[Federal Register Volume 63, Number 226 (Tuesday, November 24, 1998)]
[Proposed Rules]
[Pages 64918-64921]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-31323]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-150-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A300-600 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to all Airbus Model A300-600 series 
airplanes, that would have required repetitive eddy current inspections 
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. That proposal was prompted by reports of 
cracking due to fatigue-related stress in the radius of frame 40 
adjacent to the tension bolts at the center/outer wing junction. This 
new action revises the proposed rule by requiring ultrasonic 
inspections, in lieu of the eddy current inspection proposed 
previously. This action also reduces the compliance time to perform the 
initial inspection, increases the repetitive inspection intervals, and 
adds flight hours as a compliance option. The actions specified by this 
new proposed AD are intended to detect and correct fatigue cracking on 
the forward fittings in the radius of frame 40 adjacent to the tension 
bolts in the center section of the wings, which could result in reduced 
structural integrity of the wings.

DATES: Comments must be received by December 21, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
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.

[[Page 64919]]

    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: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 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 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-114, Attention: Rules 
Docket No. 95-NM-150-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to all 
Airbus Model A300-600 series airplanes, was published as a notice of 
proposed rulemaking (NPRM) in the Federal Register on March 6, 1996 (61 
FR 8897). That NPRM would have required repetitive eddy current 
inspections 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. That NPRM was prompted by reports 
of cracking due to fatigue-related stress in the radius of frame 40 
adjacent to the tension bolts at the center/outer wing junction. That 
condition, if not corrected, could result in reduced structural 
integrity of the wings.

Actions Since Issuance of Previous Proposal

    Since the issuance of that NPRM, the FAA has given due 
consideration to the comments received in response to the NPRM. The 
comments that have prompted a change in the proposal are explained 
below.

Request To Reference New Revision of the Service Bulletin

    Two commenters [the Air Transport Association (ATA) of America and 
the manufacturer] request that the FAA revise the proposed AD to 
reference a new revision of the service bulletin referenced in the 
proposed AD.
    The FAA concurs with the commenters' request to revise the proposed 
AD to reference a new version of the service bulletin. Since issuance 
of the NPRM, Airbus has issued Service Bulletin A300-57-6062, Revision 
02, dated January 29, 1997. That service bulletin describes procedures 
for an ultrasonic inspection, in lieu of the eddy current inspection 
described in the original issue of the service bulletin (which was 
referenced in the original NPRM as the appropriate source of service 
information), to detect cracking 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. If no cracking is detected, those 
follow-on actions consist of repetitive ultrasonic inspections. If any 
cracking is detected, the follow-on actions include installation of an 
access door or doors, repetitive eddy current inspections to confirm 
the presence of a crack, and blending of the crack or cracks, if 
necessary. If the blended area is 50 millimeters (mm) long or more, or 
exceeds 2 mm in depth, the service bulletin provides for repair in 
accordance with procedures to be provided by Airbus.
    The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, classified Airbus Service Bulletin 
A300-57-6062, Revision 02, as mandatory and issued a new French 
airworthiness directive, 95-063-177(B)R3, dated July 2, 1997, in order 
to assure the continued airworthiness of these airplanes in France.
    The FAA finds that accomplishment of the actions specified in 
Airbus Service Bulletin A300-57-6062, Revision 02, would adequately 
address the identified unsafe condition, while also providing an 
inspection method that limits the number of work hours necessary to 
gain access to the areas to be inspected, thereby minimizing the 
economic impact of the inspection. Therefore, the FAA has revised the 
proposed AD to specify Revision 02 of the service bulletin as the 
appropriate source of service information. The cost impact information 
of the proposed AD also has been revised to reflect a reduction in the 
number of work hours necessary to complete the inspection procedure.

Request To Adjust Inspection Thresholds and Intervals

    One commenter, the manufacturer, requests that the FAA revise the 
proposed AD to require inspection thresholds and repetitive intervals 
to be calculated based on average flight time using the ``adjustment 
for range'' formula referenced in both the original and revised service 
bulletins. Such adjustment is designed to account for variations in the 
amount of fatigue damage due to loading and flight length and may 
result in reductions in the inspection threshold and intervals.
    The FAA does not concur that operators should be required to 
calculate inspection thresholds and repetitive intervals using the 
``adjustment for range'' formula. Use of such a formula would introduce 
a planning burden for the operator, make enforcement difficult for the 
FAA, and potentially introduce differences between FAA inspectors and 
operators concerning when the inspection thresholds and intervals 
should be recalculated.
    However, under the provisions of paragraph (d)(2) of this 
supplemental NPRM, the FAA may approve requests for adjustment of the 
inspection thresholds and intervals. The request for extension should 
be based on the ``adjustment for range'' formula referenced in Airbus 
Service Bulletin A300-57-6062, Revision 02, and the average flight time 
per flight cycle used in the formula should be for an individual 
airplane. Average flight times for a group of airplanes may be used if 
flight times for all airplanes included in the group do not vary by 
more than 10

[[Page 64920]]

percent, and the flight times for individual airplanes within the group 
must be included with the request, for review by the FAA.
    The FAA acknowledges, however, that the inspection thresholds and 
intervals specified in the original proposal may not be conservative, 
based on the utilization of certain airplanes. Also, French 
airworthiness directive 95-063-177(B)R3 reduces the inspection 
threshold specified in the original issue of French airworthiness 
directive 95-063-177(B), dated April 12, 1995. In consideration of the 
commenter's request, and in concert with the French airworthiness 
directive, the FAA has determined that the inspection threshold for 
this proposal should be reduced from 10,500 total landings, as 
specified in the original proposal, to 7,250 total landings. The FAA 
also has determined that the inspection thresholds and intervals may be 
calculated using flight hours; thus the inspection threshold has been 
revised to provide for the inspection to be performed prior to the 
accumulation of 17,700 total flight hours.
    The repetitive inspection intervals for this proposal also have 
been increased from 4,500 landings to 6,500 landings or 16,000 flight 
hours, for airplanes on which no cracking is detected; and from 950 
landings to 2,800 landings or 7,000 flight hours, for certain airplanes 
on which cracking is detected. Paragraphs (a), (b), and (c)(1) of this 
supplemental NPRM have been revised to reduce the inspection 
thresholds, increase the repetitive inspection intervals, and add 
flight hours as a compliance option.

Differences Between the Supplemental NPRM and Foreign AD

    Operators should note that, although the service bulletin specifies 
that the manufacturer may be contacted for disposition of certain 
repair conditions, this proposal would require the repair of those 
conditions to be accomplished in accordance with a method approved by 
the FAA or the DGAC (or its delegated agent). In light of the type of 
repair that would be required to address the identified unsafe 
condition, and in consonance with existing bilateral airworthiness 
agreements, the FAA has determined that, for this supplemental NPRM, a 
repair approved by either the FAA or the DGAC would be acceptable for 
compliance with this supplemental NPRM.
    Operators also should note that the inspection thresholds and 
intervals for this supplemental NPRM differ from those specified in the 
French airworthiness directive. In developing the appropriate 
inspection thresholds and intervals for this supplemental NPRM, 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 proposed compliance time 
(7,250 total landings or 17,700 total flight hours) specified in the 
supplemental NPRM for initiating the required actions to be warranted, 
in that it represents an appropriate interval of time allowable for the 
affected airplanes to continue to operate without compromising safety.

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    The FAA estimates that 35 airplanes of U.S. registry would be 
affected by this proposed AD.
    The new inspection method proposed by this supplemental NPRM would 
not add any new additional economic burden on affected operators, other 
than, for certain airplanes, the costs that are associated with the 
initial inspection being required earlier than specified in the 
original NPRM.
    It would take approximately 2 work hours per airplane (1 work hour 
per side) to accomplish the proposed ultrasonic inspection, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of this proposed inspection on U.S. operators is estimated 
to be $4,200, or $120 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 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 U.S.C. 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)(1) 
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 detect and correct fatigue cracking on the forward 
fittings in the radius of frame 40 adjacent to the tension bolts in 
the center section of the wings, which could result in reduced 
structural integrity of the wings, accomplish the following:
    (a) Perform an ultrasonic inspection to detect cracking on the 
forward fittings in the

[[Page 64921]]

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, Revision 02, dated January 29, 1997, at the applicable 
time specified in either paragraph (a)(1) or (a)(2) of this AD.
    (1) For airplanes that have accumulated fewer than 9,100 total 
landings or 22,300 total flight hours as of the effective date of 
this AD: Inspect at the later of the times specified in either 
paragraph (a)(1)(i) or (a)(1)(ii) of this AD.
    (i) Prior to the accumulation of 7,250 total landings or 17,700 
total flight hours, whichever occurs first.
    (ii) Within 1,500 landings after the effective date of this AD.
    (2) For airplanes that have accumulated 9,100 total landings or 
more and 22,300 total flight hours or more as of the effective date 
of this AD: Inspect within 750 landings after the effective date of 
this AD.

    Note 2: Inspections that were accomplished prior to the 
effective date of this AD in accordance with Airbus Service Bulletin 
A300-57-6062, Revision 1, dated July 23, 1995, are considered 
acceptable for compliance with paragraph (a) of this AD.

    (b) If no crack is detected during the inspection required by 
paragraph (a) of this AD, repeat the ultrasonic inspection required 
by that paragraph thereafter at intervals not to exceed 6,500 
landings or 16,000 flight hours, whichever occurs first; in 
accordance with Airbus Service Bulletin A300-57-6062, Revision 02, 
dated January 29, 1997.
    (c) If any crack is detected during any inspection required by 
paragraph (a) or (b) of this AD, prior to further flight, install an 
access door, and perform an eddy current inspection to confirm the 
presence of a crack; in accordance with Airbus Service Bulletin 
A300-57-6062, Revision 02, dated January 29, 1997. Accomplishment of 
this eddy current inspection terminates the repetitive inspection 
requirement of paragraph (b) of this AD.
    (1) If no crack is detected during the eddy current inspection, 
repeat the eddy current inspection, in accordance with the service 
bulletin, thereafter at intervals not to exceed 6,500 landings or 
16,000 flight hours, whichever occurs first.
    (2) If any crack is detected during any eddy current inspection 
performed in accordance with paragraph (c) or (c)(1) of this AD, 
prior to further flight, blend out the crack and repeat the eddy 
current inspection in accordance with the service bulletin.
    (i) If the eddy current inspection performed after the blend-out 
shows that the crack has been removed, and if the blend-out is equal 
to or less than 50 millimeters (mm) long and equal to or less than 2 
mm deep, thereafter repeat the eddy current inspection at intervals 
not to exceed 2,800 landings or 7,000 flight hours, whichever occurs 
first.
    (ii) If the eddy current inspection performed after the blend-
out shows that the crack has not been removed, or if the blend-out 
is more than 50 mm long or more than 2 mm deep, prior to further 
flight, repair in accordance with a method approved by the Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate; 
or the Direction Generale de l'Aviation Civile (or its delegated 
agent).
    (d)(1) 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, International Branch, ANM-116. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, International Branch, ANM-116.
    (d)(2) Operators may request an extension to the compliance 
times of this AD in accordance with the ``adjustment-for-range'' 
formula found in Paragraph 1.B.(5) of Airbus Service Bulletin A300-
57-6062, Revision 02, dated January 29, 1997; and provided in A300-
600 Maintenance Review Board, Section 5, Paragraph 5.4. The average 
flight time per flight cycle (landing) in hours used in this formula 
should be for an individual airplane. Average flight time for a 
group of airplanes may be used if all airplanes of the group have 
flight times differing by no more than 10 percent. If compliance 
times are based on the average flight time for a group of airplanes, 
the flight times for individual airplanes of the group must be 
included for FAA review.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (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.

    Note 4: The subject of this AD is addressed in French 
airworthiness directive 95-063-177(B)R3, dated July 2, 1997.

    Issued in Renton, Washington, on November 18, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-31323 Filed 11-23-98; 8:45 am]
BILLING CODE 4910-13-U