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Here is my letter to FAA .
Please send in yours...postmarked by June 3rd... Monday !
FAA Central Region
Office Of The Regional Counsel
Attention: Rules Docket No. 2001-Ce-45-AD
901 Locust
Kansas City, Missouri 64106.</BLOCKQUOTE>
May 31, 2002
Dear Sir:
Subject: Comments on NPRM regarding Rules Document No. 2001-CE-45-AD,
applying to Univair Aircraft Corporation Alon A-2, etc.
I am an owner of an Ercoupe. I am concerned the proposed AD on center
Section spar corrosion has really gotten out of hand. I believe it is
improperly structured and is detrimental to the ultimate safety of
Ercoupes, instead of making them safe, as is the responsibility of the
FAA.
As owners of Ercoupes, we are all concerned about safety in our old
airplanes, and vigourously inspect the airplane inside and out every time
we fly, and even more thoroughly annually. If there is a structural
problem due to the design of the Ercoupe, It should be fixed, for sure.
BUT, if this is an isolated problem, then the issueing of an AD is not in
order.
I am concerned that Univair has never issued a Service Bulletin, even tho
FAA refers to this supposed Service Bulletin on this issue. I am also
concerned that the proposed SB31 seems to not have been engineered
properly and according to FAA regulations. ( See Comments below by Mr
Turner, previously an FAA DER.).
It appears that someone is rushing the issue on this potential problem and
subjecting the owners of Ercoupes to incur considerable cost to comply
with a non-existant SB, now proposed to be an AD.
The inspection of the center section rear spar can easily be accomplished
by the removal of the wings, and the use of a light and mirror. ( See Mr.
John Wright' comments below.) Mr Wright is recognized as the Ercoupe
expert throughout the world, and is an FAA liscensed AI, with over 30
years experience. He and his son restore Ercoupes throughout the year. Mr.
Wright has educated Ercoupe owners as to the potential problems on all
aluminum airplanes, including Ercoupes and their special problems. His
recomendation of wing removal and 5 year inspection period seems overly
cautious to me.
Aluminum is used in aircraft because of its inherent nature of forming a
passivity coating on its surface, preventing continued corrosion. It is
true that intergranular corrosion is a hidden potential problem. However
this does not occur suddenly, like a light bulb failing. It too occurs
over a long time period.
I strongly recommend the FAA addopt Mr. Wright's suggestion as to wing
removal and 5 year inspection periods as a very conservative and safe
alternative to Univair's proposed Service Bulletin 31.
I urge you to re-consider the implication of un-needed inspections on
airframes that in fact have withstood the test of time, and issue a
revised proposal directing the wing removal option and 5 year inspection
period.
As pilots and mechanics, we all want safe airplanes. If there is a
dangerous condition that exists, then the safe option is the one to
choose. But the safe option , in this case, surely points to a better
proceedure than one that adds more holes in the center section skin;
weakening the structure in an attempt to inspect for potential structural
damage. I am advised that with the proposed SB 31, even with holes and TV
cameras, one still cannot properly inspect every corner.
BUT, with the wing removal proceedure, one can easily inspect every inch
of the structure.
This done, without cutting more holes in the center section skin. I am
concerned that the proposed hole cutting does in fact weaken the structure
to the point the airplane fuselage is no longer structurally safe, with
the required margin of safety as required by FAA regulations. (see
comments below by Mr. Turner).
I again urge you to reconsider the AD proposal, and if an AD is in fact
required to keep our airplanes safe, then take the Mr. John Wright option
: Wing removal for inspection, with a 5 year interval. It does seem the
most conservative, least costly, maintains the structural integrity and
strength of the airframe, and is easily done without requiring the very
expensive hi-tech scope equipment as proposed in the proposed AD and
proposed SB 31.
I recognize your responsibility is to insure we have a safe airplane,
meeting the design and safety requirements of the FAA regulations. I think
if you do investigate closely, you will find the Ercoupe is one of the
safest airplanes ever built, and has a center section stronger than a
Bonanza.
I do not believe you can verify proper engineering has been accomplished
and verified, in the proposed SB 31 and resulting Proposed AD. It behooves
the FAA to take another look at the potential (possibly limited) problem
with center section spar corrosion on Ercoupes;and if the FAA finds there
really is a design/structural problem, adopt a reasonable solution as
proposed by Mr. John Wright and others. The simple solution is very often
the best solution.
As I was a previous instructor of aircraft mechanics in the USAF, I feel
somewhat qualified to evaluate this situation and the proposed SB 31 and
AD. It seems that the process has been rushed and proposed decisions made
without the proper engineering study and without input from the type
clubs, and owners. Input from experienced Ercoupe mechanics and Certified
AIs is especially important in evaluating these issues. I urge you to
re-consider the proposed SB31, and Proposed AD to include the suggestions
made by Mr. Wright and Mr. Turner - both very well qualified to comment on
this issue. Please see attachments below.
Sincerely,
Harry L. Francis
2851 sarver Road
Ellsiton, VA. 24087
540-268-2307
e-mail [EMAIL PROTECTED]
Ercoupe S/N 853
N93530
Attachments:
*Turner
*Wright
Turner Aircraft, Inc./Cavu Publishing Co.
P.O. Box 74
Cleburne, Texas 76033-0074
Phone: (817) 556-3535
Fax: (817) [EMAIL PROTECTED]
April 24, 2002
FAA Central Region
Office of the Regional Counsel
Attention: Rules Docket No. 2001-CE-45-AD
901 Locus, Room 506
Kansas City, MO 64106
Subject: Comments on NPRM regarding Rules Document No. 2001-CE-45-AD,
applying to Univair Aircraft Corporation Alon A-2, etc.
To Whom It May Concern:
I have reviewed the Rules Document No. 2001-CE-45-AD, as published in the
Federal Register, Volume 67, No. 64, dated April 3, 2002, and offer the
following comments and/or questions for your consideration:
1. The proposal states that compliance must be done in accordance
with procedures contained in Univair’s Service Bulletin No. 31. On April
23, 2002 I telephoned Univair to obtain a copy of the service bulletin.
The Univair representative told me that the FAA had not approved the
service bulletin, and that they (Univair) did not know what the FAA was
doing. Now the question: How does the FAA expect anyone to intelligently
comment on this proposed rule change without knowing what the service
bulletin contains?
2. Based on the copy of the Service Bulletin No. 31, dated July 24,
2000, published by the Ercoupe Owners Club (EOC) in “Coupe
Capers”, dated November 2001, I submit the following comments:
A. Drawing No. SB-31, dated 04-09-00, does not contain adequate
information, as required by the Code of Federal Regulations, (CFR) Part
21.31(b), and Part 45.14 i.e. Type of material and specification,
thickness of material, dimensional tolerances, finish specification, and
marking of parts are not called out.
B. Based on the dimension shown, and assuming the airplane’s bottom
fuselage skins are only 0.020 inches thick and the material is 2024T-3
aluminum allow, a simplified stress analysis shows that the reinforcement
rings and attaching rivets have negative Margins of Safety (MS). Using
the lost material theory, since the actual airplane design loads are not
available, the analysis is;
Cutout (lost material): 4.0 x 0.020 = 0.080 inches squared (4.0
in. diameter cutout)
Width of reinforcement ring: 1.0 in. Material width added: 2.0 in.
Area of material added: 0.020 x 2 = 0.040 sq. in
Not considering the type of material used, one can see that only
50% of the area of the cutout area has been replaced.
MS = 2/4 – 1 = 0.5 – 1 = Negative 0.5 x 100 = -50%. This Margin
applies regardless of the thickness of materials used.
In addition: The allowable load that a 4.0 in strip, 0.020 in thick, of
2024T-3 can carry is:
0.080 x 53,000 psi (Ref. Mil-Hnbk 5-e) = 4200 lbs. The allowable of
seven MS2047AD-3 rivets = 7 x 207 (Ref. Airplane Structures by Niles &
Newell, Vol. 1, Table 11:1, page 362) = 1449 lbs.
MS = 1449/4200 – 1= Negative 0.66 x 100 = -66%.
Unless the service bulletin has been changed lately, it is structurally
inadequate and does not comply with the FAA certification regulations.
Incidentally, I submitted the similar information to FAA Engineer Roger
Caldwell, in Denver, after he sent the FAA Airworthiness Concern Sheet,
dated October 25,2001, to the EOC. I did not receive any acknowledgment.
When Univair Service Bulletin No. 31 is approved by the FAA and
distributed by Univair, I will continue my review of it and will submit
comments as appropriate.
Sincerely,
[signed]
Eugene L. Turner
President and Chief Engineer
Alon A-2 Owner
John Wright's comments
24 April 2002
Dear Sir:
I would like to comment on docket no. 2001-CE-45-AD. This docket proposes
to adopt a new airworthiness directive to apply to all Univair aircraft,
Alon A2 & A2-A, ERCO 415-C, 415-CD, 415-D thru E & Forney F-1 & Fl-A &
Mooney M-l0.
The airplane AD would require you to repetitively inspect the wing center
section by cutting holes in the bottom side of the wing-walk area or by
the use of a borescope or endoscope that meets specified criteria. My
question is, “What constitutes specified criteria?” Also, most mechanics
do not have a borescope.
To begin with you cannot see the entire area of the center section with
the wings on. The area on the center spar behind the wing tank cannot be
inspected & this is where we are finding the most corrosion. My son & I
have been working on Coupes for several years & have found the following
Coupes to have corrosion in the center section:
N2051H had a 4" piece of the lower spar cap missing
N94827 had severe corrosion on the lower spar cap
N2428h had corroded lower skins
N2485h had corroded lower skins
N93530 had corroded skins
N3322h had corroded skins
N294TH had a top spar extremely corroded (we did not repair this aircraft)
If you would like you can come to Springfield, IL & look at these parts as
we have most
of them.
My proposal is this:
Pull the wings off so you can inspect the center section. If corrosion is
found repair it. If no corrosion is found have the I/A enter it in the
airframe log book that the inspection was performed & it will become due
in 5 years from date of inspection.
In my experience if it has no corrosion it would take at least 5 years for
corrosion to occur. The cost would be about 4 or 5 hours of labor to pull
wings off inspect & put the wings back on.
Sincerely yours,
[SIGNED]
John A. Wright, Sr.
IA333262328
958 Flossmoor, RR#6
Springfield, IL 62707
phone 217-546-0585
XXX
Copy: Skip Carden, EOC
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