Latest R22/R44 Blade AD
Join Date: Mar 2002
Location: Queensland Australia
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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.
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.
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
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
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?
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?
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.
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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.
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.
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.
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.
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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?
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?
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!
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!
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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 ....
Flimsicopter
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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/pa...0Explained.pdf and http://www.adhesionassociates.com/pa...d%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
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/pa...0Explained.pdf and http://www.adhesionassociates.com/pa...d%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
Join Date: Jun 2016
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R44 Erosion Protection Tape
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?
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?
Proposed new AD applicable to R44 and R66 main rotor blades
Helicopter Association International (HAI) posted in its May 27, 2016 newsletter this link 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?
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?
