M/R Blade AD

[bryancobb]

TO: U.S. Department of Transportation
Docket Operations
M-30, West Building Ground Floor, Room W12-140
1200 New Jersey Ave. S.E.
Washington DC 205900-001
FAX: 202-493-2251

CC: Marc Belhumeur, Senior Project Engineer
Rotorcraft Certification Office, Rotorcraft Directorate
Federal Aviation Administration
2601 Meacham Blvd.
Fort Worth, Texas 76137
PH: 817-222-5177
email marc.belhumeur@faa.gov.
SUBJ: Brantly Int’l, Inc.: Docket No. FAA-2012-1093 Directorate Identifier 2011-SW-020-AD
Outer Rotor Blade Skin Failure in the Root Area

To Whom it May Concern,

MY EXPERIENCES
As a responsible pilot with safety at the top of my list of priorities, I feel led to comment on this NPRM. I feel I am particularly qualified to present my opinion, since I owned and flew a Brantly B-2b, for more than five years. I personally experienced two occurrences of the subject “skin cracking,” in-flight, and promptly replaced the blades with used, serviceable units.

I never knew the first blade had failed while I was flying. The helicopter felt normal and the problem was only found during my walk-around before taking off, an hour or so later. The second failure could be felt as a light-to-moderate shake in the stick, but the helicopter responded normally to control inputs. This time I correctly guessed I had experienced another blade cracking.

Because of these two events, I sought to gain understanding of how these 1950-technology blades were assembled, how they functioned, and how they failed. After the second incident, I even de-skinned the damaged blade and observed how the blade was put together. I tried to get as much knowledge as possible.

Here is a list of the conclusions I came to, that kept me from feeling like I was in danger flying my little helicopter. To my knowledge:
• No crash has ever occurred or no one has ever been injured because of a Brantly blade failure
• No blade had ever failed except the 0.018” thin skin and foam, at the root area near the damper
• That area of the blade is relatively slow and produces very little lift
• The root rib/hinge-block and spar are robust, have ample strength, and do their jobs reliably
• The outboard 95% of the outer blades has always remained in tact and present to produce lift

In the mid to late 2000’s, a failure much more severe than either of mine occurred to two blades at the same time, on a Brantly in New Zealand. After looking at the pictures at that time, and knowing the pilot was able to fly to a suitable spot and land, I started to feel the 1950’s design blades were even safer than I had first believed. I preferred the problem didn’t exist, but felt there was not much that could be done.

CURRENT SITUATION
There are dozens of active Brantly pilots in the U.S. and more around the world. The admiration these pilots have for their machines is immeasurable. I’m sure all, are competent and conscientious pilots who have no interest in gambling their lives on flying a helicopter with unsafe blades. Within the last two years, the Brantly Company has moved to China and the supply of NEW outer rotor blades instantly went to ZERO! There is currently no approved facility approved to rebuild outer blades with cracked skin.
The supply of used, serviceable blades is minimal at best. These blades are not complex as many other helicopter rotor blades are, and are only made-up of six parts, not including fasteners. They are straight
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and un-twisted. No type jig or fixture was used when they were assembled at the Brantly Factory. Only standard hand-tools were used to build new blades. The materials are very low-tech.

EFFECT OF THE AIRWORTHINESS DERECTIVE
If this A.D. is adopted with its current wording, it will effectually ground all flying Brantlys until some source for new blades is found or some facility is certified to re-build the blades. The current value of a flying Brantly is approximately $50,000. I suspect that very few will pass the Eddy-Current test and the ones that do, will fall into the category of blades that may have been re-skinned in the field over the past 40 years. The defects that will be found by the Eddy-Current test do not constitute an unsafe condition, in my opinion. Blades that are suspected to be re-skinned in the field do not fall into the category of unsafe either. The now-deceased man, who may have been re-skinning blades in the field, was widely known to have been one of the persons behind developing the procedure at the Brantly Factory. He helped write the procedure manual. If anyone was available who knew how to re-build Brantly outer blades, it was he.

MY PLEA
The FAA must put safety first! Whoever placed this problem in the unsafe category made a huge mistake. At first glance, “helicopter rotor blade skin cracked” instantly goes in the unsafe category. In this specific instance, after looking closer, you see that this is not accurate. I ask all persons involved in evaluating this NPRM and deciding the final wording, to consider how many decades these helicopters have operated with this issue, without a single accident attributed to failed rotor blades. Consider the magnitude of some 70+ flying helicopters, with a collective value of more than $3.5 million, being grounded. I ask that the FAA entertain the possibility of licensing a Certified Repair Center, to rebuild these blades, if they crack, and if the spar and hinge-block have not reached their life limit. The blades then could provide many more hours of safe flying until the life of the spar and hinge-block is exhausted. I further ask that the Eddy-Current test and the suspected re-skin portions of the NPRM be eliminated and the airworthiness of these blades be left within the scope of responsibility of the A&P with the Inspection Authorization who performs the Annual Inspection each year. This has worked for more than four decades. If new blades were available, this A.D. would not be nearly as significant.


Sincerely,
Bryan Cobb, Previous Brantly Owner/Pilot, 2000-2006

[fixnfly]

You guys might want to also send a copy of whatever your response is to AOPA. IT is my understanding that the FAA wont do anything until AOPA signs off on any AD's. It seams AOPA is a little more powerful than I ever knew. I talked to a friend in our local FAA , the important thing he keeps on stressing is keeping the responses factual , no guessing or hearsay , whatever you write make sure you have something to back it up. Thanks to everyone who has & is going to respond we must work together. Bill

[chrisgerred]

Hi guys this is Chris Gerred. I recieved a call recently about the MR blade AD so I thought I would get on here and offer anything I could. I am still a Brantly enthusiast so I would like to see everyone keep their machines going. Some of you I have had contact with in the past and some of you I don't know.

As many of you know, I was involved with the issues related to MR blades at the time they came to light. I was working at the factory as a quality inspector and tech rep. I worked directly with engineering, the FAA, and the management at Brantly during that time. I also worked on some of the issues related to the TR drive components. I can't reveal information that is proprietary to Brantly but I can offer my insights into this issue.

The gentlemen at the FAA is known for pulling things out of the air and trying to put them into ADs. Examples can be found in the NPRM for the blade AD. It states that the AD is prompted by an accident for the NZ aircraft which is simply not true. There was no accident. In fact, the pilot manuevered the aircraft normally and made a safe landing with the 2 ft section of blade gone. That speaks very high of the structure of the blade. Cracks never did nor were they ever assumed to have initiated at the trailing-edge as stated in the NPRM. They initiated at the blade root near the hinge.

Advanced laboratory analysis was accomplished and the statement about hydrocarbons is true. The main concern is the age of blades and anything that could cause the foam and skin to lose their bond in the blade root area. The inboard 12 inches is the critical zone for transfer of stresses from the blade to the hinge. Any loss of bond in this area would grow quickly and eventually result in loose skin. Loose skin in that area is subject to changing pressures which try to pull the skin away from the blade, fatigue the skin and result in a crack. In a nut shell that is the reasons behind the AD.

One of the real show-stopper parts of the AD I noticed was the FAA excluding the allowance for de-bond area on the remainder of the blade. SB-111 allowed for 10 square inches which was about 1% of the blade bonded surface. I would definitely make this an argueing point. The FAA had no data to disprove this allowance. If there is no allowance, then it is likely that no blade in existence could pass. The reality is that it is not a perfect world an no one could produce a blade that has 100% pefect bond. There will be some small voids in the bond on every blade. So the question is how much? I would insist that the FAA provide some criteria that allowed for de-bond on the remainder of the blade surface. 1% is a conservative number and it could likely be much more.

There is one gentleman on the planet that understands the Brantly design of main rotor blades and knows the FAA engineer very well that might be willing to review and endorse comments made by the owners. The guys at the FAA will listen to him. If anyone would like to go that route just let me know and I will try to get in touch with him.

[bryancobb]

Hi Chris,

Thanks for your FIRST-HAND contribution. I see that you focused on the same ERROR in the NPRM that I did. That is the crazy characterization of what happened in NZ, as an A C C I D E N T. As you say, there was no accident! If this AD is stopped, my opinion is that it will be because we convince them that this problem is more of a nuisance than a SAFETY issue.

As far as I know, there has NEVER been an accident caused by skin failure on a blade?

I sure wish I had known of this SPECIAL PERSON who is most familiar with the blade design, before I sent my comments in. I had wondered if there was such person, still living, but had no idea how to find him. Do you know if he has read my comments, after I posted them here? I would like to know what changes he would have made. Can you comment?

[Ron Spiker]

Thanks for your input Chris. I also have incorporated several points that you made into the document that I'll be submitting. I specifically address the INCIDENT and background information about that, along with a LOT of other information. My document is 5 pages long.

Your first hand knowledge of this situation is quite helpful. I think I know who you refer to, and I agree that his help would be invaluable to us at this time. Please contact him and anyone else that you think can help us either get this not issued as an AD, or rewritten to be much less restrictive. As written, it will quite likely close down my flight training operation.

Thanks

[seneca2e]

Thank you very much Chris for your input!!!!!!!!! I'm pretty sure I have recently talked to and emailed the person you refer too. I have gotten no response since the NPRM has been issued. I sure hope he can find the time to help on this. His knowledge is extensive and I do think he is our best chance of getting something done on this. Please contact him and ask him to help on this issue!

[Ron Spiker]

For those of you who have not submitted comments yet to the FAA, you now have some more time to do so. Brad, Bill and I have been having conference calls with AOPA and with their help the FAA has agreed to accept and evaluate comments submitted up until Feb 15, 2013.

Here is the reply from the FAA.

After reading the comments, we find that the affected aviation community
may need more time to thoroughly review and provide comments to the
proposed AD. We also find that more time may be needed for the affected
aviation community to do some additionally research on the estimated
replacement costs for a M/R blade considering limited replacement blade
inventory and manufacturer support.

We concurs with AOPA's justification, but rather than extending the comment
period, we agree to accept and evaluate all comments, including late
comments, up until February 15, 2013.

So please continue doing research and contact others who can submit valuable comments towards this proposed AD.

[seneca2e]

Thanks for the update Ron and good work by you, Bill, and Brad. I've been doing what I can as far as contacting people that might help as well. At least one very notable person I recently talked to is going to submit a detailed comment that will bear weight with the FAA as well it should. We can only cross our fingers that common sense and economic impact will prevail. Safety is always a concern and certainly if ALL helicopters and planes were grounded air transport would be safer but that sure is an unacceptable way to promote safety. That's what would happen if the A/D is enacted. To correct what the FAA said in extending the A/D I would say there is NO factory support(not limited) and almost NO replacement blades(only a few used ones and certainly most of those just like most of the ones on the current flying fleet) would never pass this ridiculous and uncalled for A/D proposal.

[Ron Spiker]

Just a reminder that Feb 15th is the deadline for the FAA to accept comments on the proposed AD. If you haven't submitted your factual comments yet to them yet, please do so soon. Thanks to those who have already.

[Ron Spiker]

I found this file today relating to the blade AD. I was having trouble getting the link to it copied, so I just saved the PDF file itself.

Open the file here.

I don't know what it is actually telling us at this point.

[seneca2e]

Looks like the standard economic impact study they have to do with an A/D. It's total BS though as there are no new blades available at ANY price and I doubt there ever will be at this point.

[Ron Spiker]

The FAA has now issued the Blade AD.

You can see it here:
https://www.federalregister.gov/article ... elicopters

Or direct to the PDF here:
http://www.gpo.gov/fdsys/pkg/FR-2014-10 ... -23592.pdf

[bryancobb]

I feel like the FAA agonized over this for a long time, trying to find any way to not publish an A.D.. They felt they HAD to and there was no way out, so they eliminated all the parts of the inspection they possibly could eliminate.

This is a bummer.

[9121u]

HI brantly owners there is two more options for the blade AD.. start looking for the 248 -53 and the 248-100 set of blades... there is no AD on these blades.. there still 2500 hr blades with just the less forgiving in auto rotation capabilities. and if you install these blades you must use the older softer lord dampers. and get your rotor tac marked to 500 red line because these blades run faster they are lighter in tip weight I ran a set of 248-100 on my brothers old brantly when we first got it going.. not much in differents actually the rpm is easier to manage .but then again the brantlys I have seen had good blades on them they should pass the Eddy c testing....... the saying goes if there is a will there is a way... keep them flying and always be safe about it.......tom

[9121u]

HI guys this is my last post on this forum I have sold my Brantly few months ago and now own a Enstrom and will concentrate on that .