Robinson operators who operate in highly erosive environments must take extra steps in caring for their blades – especially those stainless blades affected by this most recent AD. Lanier Media Photo
On June 2, 2011, the Federal Aviation Administration issued an amended Airworthiness Directive (AD) regarding Robinson Helicopter Company (RHC) stainless steel rotor blades installed on R22 and R44 helicopters, with an effective date of July 5, 2011. Not only does this AD have immediate impact on those helicopters equipped with the stainless steel blades, it also alludes to a more far-reaching impact that owners of these affected helicopters may face in the future.
This amendment (Docket No. FAA-2011-0588; Directorate Identifier 2010-SW-074-AD;
Amendment 39-16717; AD 2011-12-10) supersedes an existing AD for specified serial numbered Robinson R22 and R44 model helicopters that required a one-time visual inspection for skin separation along the leading edge of blade skin aft of the skin-to-spar bond line on the lower surface of each main rotor blade and in the tip cap area. That AD was prompted by 11 reports (the majority of them concerning R44s) of blade debonding, some occurring in flight and some found during routine maintenance.
If any bare metal was found, a mechanic was to visually inspect the area, perform a “tap test” for detecting a separation or void in both bonded areas, repaint any exposed area of the blades, as well as remove both blade tip covers and inspect that area. If any separation or void was detected the AD required replacing the blade before further flight.
Thereafter, before each flight, the existing AD also required checking for any exposed (bare) metal along the skin-to-spar bond line on the lower surface of each blade near the tip. If any bare metal was found, that AD required an inspection by a qualified mechanic, with appropriate remedies. The AD also required maintenance logbook entries for each preflight inspection.
This new amended AD contains the same requirements but expands the applicability to include all R22 and R44 model helicopters, although it limits the applicability to specific blade part numbers. For the R22 this means the stainless steel A0164 blades, and for the R44 and R44 II, the stainless steel C016-2 and C016-5 blades, respectively. This AD also requires a repetitive 100-hour or annual inspection of the blade and any necessary rework, and a documented daily preflight inspection (that inspection need only be before the first flight of each day).
Yet the FAA may not be satisfied with this remedy in the long term, according to some troubling language in the narrative that accompanies the AD. First, however, a little history.
Debonding Problems
In 2006, the problem of skin-to-spar bond line erosion problems and delamination of the blade at this area came to light. This condition most often resulted from erosion of the protective layer of paint that exposes the edge of the skin, allowing the skin to erode and eventually peel back. In one of the reported incidents, the debonding was caused by corrosion from the lower surface of the aluminum tip cap, which is bonded to the inside of the blade tip. The corrosion caused bubbles under the skin but no peeling back of the skin from the spar. The condition was found during inspection and not in flight.
In January 2007, RHC issued a Safety Alert, which was subsequently revised in March 2007, admonishing operators to perform an inspection as part of the daily preflight of the blade at the skin-to-spar bond line. Additionally, Sections 4 and 7 of the Rotorcraft Flight Manuals for the R22 and R44 were revised to add this inspection requirement.
On December 17, 2007, the FAA issued AD 2007-26-12, Amendment 39-15314 (73 FR 397, January 3, 2008). That AD spelled out the requirements described above. As stated in the AD, “The condition, if not corrected, could result in blade failure and subsequent loss of control of the helicopter.”
At Heli-Expo, 2008, I had a discussion about this AD with Frank Robinson, as well as other officials in product support. They all indicated that the subject blades were in corrosive or erosive environments, and were not properly cared for, especially in maintaining the paint in the affected area. Frank Robinson also stated that the “gap” at the seam where the blade skin is bonded at the skin-to-spar line on some blades was a little wider than it should have been – thus allowing more opportunity for erosion. However, he also stated that (1) this issue had already been corrected at RHC and (2) it didn’t seem to impact those particular blades where the paint had been maintained.
So for the most part, things settled down for most owner/operators who dutifully inspected and cared for their blades. And then it happened.
On Nov. 24, 2009, a fatal accident due to blade delamination occurred in Israel. An R44 crashed en route to Tel Aviv in visual meteorological conditions. TAMIR Airlines Ltd was the operator of the helicopter. The two pilots and two passengers aboard were killed.
The accident investigation revealed that the operator was in possession of both the United States AD and the RHC service information but apparently failed to follow either one of those. This apparent blatant disregard for proper maintenance practices caused the deaths of four persons, and set in motion a problematic jackpot for thousands of Robinson owners.
On April 30, 2010, RHC issued another set of R22 and R44 bulletins on the subject of main rotor blade bond inspection, with detailed instructions for the inspection and a $5 kit for facilitating the inspection. The inspection was to occur either at the next 100-hour or annual inspection, or by July 31, 2010, whichever came first, and thereafter at each 100-hour or annual inspection.
Additionally, on July 6, 2010, RHC applied for, and received, an approved Alternate Method of Compliance (AMOC) to the original 2007 AD from Transport Airplane Directorate, Los Angeles Aircraft Certification Office of the FAA. This AMOC essentially deleted the requirement for documenting the daily preflight of the blades as called for in the AD. The AMOC stated that an acceptable level of safety would be maintained by adhering to the April 30, 2010 Service Bulletins.
Regardless, the FAA, in its text of this latest AD stated, “However, due to the severity of the unsafe condition, we have determined that modification of the (original) AD requirements is necessary to further aid in correcting the unsafe condition by performing the checks and inspections to prevent further fatalities.”
Besides being prompted by the fatal accident in Israel, the FAA also addressed the recording requirements in the original AD relating to the pilot checks before each flight and the burden of logging those checks. Additionally, since issuing 2007 AD, the FAA indicated that they received “various comments from 32 commenters and have given due consideration to each one.” The full narrative regarding the comments can be reviewed in the text that accompanies the amended AD.
One point made in the narrative that accompanied the AD, but not within the actual two-page AD itself was this, “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.”
It later states, “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.”
This is the one that got my attention, as well as the attention of a number of owners. However, it is interesting that some operators and service centers I talked to had not studied the narrative, and therefore had not seen that shot across the bow. I have to wonder if the FAA ever considered “why” RHC went to the newer blade, or is just using the “if it’s a newer blade, it ‘must’ be better” approach. Why else would the FAA say 100-hour, annual, and normal daily inspections are “inadequate”? Considering that “actions taken in AD 2007-26-12 have been shown to detect and to prevent the debond problem” – and that the stainless blades will all be retired and replaced by the newer blades either on condition, or no longer than 12 years from now due to timing out – the FAA is suggesting that because of an operator like the one in Israel, the rest of the affected and complying fleet may be required to scrap perfectly serviceable blades.
Next Steps
So where does it all stand now? One must immediately begin the stipulated preflight erosion visual inspection and documentation of affected aircraft and, if there are signs of erosion or worse, follow the stipulated procedures depending on the specific anomaly. And then, within the next 10 hours of service, unless done previously, a mechanic must perform the inspection procedure stipulated in the AD and associated RHC SB.
The FAA made no mention in the amendment or the accompanying narrative of the previously approved AMOC. Reading between the lines on this one, my guess is that the FAA never intended for the AMOC to be approved for such fleet-wide, nationwide use. I believe that this amended AD was an opportunity to bring that horse back into the barn.
Regardless, the preflight inspection and associated logging of that action is back in. The chances of another AMOC to negate that are probably nil. (Although instructions are given for how to apply for an AMOC. We’ll see.)
However, the AD replaces the original “before each flight'” check and maintenance logbook entry with a daily “before the first flight of each day” check and logbook entry. A “caution” to check for paint erosion on the lower surface of the blade along the skin-to-spar bond line will be a part of the pre-flight check section of the revised FAA-approved RFM, and will state that either a pilot (private or higher) or mechanic may perform this check. The amended AD changed logbook entry requirement allows a student’s flight instructor or a mechanic to make the required logbook entry before the day’s cross country activity. Students can now fly solo on cross-country flights and not have to worry about how to log the checks after each subsequent preflight.
The amended AD also allows operators to make the entries on a separate maintenance record sheet and keep that record sheet as an appendix to the logbook. RHC has developed such a record sheet and posted it on their website.
The bottom line is that if you own, operate, or fly any stainless-steel-blade equipped Robinson R22 or R44 (the R66s have the new aluminum blades and are not included), know and adhere to this amended AD.
Looking Ahead
Now, what about the more far-reaching implications of the AD? The rumor mills, and unfortunately some of the service centers, were offering some misinformation. I will say that virtually every fleet operator and service center I spoke with (even one in a highly erosive environment that repaints its blades every 400 to 500 hours) indicated that with proper care, they’ve had no problems. One overhaul center told me that out of 30 sets of blades, it only saw two bonding issues.
Now I’ll attempt to address the rumors and misinformation with some clear fact.
First, RHC is not behind the suggestion of the FAA requiring the general replacement of problem-free blades. As RHC president, Kurt Robinson, told me in a lengthy discussion for this piece, “If RHC was concerned, would we still be producing stainless steel blades for the R44s?” Indeed, RHC will continue stainless steel blade production for those used on the original R44 Astro, as well as the Raven I, until at least the end of this year, if not into 2012. All new Robinsons now come with the new aluminum blades, which are more resistant to typical daily flying hazards of dents and dings versus the very thin stainless blades. RHC’s policy has been that if it couldn’t match a single replacement blade properly, it would sell you the set of two for 50 percent off. This has not changed, contrary to some field misinformation.
But as many operators know, it’s not always a simple matter to replace an affected blade. Let’s take it model by model.
For the R22, RHC has quit making the stainless steel blades. So if you have a problem requiring the replacement of an affected blade, there is no single blade purchase available as in the past – but the 50 percent allowance applies. Changing to the new A016-6 aluminum blades from the stainless steel A016-4 blade does require changing the pitch horns along with the new blade and spindle assembly.
Next is the R44. Here it gets a little more complicated. As you may know, the original R44 as well as the subsequent hydraulic-equipped Raven I used a different designed blade from the Raven II. I say “used to” because the new aluminum blades for the Raven II will now be the same blade used for all new production, as well as (eventually) all existing Raven I’s and Astros.
The problem is you cannot just swap a pair of the new aluminum blades originally designed for the Raven II for the blades on a Raven I or Astro without some potentially expensive upgrades.
First the Astro – the original R44 without hydraulics produced from 1994 to 1998. With roughly 400 to 500 of these helicopters still in service, these operators have the biggest dilemma. Because the new aluminum blades require hydraulics, they are not compatible with the Astro unless it has been converted to a hydraulic flight control system – a $40,000 expense and only done at RHC. Installing matched aluminum blades on carbureted R44 helicopters (Astro and Raven I) also requires verifying certain upgraded components are installed or retrofitted. The list can be quite extensive including the dual tachometer, main rotor gear box version, swash plate version, upper and lower fork assemblies, yokes, and pitch horns. The entire list and variants of the components required are spelled out in RHC R44 service letter SL-37 on the website.
Since RHC requires its helicopters to be overhauled at 12 years or 2,200 hours, the entire fleet of Astros either should have been overhauled or in the process now. There is a provision for a less involved 12-year inspection if the helicopters have less than 2,200 hours time in service. But since the blades are life-limited to 12 years, that point is moot.
Some operators have sent their ships back to RHC for only the hydraulics upgrade. Others have or are contemplating early field overhauls (assuming they’ve already done one since production) so as to buy a kit with the still available stainless steel blades, thus preventing (read: delaying) the expense of going to hydraulics. The big gamble in this strategy is the chance that one or both of the stainless steel blades might be damaged after RHC quits making them. Unless some stainless blades can be found in the field with life left on them, the recently overhauled Astro will have to go back to RHC for the hydraulics conversion (and any other SL-37 items that are not current) so the new-style blades can be installed.
Consider that to have RHC overhaul an Astro, and install the hydraulics conversion, plus do the fuel bladder kit (RHC will not let a ship out of the door without all SBs being done, regardless of the reason for it being there) could easily wind up being $250,000. Since some very nice, low-time and much newer R44’s can be had for around that figure, the overhaul may not be worth it. This does not bode well for Astro owners who have not converted their ships to hydraulic flight controls. The fact that some other components of the original Astro are being phased out just adds to the problem.
For Raven I owners, as well as Astro owners who have done the hydraulics conversion, the cost of switching to the new aluminum blades is totally dependent upon the aircraft’s status as related to SL-37. Raven I’s (or Astros overhauled and converted to hydraulics years back) that are older are most likely to need the main rotor gear box upgrade, among other things. The more recent the overhaul, or the age of the Raven I, the likelihood of needing all of SL-37 to be accomplished diminishes. But the 50 percent credit still applies to the blade cost.
Raven II owners are in the best position of R44 owners, needing only to exchange the blades. Even though RHC is still making stainless steel blades, it would be dumb to order one blade to replace an affected one since RHC is offering the 50 percent cost credit to encourage the conversion to the new aluminum blades.
So to recap, if you have stainless steel blades on your R22 or R44, you now have 10 hours to accomplish the amended AD’s detailed mechanic’s inspection, unless you are already in compliance with the April 30, 2010 Service Bulletins described above. And you must immediately begin the specified preflight inspection and associated documentation. Interestingly, the FAA states, “The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability and structural integrity of the helicopter. Therefore, visually checking for any bare metal is required before further flight, and this AD must be issued immediately.” The text continues, “Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.”
Yes, this is so critical that it took the FAA over 18 months from that November crash to issue this amended AD. (Sarcasm intended.)
Weighing In
The FAA has invited us to send any written relevant data, views, or arguments regarding this AD. Use one of the following methods to comment on this AD. Federal eRulemaking Portal: go to http://www.regulations.gov and follow the instructions for submitting comments. You can fax your comments to: (202) 493-2251. Or you can send your comments to an address listed under the “ADDRESSES” section. Include the docket number “FAA-2011-0588; Directorate Identifier 2010-SW-074-AD” at the beginning of your comments. The closing date is Aug. 16, 2011. I encourage all of you who are affected to respond to the FAA regarding this AD.
Also, get on the FAA website and make sure you are registered to receive ADs via email from the FAA for any aircraft you own or fly. They no longer mail them. And keep up with the RHC website for its technical publications.
And just as important – if not more important – is: if you have a question or concern about anything that relates to the operation, safety, or serviceability of your Robinson, call the factory. Don’t fall victim to rumors and misinformation. Will you always get the answer you hoped for? It depends. For example, the 50 pecent blade discount applies to bad blades related to erosion or corrosion. If you scrap both blades due to an accident, or if you replace the blades during a normal 12-year inspection or 2,200-hour overhaul, the discount doesn’t apply. But for sure RHC will give you correct answers and, more often than not, they will work with owners who have legitimate, no-fault-of-their-own issues – especially ones as serious as this.
Robinson owners (me included) must be the first line of defense and take responsibility for properly maintaining our ships and operating them safely – not just for the obvious reason of coming home in the same condition in which we departed, but to keep the owner group as a whole from succumbing to unnecessary and possibly draconian reactions from the FAA.
As Kurt Robinson put it, “Ninety-nine percent of our operators are diligent. But as the saying goes, a team is only as strong as its weakest player.” Indeed, AD 2011-12-10 proves that just one act of negligence can screw up the whole deal.