Here's the complete text
of the notice in the Fed. Register:
DEPARTMENT OF
TRANSPORTATION
Federal Aviation
Administration
14 CFR
Part 39
[Docket No. 97-CE-79-AD]
RIN
2120-AA64
Airworthiness Directives; American Champion
Aircraft
Corporation
7, 8,
and 11 Series Airplanes
AGENCY:
Federal Aviation Administration, DOT.
ACTION: Notice
of
proposed rulemaking
(NPRM).
----------------------------------------------------------
-------------
SUMMARY:
This document proposes to adopt a new airworthiness directive
(AD)
that would
apply to American Champion Aircraft Corporation (ACAC)
7, 8, and 11
series
airplanes, excluding Model 8GCBC airplanes. The
Federal
Aviation
Administration (FAA) previously proposed similar AD
action for
the ACAC
Model 8GCBC airplanes. The proposed AD would
require installing
inspection holes on the top and bottom wing surfaces,
repetitively
inspecting
the front and rear wood spars for damage,
repairing or replacing any
damaged
wood spar, and installing
inspection
covers. Damage is defined as
cracks;
compression cracks; longitudinal
cracks through the bolt holes or
nail holes;
or loose or missing rib
nails. The proposed AD results from a
review of
the service history of
the affected airplanes that incorporate wood
wing
spars. The review was
prompted by in-flight wing structural failures
on ACAC
Model 8GCBC
airplanes, and revealed several incidents where damage
was found
on the
front and rear wood spars on the affected airplanes. The
actions
specified by the proposed AD are intended to prevent
possible
compression cracks and other damage in the wood spar wing,
which, if
not
detected and corrected, could eventually result in in-flight
structural
failure of the wing with consequent loss of the
airplane.
DATES: Comments must be received on or before January
8,
1998.
ADDRESSES: Submit comments in triplicate to the
Federal
Aviation
Administration (FAA), Central Region, Office of the Regional
Counsel,
Attention: Rules Docket No. 97-CE-79-AD, Room 1558, 601 E.
12th
Street,
Kansas City, Missouri 64106. Comments may be inspected at
this
location
between 8 a.m. and 4 p.m., Monday through Friday, holidays
excepted.
Service information that applies to the proposed
AD may
be obtained
from American Champion Aircraft Corporation, P.O. Box 37,
32032
Washington Avenue, Highway D, Rochester, Wisconsin 53167.
This
information also may be examined at the Rules Docket at the
address
above.
FOR FURTHER INFORMATION CONTACT: Mr. William
Rohder,
Aerospace Engineer,
FAA, Chicago Aircraft Certification Office, 2300
E. Devon
Avenue, Des
Plaines, Illinois 60018; telephone (847) 294-7697;
facsimile
(847)
294-7834.
SUPPLEMENTARY INFORMATION:
Comments
Invited
Interested persons are invited to
participate
in the making of the
proposed rule by submitting such written data,
views, or
arguments as
they may desire. Communications should identify
the Rules
Docket number
and be submitted in triplicate to the address specified
above.
All
communications received on or before the closing date for
comments,
specified above, will be considered before taking action on
the
proposed
rule. The proposals contained in this notice may be changed
in light
of
the comments received.
Comments are
specifically
invited on the
overall regulatory, economic, environmental, and
energy
aspects of the
proposed rule. All comments submitted will be
available, both
before and
after the closing date for comments, in the Rules Docket
for
examination
by interested persons. A report that summarizes each
FAA-public
contact
concerned with the substance of this proposal will be filed
in the
Rules
Docket.
Commenters wishing the FAA to acknowledge
receipt of
their
comments submitted in response to this notice must submit
a
self-addressed, stamped postcard on which the following statement
is
made: ``Comments to Docket No. 97-CE-79-AD.'' The postcard will be
date
stamped and returned to the commenter.
Availability of
NPRMs
Any person may obtain a copy of this
NPRM by
submitting a request to
the FAA, Central Region, Office of the
Regional
Counsel, Attention:
Rules Docket No. 97-CE-79-AD, Room 1558, 601 E.
12th
Street, Kansas
City, Missouri
64106.
Discussion
AD 87-18-09,
Amendment
39-5725, currently requires inspecting
(one-time) the sides of the
front and
rear wood spars for compression
cracks on ACAC Model 8GCBC airplanes,
repairing or replacing any wood
spar with compression cracks, and
re-inspecting immediately after any
incident involving wing damage.
AD
87-18-09 was the result of three
accidents involving ACAC Model 8GCBC
airplanes where structural damage
to the wing caused by compression
cracks in
a wood spar was considered
to be a primary factor of the
accidents.
Wood compression cracks are
failures
of wood
fibers on a plane perpendicular to the wood fiber
longitudinal axis.
Repetitive high stress can initiate these compression
cracks on the
top
surface of the wing spar that is adjacent to doubler
plate glue lines
and rib
nail holes. These high stress conditions can
occur during crop
dusting,
banner and glider tow operations, turbulence,
and rough field or
float
operations. Compression cracks can also
initiate if the wing contacts
the
ground. Compression cracks can
initiate at either the top or bottom
surface
of the spar depending on
the loads (either upward or downward) at
impact.
In-flight
structural failure of the
wing
recently occurred on an ACAC Model 8GCBC
airplane that was initially
inspected as required by AD 87-18-09. A
possible contributing factor
of this
incident was an undetected
compression crack on the right wing front
spar.
Investigation of
this accident and data
acquired
from inspections of several ACAC Model
8GCBC airplanes indicate that
wood
spar compression cracks can occur
without previous wing damage. The
data
indicates that detection of
compression crack initiation is unlikely
on the
sides of the spar,
unless the crack is in an advanced state of
propagation.
Based on this
data, the FAA believes that repetitive inspections are
necessary. The
FAA recently issued an NPRM on the Model 8GCBC
airplanes that
was
published in the Federal Register on September 26, 1997 (62
FR
50527).
This NPRM proposes to supersede AD 87-18-09, and, if issued
as a
final
rule, would require similar action to that proposed in
this
document.
Reasons for the Proposed
AD
The
above-referenced incidents on the ACAC Model 8GCBC airplanes
prompted
the FAA
to review the service history of the other ACAC 8
series airplanes,
as well
as the 7 and 11 series airplanes. The FAA has
record of eight reports
of
accidents (five fatal) on ACAC 7 and 8 series
airplanes, other than
the Model
8GCBC airplanes. Four of these accidents
are attributed to
overstress, two to
wing failure due to previous damage
going undetected, one to an
overload
condition with evidence of wing
panel failure prior to impact, and
one spar
with an out-of-specification
wood spar grain slope. This review
revealed 16
reports of spar crack
damage (spar butt end and/or longitudinal
cracks), 6
reports of
compression cracked spars, and 13 reports of loose/missing
rib
nails.
These reports break down as follows:
--Model 7AC (2,626
U.S.
registered airplanes): 12 reports of spar crack
damage, plus 2
reports of
loose/missing rib nails;
--Model 7BCM (253 U.S. registered
airplanes): 1
report of spar crack
damage;
--Model 7ECA (871 U.S. registered
airplanes): 1 report of a compression
cracked spar, plus 6
reports of
loose/missing rib nails;
--Model 7GCBC (829 U.S. registered
airplanes): 1
report of a
compression
cracked spar;
--Model 7KCAB (482 U.S.
registered airplanes): 2 reports of spar crack
damage, 2 reports
of
compression cracked spars, and 3 reports of
loose/
missing rib
nails;
and
--Model 8KCAB (480 U.S. registered airplanes): 1 report of spar
crack
damage, 2 reports of compression cracked spars, and 2
reports
of
loose/
missing rib nails.
The FAA
believes
that many cracked/damaged spars are not reported
because
general
aviation operators (operating in accordance with part
91 of the
Federal
Aviation Regulations (14 CFR part 91)) are not
required to submit
service
difficulty reports.
Relevant Service
Information
The FAA has reviewed and approved
the
technical contents of ACAC
Service Letter 406, dated March 28, 1994,
and ACAC
Service Letter 417,
Revision A, dated October 2, 1997. ACAC Service
Letter
406, dated March
28, 1994, includes procedures for conducting a
detailed
visual
inspection of both the front and rear wood wing spars for
cracks;
compression cracks; longitudinal cracks through the bolt
holes or
nail
holes; and loose or missing rib nails (referred to as damage
hereafter).
ACAC Service Letter 417, Revision A, dated October 2,
1997,
includes
procedures for installing inspection holes and surface
covers
and
assuring that all applicable lower surface drain holes are
installed.
The FAA's Determination
After
examining the circumstances and reviewing all available
information
related
to the incidents and accidents described above,
including the
referenced
service information, the FAA has determined
that (1) the wing design
of all
7, 8, and 11 series airplanes equipped
with wood spars is similar and
is
conducive to spar cracks/damage; and
(2) AD action should be taken to
prevent
possible compression cracks and
other damage in the wood spar wing,
which, if
not detected and
corrected, could eventually result in in-flight
structural
failure of
the wing with consequent loss of the
airplane.
Explanation
of the Provisions of the Proposed AD
Since an
unsafe condition has been identified that is likely to exist
or
develop in
other ACAC 7, 8, and 11 series airplanes (excluding the
Model 8GCBC
airplanes) of the same type design, the FAA is proposing AD
action.
The
proposed AD would require installing inspection holes on
the top and
bottom
wing surfaces, repetitively inspecting the front and
rear wood spars
for
damage, repairing or replacing any damaged wood
spar, and installing
surface
covers. Accomplishment of the proposed
actions would be as
follows:
--Installations: in accordance with ACAC Service Letter
417,
Revision
A, dated October 2, 1997;
--Inspections: in accordance
with ACAC
Service Letter 406, dated March
28, 1994; and
--Spar Repair and
Replacement, as applicable: in accordance with Advisory
Circular (AC)
43-13-1A, Acceptable Methods, Techniques and Practices; or
other data
that
the FAA has approved for spar repair and replacement.
Differences
Between
This Proposed AD and ACAC Service Letter
406
ACAC Service Letter 406, dated March 28, 1994, specifies the
same
inspections
as are proposed in this notice of proposed
rulemaking
(NPRM). The
differences between the service letter and NPRM are:
--the
service
letter
specifies the proposed action within the next 30 days or
10
flight
hours and at each 100 hour/annual inspection thereafter. The
FAA has
determined that a more realistic and enforceable compliance
time
would be to
require:
1. The proposed initial
inspection at
the first annual
inspection that occurs 3 calendar months or more
after the
effective date
of the AD or within 15 calendar months after the
effective
date of the
AD, whichever occurs first; and
2.
The proposed repetitive inspections thereafter at intervals
not
to
exceed 12 calendar months or 500 hours time-in-service
(TIS),
whichever
occurs first;
and
--the service letter applies to all ACAC 7
and 8
series airplanes,
whereas the NPRM applies to ACAC 7, 8, and 11
series
airplanes with
similar design, except for the Model 8GCBC airplanes.
The FAA
previously
proposed similar AD action for the ACAC Model 8GCBC
airplanes,
Docket
No. 97-CE-33-AD (62 FR 50527, September 26,
1997).
Compliance
Time of the Proposed AD
The compliance
time of
the proposed AD is presented in calendar time
and hours TIS.
Although
the unsafe condition specified in the proposed
AD is a result
of
airplane operation, operators of the affected
airplanes utilize their
airplanes in different ways.
For example,
an
operator
may utilize his/her airplane 50 hours TIS in a year while
utilizing
the
aircraft in no or very little crop dusting operations,
banner and
glider tow
operations, or rough field or float operations.
This airplane would
obviously
have a lower crack propagation rate than
an airplane operated 300
hours TIS a
year in frequent crop dusting
operations, banner and glider tow
operations,
or rough field or float
operations. However, this airplane could have
pre-existing and
undetected wood spar damage that occurred during
previous
operations. In
this situation, the damage to the wood spar would
propagate at
a level
that depends on the operational exposure of the airplane and
severity
of
the initial wood spar damage.
To assure that
compression cracks do
not go undetected in the wood spars of the
affected
airplanes, the FAA
has determined that the following compliance times
should
be used:
1. The proposed initial
inspection at
the first annual inspection
that occurs 3 calendar months or more
after the
effective date of the AD
or within 15 calendar months after the
effective
date of the AD,
whichever occurs first; and
2.
The proposed repetitive inspections thereafter at intervals
not
to
exceed 12 calendar months or 500 hours TIS, whichever occurs
first.
Cost
Impact
The FAA estimates that 6,440 airplanes
in the
U.S. registry would be
affected by the proposed AD, that it
would take
approximately 6
workhours (Installations: 5 workhours; Initial
Inspection: 1
workhour)
per airplane to accomplish the proposed action, and
that the
average
labor rate is approximately $60 an hour. Parts cost
approximately
$292
per airplane, provided that each airplane would only need 11
additional
standard inspection hole covers per wing bottom surface
(total of
22 new
covers per airplane). If the airplane would require the
installation
of
more inspection covers (i.e., a result of previous non-factory
wing
recover work), the cost could be slightly higher. Based on
these
figures, the total cost impact of the proposed AD on U.S
operators is
estimated to be $4,198,880 or $652 per
airplane.
This cost figure is
based on the
presumption
that no affected airplane owner/operator has
accomplished the
installations
or the initial inspection. The FAA has no
knowledge of any
owner/operator of
the affected airplanes that has
already accomplished the
installations and
initial inspection.
This
cost figure also does
not
account for repetitive inspections. The FAA
has no way of
determining
the number of repetitive inspections each
owner/operator of the
affected
airplanes will incur over the life of
his/her airplane. However,
each
proposed repetitive inspection would
cost substantially less than the
initial
inspection because of the cost
of the initial proposed
inspection hole
and cover installations would
not be repetitive. The inspection
covers allow
easy access for the
inspection of the wood spars, and the
proposed
compliance time would
enable the owners/operators of the affected
airplanes
to accomplish the
repetitive inspections at regularly scheduled
annual
inspections.
Regulatory Impact
The
regulations proposed herein would not have substantial
direct
effects
on the States, on the relationship between the national
government
and the
States, or on the distribution of power and
responsibilities among
the
various levels of government. Therefore, in
accordance with Executive
Order
12612, it is determined that this
proposal would not have sufficient
federalism implications to warrant
the preparation of a Federalism
Assessment.
For the reasons discussed
above, I
certify
that this action (1) is not a "significant regulatory
action''
under
Executive Order 12866; (2) is not a ``significant rule''
under DOT
Regulatory
Policies and Procedures (44 FR 11034, February 26,
1979); and (3) if
promulgated, will not have a significant economic
impact, positive or
negative, on a substantial number of small entities
under the
criteria of the
Regulatory Flexibility Act. A copy of the
draft regulatory evaluation
prepared for this action has been placed in
the Rules Docket. A copy
of it
may be obtained by contacting the Rules
Docket at the location
provided under
the caption ADDRESSES.
List of Subjects in 14 CFR Part
39
Air transportation, Aircraft,
Aviation
safety, Safety.
The Proposed
Amendment
Accordingly, pursuant to the authority delegated to me by
the
Administrator,
the Federal Aviation Administration proposes to
amend
14
CFR part 39 of the Federal Aviation Regulations as
follows:
PART 39--AIRWORTHINESS
DIRECTIVES
1.
The authority citation for part 39 continues to read as
follows:
Authority: 49 U.S.C. 106(g), 40113,
44701.
[[Page 59313]]
Sec. 39.13
[Amended]
2. Section 39.13 is amended by
adding a new
airworthiness directive
(AD) to read as follows:
American
Champion
Aircraft Company: Docket No. 97-CE-79-AD.
Applicability: The following airplane models, all serial
numbers,
certificated in any category, that are equipped with wood
wing
spars:
7AC
7BCM
(L-16A)
7DC
S7EC
7GC
7GCB
7HC
7KCAB
S11AC
7ACA
7CCM
(L-16B)
S7DC
7ECA
7GCA
7GCBA
7JC
8KCAB
11BC
S7AC<
BR>S7CCM
7EC
7FC
7GCAA
7GCBC
7KC
11AC
S11BC
&
nbsp;
Note 1: This AD applies to each airplane identified in the
preceding
applicability provision, regardless of whether it has been
modified,
altered, repaired, or reconfigured in the area subject to
the
requirements of this AD. For airplanes that have been modified,
altered,
repaired, or reconfigured so that the performance of the
requirements of
this AD is affected, the owner/operator must request
approval
for an
alternative method of compliance in accordance with paragraph
(e)
of
this AD. The request should include an assessment of the effect of
the
modification, alteration, or repair on the unsafe condition
addressed
by
this AD; and, if the unsafe condition has not been eliminated,
the
request should include specific proposed actions to address
it.
Compliance: Required as indicated in the
body of
this AD, unless
already accomplished.
To
prevent
possible compression cracks and
other damage in the wood spar wing,
which, if
not detected and
corrected, could eventually result in in-flight
structural
failure of
the wing with consequent loss of the airplane, accomplish
the
following:
(a) At the first annual
inspection that
occurs 3 calendar
months or more after the effective date of this AD
or
within the next 15
calendar months after the effective date of this
AD,
whichever occurs
first, accomplish the
following:
(1)
Install inspection holes in the
top and bottom surface of each wing
in
accordance with American Champion
Aircraft Corporation (ACAC) Service
Letter
417, Revision A, dated
October 2, 1997. Assure that all drainage
holes are
installed as
depicted in this service letter, and install drainage
holes
as
necessary.
(2) Inspect (detailed visual)
both the
front and rear
wood wing spars for cracks; compression cracks;
longitudinal
cracks
through the bolt holes or nail holes; and loose or missing rib
nails
(referred to as damage hereafter). Accomplish these inspections
in
accordance with ACAC Service Letter 406, dated March 28,
1994.
(3)
If any spar damage is found, prior to
further
flight, accomplish the
following:
(i) Repair or
replace
the wood wing spar in accordance
with Advisory Circular (AC)
43-13-1A,
Acceptable Methods, Techniques and
Practices; or other data that is
approved
by the FAA for wing spar
repair or replacement.
(ii) If
the wing is recovered, accomplish the
installations required by
paragraph
(a)(1) of this AD, as applicable.
(4) Install inspection hole
covers on
the top and bottom surface of the
wing in accordance with ACAC
Service Letter
417, Revision A, dated
October 2, 1997.
(b)
Within 12
calendar months or 500 hours TIS
(whichever occurs first) after
accomplishing
all actions required by
paragraph (a) of this AD, and thereafter at
intervals
not to exceed 12
calendar months or 500 hours TIS, whichever occurs
first,
accomplish the
inspection, repair, replacement, and installation
required by
paragraphs
(a)(2), (a)(3), as applicable; including its
subparagraphs; and
(a)(4)
of this
AD.
(c) If, after the
effective date
of this AD, any of the affected
airplanes are involved in an
incident/accident that involves wing
contact damage (e.g., surface
deformations such as abrasions, gouges,
scratches, or dents, etc.),
prior to
further flight after that
incident/accident, accomplish the
inspection,
repair, replacement, and
installation required by paragraphs (a)(2),
(a)(3),
as applicable;
including its subparagraphs; and (a)(4) of this
AD.
(d) Special
flight permits may be issued in
accordance with sections 21.197 and
21.199 of the Federal
Aviation Regulations (14 CFR 21.197 and 21.199)
to operate the
airplane to a
location where the requirements of this AD
can be
accomplished.
(e) An alternative method of
compliance
or
adjustment of the initial or repetitive compliance time that
provides
an
equivalent level of safety may be approved by the Manager,
Chicago
Aircraft Certification Office (ACO), 2300 E. Devon Avenue,
Des
Plaines,
Illinois 60018. The request shall be forwarded through an
appropriate
FAA Maintenance Inspector, who may add comments and then
send it
to the
Manager, Chicago ACO.
Note 2:
Information
concerning the existence of approved alternative
methods of
compliance with
this AD, if any, may be obtained from the
Chicago
ACO.
(f) All persons affected by this
directive may
obtain copies of the
documents referred to herein upon request to
American
Champion Aircraft
Corporation, P.O. Box 37, 32032 Washington Avenue,
Highway
D, Rochester,
Wisconsin 53167; or may examine these documents at the
FAA,
Central
Region, Office of the Regional Counsel, Room 1558, 601 E.
12th
Street,
Kansas City, Missouri 64106.
Issued in
Kansas
City, Missouri, on
October 27, 1997. Mary Ellen A. Schutt,
Acting
Manager, Small Airplane
Directorate, Aircraft Certification
Service.
[FR
Doc. 97-28984 Filed
10-31-97; 8:45 am]
Sincerely,
H.G.
Frautschy
Editor, Vintage Airplane
Associate Editor, Sport
Aviation