[Federal Register Volume 63, Number 42 (Wednesday, March 4, 1998)]
[Proposed Rules]
[Pages 10576-10579]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-5605]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-153-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 adoption of a new airworthiness 
directive (AD) that is applicable to certain Airbus Model A300-600 
series airplanes. This proposal would require repetitive inspections to 
detect cracks in the angle fitting at frame 40 of the center wing box, 
and corrective actions, if necessary; and eventual modification of that 
angle fitting, which would terminate the repetitive inspections. 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 cracks in the 
center wing box angle fitting, which could result in the failure of the 
center wing box at frame 40, and consequent reduced structural 
integrity of the airplane.

DATES: Comments must be received by April 3, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-153-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 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

[[Page 10577]]

Docket Number 97-NM-153-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. 97-NM-153-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Generale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on certain Airbus Model A300-600 series airplanes. 
The DGAC advises that, during inspections of the lower outboard radius 
of frame 40 on Model A300 series airplanes, operators have found 30 
cases of cracking in this area. The cracking originated in a fastener 
hole. Based on design similarity, analysis has shown that cracking also 
could occur in this area on Model A300-600 series airplanes. This 
condition, if not detected and corrected in a timely manner, could 
result in the failure of the center wing box at frame 40, and 
consequent reduced structural integrity of the airplane.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A300-57-6052, Revision 1, dated 
July 22, 1996, which describes procedures for repetitive inspections to 
detect cracks in the angle fitting at frame 40 of the center wing box, 
and follow-on corrective actions, if necessary. The follow-on 
corrective actions include repetitive eddy current inspections, and 
temporary repair of the area prior to accomplishment of a permanent 
modification.
    Airbus also has issued Service Bulletin A300-57-6053, Revision 1, 
dated October 31, 1995, which describes procedures for a modification 
to the angle fitting at frame 40, which would eliminate the need for 
the repetitive inspections. The modification involves the installation 
of new angle fittings and taper-lok fasteners. Accomplishment of the 
actions specified in this service bulletin is intended to adequately 
address the identified unsafe condition.
    The DGAC classified Airbus Service Bulletin A300-57-6052, Revision 
1, dated July 22, 1996, as mandatory and issued French airworthiness 
directive (CN) 95-111-181(B)R1, dated October 23, 1996, 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 require accomplishment of 
the actions specified in the service bulletins described previously, 
except as discussed below.

Differences Between the Proposed Rule and the Related Service 
Bulletin

    The proposed rule would differ from Airbus Service Bulletin A300-
57-6052 in that, unlike the compliance time thresholds and intervals 
provided in the service bulletin, this proposed AD would require 
accomplishment of the actions at compliance time thresholds and 
intervals based on the Average Flight Time (AFT) of the airplane, as 
specified in Table 1 of this AD. The threshold and intervals defined in 
the service bulletin are based on an AFT of 125 minutes. For airplanes 
that are operated with different flight durations, adjustments must be 
made to the thresholds and intervals. To provide clarification of the 
appropriate thresholds and intervals, Table 1 has been included in this 
proposed AD. The thresholds and intervals provided in Table 1 have been 
adjusted for various AFT's.
    The proposed rule also would differ from the service bulletin in 
that the service bulletin recommends the visual inspection be 
accomplished with or without the nut removed, while this proposed AD 
requires that any inspection, whether visual, eddy current, or liquid 
penetrant, be performed with the nut removed. The FAA has determined 
that, without removal of the nut, a visual inspection technique is not 
an appropriate method of compliance with the proposed AD, due to the 
time required to gain access to the area to be inspected and the 
necessity to perform frequent subsequent inspections if the inspection 
is done without removal of the nut.
    Operators should also note that, unlike the procedures described in 
the service bulletin, this proposed AD would not permit further flight 
with cracking detected in the forward angle fitting of frame 40. The 
FAA has determined that, due to the safety implications and 
consequences associated with such cracking, all fittings that are found 
to be cracked must be replaced prior to further flight.
    Further, 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.
    Additionally, operators should note that this AD proposes to 
mandate, within 4 years after the effective date of this AD, the 
modification described in Airbus Service Bulletin A300-57-6053, 
Revision 1, dated October 31, 1995, as terminating action for the 
repetitive inspections. (Incorporation of the terminating action 
specified in this service bulletin is optional in French airworthiness 
directive 95-111-181(B) R1, dated October 23, 1996.) The FAA has 
determined that long-term continued operational safety will be better 
assured by design changes to remove the source of the problem, rather 
than by repetitive inspections. Long-term inspections may not be 
providing the degree of safety assurance necessary for the transport 
airplane fleet. This, coupled with a better understanding of the human 
factors associated with numerous continual inspections, has led the FAA 
to consider placing less emphasis on inspections and more emphasis on 
design improvements. The proposed modification requirement is in 
consonance with these conditions.

Cost Impact

    The FAA estimates that 54 Model A300-600 series airplanes of U.S. 
registry would be affected by this proposed AD.
    It would take approximately 36 work hours per airplane to 
accomplish the proposed inspection, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the inspection 
proposed by this AD on U.S. operators is estimated to be $116,640, or 
$2,160 per airplane, per inspection cycle.
    It would take approximately 754 work hours per airplane to 
accomplish the proposed modification, at an average labor rate of $60 
per work hour. Required parts would cost

[[Page 10578]]

approximately $11,605 per airplane. Based on these figures, the cost 
impact of the modification proposed by this AD on U.S. operators is 
estimated to be $3,069,630, or $56,845 per airplane.
    The cost impact figures discussed above are 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: Docket 97-NM-153-AD.

    Applicability: Model A300-600 series airplanes on which Airbus 
Modification 10453 has not been installed; certificated in any 
category.

    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 (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, unless accomplished 
previously.
    To prevent cracks in the center wing box angle fitting, which 
could result in the failure of the center wing box at frame 40, and 
consequent reduced structural integrity of the airplane, accomplish 
the following:
    (a) Prior to the accumulation of the threshold specified in 
Table 1 of this AD, as applicable, or within 1,500 flight cycles 
after the effective date of this AD, whichever occurs later: Perform 
a detailed visual, eddy current, or liquid penetrant inspection to 
detect cracking in the angle fitting of frame 40 (both left and 
right), with the nut removed, in accordance with Airbus Service 
Bulletin A300-57-6052, Revision 1, dated July 22, 1996. Thereafter, 
repeat the inspections at the interval specified in Table 1 of this 
AD, as applicable, until the actions required by paragraph (c) of 
this AD have been accomplished.

                                 Table 1                                
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                                                                 Eddy   
                                                               current/ 
                                                   Visual       liquid  
Average flight time (AFT): Flight   Threshold    inspection   penetrant 
       hours/flight cycles           (flight      interval    inspection
                                     cycles)      (flight      interval 
                                                  cycles)      (flight  
                                                               cycles)  
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2.10-2.49........................        5,900        4,700        6,300
2.50-2.99........................        5,600        4,400        4,900
3.00-3.49........................        5,200        4,100        4,600
3.50-3.99........................        4,800        3,800        4,200
4.00-4.49........................        4,400        3,500        3,900
4.50-4.99........................        4,000        3,200        3,500
5.00-5.49........................        3,600        2,800        3,200
5.50-5.99........................        2,300        2,500        2,800
6.00-6.50........................        2,800        2,200        2,500
------------------------------------------------------------------------

    (b) Except as provided by paragraph (d) of this AD, if any crack 
is found during an inspection required by paragraph (a) of this AD, 
prior to further flight, accomplish follow-on corrective actions in 
accordance with the procedures specified in Airbus Service Bulletin 
A300-57-6052, Revision 1, dated July 22, 1996.
    (c) Within 4 years after the effective date of this AD, modify 
the angle fitting at frame 40 (both left and right) in accordance 
with Airbus Service Bulletin A300-57-6053, Revision 1, dated October 
31, 1995. Accomplishment of the modification constitutes terminating 
action for the repetitive inspections required by paragraph (a) of 
this AD.
    (d) If any crack is found during an inspection required by 
paragraph (a) of this AD, and the applicable service bulletin 
specifies to contact the manufacturer for an appropriate action: 
Prior to further flight, repair in accordance with a method approved 
by the Manager, International Branch, ANM-116, FAA, Transport 
Airplane Directorate.
    (e) 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.

    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.


[[Page 10579]]


    (f) 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 (CN) 95-111-181(B) R1, dated October 23, 
1996.

    Issued in Renton, Washington, on February 26, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-5605 Filed 3-3-98; 8:45 am]
BILLING CODE 4910-13-U