[Federal Register Volume 65, Number 77 (Thursday, April 20, 2000)]
[Proposed Rules]
[Pages 21157-21159]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-9899]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-164-AD]
RIN 2120-AA64


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 supersedure of an existing 
airworthiness directive (AD), applicable to certain Airbus Model A300-
600 series airplanes, that currently requires repetitive ultrasonic 
inspections to detect cracks in the bolt holes inboard and outboard of 
rib 9 on the bottom booms of the front and rear wing spars, and repair, 
if necessary. This action would revise the compliance thresholds for 
the inspection and would require that the inspections be repeated at 
reduced intervals. This proposal is prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. The actions specified by the proposed AD are intended to 
prevent fatigue cracks in the bolt holes of the wing spars, which could 
result in reduced structural integrity of a wing spar.

DATES: Comments must be received by May 22, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-164-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: 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

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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 98-NM-164-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. 98-NM-164-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On March 29, 1995, the FAA issued AD 95-07-05, amendment 39-9187 
(60 FR 17990, April 10, 1995), applicable to certain Airbus Model A300-
600 series airplanes, to require repetitive ultrasonic inspections to 
detect fatigue cracks in the bolt holes inboard and outboard of rib 9 
on the bottom booms of the front and rear wing spars, and repair, if 
necessary. That action was prompted by the discovery of fatigue cracks 
that emanated from the bolt holes inboard and outboard of rib 9 in the 
bottom booms of the front and rear wing spars. The requirements of that 
AD are intended to prevent cracks in the bolt holes of the wing spars, 
which could result in reduced structural integrity of a wing spar.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the Direction Generale de l'Aviation 
Civile (DGAC), which is the airworthiness authority for France, 
received a report indicating that, during routine maintenance, a 
fatigue crack of 3.58 inches (91 millimeters) in length was discovered 
on the bolt holes of the wing spars on a Model A300 series airplane 
that had accumulated 29,919 total flight cycles. Investigation revealed 
that an initial inspection to detect cracks in the bolt holes of the 
wing spars, in accordance with that AD, had been performed on this 
airplane at 23,545 total flight cycles. Procedures for this inspection 
are described in Airbus Service Bulletin A300-57-6039, dated August 1, 
1994 (which was referenced in AD 95-07-05 as the appropriate source of 
service information).
    That service bulletin specified an interval not to exceed 9,000 
flight cycles for repetitive inspections, which would have resulted in 
accomplishment of the next inspection on this airplane at 32,545 total 
flight cycles. Accomplishment of the next inspection at the scheduled 
compliance time would have allowed the cracking on this airplane to 
remain undetected for 2,626 flight cycles. Therefore, the DGAC has 
concluded that the existing repetitive interval for these inspections 
does not detect such cracking in a timely manner, and advises that the 
interval should be reduced.

Explanation of Relevant Service Information

    Subsequent to the finding of this new cracking, Airbus issued 
Service Bulletin A300-57-6037, Revision 1, dated August 31, 1995. The 
inspection and repair procedures described in Revision 1 of the service 
bulletin are essentially identical to those described in the original 
issue of the service bulletin. However, Revision 1 of the service 
bulletin reduces the repetitive inspection intervals from 9,000 flight 
cycles, as specified in the original issue of the service bulletin, to 
4,800 flight cycles.
    The DGAC classified Revision 1 of this service bulletin as 
mandatory and issued French airworthiness directive 94-208-169(B)R2, 
dated October 8, 1997, in order to assure the continued airworthiness 
of these airplanes in France.

FAA's Conclusions

    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.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would supersede AD 95-07-05 to 
continue to require repetitive ultrasonic inspections to detect cracks 
in the bolt holes inboard and outboard of rib 9 on the bottom booms of 
the front and rear wing spars, and repair, if necessary. This proposed 
AD would require that the repetitive inspections be accomplished at a 
revised threshold and at reduced intervals. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, unlike particular provisions in the 
service bulletin regarding adjustment of the compliance times using an 
``adjustment-for-range'' formula, this proposed AD would not permit 
formulaic adjustments of the inspection compliance times. The FAA has 
determined that such adjustments may present difficulties in 
determining if the applicable inspections and modifications have been 
accomplished within the appropriate time frame. Further, while such 
adjustable compliance times are utilized as part of the Maintenance 
Review Board program, they do not fit practically into the AD tracking 
process for operators or for Principal Maintenance Inspectors 
attempting to ascertain compliance with AD's. Therefore, the FAA has 
determined that fixed compliance times should be specified for 
accomplishment of the actions required by this AD.
    Additionally, after discussions with the DGAC and the manufacturer, 
the FAA has determined that flight-hour maximums should be included as 
part of the compliance threshold and repetitive intervals for the 
inspections required by this proposed AD. Inclusion of a compliance 
threshold in terms of total flight hours as well as total flight 
cycles, and requiring inspection at the earlier of those times, will 
ensure that airplanes with longer-than-average flight times are 
inspected at a threshold and intervals necessary to maintain safety. 
Accordingly, the FAA has specified that the initial inspection must be 
accomplished at the earliest time an airplane reaches certain 
accumulated total flight cycles or total flight hours, and that 
repetitive inspections are to be accomplished at intervals not to 
exceed certain flight cycles or flight hours, whichever occurs first.
    The FAA has determined that such revision of the inspection 
threshold and

[[Page 21159]]

reduction of the intervals of the existing AD does not adversely impact 
any U.S. operators, since no airplanes on the U.S. Register have yet 
reached those accumulated flight-cycle or flight-hour thresholds.

Cost Impact

    There are approximately 75 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspection that is currently required by AD 95-07-05, and 
retained in this AD, takes approximately 1 work hour per airplane to 
accomplish (excluding 10 work hours for access and close-up), at an 
average labor rate of $60 per work hour. Based on this figure, the cost 
impact of the currently required inspection on U.S. operators is 
estimated to be $4,500, or $60 per airplane, per inspection cycle.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the current or 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 a substantial direct 
effect 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, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    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 removing amendment 39-9187 (60 FR 
17990, April 10, 1995), and by adding a new airworthiness directive 
(AD), to read as follows:

Airbus Industrie: Docket 98-NM-164-AD. Supersedes AD 95-07-05, 
Amendment 39-9187.
    Applicability: Model A300-600 series airplanes, certificated in 
any category, on which Airbus Modification 10161 has not been 
installed in production.

    Note 1:
    This AD applies to each airplane identified in the preceding 
applicability provision, regardless of whether it has been otherwise 
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 (c) 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 cracks in the bolt holes of the wing spars, 
which could result in reduced structural integrity of a wing spar, 
accomplish the following:

Ultrasonic Inspections

    (a) Perform an ultrasonic inspection to detect fatigue cracking 
of the bolt holes inboard and outboard of rib 9 on the bottom booms 
of the front and rear wing spars, in accordance with Airbus Service 
Bulletin A300-57-6037, dated August 1, 1994, or Revision 1, dated 
August 31, 1995, at the applicable time specified in paragraph 
(a)(1) or (a)(2) of this AD. Repeat the inspection thereafter at 
intervals not to exceed 4,800 flight cycles or 11,000 flight hours, 
whichever occurs first.
    (1) For airplanes on which Airbus Modification 8842 (reference 
Airbus Service Bulletin A300-57-6039) has not been installed: 
Inspect at the earlier of the times specified by paragraphs 
(a)(1)(i) and (a)(1)(ii) of this AD.
    (i) Prior to the accumulation of 17,000 total flight cycles, or 
within 2,000 flight cycles after May 10, 1995 (the effective date of 
AD 95-07-05, amendment 39-9187), whichever occurs later.
    (ii) Prior to the accumulation of 39,000 total flight hours.
    (2) For airplanes on which Airbus Modification 8842 has been 
installed: Inspect at the earlier of the times specified by 
paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
    (i) Within 17,000 flight cycles after accomplishment of Airbus 
Modification 8842, or within 2,000 flight cycles after May 10, 1995, 
whichever occurs later.
    (ii) Within 39,000 flight hours after accomplishment of Airbus 
Modification 8842.

Corrective Action

    (b) If any crack is found, prior to further flight, repair in 
accordance with Airbus Service Bulletin A300-57-6037, dated August 
1, 1994, or Revision 1, dated August 31, 1995. Thereafter, perform 
the repetitive inspections required by paragraph (a) of this AD.

Alternative Methods of Compliance

    (c) 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, FAA, 
Transport Airplane Directorate. 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.

    Note 2:
    Information concerning the existence of approved alternative 
methods of compliance with this AD, if any, may be obtained from the 
International Branch, ANM-116.

Special Flight Permits

    (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.

    Note 3:
    The subject of this AD is addressed in French airworthiness 
directive 94-208-169(B)R2, dated October 8, 1997.


    Issued in Renton, Washington, on April 14, 2000.
Charles D. Huber,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-9899 Filed 4-19-00; 8:45 am]
BILLING CODE 4910-13-P