as a conductor and bypasses the CBs, that was the nub of the problem.
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"Somewhat concerned" questions from an aircrew bod:
1. Scheduled servicing intervals - have they increased? [I keep remembering the Air Alaska MD incident]. Why did they increase?
2. Re the YG system & Kapton wiring - is this why the CB issue is so important re Pod overheating or Fan failures?
1. Scheduled servicing intervals - have they increased? [I keep remembering the Air Alaska MD incident]. Why did they increase?
2. Re the YG system & Kapton wiring - is this why the CB issue is so important re Pod overheating or Fan failures?
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Kapton
Well, for what it's worth I think Kapton wiring installations** that have been properly designed, correctly installed AND maintained are ok. However when added "ad hoc" to airframes as "short term modifications" that then are still flying some 20+ years (in some cases) later it does call into question the integrity of the engineering processes that STILL call for these mods to be left in the airframes.
Re the YG system & Kapton wiring - is this why the CB issue is so important re Pod overheating or Fan failures?..
..Basically after the topcoat becomes damaged the kapton degrades as an insulator until it "flashes over" and basically becomes a conductor liberating a lot of energy as heat (<3000C). It also can support the current demands of the consumer units thus not providing the crew with any type of system failure as a warning whilst it can have the very sneaky practice of not tripping cb's due to the short duration of the flashovers. It can also spread ALONG a harness.
**No I wouldn't call the battery/avionics compartment of your average Tornado such a suitable installation/zone.
Mojo
Re the YG system & Kapton wiring - is this why the CB issue is so important re Pod overheating or Fan failures?..
..Basically after the topcoat becomes damaged the kapton degrades as an insulator until it "flashes over" and basically becomes a conductor liberating a lot of energy as heat (<3000C). It also can support the current demands of the consumer units thus not providing the crew with any type of system failure as a warning whilst it can have the very sneaky practice of not tripping cb's due to the short duration of the flashovers. It can also spread ALONG a harness.
**No I wouldn't call the battery/avionics compartment of your average Tornado such a suitable installation/zone.
Mojo
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Mojo
http://www.iasa.com.au/folders/Safet...RAFKapton.html
It is worth emphasizing that polyimide wiring was implicated as a contributing factor in the loss of two Tornados.
Furthermore, numerous ground fires have been recorded as a result of damage to this type of wiring. Laboratory tests have shown that the power of the Carbon Arc not only can destroy wiring looms, but can severely damage structures.
Without doubt, complacency cannot be allowed to creep in when handling polyimide wiring. It is no longer a ‘fit and forget’ component or a suitable place for hanging your torch in confined areas. To maintain our aircraft in an airworthy condition, it is essential that cables be continually inspected, cleaned and re-cleated. It should be noted that this form of inspection and maintenance will be with us for some time as Harrier GR5, Sentry AEW and Tristar all contain a polyimide construction of cable that is even more susceptible to carbon arc tracking than Tornado wiring.
http://www.iasa.com.au/folders/Safet...RAFKapton.html
It is worth emphasizing that polyimide wiring was implicated as a contributing factor in the loss of two Tornados.
Furthermore, numerous ground fires have been recorded as a result of damage to this type of wiring. Laboratory tests have shown that the power of the Carbon Arc not only can destroy wiring looms, but can severely damage structures.
Without doubt, complacency cannot be allowed to creep in when handling polyimide wiring. It is no longer a ‘fit and forget’ component or a suitable place for hanging your torch in confined areas. To maintain our aircraft in an airworthy condition, it is essential that cables be continually inspected, cleaned and re-cleated. It should be noted that this form of inspection and maintenance will be with us for some time as Harrier GR5, Sentry AEW and Tristar all contain a polyimide construction of cable that is even more susceptible to carbon arc tracking than Tornado wiring.
The attitude towards resetting any tripped CBs in flight changed radically in the civil airline world after the Swissair crash near Halifax.
For example, although it is sometime permitted to pull and reset certain specific CBs to 'reboot' some systems, it is never acceptable to reset a tripped CB in flight in most modern airliners.
On the military large aircraft program in which I'm involved, I asked whether a 'once only' reset of a CB was acceptable in flight. The answer from the OEM was an emphatic "NO!"
What is the current RAF teaching?
For example, although it is sometime permitted to pull and reset certain specific CBs to 'reboot' some systems, it is never acceptable to reset a tripped CB in flight in most modern airliners.
On the military large aircraft program in which I'm involved, I asked whether a 'once only' reset of a CB was acceptable in flight. The answer from the OEM was an emphatic "NO!"
What is the current RAF teaching?
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Hi Beagle,
Current policy on most types is to allow one reset/replacement of a CB or fuse, where it is known that the wiring is not Kapton. Even if it is Kapton, if the reason for the CB trip is known by the crew, ie a power surge or interrupt throughout the jet or a switch pigs, and it is safe to do so, then it can and should be reset. We have a job to do.
Current policy on most types is to allow one reset/replacement of a CB or fuse, where it is known that the wiring is not Kapton. Even if it is Kapton, if the reason for the CB trip is known by the crew, ie a power surge or interrupt throughout the jet or a switch pigs, and it is safe to do so, then it can and should be reset. We have a job to do.
I don't own this space under my name. I should have leased it while I still could
Tappers Dad,
Following your link above I am not sure how it arrived at the fact that Kapton wiring was implicated in the crash of two Tornadoes. It could be sloppy writing but this statement occurs for the first time in the conclusion. Conventionally mention of the Tornado should be made in the body first.
However I am pasting some extracts from web searches.
The first shows that Kapton wiring was fitted to the Boeing Harrier GR5.
The second, from Hansard, refers to two incidents of electrical fires on GR5s. I suspect this is pre-labour spin and it is possible these were accidents or, in other words, crashes. The final extract refers to Harrier crashes.
I don't doubt the accuracy of your quote; I doubt the accuracy of your source.
<<The BAE Systems/Boeing Harrier II (GR5, GR7, and GR9 series) is a second generation vertical/short takeoff and landing (V/STOL) jet aircraft used by the Royal Air Force (RAF) and, since 2006, the Royal Navy. It was developed from the earlier Hawker Siddeley Harrier and is very closely related to the US built AV-8B Harrier II. Both are primarily used for light attack or multi-role tasks, and are often operated from small aircraft carriers.
Pasted from <http://en.wikipedia.org/wiki/BAE_Harrier_II>
<<Pasted from <http://www.publications.parliament.uk/pa/cm199900/cmhansrd/vo991213/text/91213w07.htm>
13 Dec 1999 : Column: 24W
Mrs. Dunwoody: To ask the Secretary of State for Defence how many military aircraft have been grounded as a result of advice on the safety of Kapton wiring. [100925]
Mr. Spellar: None. However, following two instances of electrical fires on RAF Harrier aircraft in 1991, the Harrier GR5 and GR7 fleets were restricted to operational flying only for a short period. Subsequent investigation showed that the fires had occurred as a result of the mis-routeing of wires. Modifications were subsequently introduced to improve the electrical installation.
Kapton - the aromatic polyimide wiring insulation around the wire strands - has no place, he says, in passenger-carrying aircraft. He says that the main reason is that, in an electrical short, the wiring insulation chars to a conductive carbon residue and ignites like a dynamite fuse, affecting the whole wiring bundle (and therefore many disassociated systems).
<<Pasted from <http://www.vision.net.au/~apaterson/aviation/kapton_mangold.htm>
Although the United States Navy has banned Kapton and the insulation is no longer used by Boeing since 1992, the world's largest planemaker Airbus Industrie continue to use a version of it in their new planes. Even though the British CAA (Civil Aviation Authority) has forbidden the use of Kapton insulation in new aircraft designs, a loophole allows it to be used in current designs.
Despite ample warning about its dangers, the Royal Air Force took delivery of Kapton-wired Harrier GR5s. Two crashed because of the wire before the RAF embarked on a program to modify the use of Kapton in all the vulnerable parts of their planes.
British Airways admit they use Kapton widely in their aircraft, but that its use meets the requirements of regulatory authorities. Panorama understands, however, that British Airways was warned of the dangers of Kapton insulation and did make its concerns known to Boeing, its principal supplier. BA has declined to confirm or deny this.
Kapton insulation (a DuPont trade name, although their patent has now expired and they are no longer the sole manufacturers) seemed to be the dream wire insulation for commercial and military fleets in the 1970s and '80s. Wiring is like a plane's blood vessels, and the average big jet carries up to 250 kilometres of it. When the giant aircraft manufacturers were looking for something extremely light, tough and flame resistant they settled for Dupont's Kapton. Boeing, McDonnell Douglas, Lockheed and later Airbus Industrie all installed it in good faith in their models during the '70s and '80s. Today, 40 per cent of all planes still carry Kapton-insulated wiring.
Pasted from <http://www.vision.net.au/~apaterson/aviation/kapton_mangold.htm>
Following your link above I am not sure how it arrived at the fact that Kapton wiring was implicated in the crash of two Tornadoes. It could be sloppy writing but this statement occurs for the first time in the conclusion. Conventionally mention of the Tornado should be made in the body first.
However I am pasting some extracts from web searches.
The first shows that Kapton wiring was fitted to the Boeing Harrier GR5.
The second, from Hansard, refers to two incidents of electrical fires on GR5s. I suspect this is pre-labour spin and it is possible these were accidents or, in other words, crashes. The final extract refers to Harrier crashes.
I don't doubt the accuracy of your quote; I doubt the accuracy of your source.
<<The BAE Systems/Boeing Harrier II (GR5, GR7, and GR9 series) is a second generation vertical/short takeoff and landing (V/STOL) jet aircraft used by the Royal Air Force (RAF) and, since 2006, the Royal Navy. It was developed from the earlier Hawker Siddeley Harrier and is very closely related to the US built AV-8B Harrier II. Both are primarily used for light attack or multi-role tasks, and are often operated from small aircraft carriers.
Pasted from <http://en.wikipedia.org/wiki/BAE_Harrier_II>
<<Pasted from <http://www.publications.parliament.uk/pa/cm199900/cmhansrd/vo991213/text/91213w07.htm>
13 Dec 1999 : Column: 24W
Mrs. Dunwoody: To ask the Secretary of State for Defence how many military aircraft have been grounded as a result of advice on the safety of Kapton wiring. [100925]
Mr. Spellar: None. However, following two instances of electrical fires on RAF Harrier aircraft in 1991, the Harrier GR5 and GR7 fleets were restricted to operational flying only for a short period. Subsequent investigation showed that the fires had occurred as a result of the mis-routeing of wires. Modifications were subsequently introduced to improve the electrical installation.
Kapton - the aromatic polyimide wiring insulation around the wire strands - has no place, he says, in passenger-carrying aircraft. He says that the main reason is that, in an electrical short, the wiring insulation chars to a conductive carbon residue and ignites like a dynamite fuse, affecting the whole wiring bundle (and therefore many disassociated systems).
<<Pasted from <http://www.vision.net.au/~apaterson/aviation/kapton_mangold.htm>
Although the United States Navy has banned Kapton and the insulation is no longer used by Boeing since 1992, the world's largest planemaker Airbus Industrie continue to use a version of it in their new planes. Even though the British CAA (Civil Aviation Authority) has forbidden the use of Kapton insulation in new aircraft designs, a loophole allows it to be used in current designs.
Despite ample warning about its dangers, the Royal Air Force took delivery of Kapton-wired Harrier GR5s. Two crashed because of the wire before the RAF embarked on a program to modify the use of Kapton in all the vulnerable parts of their planes.
British Airways admit they use Kapton widely in their aircraft, but that its use meets the requirements of regulatory authorities. Panorama understands, however, that British Airways was warned of the dangers of Kapton insulation and did make its concerns known to Boeing, its principal supplier. BA has declined to confirm or deny this.
Kapton insulation (a DuPont trade name, although their patent has now expired and they are no longer the sole manufacturers) seemed to be the dream wire insulation for commercial and military fleets in the 1970s and '80s. Wiring is like a plane's blood vessels, and the average big jet carries up to 250 kilometres of it. When the giant aircraft manufacturers were looking for something extremely light, tough and flame resistant they settled for Dupont's Kapton. Boeing, McDonnell Douglas, Lockheed and later Airbus Industrie all installed it in good faith in their models during the '70s and '80s. Today, 40 per cent of all planes still carry Kapton-insulated wiring.
Pasted from <http://www.vision.net.au/~apaterson/aviation/kapton_mangold.htm>
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Despite ample warning about its dangers, the Royal Air Force took delivery of Kapton-wired Harrier GR5s. Two crashed because of the wire before the RAF embarked on a program to modify the use of Kapton in all the vulnerable parts of their planes.
The mod's called KT in generic terms, all harriers still have a % of Kapton left installed no mind whatever MOD/BAe say, back end of a modern Harrier is not a pretty sight.
MoJo
The mod's called KT in generic terms, all harriers still have a % of Kapton left installed no mind whatever MOD/BAe say, back end of a modern Harrier is not a pretty sight.
MoJo
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According to Jeremy Vine at the end of this evenings 'Panorama' [28/05/07]
Next weeks [04/06/07] is all about the 'Nimrod Problems'.
Next weeks [04/06/07] is all about the 'Nimrod Problems'.
Not wanting to sound too negative here, but giving the absolutely appalling standard of reporting on Panorama this year, I wouldn't get too excited. The wi-fi episode was utterly, utterly biased and showed little or no understanding of the technical issues. http://www.badscience.net/?p=418
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Panorama has turned to dog poo
Yes it HAS gone down the soundbite route, probably easier to produce and costs less, that presenter, Vine is it?; sounds good on the radio but if you take a step back and look at the structure of the program it's the old "we think this so it must be right" scenario again from bliars broadcasting corporation.
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Mojo
Agreed, it's become the Jeremy Vine video show. It's all sound and light and fury, all about the surface froth and no digging down to the real substance of the subject as used to happen. I suppose that takes time, effort, talent and money.
Agreed, it's become the Jeremy Vine video show. It's all sound and light and fury, all about the surface froth and no digging down to the real substance of the subject as used to happen. I suppose that takes time, effort, talent and money.