[Federal Register Volume 61, Number 45 (Wednesday, March 6, 1996)]
[Proposed Rules]
[Pages 8897-8899]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-5221]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-150-AD]
Airworthiness Directives; Airbus Model A300-600 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to all Airbus Model A300-600 series
airplanes. This proposal would require an eddy current inspection to
detect cracks on the forward fittings in the radius of frame 40
adjacent to the tension bolts in the center section of the wings, and
various follow-on actions. This proposal is prompted by reports of
cracking in the radius of frame 40 adjacent to the tension bolts at the
center/outer wing junction due to fatigue-related stress. The actions
specified by the proposed AD are intended to prevent such fatigue-
related cracking, which could result in reduced structural integrity of
the wings.
DATES: Comments must be received by April 12, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-150-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056. Comments may be inspected at this
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except
Federal holidays.
The service information referenced in the proposed rule may be
obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707
Blagnac Cedex, France. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Charles Huber, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2589; fax (206) 227-1149.
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 shall 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
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summarizing 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 Number 95-NM-150-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, Transport Airplane Directorate, ANM-103, Attention: Rules
Docket No. 95-NM-150-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On January 15, 1993, the FAA issued AD 93-01-24, Amendment 39-8478
(58 FR 6703, February 2, 1993), which is applicable to all Airbus Model
A300 B2, B4-100, and B4-200 series airplanes. That AD requires
supplemental structural inspections to detect fatigue cracking, and
repair or replacement, if necessary; or the installation of specific
modifications. That action was prompted by a structural reevaluation,
which identified certain significant structural components to inspect
for fatigue cracks as these airplanes approach and exceed the
manufacturer's original fatigue design life goal. The requirements of
that AD are intended to prevent reduced structural integrity of these
airplanes.
Since the issuance of that AD, the Direction Generale de l'Aviation
Civile (DGAC), which is the airworthiness authority for France,
recently notified the FAA that an unsafe condition may exist on all
Airbus Model A300-600 series airplanes. The DGAC advises that, during
sampling inspections required by AD 93-01-24, cracking was found in the
radius of frame 40 adjacent to the tension bolts at the center/outer
wing junction. The cracking occurred on Model A300 B2 and B4 series
airplanes that had accumulated between 15,000 and 24,000 total flight
cycles. The cause of such cracking has been attributed to fatigue-
related stress. Such fatigue-related cracking, if not corrected, could
result in reduced structural integrity of the wings.
The subject area on certain Model A300-600 series airplanes is
almost identical to that on the affected Model A300 B2 and B4 series
airplanes. Therefore, those Model A300-600 series airplanes may be
subject to the same unsafe condition revealed on the Model A300 B2 and
B4 series airplanes.
Explanation of Relevant Service Information
Airbus has issued Service Bulletin A300-57-6062, dated February 14,
1995, which describes procedures for an eddy current inspection to
detect cracks on the forward fittings in the radius of frame 40
adjacent to the tension bolts in the center section of the wings, and
various follow-on actions. (These follow-on actions include applying a
sealant, eddy current inspections, and blending of cracks.) This
service bulletin permits further flight, under certain conditions, with
forward fittings that are cracked within certain limits. The DGAC
classified this service bulletin as mandatory and issued French
airworthiness directive 95-063-177(B), dated April 12, 1995, in order
to assure the continued airworthiness of these airplanes in France.
Explanation of the Proposed Rule
This airplane model is manufactured in France and is type
certificated for operation in the United States under the provisions of
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and
the applicable bilateral airworthiness agreement. Pursuant to this
bilateral airworthiness agreement, the DGAC has kept the FAA informed
of the situation described above. The FAA has examined the findings of
the DGAC, reviewed all available information, and determined that AD
action is necessary for products of this type design that are
certificated for operation in the United States.
Since an unsafe condition has been identified that is likely to
exist or develop on other airplanes of the same type design, the
proposed AD would require an eddy current inspection to detect cracks
on the forward fittings in the radius of frame 40 adjacent to the
tension bolts in the center section of the wings, and various follow-on
actions. The actions would be required to be accomplished in accordance
with the service bulletin described previously.
Differences Between the Proposed Rule and Relevant Service
Information
Operators should note that, unlike the procedures described in the
referenced service bulletin, this proposed AD would not permit further
flight with cracking detected in the forward fittings. The FAA has
determined that, due to the safety implications and consequences
associated with such cracking under certain conditions, the subject
forward fittings that are found to be cracked must be repaired. In
addition, if any crack is removed and the blend out is greater than 50
mm long and/or 2 mm deep, the forward fitting must be repaired. These
repairs would be required to be accomplished in accordance with a
method approved by the FAA.
In addition, the service bulletin specifies that inspection
thresholds and intervals should be adjusted based on the average
utilization rate of the airplane. However, the FAA has determined that,
in some cases, such adjustments would not address the unsafe condition
in a timely manner. Therefore, this proposed AD does not permit such
adjustments. In developing the appropriate inspection thresholds and
intervals for the proposed rule, the FAA considered not only the
manufacturer's recommendation and the average utilization rate of the
affected U.S. registered airplanes, but the safety implications
involved with cracking in the radius of frame 40 adjacent to the
tension bolts at the center/outer wing junction. In light of these
factors, the FAA finds the compliance times specified in the proposed
AD for initiating the required actions to be warranted, in that they
represent an appropriate interval of time allowable for the affected
airplanes to continue to operate without compromising safety.
Furthermore, the service bulletin specifies that operators need not
count touch-and-go landings in determining the total number of landings
between two consecutive inspections, even if those landings are less
than five percent of the landings between inspection intervals. Since
fatigue cracking that was found in the radius of frame 40 adjacent to
the tension bolts at the center/outer wing is aggravated by landing,
the FAA finds that all touch-and-go landings must be counted in
determining the total number of landings between two consecutive
inspections.
Cost Impact
The FAA estimates that 35 airplanes of U.S. registry would be
affected by this proposed AD, that it would take approximately 22 work
hours per airplane to accomplish the proposed actions, and that the
average labor rate is $60 per work hour. Based on these figures, the
cost impact of the proposed AD on U.S. operators is estimated to be
$46,200, or $1,320 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the proposed requirements of
this AD action, and that no operator would
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accomplish those actions in the future if this AD were not adopted.
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 proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the 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 is contained 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
part 39 of the Federal Aviation Regulations (14 CFR part 39) as
follows:
PART 39--AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Airbus Industrie: Docket 95-NM-150-AD.
Applicability: All Model A300-600 series airplanes, certificated
in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired 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 (d) 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, unless accomplished
previously.
To prevent fatigue-related cracking, which could result in
reduced structural integrity of the wing, accomplish the following:
(a) Perform an eddy current inspection to detect cracks on the
forward fittings in the radius of frame 40 adjacent to the tension
bolts in the center section of the wings, in accordance with Airbus
Service Bulletin A300-57-6062, dated February 14, 1995, at the
applicable time specified in either paragraph (a)(1) or (a)(2) of
this AD.
(1) For airplanes that have accumulated 12,400 total landings or
less as of the effective date of this AD: Inspect prior to the
accumulation of 10,500 total landings, or within 1,500 landings
after the effective date of this AD, whichever occurs later.
(2) For airplanes that have accumulated more than 12,400 total
landings as of the effective date of this AD: Inspect within 750
landings after the effective date of this AD.
(b) If no crack is detected during the inspection required by
paragraph (a) of this AD, prior to further flight, apply sealant, in
accordance with Airbus Service Bulletin A300-57-6062, dated February
14, 1995. Repeat the eddy current inspection thereafter at intervals
not to exceed 4,500 landings.
(c) If any crack is detected during the inspection required by
paragraph (a) of this AD, prior to further flight, blend it out in
accordance with Airbus Service Bulletin A300-57-6062, dated February
14, 1995. Prior to further flight after accomplishing the blend out,
perform an eddy current inspection to verify that the crack has been
removed, in accordance with the service bulletin.
(1) If any crack is removed and the blend out is equal to or
less than 50 mm long and/or 2 mm deep, repeat the eddy current
inspection required by paragraph (a) of this AD thereafter at
intervals not to exceed 950 landings.
(2) If any crack exists, or if any crack is removed and the
blend out is more than 50 mm long and/or 2 mm deep, prior to further
flight, repair in accordance with a method approved by the Manager,
Standardization Branch, ANM-113, FAA, Transport Airplane
Directorate.
(d) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used if approved by the Manager, Standardization Branch, ANM-113.
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Standardization Branch, ANM-113.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(e) 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.
Issued in Renton, Washington, on February 27, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-5221 Filed 3-5-96; 8:45 am]
BILLING CODE 4910-13-P
