[Federal Register Volume 63, Number 71 (Tuesday, April 14, 1998)]
[Proposed Rules]
[Pages 18158-18160]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-9758]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-197-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A320 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 A320 series 
airplanes. This proposal would require repetitive inspections for 
fatigue cracking of the bottom flanges of the longitudinal floor beams 
at frame 43; and repair, if necessary. This proposal also would require 
a one-time inspection for fatigue cracking of the fastener holes in the 
longitudinal floor beams, and modification of the floor beams, which 
would constitute terminating action for 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 
fatigue cracking on the bottom flanges of the longitudinal floor beams, 
which could result in reduced structural integrity of the airplane.

DATES: Comments must be received by May 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-197-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this

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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 Docket Number 97-NM-197-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-197-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 A320 series airplanes. The 
DGAC advises that, during full-scale testing on a Model A320 test 
article, fatigue cracks occurred at 66,775 and 72,398 simulated flights 
near frame 43 on the right- and left-side of the lower inboard flange 
of the longitudinal floor beam. Such fatigue cracking, if not detected 
and corrected in a timely manner, could result in reduced structural 
integrity of the airplane.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A320-53-1085, dated March 31, 
1995, which describes procedures for performing repetitive visual 
inspections for fatigue cracking of the bottom flanges of the 
longitudinal floor beams at frame 43, and repair, if necessary.
    In addition, Airbus has issued Service Bulletin A320-53-1008, dated 
March 31, 1995. This service bulletin describes procedures for 
performing a one-time eddy current (rotary probe) non-destructive test 
(NDT) inspection for fatigue cracking at the fastener holes on the 
longitudinal floor beams at frame 43, and modification of the floor 
beam fasteners. Accomplishment of this inspection and modification 
would eliminate the need for the repetitive inspections described in 
Airbus Service Bulletin A320-53-1085. The modification involves cold 
expanding the crack-free fastener holes and replacing the fasteners 
with new parts.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition. The 
DGAC classified Airbus Service Bulletin A320-53-1085 as mandatory and 
issued French airworthiness directive 96-236-089(B), 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. Accomplishment of the inspection and 
modification described in Airbus Service Bulletin A320-53-1008 would 
constitute terminating action for the repetitive inspection 
requirements of this AD.

Differences Between Proposed Rule and Service Bulletins

    Operators should note that, unlike the procedures described in 
Airbus Service Bulletin A320-53-1085 and Airbus Service Bulletin A320-
53-1008, both dated March 31, 1995, this proposed AD would not permit 
further flight if cracking is detected on the bottom flanges or at the 
fastener holes of the longitudinal floor beams. The FAA has determined 
that, because of the safety implications and consequences associated 
with such cracking, any subject bottom flange or fastener hole that is 
found to be cracked must be repaired or modified prior to further 
flight.
    In addition, operators should note that, although the service 
bulletins specify 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.

Differences Between Proposed Rule and Foreign AD

    The proposed AD would differ from the parallel French airworthiness 
directive in that it would mandate the accomplishment of the 
terminating action for the repetitive inspections. The French 
airworthiness directive provides for that action as optional.
    Mandating the terminating action is based on the FAA's 
determination that long-term continued operational safety will be 
better assured by modifications or 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

[[Page 18160]]

design improvements. The proposed modification requirement is in 
consonance with these conditions.

Cost Impact

    The FAA estimates that 5 airplanes of U.S. registry would be 
affected by this proposed AD. It would take approximately 3 work hours 
per airplane to accomplish the proposed inspection of the bottom 
flanges, 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 $900, or $180 per airplane, per inspection 
cycle.
    It would take approximately 32 work hours per airplane to 
accomplish the proposed inspection of the fastener holes and proposed 
modification, at an average labor rate of $60 per work hour. Required 
parts would cost between $649 and $3,056 per airplane, depending on the 
service kit purchased. Based on these figures, the cost impact of the 
inspection of the fastener holes and modification proposed by this AD 
on U.S. operators is estimated to be as low as $12,845, or $2,569 per 
airplane, and as high as $24,880, or $4,976 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 Industrie: Docket 97-NM-197-AD.

    Applicability: Model A320 series airplanes, on which Airbus 
Modification 20904 (reference Airbus Service Bulletin A320-53-1008, 
dated March 31, 1995) has not been accomplished, 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 (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 cracking on the bottom flanges of the 
longitudinal floor beams at frame 43, which could result in reduced 
structural integrity of the airplane, accomplish the following:
    (a) Prior to the accumulation of 20,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later, perform a visual inspection for fatigue 
cracking of the longitudinal floor beams at frame 43, in accordance 
with Airbus Service Bulletin A320-53-1085, dated March 31, 1995.
    (1) If no cracking is detected, repeat the visual inspection 
thereafter at intervals not to exceed 6,000 flight cycles.
    (2) If any cracking is detected, prior to further flight, repair 
in accordance with a method approved by the Manager, International 
Branch, ANM-116, FAA, Transport Airplane Directorate.
    (b) Prior to the accumulation of 32,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later, accomplish paragraphs (b)(1) and (b)(2) of 
this AD. Accomplishment of paragraphs (b)(1) and (b)(2) constitutes 
terminating action for the repetitive inspection requirements of 
this AD.
    (1) Perform a one-time eddy current (rotary probe) non-
destructive test (NDT) inspection for fatigue cracking of the 
fastener holes on the longitudinal floor beams at frame 43, in 
accordance with Airbus Service Bulletin A320-53-1008, dated March 
31, 1995. If any cracking is detected, prior to further flight, 
repair in accordance with a method approved by the Manager, 
International Branch, ANM-116.
    (2) Modify the floor beam fasteners in accordance with Airbus 
Service Bulletin A320-53-1008, dated March 31, 1995.
    (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. 
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.

    (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 96-236-089(B), dated October 23, 1996.

    Issued in Renton, Washington, on April 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-9758 Filed 4-13-98; 8:45 am]
BILLING CODE 4910-13-U