[Federal Register Volume 64, Number 107 (Friday, June 4, 1999)]
[Proposed Rules]
[Pages 29969-29972]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-14130]


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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 (FAA), DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: This document withdraws a notice of proposed rulemaking (NPRM) 
that would have applied to all American Champion Aircraft Corporation 
(ACAC) 7, 8, and 11 series airplanes, excluding Model 8GCBC airplanes. 
The proposed AD would have required 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 FAA received comments on the NPRM that 
recommended alternative methods of complying with the proposed AD and 
recommended combining the proposed AD with the actions of the current 
AD required for the ACAC Model 8GCBC airplanes. The FAA has determined 
that the ideas in the above-referenced comments have merit and should 
be implemented, and is therefore withdrawing the NPRM and proposing 
these actions in a new AD that would supersede the current AD required 
for ACAC Model 8GCBC airplanes.

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:

Events Leading to This Action

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to include an AD that would apply to all ACAC 7, 8, and 11 
series airplanes (excluding the Model 8GCBC airplanes) was published in 
the Federal Register as a notice of proposed rulemaking (NPRM) on 
November 3, 1997 (62 FR 59310). The NPRM proposed to 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 as specified in the NPRM would 
be required 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.

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Comment Issue No. 1: Combine the Actions of the Proposed AD With 
Those of AD 98-05-04

    Two commenters recommend that the FAA combine the actions of the 
proposed AD with those currently required by AD 98-05-04, which applies 
to the Model 8GCBC airplanes. These commenters feel that this would

[[Page 29970]]

provide a successful and consistent inspection program for all 
airplanes in the production line.
    The FAA concurs that combining the actions of the proposed AD and 
AD 98-05-04 would provide a consistent inspection program for all ACAC 
airplanes in the production line. As discussed in this document, the 
FAA is withdrawing the NPRM (Docket No. 97-CE-79-AD) and will propose 
to supersede AD 98-05-04 with a new AD (will be initiated as an NPRM) 
that would affect all 7, 8, and 11 series airplanes and incorporate 
recommended alternative methods for complying with the actions.

Comment Issue No. 2: Allow an Alternative Spar Inspection Method

    Three commenters state that inspecting the spar through the 
utilization of inspection holes on the bottom of the spar using mirrors 
and a small high intensity light source is an effective method of 
inspection. The commenters believe that allowing this inspection method 
will save the owners thousands of dollars in inspection costs. Also, 
because the additional inspection covers would not be needed, the 
aesthetics of the aircraft would be preserved.
    The FAA concurs that inspecting the spar through the utilization of 
inspection holes in the bottom of the spar using mirrors and a small 
high intensity light is a valid inspection method provided an inspector 
with wood spar compression failure experience accomplishes the 
inspection. For example, the inspection method was useful in detecting 
spar failure on one of the commenter's airplanes, and a member of the 
FAA's Chicago Aircraft Certification Office staff detected a 
compression failure in the rear spar of a Model 7AC airplane using this 
method.
    ACAC has incorporated procedures to accomplish this inspection 
method into Service Letter 406, Revision A, dated May 6, 1998, and the 
FAA has approved this inspection method as an alternative method of 
compliance to AD 98-05-04, which applies to the Model 8GCBC airplanes. 
The owners of the Model 8GCBC have been informed of this inspection 
alternative through a special airworthiness information bulletin 
(SAIB).
    As discussed in this document, the FAA is withdrawing the NPRM 
(Docket No. 97-CE-79-AD) and will propose to supersede AD 98-05-04 with 
a new AD (will be initiated as an NPRM) that would affect all 7, 8, and 
11 series airplanes and incorporate recommended alternative methods for 
complying with the actions. The FAA will incorporate the inspection 
method discussed above into the combined proposed AD.

Comment Issue No. 3: Exclude Certain Airplanes From the Proposed AD

    Numerous commenters request that the FAA exclude certain airplanes, 
such as the Model 7AC. The commenters state that the light-weight and 
low-horsepower airplanes manufactured by Aeronca and Champion Aircraft 
are not certificated for aerobatic flight and induce lower stresses in 
the spars. The commenters feel there is no justification for including 
them in this AD action.
    The FAA does not concur that these light-weight and low-horsepower 
airplanes should be removed from the proposed AD. Section 39.1 of the 
Federal Aviation Regulations (14 CFR 39.1) specifies that the FAA 
should issue an airworthiness directive against aircraft of the same 
type design where the unsafe condition exists or is likely to develop. 
Since there have been compression failures and spar damage reports on 
the light-weight and low-horsepower airplane models (i.e., Model 7AC), 
the AD should address these models.
    No changes have been made to the AD as a result of these comments. 
However, as discussed in this document, the proposal is being withdrawn 
and the actions revised and combined with the actions of the current AD 
required for the ACAC Model 8GCBC airplanes.

Comment Issue No. 4: The Proposed AD Should Only Apply to Airplanes 
With Previous Wing Damage or Evidence of Compression Failures

    Several commenters request that the proposed AD only apply to those 
airplanes that have a history of wing damage. The commenters state that 
spar compression failures and spar damage are a direct result of the 
airplane flipping, ground looping, or other similar type of activity 
that causes wing damage.
    The FAA does not concur that the proposed AD should only apply to 
those airplanes that have a history of wing damage. The FAA agrees that 
incidents involving wing damage are a major cause of compression 
failures and other spar damage; however, the FAA has received reports 
of compression failures in airplanes without previous wing damage.
    However, to better understand all causes of spar damage of the 
affected airplanes, the FAA has determined that all findings of 
aircraft wing damage should be submitted on a Malfunction or Defect 
Report (M or D), FAA Form 8010-4, describing the damage and a copy of 
the report sent to the Chicago Aircraft Certification Office. The FAA 
could then initiate further rulemaking action that increases or reduces 
the burden upon the owners/operators of the ACAC 7, 8, and 11 series 
airplanes, as justified.
    As discussed in this document, the FAA is withdrawing the NPRM 
(Docket No. 97-CE-79-AD) and will propose to supersede AD 98-05-04 with 
a new AD (will be initiated as an NPRM) that would affect all 7, 8, and 
11 series airplanes and incorporate recommended alternative methods for 
complying with the actions. The FAA will incorporate this reporting 
requirement into the combined proposed AD.

Comment Issue No. 5: The Proposed AD Should Not Apply to the 7 and 
11 Series Airplanes

    One commenter objects to an AD against the ACAC 7 and 11 series 
airplanes because the market value of these airplanes will decrease by 
several thousand dollars. The commenter believes that simply mailing 
the manufacturer's service instructions to the owners of the 7 and 11 
series airplanes will result in the desired effect.
    The FAA does not concur. The FAA's duty to public safety must 
outweigh considerations of an aircraft's market value. The FAA has 
worked with associations and type clubs that are interested in the 
safety and market value of these airplanes in order to decrease the 
economic impact of the proposed AD's inspection requirements. Service 
history of all models of the ACAC 7, 8, and 11 series airplanes reveals 
susceptibility to wing spar cracking and compression failures. The FAA 
has no reason to believe that compliance will be guaranteed on a 
voluntary basis alone.
    No changes have been made to the proposed AD as a result of these 
comments.

Comment Issue No. 6: The Proposed AD Should Not Address Loose and 
Missing Nails

    Four commenters feel that the proposed AD should not include 
procedures for inspecting for and replacing loose or missing nails in 
the wing spars of the ACAC 7, 8, and 11 series airplanes. The 
commenters state that the nails are only used during manufacture of the 
wing to hold the ribs in place.
    The FAA does not concur. Rib nails are required to transfer the 
load from the ribs to the spar. If the rib nails are loose or missing, 
damage to the wing spar could result from the ribs chafing

[[Page 29971]]

against the spar. For this reason, the FAA has determined the 
procedures for inspecting for and replacing loose or missing nails are 
justified.
    No changes have been made to the proposed AD as a result of these 
comments.

Comment Issue No. 7: Properly Performed Annual Inspections 
Eliminate the Need for the Proposed AD

    Several commenters object to the proposed AD because they feel that 
a properly performed annual inspection is adequate to detect spar 
damage. These commenters state that the maintenance manual specifies 
regular inspections of the wing spars for cracks.
    The FAA concurs that the maintenance manual for the ACAC 7, 8, and 
11 series airplanes specifies inspecting the wing spars for cracks 
during annual and 100-hour inspections, particularly at the butt and 
strut attach points. However, sufficient guidance is not given on 
accessing the spar or identifying compression failures. These 
compression failures appear as hardly visible, minute, and jagged 
series of lines that run across the grain on the top or bottom of the 
spar. If not viewed with detailed instruction and the right equipment, 
they may be overlooked. For these reasons, the FAA does not concur that 
the inspections specified in the maintenance manual are adequate to 
detect all wing spar cracks and compression failures.
    No changes have been made to the proposed AD as a result of these 
comments.

Comment Issue No. 8: Compliance Extension for Airplanes With Wings 
That Have Been Rebuilt

    Several commenters request an extension to the compliance time for 
those airplanes where the wing has been rebuilt. The commenters state 
that the wing spar was inspected during the rebuild.
    The FAA does not concur. In order to adequately inspect the wing 
spars for cracks and compression failures, the detailed inspection 
procedures detailed in ACAC Service Letter 406, Revision A, dated May 
6, 1998 (or procedures approved to be acceptable by the FAA), must be 
utilized to adequately perform the inspection. The FAA has determined 
that cracks and compression failures have been overlooked because these 
procedures were not followed.
    No changes have been made to the proposed AD as a result of these 
comments.

Comment Issue No. 9: Reopen and Extend the Comment Period for the 
NPRM

    Two commenters request that the FAA reopen the comment period and 
allow more time for the public to comment on the NPRM. These commenters 
cite the large public interest as the reason for this request.
    The FAA will establish a new comment period. As discussed in this 
document, the FAA is withdrawing the NPRM (Docket No. 97-CE-79-AD) and 
will propose to supersede AD 98-05-04 with a new AD (will be initiated 
as an NPRM) that would affect all ACAC 7, 8, and 11 series airplanes 
and incorporate recommended alternative methods for complying with the 
actions. The FAA will utilize an NPRM with a 45-day comment period to 
propose this new AD to combine the actions.

Comment Issue No. 10: Eliminate, Minimize, or Provide Alternatives 
to Installing Inspection Covers

    Numerous commenters express some opposition to the proposed 
requirement of installing inspection covers on the wings of the ACAC 7, 
8, and 11 series airplanes. These comments include the following:

--Top wing inspection covers could leak, causing water damage to the 
spar and resulting in a reduction of wing structural integrity;
--Top wing inspection covers could come off during flight due to the 
negative pressure on the top surface, which could result in wing 
damage;
--Top wing inspection covers will cause aerodynamic and performance 
concerns; and
--The FAA should allow fabric patches in place of top wing inspection 
covers.

    The FAA does not concur that water damage to the wing spar, 
resulting in wing structural integrity reduction, or aerodynamic and 
performance concerns, will occur when inspection covers are installed 
on the wings of the affected airplanes. To address the concern of water 
damage, ACAC added a water-tight seal to the wing inspection cover 
installation, which the FAA approved. As for aerodynamic and 
performance concerns, the top inspection covers were designed as low-
profile covers and FAA flight test pilots have evaluated and approved 
them. Also, out of the over 200 sets of top inspection covers delivered 
to the field, the FAA has not received any reports of decreased 
performance.
    The FAA does not concur that the top inspection covers would cause 
wing damage if they came off the airplane while in flight. The covers 
are designed not to damage the reinforced cutout if the eight screws 
that attach the covers were inadvertently left off or not tightened and 
the cover came off the airplane.
    The FAA concurs with the request of allowing fabric patches in 
place of the top wing inspection covers, as an acceptable standard 
practice. ACAC Service Letter 417, Revision C, dated May 6, 1998, 
includes procedures for installing fabric patches.
    As discussed in this document, the FAA is withdrawing the NPRM 
(Docket No. 97-CE-79-AD) and will propose to supersede AD 98-05-04 with 
a new AD (will be initiated as an NPRM) that would affect all 7, 8, and 
11 series airplanes and incorporate recommended alternative methods for 
complying with the actions. One of these alternative methods will 
include the installation of these fabric patches.

Comment Issue No. 11: FAA Underestimated the Cost Impact of the 
Proposed AD

    Numerous commenters believe that the cost of installing the 
inspection covers will be significantly greater than the FAA estimated 
in the NPRM.
    The FAA does not concur and believes that the cost impact specified 
in the NPRM was indicative of the initial inspection and inspection 
cover installation costs associated with the proposed action. The cost 
reflected an 11-inspection hole installation on each wing (a total of 
22). Utilizing the alternative inspection method referenced in ACAC 
Service Letter 406, Revision A, dated May 6, 1998, would reduce the 
number of inspection holes required and consequently would reduce the 
cost impact upon the public.
    The FAA is incorporating this service information into a new AD 
(will be initiated as an NPRM) that would combine both the actions in 
the NPRM (Docket No. 97-CE-79-AD) and AD 98-05-04.

Comment Issue No. 12: Require Additional Training for Inspectors

    Three commenters state that compression failures are extremely 
difficult to detect and are easily overlooked. For these reasons, the 
commenters believe that the inspectors should obtain additional 
training in the detection of compression failures on ACAC 7, 8, and 11 
series airplanes.
    The FAA concurs that the compression failures are difficult to 
detect and could be easily overlooked by inspectors who are untrained 
in this area. ACAC Service Letter 406, Revision A, dated May 6, 1998, 
contains a more

[[Page 29972]]

detailed description of compression failures than the original issue of 
this service letter, and also includes a recommendation that inspectors 
should have previous compression failure detection experience. The FAA 
has determined that this more detailed description, combined with the 
inspection procedures included in the service letter, should give the 
inspectors adequate information to detect compression failures in the 
wing spars of ACAC 7, 8, and 11 series airplanes.
    The FAA is incorporating this service information into a new AD 
(will be initiated as an NPRM) that would combine both the actions in 
the NPRM (Docket No. 97-CE-79-AD) and AD 98-05-04.

Comment Issue No. 13: Delete the Proposed Requirement To Install 
Additional Bottom Inspection Covers

    Several commenters state additional inspection covers over that 
which already exist may not be required for some aircraft. These 
commenters suggest that the FAA delete the specific proposed 
requirement in the NPRM of installing additional bottom inspection 
covers.
    The FAA concurs. The inspection-authorized mechanic who is 
performing the inspection is in the best position to determine the 
number of bottom inspection covers needed to accomplish the intent of 
the AD. The selected inspection method and the location of previously 
installed inspection covers will determine the number and location of 
the additional inspection covers required to perform a thorough 
inspection. The service information referenced in the NPRM has been 
revised and clarifies that additional inspection covers need only be 
installed in order to accomplish a thorough spar inspection.
    The FAA is incorporating this service information into a new AD 
(will be initiated as an NPRM) that would combine both the actions in 
the NPRM (Docket No. 97-CE-79-AD) and AD 98-05-04.

Comment Issue No. 14: The FAA Proposed This AD Only for the 
Manufacturer's Benefit

    Numerous commenters object to the proposal and believe that the 
only reason the FAA issued an NPRM is because ACAC requested an AD to 
dodge a liability issue or make a profit.
    The FAA does not concur. The FAA has an obligation to implement AD 
action when an unsafe condition is found in a product and that unsafe 
condition could develop in other products of the same type design. The 
service history of all the affected airplane models indicates that 
cracks and compression failures in the wing spars are unsafe conditions 
that need to be addressed through AD action.
    No changes to the proposal have been made as a result of these 
comments.

Comment Issue No. 15: Prohibit Aerobatic Flight Instead of 
Requiring Repetitive Inspections

    Five commenters state that spar damage is a direct result of 
aerobatic flight. Because of this, the commenters suggest that the FAA 
change the proposal to include a placard that specifies prohibiting 
aerobatic flight instead of the repetitive inspection requirement 
currently proposed.
    The FAA does not concur. Not all of the affected airplanes are 
certificated for aerobatic flight. However, spar damage has been found 
on many of the affected airplane model designs, regardless of whether 
they have been certificated for aerobatic flight.
    No changes to the proposal have been made as a result of these 
comments.

Comment Issue No. 16: Install a ``G'' Meter Instead of Requiring 
Repetitive Inspections

    Three commenters state that installing a ``G'' meter in the 
airplane will help limit the peak accelerations. The commenters request 
that the FAA propose the ``G'' meter installation instead of repetitive 
inspections.
    The FAA does not concur. While the FAA believes that installing a 
``G'' meter may aid in limiting peak accelerations, this will not 
account for all wing loading conditions or detect existing spar damage 
before structural failure of the wing.
    No changes to the proposal have been made as a result of these 
comments.

Comment Issue No. 17: Allow the Use of a Borescope as an 
Alternative Method of Compliance to the Proposed Inspections

    Several commenters request that the FAA allow the use of a 
borescope as an alternative method of compliance to the inspections 
proposed in the NPRM.
    The FAA concurs that a borescope, when available, is an acceptable 
alternative inspection method. Therefore, this inspection method is 
being incorporated into a new AD (will be initiated as an NPRM) that 
would combine both the actions in the NPRM (Docket No. 97-CE-79-AD) and 
AD 98-05-04. This inspection method is referenced in ACAC Service 
Letter 406, Revision A, dated May 6, 1998.

The FAA's Determination

    After careful review of all available information related to the 
subject presented above, including the comments submitted to the NPRM 
(Docket No. 97-CE-79-AD), the FAA has determined that:

--The proposed rule should be withdrawn; and
--A new NPRM should be issued in a different action that would 
supersede AD 98-05-04 with a new AD (will be initiated as an NPRM) that 
would affect all 7, 8, and 11 series airplanes and incorporate 
recommended alternative methods for complying with the actions.

    Withdrawal of this NPRM constitutes only such action, and does not 
preclude the agency from issuing future rulemaking on this issue, nor 
does it commit the agency to any course of action in the future. 
Combining the proposed actions of this NPRM and AD 98-05-04 will be 
initiated in a different AD action.
    Since this action only withdraws an NPRM, it is neither a proposed 
nor a final rule and therefore, is not covered under Executive Order 
12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Withdrawal

    Accordingly, the notice of proposed rulemaking, Docket No. 97-CE-
79-AD, published in the Federal Register on November 3, 1997 (62 FR 
59310), is withdrawn.

    Issued in Kansas City, Missouri, on May 26, 1999.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 99-14130 Filed 6-3-99; 8:45 am]
BILLING CODE 4910-13-P