Latest R22/R44 Blade AD
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Latest R22/R44 Blade AD
R22/R44 Blades AD
Although not required by this AD, Robinson has developed replacement blades, part number C016-7, for the Model R44 helicopter, and part number A016-6 for the Model R22 helicopter. The FAA may require installing these replacement blades in a future AD.
If you own a Robinson and don't already have these latest blades start saving up as it sounds like there will be another AD before long.
Although not required by this AD, Robinson has developed replacement blades, part number C016-7, for the Model R44 helicopter, and part number A016-6 for the Model R22 helicopter. The FAA may require installing these replacement blades in a future AD.
If you own a Robinson and don't already have these latest blades start saving up as it sounds like there will be another AD before long.
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Does anyone know if an STC is needed to apply blade tape to an R-22 or R-44? US and the rest of world will have different answers, but would like answers from all over...
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We had blade tape on one of the training R22's at my school, just for a trial period. That was a failure, it lasted maybe 3 weeks( about 4-5 hours flight time every day.) It has now been removed.
Maybe there are other types of blade tape out there...
Maybe there are other types of blade tape out there...
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If you read the whole of the AD the following text below appears to rule out the use of blade tape to correct this problem.
We do not agree that blade tape will resolve the unsafe condition even though tape is designed to
provide longer resistance to erosion than paint. The same unsafe condition exists with both.
We do not agree that blade tape will resolve the unsafe condition even though tape is designed to
provide longer resistance to erosion than paint. The same unsafe condition exists with both.
Lets go back a bit, blades start peeling Robinson say it is because you have not kept the paint on leading edge joint ? so AW get STC for tape to overcome problem of paint erosion?, I would expect that part of the AW instructions was to at least touch up paint before fitting tapes.(don't know never seen kit)
Wonder if this affected someone's bottom line.
Seen tapes last 12 months on a 300 used for training, the blades & tape want to be at least warm when fitting, and left for few hour before flying.
strey
Are you flying in rain\snow or heavy dust conditions
Interesting wording, from the AD (my bold)
We do not believe that this blade debond is due to a manufacturing problem. This debond issue appears to be due to the basic design and maintenance, and the actions taken in AD 2007-26-12 have been shown to detect and to prevent the debond problem. However, reliance on continued inspections
is an inadequate long term solution. We are considering a subsequent AD to terminate the inspection requirement by mandating the replacement of these rotor blades.
Wonder if this affected someone's bottom line.
Seen tapes last 12 months on a 300 used for training, the blades & tape want to be at least warm when fitting, and left for few hour before flying.
strey
Are you flying in rain\snow or heavy dust conditions
Interesting wording, from the AD (my bold)
We do not believe that this blade debond is due to a manufacturing problem. This debond issue appears to be due to the basic design and maintenance, and the actions taken in AD 2007-26-12 have been shown to detect and to prevent the debond problem. However, reliance on continued inspections
is an inadequate long term solution. We are considering a subsequent AD to terminate the inspection requirement by mandating the replacement of these rotor blades.
Last edited by 500e; 20th Jun 2011 at 16:14.
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I'm simply a student so I do not have thorough knowledge on the matter, but my instructor told me R22 with the blade tape was a trial. The helicopter was squaked for vibrations as the tape was coming of, and was removed after that.
I can only assume it was properly attached by the mechanics.
Edit: The flying is conducted in "normal weather", 5-20 degrees celsius in rain and dry weather.
I can only assume it was properly attached by the mechanics.
Edit: The flying is conducted in "normal weather", 5-20 degrees celsius in rain and dry weather.
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OK, so Robinson get the design wrong, then scrap all the blades that have been paid for and make you buy new ones...? Would this happen in any other industry - i.e. the car industry, no they would issue a free of charge replacement.
Kev.
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Blade failure issues
I have some experience in this specific issue based on my involvement as a consultant on a particular crash investigation. The relevant aviation authority has so far not released the final report. (Why???)
I note the comment from Kev
. That is not entirely true. The DESIGN is not the cause of this problem. I know that this is an adhesive bond durability issue which is almost certainly related to the surface preparation processes used during production. It has very little if anything to do with erosion of the paint layer. I have personally seen only one example of erosion, but I have seen many more examples of bond failure where there was negligible evidence of erosion.
The tape is not the answer, and anything other than a clear transparent tape makes the issue of inspection even worse.
The real issue here is: Did RHC do everything required by the regulators to produce a reliable structure? The answer is probably YES. The FARs require static strength and fatigue testing. They would not have recieved certification unless they did those tests.
FAR 29.603 requires that critical bonded structures demonstrate strength by one of three methods, one of which is by reliable NDI, and another is by static testing. I know that RHC inspects every blade (I am not that confident with tap testing) and undertakes a series of QA tests on companion samples cured with the blades. I know RHC undertake a static strength test on 1/100 blades, and I expect that these results will show that the blades are "sound".
FAR 29.605 requires the use of processes "known to produce a sound structure". How do you define a "sound" structure? If it passes NDI and QA testing, is it a sound structure? In the short term YES. In the long term, the same structure may not be "sound".
I therefore believe that RHC has done everything they could to comply with the FARs.
So where does the problem originate? The essence of this problem (and a number of other similar bond failure examples) is that there is no requirement in the FARs to demonstrate long term resistance to degradation of adhesive bonds. This requirement is referred to indirectly in AC20-107B, but its lack of prominence does not reflect the dire consequences of failure to address adhesive bond durability before any certification tests are undertaken.
The mechanism of bond degradation for most metallic surfaces is hydration of the surface of the metal and this takes some time in service to occur. The classic example is for aluminium surfaces where Al2O3 oxides hydrate to form Al2O3.2H2O. In the process, the chemical bonds between the oxides and the adhesive dissociate so the hydrate can form, resulting in disbonding. I have no conclusive evidence that this occurs with stainless steels such as the current RHC blades, but I would be very surprised if there was not a similar hydration mechanism involved in these failures.
The hydration process takes time and is exacerbated by operation in areas of high temperature and humidity. Hence, short-term static strength and fatigue tests will not prevent these failures unless they are conducted after a considerable period of environmental exposure, and the FARs do not require such exposure tests.
There are in existence short term tests which will provide evidence of bond durability and these tests are supported by between 15 and twenty years of military experience with negligible bond failures for bonded repairs performed using compliant processes.
The answer to this problem is to mandate these tests, not just by RHC but by all manufacturers of all adhesive bonded structures.
Regards
Blakmax
I note the comment from Kev
OK, so Robinson get the design wrong
The tape is not the answer, and anything other than a clear transparent tape makes the issue of inspection even worse.
The real issue here is: Did RHC do everything required by the regulators to produce a reliable structure? The answer is probably YES. The FARs require static strength and fatigue testing. They would not have recieved certification unless they did those tests.
FAR 29.603 requires that critical bonded structures demonstrate strength by one of three methods, one of which is by reliable NDI, and another is by static testing. I know that RHC inspects every blade (I am not that confident with tap testing) and undertakes a series of QA tests on companion samples cured with the blades. I know RHC undertake a static strength test on 1/100 blades, and I expect that these results will show that the blades are "sound".
FAR 29.605 requires the use of processes "known to produce a sound structure". How do you define a "sound" structure? If it passes NDI and QA testing, is it a sound structure? In the short term YES. In the long term, the same structure may not be "sound".
I therefore believe that RHC has done everything they could to comply with the FARs.
So where does the problem originate? The essence of this problem (and a number of other similar bond failure examples) is that there is no requirement in the FARs to demonstrate long term resistance to degradation of adhesive bonds. This requirement is referred to indirectly in AC20-107B, but its lack of prominence does not reflect the dire consequences of failure to address adhesive bond durability before any certification tests are undertaken.
The mechanism of bond degradation for most metallic surfaces is hydration of the surface of the metal and this takes some time in service to occur. The classic example is for aluminium surfaces where Al2O3 oxides hydrate to form Al2O3.2H2O. In the process, the chemical bonds between the oxides and the adhesive dissociate so the hydrate can form, resulting in disbonding. I have no conclusive evidence that this occurs with stainless steels such as the current RHC blades, but I would be very surprised if there was not a similar hydration mechanism involved in these failures.
The hydration process takes time and is exacerbated by operation in areas of high temperature and humidity. Hence, short-term static strength and fatigue tests will not prevent these failures unless they are conducted after a considerable period of environmental exposure, and the FARs do not require such exposure tests.
There are in existence short term tests which will provide evidence of bond durability and these tests are supported by between 15 and twenty years of military experience with negligible bond failures for bonded repairs performed using compliant processes.
The answer to this problem is to mandate these tests, not just by RHC but by all manufacturers of all adhesive bonded structures.
Regards
Blakmax
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OK, so Robinson get the design wrong, then scrap all the blades that have been paid for and make you buy new ones...? Would this happen in any other industry - i.e. the car industry, no they would issue a free of charge replacement.
Kev.
Kev.
Go to any auto repair shop and ask what the common failures are on any given make, they'll know off the top of their heads. For years, Smart car engines up to about 2002 regularly failed on one particular cylinder after about 45k miles. Smart offered no free repairs outside warranty. Fiat punto head gaskets go with alarming regularity around 65k miles, some Toyota cat's fail way too early, the list is endless.
The car manufacturers "do their best" (to be generous to them). Caveat Emptor once the warranty is through.
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Robinson blade AD
I have been reading through the blog and would like to add some comments.
Airwolf obtained and AMOC for the earlier AD and has applied for an AMOC for the new AD. Both the new AD and the previous AD require paint to be present on the bond line to prevent corrosion. The Airwolf Protective Blade Tape works by insuring that the paint remains on the bond line. The protective tape (which requires an STC) should last 500-700 hours depending on the environment. The tape is designed to be sacrificial. It is replaced when worn out so the blade is protected. The life of the tape far exceeds the life of paint. Even if the blade tape were to last only 400 hours it is still advantageous over doing a complete stripping and painting of the blades. Blade painting would have to be done repeatedly in a 400 hour period. Flying in one rain storm once could result in the need for new paint. Some operators are complying with the AD by hitting the bond line with a spray can when it is exposed. This shortcut is worthless and will not give the desired protection from corrosion.
One person wrote that they had problems with vibration during a trial run with blade tape. It is possible that the tape was not properly installed. The Airwolf tape kits come with very detailed instructions. If installed properly no vibration or peeling of the blade tape will occur.
As you can tell I am a big advocate of the Airwolf blade tape. I have documented at least 30 instances of delamination of Robinson blades. You can buy or install just one blade so per the AD if you find delamination it will cost just over $36k for set of new R22 blades and just under $50k for a set of R44 blades. The blade tape, of course, won’t fix delamination. Once it occurs the blades are scrap.
Airwolf obtained and AMOC for the earlier AD and has applied for an AMOC for the new AD. Both the new AD and the previous AD require paint to be present on the bond line to prevent corrosion. The Airwolf Protective Blade Tape works by insuring that the paint remains on the bond line. The protective tape (which requires an STC) should last 500-700 hours depending on the environment. The tape is designed to be sacrificial. It is replaced when worn out so the blade is protected. The life of the tape far exceeds the life of paint. Even if the blade tape were to last only 400 hours it is still advantageous over doing a complete stripping and painting of the blades. Blade painting would have to be done repeatedly in a 400 hour period. Flying in one rain storm once could result in the need for new paint. Some operators are complying with the AD by hitting the bond line with a spray can when it is exposed. This shortcut is worthless and will not give the desired protection from corrosion.
One person wrote that they had problems with vibration during a trial run with blade tape. It is possible that the tape was not properly installed. The Airwolf tape kits come with very detailed instructions. If installed properly no vibration or peeling of the blade tape will occur.
As you can tell I am a big advocate of the Airwolf blade tape. I have documented at least 30 instances of delamination of Robinson blades. You can buy or install just one blade so per the AD if you find delamination it will cost just over $36k for set of new R22 blades and just under $50k for a set of R44 blades. The blade tape, of course, won’t fix delamination. Once it occurs the blades are scrap.
Had a tapes on a 300 about 4 inches long covering erosion strip to blade interface (been on 200H +) just a corner lifted vibe started & progressed to bigger shake Vquick, not pleasant with only 50 hours or so, we landed peeled the tapes off all blades.
You have to fit correctly not easy if blades on machine, blades must be clean free, from polish, & warm, tape must be warm also.
Most of the adhesives require a time period to cure completely, or so I was told by a 3M man.
You have to fit correctly not easy if blades on machine, blades must be clean free, from polish, & warm, tape must be warm also.
Most of the adhesives require a time period to cure completely, or so I was told by a 3M man.
Last edited by 500e; 24th Jun 2011 at 17:26.
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Originally Posted by chriswhi
Watch the prices of robbos fall
Well-researched Vertical Mag feature on the latest AD here.
I/C
OK, so Robinson get the design wrong, then scrap all the blades that have been paid for and make you buy new ones...? Would this happen in any other industry - i.e. the car industry, no they would issue a free of charge replacement.
Kev.
Kev.
Go to any auto repair shop and ask what the common failures are on any given make, they'll know off the top of their heads. For years, Smart car engines up to about 2002 regularly failed on one particular cylinder after about 45k miles. Smart offered no free repairs outside warranty. Fiat punto head gaskets go with alarming regularity around 65k miles, some Toyota cat's fail way too early, the list is endless.
The car manufacturers "do their best" (to be generous to them). Caveat Emptor once the warranty is through.
Lafite
Latest example: all the recent car recalls. I don't remember hearing anyone say "sorry, your brakes have been recalled, but you have to pay for it because the warranty is over." If anything, a recall comes with an apology and sometimes a free gift, like a rental car, to apease the irate customer..
Another example: 16 years ago Toyota did a recall for their 4Runner 4WD due to faulty headgaskets on a certain engine model. Toyota honors that recall up to this date, and if you have a vehicle in the affected serial# range, you can get it repaired, for free, today, even if you are not the original owner.
Remains the question: What would happen to the price of a new R44 (or any other helicopter) if the manufacturers were obligated to pay for their stuff-ups in a similar way?
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Whether a recall happens or not generally doesn't depend on the severity of the fault (except in really extreme cases); it depends on whether the manufacturer thinks they can get away with a small (for varying values of 'small') PR hit if they don't institute a recall. When the PR cost outweighs the cost of a recall, you have a recall.
In addition, having a recall involves admitting that there was something wrong; if there's nothing wrong with the original design, it's just that the new one is 'better', then why would you recall the old one? There may be legal ramifications to admitting fault, particularly in places like the USA. So the cost of a recall isn't just the cost of shipping and new bits.
The market for helicopters, even small, comparitively cheap ones, is pretty small. Also, the general public probably don't really care whether a bunch of rich buggers have to pay more to fix their toys. Hence, there probably won't be a recall, because Robinson can get away with making people pay instead.
In addition, having a recall involves admitting that there was something wrong; if there's nothing wrong with the original design, it's just that the new one is 'better', then why would you recall the old one? There may be legal ramifications to admitting fault, particularly in places like the USA. So the cost of a recall isn't just the cost of shipping and new bits.
The market for helicopters, even small, comparitively cheap ones, is pretty small. Also, the general public probably don't really care whether a bunch of rich buggers have to pay more to fix their toys. Hence, there probably won't be a recall, because Robinson can get away with making people pay instead.
R44 Blades AD
There was a hint in the FAA directive that there may be a directive to replace blades - something along the lines of "the FAA does not rule out...."
There was a lot of speculation that one reason they didn't do that was because of the lack of replacement stock, but it seems rob-heli has been building up a stock.
I've been seeing a quite a few ads for used R44s with ali blades and I suppose from time to time, blades need to be replaced when damaged, but generally people will not go out and spend 30K on new blades without being forced to do so.
It's all gone quiet in the last few months has anyone heard anymore?
CC
There was a lot of speculation that one reason they didn't do that was because of the lack of replacement stock, but it seems rob-heli has been building up a stock.
I've been seeing a quite a few ads for used R44s with ali blades and I suppose from time to time, blades need to be replaced when damaged, but generally people will not go out and spend 30K on new blades without being forced to do so.
It's all gone quiet in the last few months has anyone heard anymore?
CC