Here's My shot!
Posted: Wed Oct 24, 2012 4:33 pm
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
Page 2
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
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
Page 2
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