Latest R22/R44 Blade AD

[FSXPilot]

R22/R44 Blades AD (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/7950dff2185691fa862578b2004d6912/$FILE/2011-12-10.pdf)

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.

[Shawn Coyle]

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...

[strey]

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...

[lelebebbel]

Was that the airwolf tape? May I ask why it was considered a failure?

[Chopper Doc]

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.

[chriswhi]

Watch the prices of robbos fall

[500e]

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.:{

[Runway101]

Makes you wonder what other "continued inspections" we are relying on will be considered "an inadequate long term solution" next?

[strey]

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.

[kevin_mayes]

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.

[blakmax]

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 OK, so Robinson get the design wrong . 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

[rjtjrt]

How do the A016-6 blades differ from the -4 blades.
Is it a fundamental design difference, or a changed bonding method?
John

[61 Lafite]

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.


Well... no, as a matter of fact. It's exactly the same situation as Robinson. If you're in warranty, you're in luck. If you're out of warranty, then (unless there has been a big publicity splash about the problem), you have to live with the failure and pay for the repair.

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

[Heli-wolf]

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.

[500e]

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.

[Ian Corrigible]

Watch the prices of robbos fall
You could always try selling to the Philippine National Police...PNP buy 5-yr old R44s for $785K apeice (http://www.mb.com.ph/articles/325399/lacson-questions-police-helicopter-purchase) :E

Well-researched Vertical Mag feature on the latest AD here (http://www.verticalmag.com/control/news/templates/?a=17360).

I/C

[lelebebbel]

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.
Well... no, as a matter of fact. It's exactly the same situation as Robinson. If you're in warranty, you're in luck. If you're out of warranty, then (unless there has been a big publicity splash about the problem), you have to live with the failure and pay for the repair.

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

When a safety-relevant part is found faulty by design on a car (or car part, bike, toy, kitchen appliance), there is usually a product recall. The part or the whole item is then either replaced at the manufacturers cost, or the purchase price is refunded to the customer in full.
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?

[Pandalet]

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.

[787-1]

How do the A016-6 blades differ from the -4 blades.

I believe they are once again Aluminium rather than Stainless Steel.

[chopperchappie]

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

[RobboRider]

Well... no, as a matter of fact. It's exactly the same situation as Robinson. If you're in warranty, you're in luck. If you're out of warranty, then (unless there has been a big publicity splash about the problem), you have to live with the failure and pay for the repair.


Well yes and no. As stated before - a defective part recall is regardless of warranty period, and a manufacturing problem that is not a design issue is covered by warranty) In both situations In the auto industry they do the lot - Provide you with the parts, Physically do the replacement and give it back to you in working order.

A few years back I ran into Robinson's policy when one of my R22 blades corroded at the tip (along that same overlap in question) after a few months , even fewer hours of use while kept in a hangar etc etc. and both blades had to be replaced. After eventually providing me with the parts for free, I had to fork out the cost of the transport of the corroded tips and the blade hubs to the states then the cost of the new blades from the states, pay the LAME to install them and as it happened needed a few hours to track & balance all at my cost of some $10,000.

There is no way an auto manufacturer would require you to pay those costs either under warranty or recall. So it's not quite the same as the auto industry.

[chopperchappie]

Thanks - All probably true and it does seem that cars are treated differently to aircraft (surely it should be the other way around though!).

I am really interested to know if anyone heard of anything to say that the replacement of blades will be mandated at some point.

Any whispers?

Also does anyone know what the outcome of the EASA night VFR equipment specification review was (or am I being optimistic expecting a response by now)?


CC

[fdr]

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

BlacMax is quite authoritative in this area, and I can personally attest to the rational position he has on this matter. BM has specific specialist knowledge in the applicable disciplines and has a cogent argument that has far more face validity than the FAA's tail chasing process that appears to be entering another cycle of costs for owners without achieving the required safety outcome.

The failure modes of the early to later blades are quite different, and the design change to the latest dash's does not necessarily change the early or later failure mode. A question exists in one particular area of design that may have been changed that could increase the long term reliability of the latest blades, if incorporated, but there is no direct evidence that this aspect has been altered.

Cared for properly, the RHC product is capable of doing the task that it is designed for. It is intolerant of poor maintenance, and in some cases the level of neglect beggars belief...

refer the "Mareeba delamination", aair200701625_001.pdf, ATSB TRANSPORT SAFETY INVESTIGATION REPORT
Aviation Occurrence Investigation – 200701625 Final Main rotor blade skin separation 15 March 2007 Mareeba Aerodrome, Qld VH-HPI Robinson Helicopter Company R22 Beta II

The A016-4 and C016-5 blades should be able to serve their service life out with just normal levels of maintenance; the failure modes of the blades if viewed by age/TTIS does not indicate a defect in design that is not able to be managed by normal levels of care in the blade, in fact they pretty much indicate the exact opposite of what the FAA ACO has been so often alluding to.

Abuse a robbie, and it may well get it's own back, a form of natural selection.

[anti-talk]

Hmmm to throw Petrol on the fire and counteract RHC's argument about poor maintenance.
We have just found corrosion UNDER the tip cap on the end of a NEW -6 blade this corrosion is UNDERNEATH the original factory paint - the blade has 95 days service and 285 hours on it.

[JimBall]

Anti-talk: Don't doubt your "find" but at 295H it can't reliably be blamed on the factory. You're in FL. You guys breathe salt by the second. Any small blemish in the paint - maybe caused by airborne grit, sand etc - can let that salt in and you have the perfect climate for corrosion.

Ever seen the window frames of a beach property and compared the corrosion with ones inland?

We're UK based and have just overhauled an R44 RII. The blades were in perfect condition and could carry on flying if permitted. Never delaminated. Never corroded - and we are just as moist as Florida. If you get my drift! (With a lot less baking sun.)

On the other hand, our machine wasn't used for training or SFH and the blades were washed every few weeks. A lot of Robinson "problems" are caused by pilot/operator abuse.

[anti-talk]

I dissagree strongly, less than 100 days in service and unbroken paint on the blade tip with around 2.5 inches of bubbling corrosion under the original factory INTACT paint. These blades are washed daily and the aircraft is in MX for a 100hr every 3 weeks.
We have seen a very concerning trend with post 2007 blades (strangely enough around the time the EPA made RHC change the painting proceedure to water based paint)
All of our older blades comfortably made 2200 overhaul including 2 R44's that were made in 2006 (we have yet to see a 44 Blade delaminate and we operate 6 of them). BUT we have 7 post 2007 manufacture R22's (11 in total) and we have seen 5 blade problems (2 were repaired under warranty) on those 7 aircraft. Our pre 2007 blades have held up fine.
Up until 2007 we didnt see a single delamination. Our maintenance proceedures are now MUCH tighter than we were previously when it comes to blade care and I dont accept the allegation that its as a result of operator mis-use we have been completely ANAL about blade care knowing the cost of failure.
As a matter of interest did you see any corrosion on the 44 tail and what year of manufacture was it?

[JimBall]

Anti-talk: Very interesting and thanks for sharing your experiences. There's no doubt that the EPA paint change was for the worse. Our 04 machine had perfect paint at overhaul. The 06 machine (same colour, and both RHC painted) lost areas of paint around the windshield within 12 months of new.

Blades - we'll keep a close eye.

Corrosion - slight amount at tailcone near TR gearbox - but was not serious.

Other than that, the product delivers reliability, performance and financial efficiency. Even though it's a helicopter!

The biggest surprise we've had was the 06 machine after 1200hrs we had to replace all spindles. It emerged that the surface of one was damaged at manufacture with a horizontal scoring from something foreign. That's $15,000 from maint reserve!

[lotusexige]

So I suppose one of the questions is does Robinsons optional corrosion proofing include proper non EPA paint?

[500e]

There is a post regarding this somewhere on PP, can never find things with the search,
:{

[John R81]

Is this also true of the Clipper II? I understood that the Clipper II had additional anti-corrosion treatment.

[Arnie Madsen]

On the subject of adhesive failures ..... some time ago I was reading about de-bonding of root doublers on Robinson blades ..... which seemed strange to me ..... because their rotor head uses coning hinges designed to relieve bending stress at the root .... yet they come unglued ....

[Vertical Freedom]

:{ one word :yuk:

[blakmax]

Arnie

I have discussed this at length in other postings.

There are three types of bond failures: 1. Cohesion failures, where the adhesive material fractures, 2. Adhesion failures, where the bond fails at the interface between the adhesive and the substrate, and 3. Mixed-mode failures where there is a mixture of cohesion and adhesion failures, and mixed mode failures are only adhesion failures which occur before the interface has fully degraded.

Cohesion failures are high-strength failures and are usually related to design deficiencies and result in fracture through the middle of the adhesive layer. Now from my own observations the adhesive RHC use is almost certainly FM 73M and that adhesive has a "carrier cloth" incorporated during production of the film adhesive to aid handling. (Without it the adhesive fragments during handling.) If the failure is due to a design deficiency then the bond will fail by fracture through the plane of the carrier cloth. This type of failure requires a high load to cause failure and one would normally expect that such failures would be identified by certification testing. These are the bond failures you feel would be prevented by coning hinges etc.

In contrast adhesion failures occur at the interface between the adhesive and the adherends. They are low strength failures, and in some cases are ZERO strength failures. These have no relation to loads and are as a direct result of failure of the chemical bonds between the adhesive and the surface of the adherend. THEY CAN OCCUR AFTER NO FLIGHT LOADS WHATSOEVER. Google aair200302820_002 and look at Appendix B items 48 and 49 where disbonds were reported after ZERO flight hours. Ignore the findings of the report because the alleged "fatigue" in Figure 40 is not credible. Fatigue will result in "cohesion" failure and the example in Figure 40 shows "adhesion" failure. The features in Figure 40 are wrongly attributed. Fatigue can only result in cohesion failure which would occur through the plane of the carrier cloth and while the photo identifies features in the plane of the carrier cloth, the actual failure adjacent to the "features' occurs at the interface.

In the extreme, adhesion failures have ZERO shear or peel strength. PM me if you want further elaboration.

Mixed mode failure occurs when a bond which is susceptible to adhesion failure experiences a moderate (within the flight envelope) load before the interface has fully degraded, so there is some adhesion failure and some cohesion failure. Let me be clear. A mixed mode failure is a potential adhesion failure which experienced failure at normal flight loads before it had degraded to zero strength. At production and certification testing, it may and probably will exhibit adequate strength because the interfacial degradation mechanism described in the next para has not had time to manifest itself before testing occurred.

What drives adhesion and mixed-mode failures is the resistance of the interface to degradation and the most common form of degradation is hydration of the oxides on the surface of metals. To form the hydrated oxide, the chemical bonds formed during initial production dissociate so that the metal oxides can hydrate, and the tell-tale sign for this failure is that the bond fails leaving the adhesive on one surface at any given location. In mixed-mode failures, the locus of failure will migrate from the plane of the carrier cloth towards the interface.

Now, how does one control hydration? The surface preparation process used during manufacture is the sole determinant because this will establish resistance (or lack of resistance) to hydration. The same is true for paint adhesion. The condition of protective paint, the frequency of washing, the buffing of surface finishes and flight loads can not of themselves induce or prevent interfacial or mixed-mode failures unless the surface was already predisposed to adhesion failure. Nor will such stupid specifications of the use of specific wash fluids or stipulations that the blades be washed by (tongue in cheek here) left handed virgins from Gybrobia.

Please read http://www.adhesionassociates.com/papers/56%20Assessing%20Adhesive%20Bond%20Failures%20-%20Mixed-Mode%20Bond%20Failures%20Explained.pdf and http://www.adhesionassociates.com/papers/57%20Safety%20Risks%20in%20Applying%20Damage%20Tolerance%20A nalysis%20to%20Certification%20of%20Adhesively%20Bonded%20St ructures%20and%20Joints.doc

These papers contain actual photographs of R44 blade failures which exhibit adhesion and mixed-mode failures. Of particular relevance, the latter paper suggests that the current method of managing blade flight safety based on regular inspection MAY be open to review and should be subject to further investigation. The paper suggests that if interfacial degradation occurs in short bond overlap joints (such as RHC R22 and R44 blades) then failure may occur because the bond strength decays below an acceptable level BEFORE a detectable defect can be determined by NDI, especially with methods with low accuracy such as tap testing.

So why do interfacial and mixed mode failures occur? Because there is currently no requirement to demonstrate long-term bond strength. The papers explain why current regulatory requirements are inadequate. To be fair to RHC they probably meet the current requirements.

Will someone please ask the CAAFI why the report on the crash of DQ-IHE has not been released after they have had the report from the IIC for more than two years.

Regards

Blakmax

[Nobby18]

I am an operator of 3 R44s and am considering trying out the Airwolf STC. I have heard mixed reviews.


I am located on the beach and have to repaint my blades on a regular basis.


Any feedback would be great. I saw that it costs roughly $2500. How long should I expect the tape to last?

[Hot and Hi]

Helicopter Association International (HAI) posted in its May 27, 2016 newsletter this link (https://www.rotor.org/RotorNews/May16/AD_Robinson-27.pdf) that apparently shows a new airworthiness directive (AD) proposed by the FAA.

The proposed AD would apply to "Robinson Model R44 and R44 II helicopters with an MRB part number (P/N) C016–7, Revisions N/C, A through Z, and AA through AE; and Model R66 helicopters with an MRB P/N F016–2, Revisions A through E."

"The proposed AD would require a one-time inspection of the MRB for a crack, corrosion, dent, nick, or scratch, and either altering the MRB or removing it from service."

Comments regarding this new proposed AD can be addressed to the FAA and must be received by July 26, 2016. Are operators sending comments, and what would be your position?