Docket No: FAA-2012-1093 

Directorate ID: 2011-SW-020-AD 

Originating Office Tracking No.: 

Disposition Comments 

Next Step: iZ1 FRAN 0 SNPRM 

D These comments are in 

response to an SN PRM 

D No Comments/Only Supportive Comments Received - ljthis box is checked, no signatures are 

required 

Yes Has the referenced service information been revised since the NPRM was issued? If yes, 

list latest revision and attach a copy. Note that changes beyond the scope of the previously 

published NP RM will require a new notice. Contact the Directorate focal point for guidance. 

See the next pages 

Instructions: Summarize all comments by issue (not by commenter) and provide your recommended resolution of 

each issue. All comments relating to the same issue should be discussed together. Do not list all of the issues 

from one commenter together. If changes to the AD are required based on the comments received, explain why and 

describe in detail what change(s) you recommend. Reference FAA-IR-M-8040.1 C Chapter 9. 

ISSUE 1: Select one of the following: 

If other, explain: 

Commenter( s ): 

What change to the AD action is requested? 

Why is the change requested or how is it justified? 

Do we agree? 

If YES, we agree because Make the following changes to the AD: 

JfPARTIALLY AGREE, we agree with because We disagree with because 

Make the following changes to the AD: 

If NO, we don't agree because 

ISSUE 2: Select one of the following: 

If other, explain: 

Commenter( s ): 

What change to the AD action is requested? 

Why is the change requested or how is it justified? 

Do we agree? 

If YES, we agree because Make the following changes to the AD: 

lfPARTIALLY AGREE, we agree with because We disagree with because 

Make the following changes to the AD: 

Page 1 of3 
If NO, we don't agree because 

For additional issues, double-click here 

Page 2 of3 
Signature Section 

Signature indicates concurrence with this action. 

Originating Office Tracking No.: 

ASE Printed 

~ Name: Marc Belhumeur { ate 

Branch Manager 

Page 3 of3 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

I. Issue: Other 

(Kevlar Clutch) 

2. Issue: Other 

(Education and training) 

3. Issue: Other 

(Allowing some amount of cracks) 

4. Issue: Other 

(Allowing some delamination) 

5. Issue: ApplicabilitY 

(Remove 248-10 I and 248-202 blades from the AD) 

6. Issue: Other 

(Identify unapproved blade spars and hinge blocks) 

7. Issue: Withdraw the NPRM 

(Questions asked) 

8. Issue: Oelav Issuance of AD 

() 

9. Issue: Other 

(Modify the NPRM) 

10. Issue: Other 

(Allowing dent, nick, crease, wrinkle, bend) 

II. Issue: Other 

(Certified repair center and repair process specitication) 

12. Issue: Other 

(Lessen inspection requirements) 

13. Issue: Withdraw the NPRM 

(Eliminate AD- Follow Maintenance Manual) 

14. Issue: Service Info 

(Rewrite/eliminate the Service Bulletin SB-111) 

15. Issue: :Service Info 

(Proposed SAIB) 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

1. Issue: Other 

(Kevlar clutch) 

Commenters: Jerry L. Toms 

What they want changed: This commenter saw the need to equip these aircraft with Kevlar clutch lining. 

How they justify it: The Kevlar clutch dramatically reduces some of these blade overloads that cause the 

wrinkles, cracks etc. They do not create clutch dust in the main centrifugal drive and offer an incredible 

difference in rapid engagements without sticking or other known operational issues. And it was 

inexpensive. 

FAA Response: We disagree. We have no basis to require the manufacturer to obtain FAA approval for a 

design that it has not proposed, particularly when we have been provided with no supporting data to justify 

that it will address the unsafe condition. 

2. Issue: Other 

(Education and training) 

Commenters: Jerry L. Toms 

What they want changed: This commenter recommended a training program for maintenance providers, 

operators, and owners with respect to the blades, regarding several subjects including: the significance of 

the placards, TCDS instructions, operating limitations and the FAA Approved Rotorcraft Flight. 

How they justify it: He saw the real issue to be educational and proper maintenance and operation of the 

aircraft and its components. One of his goals is to have those responsible for maintaining these machines 

and all other GA aircraft. to see the drastic need these days for seeking additional training and taking it 

seriously so that GA can remain fun and safe. He believed the need is for education about the machine, the 

engineering and safety which already exists, and the greater need for transferring the knowledge that 

existed in the high utilization and activity years of development of the Brantly helicopter; to those involved 

with it today as operators, maintenance providers, and regulators charged with safety of the fleet. 

FAA Response: We disagree. Individuals responsible for maintaining and operating an airworthy 

helicopter are required to know the significance of placards, TCDS instructions, and operating limitations. 

More training could be beneficial, but we have received no infonnation that it would address the unsafe 

condition. 

3. Issue: Other 

(Allowing some amount of cracks) 

Commenters: Ronald Spiker, Jerry L. Toms 

What they want changed: Crack should be allowed per the approved factory maintenance inspection 

procedures. 

How they justify it: Method of inspections and criteria for permissible crack size and location are 

available in the Maintenance Manual and Service Letters. One of the commenters noted he was very 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

involved in the manufacturing of these blades and the implementation of approved repair process 

specifications and clarification of limits of acceptable cracks in the skin, hinge block, and spar attachment 

hole. Those limits are published in historical TC Holder documents including service documents. 

FAA Response: We disagree. Allowing any cracks in a blade would be unacceptable. No data suppotts 

that a crack in these blades is a safe condition. 

4. Issue: Other 

(Allowing some delamination) 

Commenters: Ronald Spiker, Alan Bowles, Jerry L. Toms 

What they want changed: Delamination should be allowed per the service bulletin. 

How they justify it: The service bulletin allows for up to I 0 sq.in of delamination outside of the inboard 

12 in. of the main rotor blade; which they stated is closer to industry standard for other helicopter 

manufacturer's maintenance procedures and is allowed per Brantly maintenance manuals. There is also 

acceptable delamination limits published when the Brantly B2 was highly used. 

FAA Response: We partially agree. We agree that not allowing any delamination outside of the inboard 

12 inches doesn't align to industry standards. We disagree with allowing up to I 0 square inches of 

delamination per the service bulletin because I 0 square inches is too large to align with industry standards 

and also because there is no supporting data that justifies that a larger delamination area in these blades 

would address the unsafe. condition. We will allow for up to 2 square inches of delamination outside of the 

inboard 12 inches. We wi ll define the unsafe condition for the outboard of the inboard 12 inches as 2 or 

more square inches of delamination. 

5. Issue: Applicabilitv 

(Remove 248-10 I and 248-202 blades from the AD) 

Commcnters: Gerald E. Goldsberry, Jerry L. Toms 

What they want changed: One commenter requested that the 248-10 I and 248-202 blades be removed 

from the AD. The other asked to address 248-10 I and 248-202 blades separately from 248-404 blades. 

How they justify it: The 248-10 I and 248-202 have been good blades for over 50 years; the only reason 

the get cracks is because of improper maintenance, rigging, and operation. The 248-1 0 I and 248-202 

blades have FAA approved process specifications for authorized repair station to overhaul and repair those 

blades. The 248-202 blades and the 248-404 blades are significantly different in composition and bonding 

agent. The 248-404 was more susceptible to bonding separation; from 200 I to 2006, the DER experimented 

on the 248-404 trying to find the proper replacement foam and bonding agent. There are limited 248-202 

used blades that are airworthy and no factory support on any parts. Issuing the AD as is will put all Brantly 

owners out of business. 

FAA Response: We disagree because failures and fractures have occurred in the PIN 248-202 blades. 

These failures have occun-ed in the field and show that the previous specifications the commenters 

referenced are inadequate. We have been provided with no supporting data that shows a crack occurred 

because of improper rigging, maintenance, or operation of the aircraft. These issues are already addressed 

in Brantly's maintenance manuals, flight manual supplements (FMS), service bulletins, and service 

instructions. Brantly, with help from a laboratory report written by a metallurgical engineering company, 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

concluded that the M/R blades' failure was caused by hydrocarbons contamination inside the blades' skinto-foam bond and that the fractures originated near the trailing edge. The P/N 248-10 I and PIN 248-404 

are similar in construction to the PIN 248-202 blades, and thus need to be included and addressed in the 

AD. We have been provided with no data that shows that the PIN 248-404 is more susceptible to bonding 

separation. The PIN 248-10 I and 248-202 blades have been addressed separately from PIN248-404 blades 

in that the AD does not require the PIN 248-404 blades to do many of the inspections until after 10 years or 

1,000 hours TIS, instead of within 8 hours TIS like the other blades. We do not issue an AD based on 

whether spare parts are available or can be produced. While every effort is made to avoid grounding 

aircraft, we must address the unsafe condition. 

6. Issue: Other 

(Identify unapproved blade spars and hinge blocks) 

Commenters: Jerry L. Toms 

What they want cha nged: This commenter recommended a mandatory inspection to identifY unapproved 

blade spars and hinge blocks using a developed main rotor blade rivet hole template for comparison. 

How t hey justify it: This will help identifY unapproved blade spars and hinge blocks. There is a need to 

attempt to identifY main rotor blades which were not produced or repaired using an FAA approved quality 

system or materials or processes: Where rivet hole edge distance or pattern has been cited in your NPRM 

documentation; any improper edge distance identified by the template should be addressed appropriately. 

FAA Response: We disagree because the lab report concluded that the M/R blade failure was caused by 

hydrocarbons contamination inside the blades' skin-to-foam bond and that the fracture originated near the 

trailing edge. Obviously, parts produced or repaired using an FAA-approved quality system, materials or 

processes is important and eliminating short rivet hole edge distances is good design practice. But no data 

supports that the spar or hinge block was unapproved or that the rivet hole edge distance or pattern caused 

the unsafe condition. 

7. Issue: W ithdraw the NPRM 

(Questions asked) 

Commenters: Jerry L. Toms 

What they want cha nged: To withdraw the AD until more analysis/testing is performed. 

How they j ustify it: 

It is prudent to understand these additional stress sources and moments before making conclusions about 

the root cause factors of cracks in the stated skin locations; and certainly before asserting these are related 

to "age" and "fatigue''. Prior to issuing an Airworthiness Directive, the root cause should be identified with 

specificity, with the particular manufacturing method and materials identified to ensure that the corrective 

action is appropriate. 

Questions: 

I. What testing was performed to determine that the spars and hinge blocks. based on "age", no 

longer meet the minimum design specifications under which they were selected and approved as 

the structural blade components for the 82 Series? 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

2. Can you supply me with the name of a lab who could perform destructive testing on a blade or two 

and provide me with a report concerning whether it actually no longer meets the minimum design 

specification as related to the airworthiness requirements and strength? 

3. Did you perform this analysis in conjunction with this NPRM? 

4. How many blade failures of the spar and hinge block assembly were documented in preparation of 

this NPRM Proposal for an Airworthiness Directive? 

5. What is the structural significance of the rivet hole statements related to the leading edge spar and 

the root hinge block where the skin attaches? What is the function of these rivet holes and rivets? 

6. In this proposal, there is mention of one event in New Zealand, referenced as an "accident"; and 

half a dozen other blades with either skin cracks or delamination defects. What percentage of the 

estimated four thousand (4000) 248-10 I and 248-202 blades manufactured or repaired using FAA 

approved methods, does this represent? 

7. What serial number sequences were involved? Which bonding materials? Which foam core 

material? Which type of rivets was involved? Which model blades? 

8. Your Cost assessment fails to address the FAA approved dra .. vings which state that a 248-404 

blade cannot be used in place of a -202 blade: Are they still required to be replaced in sets of 

three? 

FAA Response: We disagree. The AD was issued because it addressed an unsafe condition. The root 

cause of the fai lures has been demonstrated by Brantly with help from a laboratory report written by a 

metallurgical engineering company. The report took into account stresses and loading, and determined that 

skin fracture was propagated by corrosion-fatigue and mechanical fatigue. That report concluded that the 

M/R blades failure was caused by hydrocarbons contamination inside the blades' skin-to-foam bond and 

that the fracture originated near the trailing edge. 

Answers to questions above: 

(I) The original blades were certified using a crack initiation methodology (e.g., using the S-N curves and 

Miner's Rule). Shortly after certification, a fatigue test was accomplished on the mid-span of the spar and 

skin. No supporting data or test results were provided to determine if the spars and hinge blocks no longer 

meet the design specifications. Stereomicroscopy, wavelength dispersive X-ray spectroscopy, combustion 

testing, tensile testing, peel testing, scanning electron microscopy, micro Fourier infrared spectroscopy, and 

hardness testing were all performed and documented to determine the causes of the delamination and crack 

propagation. No testing is needed to detennine whether blades with delamination and cracks do not meet 

the design. 

(2) The name of the company that performed the Failure Analysis is Metallurgical Engineering Services. 

We are not distributing the lab report. A copy must be requested from Brantly. No lab report is needed to 

determine that blades with delamination and cracks are not airworthy or have reduced strength. 

(3) A M/R Blade Failure Analysis, Risk Analysis, Cost Analysis, and Economic Analysis were performed 

before the NPRM was issued. 

(4) None. The failures were found in the skin to foam bond and in the skin and rivets at the rivet joints 

attaching the skin to the hinge block and/or spar. 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

(5) The cracks originated near the skins' trailing edge and propagated bet'vveen rivet holes and into the 

leading edge rivet holes. These rivets carry shear between the hinge block and skin and the spar and skin. 

(6) The percentage has not been determined or needed for this AD. 

(7) No serial number sequence has been determined or was needed since the part numbers are only needed 

to identify the applicable blades. Per the laboratory report, the bonding material between the skin to foam 

was 3M 1239 & 3M 11239A, the foam core was Stafoam AA604, the type of rivets were AAIIOO, and the 

blade was PIN 248-202. 

(8) All three blades installed on one helicopter must have matching part numbers. The cost analysis 

already assumes that the replacement blade must match what it is replacing, thus no new cost analysis is 

needed. It doesn't assume that three blades must be replaced because the AD doesn't require it. 

8. Issue: Delay Issuance of AD 

Commenters: AOPA, Jerry L. Toms 

What they want changed: Extend comment period. 

How they justify it: So the owners/operators can do some research on the AD and on the costs of 

replacement blades, a thorough review of the NPRM, and provide adequate comments. Because the 

conclusions drawn by the FAA from the limited findings; are inconsistent with the historical research by 

the original TC Holder, the PC holder, and the Certified Repair Stations which were affiliated with the TC 

Holder in the 1960's and 1970's into the 1980's, when there were high utilization operators in Illinois, 

Pennsylvania, Florida and other states. Also the causal factors are well defined, and not related to fatigue 

or failures in the FAA Approved manufacturing and repair process specifications. 

FAA Response: We disagree because the FAA has included and accepted all comments received after the 

comment period ended. We notified AOPA and the other commenter prior to the comment period ending 

that we would include all comments received until February 15, 2013. The FAA also had adequate 

information to make its detenninations. The root cause of the failures has been demonstrated by Brantly, 

with help trom a laboratory report written by a metallurgical engineering company. That report concluded 

that the M/R blades failure was caused by hydrocarbons contamination inside the blades' skin-to-foam 

bond and that the fracture originated near the trailing edge. No supporting data has been provided that 

shows that the AD is inconsistent with history or that the root cause is not related. The issuance of an AD 

cannot be determined on the cost of replacement blades. While every effort is made to avoid grounding of 

aircraft, we are required to address the unsafe conditions. 

9. Issue: Other 

(Modify the NPRM) 

Commenters: Neil Freeman 

What they want changed: The commenter requested that the proposed AD be modified. He proposed that 

all used blades installed initially be checked. 

How they justify it: The commenter attributed the cause of the blade condition to the incorrect installation 

of the blade damper units as he experienced it. The check would be fairer to owners who currently can't 

buy new blades. He stated the New Zealand Brantly that initiated the AD appeared to be maintained on a 

farm. 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

FAA Response: We disagree because no data shows that the damper caused the unsafe condition. An 

initial check for improper damper installation is not merited. There is history that the incident helicopter 

may have had quick starts, and that the dampers had to be replaced, but the quick starts and damper issues 

have not been substantiated to be the root cause. Proper damper installation is paramount, but there are 

already adequate damper inspections and installation instructions in the maintenance manual and service 

instructions. 

10. Issue: Other 

(Allowing dent, nick, crease, wrinkle, bend) 

Commenters: Gary Goldsberry, Ronald Spiker, Alan Bowles, Cy A. Russum, Jerry L. Toms 

What they want changed: Overall, the commenters requested that small dent, nick, crease, wrinkle, or 

bend be allowed in the blades per the approved factory maintenance inspection procedures. One of these 

commenters did state that blades with wrinkled skins should be replaced. 

How they justify it: A small dent, nick, crease, wrinkle, or bend in the skin of the blade, especially in the 

middle or trailing edge, does not cause the blade to crack and is not necessarily a safety issue. All Brantly 

blades are tabbed on the last 18" of the blade to get cyclic pressures correct or to cure a climbing or diving 

blade. During certification and flight there are procedures which require the outboard end of the trailing 

edge of the blade to be bent. Wrinkles, bends, and nicks should be allowed as previously listed in the 

approved factory maintenance inspection procedures. One of the commenters noted he was very involved 

in the manufacturing of these blades and the implementation of approved repair process specifications and 

clarification of limits of acceptable blade skin \-vrinkles, bends, and other approved conditions. Those limits 

are published in historical TC Holder documents including service documents. Most Brantlys will end up 

being grounded due to slight imperfections in the main rotor blades that are not a safety issue. Even one 

blade with a small dent in the skin, a nick, or even a bend from being tabbed would ground the helicopter 

due to pulling the blade from service. 

FAA Response: We agree. The data we have does not support that a crack in the Brantly rotor blade skins 

was caused by small dents, nicks, creases, wrinkles, bends, extra hole, and inadequate rivet spacing, though 

eliminating them is good design practice. We will remove the dent, nick, crease, wrinkle, bends, extra 

hole, inadequate rivet spacing requirements. 

11. Issue: Other 

(Certified repair center and repair process specification) 

Commenters: Bryan Cobb, Jerry L. Toms 

What they want changed: One of the commenters asked for the possibility to license a certified repair 

center to rebuild the blades, if the crack and the spar and hinge-block have not reached their life limit. The 

other asked to locate and update the approved process specifications which existed at the FAA Approved 

Repair Station, and establish a method to revive the repair process specifications including the approved 

blade re-skinning, using currently available materials and processes. The commenters requested that thereskinning of the blades be allowed in the field. 

How they justify it: The repaired blades could provide more hours of safe flying until the life of the spar 

and hinge-block is exhausted. There is currently no approved facility approved to rebuild outer blades with 

cracked skin. The supply of used, serviceable blades is minimal at best. Owners will not be able to replace 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

these blades. These blades are not complex as many other. These helicopters have operated with this issue 

for decades without a single accident attributed to failed rotor blades. Blades that are suspected to be reskinned in the field do not fall into the category of unsafe blades. One commenter said he participated in 

the Brantly's blade repair processes in the mid 1970's; these processes performed in repair station involved 

re-skinning of the 248-202 blades using the approved methods. The update of these specifications will 

enable FAA approved blade repairs and updates; coupled with detail evaluations of each blade received for 

rebuilding, to enhance the database of issues. Within the last two years, the Brantly Company has moved 

to China and the supply ofNEW outer rotor blades instantly went to ZERO! 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. 

FAA Response: We disagree. The FAA does not license repair centers, we certificate them. We do not 

have the approved process specifications or data to locate or to revise/update/support returning 

/rebuilding/re-skinning blades to an airworthy condition. Repairs that eliminate the cracks (stop drilling is 

not allowed) and delamination can be accomplished by appropriately rated skilled mechanics and repair 

stations. The repairs must be done with adequate tooling, perF AA approved repair data, and approved for 

return to service as a major repair. FAA cannot base an AD on whether spare parts are available or can be 

produced. While every effort is made to avoid grounding aircraft, we must address the unsafe condition 

12. Issue: Other 

(Lessen inspection requirements) 

Commenters: Bryan Cobb, Gerald E. Golsberry, Ronald Spiker, Alan Bowles, Gregory Thomas 

What they want changed: Several commenters requested that the eddy current inspection be eliminated 

from the AD. One of the individuals asked to consider performing a verification and validation of the eddy 

current inspection prior to issuing the AD. Some requested a I OX magnification glass inspection for cracks 

and delamination each 50 or I 00 hour inspection, similar to the Robinson AD 2011-12-10. One commenter 

recommended visual inspection for cracks utilizing a 3 to 5 magnification magnifying glass; with possible 

chemical stripping prior to the inspection. One commenter asked that the blades inspection be perform by 

an authorized A&P annually; another that the blades be inspected at their locations. There was also a 

request that the visual inspection prior to the first flight of each day be performed by the helicopter owner 

or operator. 

How they justify it: The eddy current testing can't be done successfully at certain locations on the Brantly 

helicopter blade, especially between the leading edge of the skin to the main spar, due to the closeness of 

the rivets in the blade spar at the edge. It can cause erroneous indications that would lead to inaccurate 

results; because the defects that will be found the eddy current test do not constitute an unsafe. condition. 

Due to the very thin material thickness, cracks should be through the material should be visible utilizing a 

magnifying glass between 3 to 5 magnification. Larger magnifying optics could be used, but they begin to 

be very hard to focus and the images become distorted. The area between the rivet and the skin edge 

should be stripped as necessary to allow better visibility. Chemical stripping would be best to keep the 

metal from being "smeared" which could happen by mechanical stripping. These helicopters have operated 

with this issue for decades without a single accident attributed to fail ed rotor blades. One commenter stated 

it was suggested that it would destroy the blade itself. Another commenter listed different costs associated 

with getting blades through an eddy current inspection as well as possibility of damage and down time. 

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. Owners will not be able to replace these blades. l f 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

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. 

FAA Response: We partially agree. Reducing the eddy current inspection area to just the tirst inboard 12 

inches is adequate because this is where the fracture is located. Eddy current inspecting the outboard area 

would not be effective in finding the unsafe condition. We disagree with eliminating the eddy current 

inspection procedure altogether because the inspection should find the unsafe condition, is reasonable, 

widely used, is cost effective, and has been addressed in the AD impact analysis. No alternate procedure 

has been provided that can address the unsafe condition as reliably. The eddy cuJTent inspection procedure 

has been validated and is similar to other blade crack inspections. The procedure takes edge effect into 

account. There may be some false indication, but these should be false positives, which can be reevaluated. The procedure is a nondestructive inspection (NDI) and if done correctly, will not destroy any 

blade. The procedure can be done in the field if the inspection area is clean, has proper lighting, there is the 

proper equipment, and can be done by a qualified inspector. The procedure is needed to find small cracks 

around the rivet holes that can quickly link up, called multiple site damage (MSD), and cause rapid failure. 

The procedure is too specialized to allow any A&P to do unless he or she is a qualified to Level II or 

equivalent. Visual and/or magnifying glass inspections are not as effective as eddy current and are already 

being done every 25 hours with a I Ox magnifying glass. The 3x or 5x is magnifying glass may miss cracks. 

The 25 hours matches the regular Brantly maintenance inspection schedule, and no data has been provided 

that supports that increasing the interval to 50 or I 00 hours would address the unsafe condition. We agree 

with the visual inspection before the first flight of each day being performed by the helicopter owner or 

operator since this is best accomplished as part of the other daily inspections and does not require tools. 

The issuance of an AD cannot be determined on whether spare parts are available or can be produced. 

While every effort is made to avoid grounding of aircraft, we must address the unsafe condition. Make the 

following changes: Reduce the eddy current inspection area to just the first inboard 12 inches. Define that 

a crack in the first 12 inches is the unsafe condition. Allow helicopter owners and operators to perfonn the 

visual inspection before the first flight of each day. 

13. Issue: Withdraw the NPRM 

(Eliminate AD- Follow Maintenance Manual) 

Commenters: Cy A Russum, Anonymous, Allen Bowles, Jerry L. Toms, Neil Freeman, Bill Mott 

What they want changed: These commenters requested withdrawal of the AD with the proposal to use the 

original Maintenance Manual's blade inspection and Service Letter(s) instead. 

How they justify it: The commenters attributed the cause of the cracking of the blades to improper rigging, 

maintenance or operation of the aircraft. The Brantly has some unique designs to include that the rotor 

brake must be on for starting. If this procedure is not followed there will be excessive torque applied on the 

attachment point of the main rotor blade. Damage depends on the severity of the quick start and may 

include damage to the skin or breaking the bond. Commenters believes that the reasons a 248-10 I or 248-

202 blade gets cracks is the lack of maintenance, bad inboard bearings, bad dampers or rotor system out of 

phase. The maintenance manual has adequate inspection methods when followed properly. Many defects 

cited as unsafe conditions in the NPRM are allowed per the original maintenance and overhaul manuals. 

The NPRM has not demonstrated there is any unsafe condition involving the structural blade elements 

manufactured or produced or repaired in the FAA approved quality system or in the approved repair 

process specifications. During initial testing, for military use, the helicopter was demonstrated to have the 

ability to be flown and land safely with portions of the blade removed. There has not been an accident 

related to blade fai lure in over forty years. There has been only one accident attributed to blade failure in 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

the entire history of Brantly. The incident in New Zealand promoted the proposed AD. The aircraft was 

able to land safely even with a huge piece of the blade missing. Few used blades would meet the onerous 

working in the Service Bulletin/ AD effectively grounding the entire fleet of Brantlys. Additionally the 

company that wrote the Service Bulletin referenced in the AD did not have the authority to make parts for 

the rotor blades or produce this aircraft. Few used blades would meet the requirement of the AD. It would 

be financially devastating to the majority of owners and lead to grounding the fleet. 

FAA's Response: We disagree because the failures that have occurred in the field show that the blades 

have an unsafe condition and that the original maintenance manual and service letters do not have adequate 

inspection methods to address them. We have not been provided with any supporting data that justifies 

eliminating the AD or that shows that cracking is caused by improper rigging, maintenance, quick starts, 

bad dampers, bad bearings, phasing, operation of the aircraft, or because they were not produced or 

repaired in the FAA approved quality system or with an approved repair process specifications. The 

incident helicopter may have had quick starts and dampers that needed to be replaced, but that has never 

been substantiated to be the root cause. Also, since improper rigging, quick starts, bad dampers, bad 

bearings, phasing, maintenance, and or operation of the aircraft are already addressed in Brantly's 

maintenance manuals, Flight Manual Supplement (FMS), service instruction, and service letters, they 

should not cause cracking if the aircraft is operated and maintained properly. Whether they contribute to 

cracking or not, they should be found by the normal maintenance inspections. Brantly, with help from a 

laboratory report written by a metallurgical engineering company, concluded that the M/R blades failure 

was caused by hydrocarbons contamination inside the blades skin-to-foam bond and that the fracture 

originated near the trailing edge. We do not issue an AD based on whether spare parts are available or can 

be produced. While every effort is made to avoid grounding of aircraft, we must address the unsafe 

condition. 

14. Issue: Service Info 

(Rewrite/eliminate the Service Bulletin SB-I II) 

Commenters: Bill Mott, Allen Bowles, Gregory Thomas 

What they want changed: The commenters requested a rewrite of the Service Bulletin SB-111 and one of 

them provided the suggested content. Another commenter asked that the Service Bulletin SB-11 I be 

rescinded and requested that the original Maintenance Manual's blade inspection and Service manuals be 

followed. 

Brantly Service Bulletin No: Ill -Suggested Rewrite or Replacement 

Introduction No changes necessary. 

Applicability No changes necessary. 

Compliance 

For Outboard Main Rotor Blades PIN 248-I 0 I, 248-202, and 248-404, before further flight, comply with 

sections I and 2 of this service bulletin. Thereafter at intervals not to exceed I 00 flight hours or 5 calendar 

years, whichever occurs first, comply with section I, and at intervals not to exceed 25 flight hours comply 

with section 2. Also comply with section 3 of this service bulletin before the first flight of each day. 

Contact No changes necessary. 

I Crack Inspection ( I 00 Hour Inspection) 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

1.1 Remove the outboard main rotor blade. Clean surface to be inspected. Remove any contaminates that 

might interfere with the discovery of existing surface indications. Use a suitable light and a lOX magnifying 

glass to inspect for cracks in the main rotor blade. Pay particular attention to areas around rivet holes, the 

blade root area, and the trailing edge. 

1.2 No cracks are permitted. Verify adequate edge distance between holes such that no additional holes 

have been added or extra rivets used to fill stop drilled holes in the root fitting. Any blade that has cracks 

(especially around the root of the blade), extra rivets, or stop drilled holes must be removed fi·om service. If 

any of these defects are found, remove the blade fTom service and replace with an airworthy part. Record 

the results in section 4 of this service bulletin. 

1.3 Perform the 25 hour delamination inspection as described below. 

2 Delamination Inspections (25 Hour Inspection) 

2.1 Clean surface of the outboard main rotor blade to be inspected. Remove any contaminates that might 

interfere with the discovery of existing surface indications. Use a suitable light to inspect for cracks in the 

main rotor blade. Pay particular attention to areas around rivet holes, the blade root area, and the trailing 

edge. 

2.2 No cracks are permitted. Verify adequate edge distance between holes such that no additional holes 

have been added or extra rivets used to fill stop drilled holes in the root fitting. Any blade that has cracks 

(especially around the root of the blade), extra rivets, or stop drilled holes must be removed from service. If 

any of these defects are found, remove the blade from service and replace with an airworthy part. Record 

the results in section 4 of this service bulletin. 

2.3 Inspect the blade for delamination using a tap test. Use a metallic coin or tap hammer to lightly tap the 

blade in the areas that are bonded. Pay particular attention to the inboard 12 inches (.305m) on the top and 

bottom. Mark all delaminated areas with a grease pencil or chalk. 

NOTE Delaminated areas will have a duller, low pitched sound when compared to areas that are not 

delaminated. They may also have a spongy or loose feeling when pressed with the hand. 

2.4 No delamination is permitted on the inboard 12 inches (.305m). Delamination is permitted outboard of 

this area provided the total delaminated areas do not exceed I 0 in2 (.254m2). Record the results in section 

4 of this service bulletin. 

3 Daily Inspections 

3.1 Before the first flight of each day, visually inspect the outboard main rotor blade for cracks. Pay 

particular attention to the blade root area and the area around the lead/lag damper mounting fork. 

3.2 No cracks are permitted. If any are found, remove the blade from service and replace with an airworthy 

part. Record the results in section 4 of this service bulletin. 

4 Inspection Report for SB-I II No changes necessary 

How they justify it: There has only been one accident related to the main rotor blades; more than 40 years 

ago. The Brantly in New Zealand landed safely, even with a huge piece of the blade missing. Improper 

maintenance and operation are the causes of the problems found with the blades. The Brantly factory 

service manual and operating manual address these issues and allow continued safe flight. The eddy current 

inspection in SB-111 is not appropriate. Some of the individual who participated in the proposed rewrite 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

included people who worked on the development of that helicopter, flight school operators and mechanics. 

Issuing the AD as is will be devastating to Brantly's stakeholders (flight schools, instructors, entities selling 

parts, maintenance facilities, owners,). Small deformation in the skin should be excepted unless they are in 

the area of the rivets. Wrinkles and bends are common in these blades due to tabbing that was performed at 

the factory during the initial tracking and should still be allowed. In addition delamination in certain areas 

should be allowed. The service bulletin allows for up to I 0 square inches of delamination outside of the 

inboard 12 inches of the M/R blade. Similar criteria are used for other OEMs. 

FAA Response. We partially agree. Because the Brantly in New Zealand landed without further damage, 

it was involved in an incident instead of an accident. The Final Rule will reflect this change. We agree with 

allowing some imperfections (See Issue: Allow Some Imperfections). We disagree with rewriting the 

service bulletin because the FAA did not produce it. We also disagree that improper maintenance and 

operation caused the blades' problems and that the Brantly factory service manual and operating manual 

address these issues and allow continued safe flight (See Issue: Replace the AD). We also disagree with 

changing the inspections cited in the proposed service bulletin because the proposal eliminates a necessary 

eddy current inspection and allows too much duration between the magnifying glass inspections (See Issue: 

Reduce Inspection Requirements) and pennits delamination up to 10 square-inches (See Issue: Allow some 

delamination). Also, ADs are not issued based on the cost of remedying the safety issue. While every 

effort is made to avoid grounding of aircraft, we address the unsafe condition. 

t 5. Issue: Service info 

(Proposed SAJB) 

Commenters: Jerry Toms 

What they want changed: This commenter proposed an SAIB and provided its content as follows: 

I. On a one time basis for those helicopters where such an inspection has not been documented; 

remove the outboard blades and inspect the outboard main rotor hinge for binding. chaffing at the 

outboard !lapping hinge bearings and condition of the attachment hardware. 

2. Inspect the main rotor lag damper for delamination, chaffing of the metal plates with the 

damper cage, and polish any grooves in the inside diameter of the damper cage smooth to stop 

inadvertent loss of damping action; and reassemble the damper and cage assembly. 

3. Inspect the damper attachment lugs (threaded portion) to ensure it is not hitting the trailing 

edge blade cross section and if so. grind the end slightly to ensure clearance when properly 

adjusted in accordance with the manufacturers rigging instructions. 

4. Weigh each main rotor blade (outboard) and compare static weights. If any blade is more 

than 2 ounces different, contact a service facility which can match balance the blades using the 

approved method. 

5. Once blades are match balanced, reinstall them and rig them in accordance with the 

manufacturer's maintenance manual. 

6. Dynamically balance the main rotor system using an ACES or Chadwick or similar system 

until the vibration is below .08 ips (it is possible with properly matched and rigged blade systems 

to achieve levels as low as 0.0 I ips from a hover to Vne). 

Repetitive Inspections: 

I. On a daily basis, perform a tap test in accordance with the original Brantly Maintenance 

Publications. checking for any evidence of delamination or the sk in to the foam core. 

2. At the Annua l Inspection for low utilization personal aircraft and at each 100 hour inspection 

for aircraft used in flight training or commercial operations of higher utilization. visually check the 

rivet areas at the leading edge spar and hinge block for defonnation and cracking. following the 

limits published in the original Brantly maintenance publications. 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

Special Inspections: After any overload event such as a "Quick Start" or "hard landing" or failure to 

bottom the collective below 250 rotor rpm. perform the following special inspections: 

I. Inspect main rotor centrifugal clutch area for dust and clean out with compressed air 

2. Check attachment of the clutch to the fonnsprag clutch component for distortion 

3. Check main rotor dampers, disassembling the damper from the cage and performing polishing if 

any wear is notices as a groove or detent. 

4. Inspect blades visually with at least lOX glass for cracking of the skin at the rivet locations at 

the leading edge spar or hinge root block 

5. If cracks are noticed wh ich are questionable after revievving the manufacturers maintenance 

publications, perform an eddy current inspection of these questioned areas. 

6. Inspect for any "overload" based stress wrinkles in the blade skins adjacent the hinge root block 

area of stress concentration and if limits exceed those in the manufacturers maintenance 

publications, remove the blade fi·om service until properly repaired by an FAA Approved Repair 

Station with authority to perform blade repairs or re-skinning in accordance with approved process 

specifications. 

Any findings should be reported in the FAA Service Difficulty Reporting System with full details and the 

manufacturer should be notified in writing with photographs of the damage round and results of the 

above inspections. 

How they justify it: The AD is premature. There hasn't been appropriate research or analysis to determine 

there is an unsafe condition; and the root cause is not clearly identified. Many defects cited as unsafe 

conditions in the NPRM are allowed per the original maintenance and overhaul manuals. The proposed 

changed practices/inspections to the SAIB will stop the blade skins t-J·om cracking or delaminating li·om the 

foam core due to random overload events and improper operation. Note: While we were still operating a 

flight school pulling over 200 hours per month on Brantly B2B's. we noticed that in the newly 

manuf.1ctured ones, the outboard hinge plates were not properly manulaclured as it relates to alignment of 

the attachment hardware supp011ing the flapping hinge bearings and blocks. This caused premature bearing 

wear. chaffing. and interference which resulted in vibrations not normal for a Brantly. I notitied the factory 

ofthe issue, with drawings and dimensions and photos ofthe premature wear at about 120 hours total time; 

and they reportedly found a problem and fixed it. 

FAA Response: We partially agree. We agree with allowing some imperfections (See Issue: Allow Some 

Imperfections). We disagree with issuing an SAIB because the FAA has data that supports that an unsafe 

condition exists and that it must be addressed with an AD. SAIBs only provide information and do not 

mandate the needed actions to correct the unsafe condition. We also disagree that the AD is premature 

because the FAA has adequate information to make its determinations. The root cause of the failures has 

been demonstrated by Brantly, the TC holder, with help !Tom a laboratory report written by a metallurgical 

engineering company. That report concluded that the M/R blades failure was caused by hydrocarbon 

contamination inside the blades skin-to-foam bond and that the rracture originated near the trailing edge. 

We disagree that Brantly's original maintenance and overhaul manuals adequately address the unsafe 

condition. (See Issue: Replace the AD). We also disagree with the following contents !Tom the proposed 

SAIB: 

1. On a one time basis for those helicopters where such an inspection has not been documented; remove the 

outboard blades and inspect the outboard main rotor hinge for binding, chaffing at the outboard flapping 

hinge bearings and condition of the attachment hardware. 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

2. Inspect the main rotor lag damper for delamination, chaffing of the metal plates with the damper cage, 

and polish any grooves in the inside diameter of the damper cage smooth to stop inadvertent loss of 

damping action; and reassemble the damper and cage assembly. 

3. Inspect the damper attachment lugs (threaded portion) to ensure it is not hitting the trailing edge blade 

cross section and if so, grind the end slightly to ensure clearance when properly adjusted in accordance 

with the manufacturers rigging instructions. 

4. Weigh each main rotor blade (outboard) and compare static weights. If any blade is more than 2 ounces 

different, contact a service facility which can match balance the blades using the approved method. 

5. Once blades are match balanced, reinstall them and rig them in accordance with the manufacturer's 

maintenance manual. 

6. Dynamically balance the main rotor system using an ACES or Chadwick or similar system until the 

vibration is below .08 ips (it is possible with properly matched and rigged blade systems to achieve levels 

as low as 0.01 ips from a hover to Vne). 

Repetitive Inspections: 

I. On a daily basis, perform a tap test in accordance with the original Brantly Maintenance Publications, 

checking for any evidence of delamination of the skin to the foam core. 

2. At the Annual Inspection for low utilization personal aircraft and at each I 00 hour inspection for aircraft 

used in flight training or commercial operations of higher utilization, visually check the rivet areas at the 

leading edge spar and hinge block for deformation and cracking, following the limits published in the 

original Brantly maintenance publications. 

Special Inspections: After any overload event such as a "Quick Start" or "hard landing" or failure to bottom 

the collective below 250 rotor rpm, perform the following special inspections: 

I. Inspect main rotor centrifugal clutch area for dust and clean out with compressed air 

2. Check attachment of the clutch to the fonnsprag clutch component for distortion 

3. Check main rotor dampers, disassembling the damper from the cage and performing polishing if any 

wear is notices as a groove or detent. 

4. Inspect blades visually with at least lOX glass for cracking of the skin at the rivet locations at the leading 

edge spar or hinge root block 

5. If cracks are noticed which are questionable after reviewing the manufacturers maintenance publications, 

perfonn an eddy current inspection of these questioned areas. 

6. Inspect for any "overload" based stress wrinkles in the blade skins adjacent the hinge root block area of 

stress concentration and if limits exceed those in the manufacturers maintenance publications, remove the 

blade from service until properly repaired by an FAA Approved Repair Station with authority to perform 

blade repairs or re-skinning in accordance with approved process specifications. 
Brantly M/R Blade AD, Docket No. FAA-2012-1093, Disposition of comments: 

Any findings should be reported in the FAA Service Difficulty Reporting System with full details and the 

manufacturer should be notified in writing with photographs of the damage found and results of the above 

inspections. 

We disagree with these proposed SAlB contents because no supporting data has been provided that shows 

that the proposed changed practices/inspections to the SAIB would stop the blade skins from cracking or 

delaminating from the foam core because of random overload events and improper operation. Also, no 

supporting data has been provided that showed that an improper manufactured or installed hinge block 

caused the unsafe condition. We also disagree with changing the inspections required in the AD as 

prescribed because the proposal eliminates the necessary eddy current inspection and reduces the I Ox 

magnifying glass inspection (See Issue: Reduce Inspection Requirements), and permits delamination that 

are too large, (See Issue: Allow Some Delamination), which is required to correct the unsafe condition.