[Federal Register Volume 65, Number 28 (Thursday, February 10, 2000)]
[Proposed Rules]
[Pages 6566-6569]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-3132]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-99-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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[[Page 6567]]

SUMMARY: This document proposes the supersedure of two existing 
airworthiness directives (AD), applicable to certain Airbus Model A320 
series airplanes, that currently require modification of the rear spar 
web of the wing and cold expansion of certain attachment holes for the 
forward pintle fitting and certain holes at the actuating cylinder 
anchorage of the main landing gear (MLG). This proposed action would 
add a requirement for repetitive inspections to detect fatigue cracking 
in certain areas of the rear spar of the wing, and corrective action, 
if necessary. This proposed action would also provide for optional 
terminating action for the requirements of this AD. 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 detect and correct fatigue cracking, 
which may lead to reduced structural integrity of the wing and the MLG.

DATES: Comments must be received by March 13, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-99-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 Docket Number 98-NM-99-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-99-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On April 26, 1993, the FAA issued AD 93-08-15, amendment 39-8563 
(58 FR 27923, May 12, 1993), applicable to certain Airbus Model A320 
series airplanes, which requires modification of the rear spar web of 
the wing.
    On December 21, 1993, the FAA issued AD 93-25-13, amendment 39-8777 
(59 FR 1903, January 13, 1994), applicable to certain Airbus Model A320 
series airplanes, which requires cold expansion of certain attachment 
holes for the forward pintle fitting and certain holes at the actuating 
cylinder anchorage of the main landing gear (MLG).
    Those actions were prompted by the results of fatigue testing 
conducted by the manufacturer. The requirements of those ADs are 
intended to prevent fatigue cracking, which may lead to reduced 
structural integrity of the wing and MLG.

Actions Since Issuance of Previous Rules

    Since the issuance of AD 93-08-13 and AD 93-25-13, the Direction 
Generale de l'Aviation Civile (DGAC), which is the airworthiness 
autority for France, has advised the FAA that cracks were found on a 
Model A320 series airplane despite compliance with the requirements of 
those ADs. Investigation by the manufacturer provided further 
indication that an airplane on which the modifications required by that 
AD were installed could experience cracking prior to reaching the 
design life limits of the airplane. In response to these findings, the 
DGAC mandated repetitive ultrasonic inspections to detect fatigue 
cracks on the rear spar to ensure the structural integrity of the 
airplane.
    Subsequent analysis of the results of the ultrasonic inspections 
indicated that reducing the inspection threshold for selected holes 
would ensure the structural integrity of the area and prevent the need 
for extensive repairs of the wing inner rear spar.

Explanation of Relevant Service Information

    Airbus issued Service Bulletin A320-57-1088, dated September 30, 
1996; Revision 01, dated September 17, 1997; and Revision 02, dated 
July 29, 1999. This service bulletin describes procedures for 
repetitive ultrasonic inspections to detect cracking of the rear spar 
of the wing in the area of holes for the attachment of the gear rib, 
the forward pintle fitting, and the MLG actuating cylinder anchorage. 
Revision 02 specifies a reduced threshold for the initial inspection of 
certain holes [holes 52 through 55 (actuating cylinder anchorage) and 
holes 82, 83, 87, and 88 (gear support rib)]; the compliance time for 
the initial inspection of the remaining 32 holes is unchanged.
    Accomplishment of the actions specified in the service bulletin 
described previously is intended to adequately address the identified 
unsafe condition. The DGAC classified Airbus Service Bulletin A320-57-
1088 as mandatory and issued French airworthiness directive 1999-264-
135(B), dated June 30, 1999, in order to ensure the continued 
airworthiness of these airplanes in France.
    Airbus also issued Service Bulletin A320-57-1089, dated December 
22, 1996, Revision 01, dated April 17, 1997; and Revision 02, dated 
November 6, 1998. This service bulletin describes a modification of all 
affected fastener holes in the rear spar of the wing. The modification 
involves a cold re-expansion of the holes in the rear spar of the wing 
for the attachment of gear rib 5, the forward pintle fitting, and the 
actuating cylinder anchorage; cold expansion of the pintle fitting and 
gear rib 5; and installation of interference fit fasteners into the 
rear spar and gear rib 5 while maintaining a clearance fit in the 
actuating cylinder anchorage and pintle fitting. This service bulletin 
specifies that the modification would

[[Page 6568]]

eliminate the need for the repetitive ultrasonic inspections specified 
by Airbus Service Bulletin A320-57-1088. It would also eliminate the 
need for the modification specified by Airbus Service Bulletin A320-57-
1004 and the cold expansion specified by Airbus Service Bulletin A320-
57-1060, if accomplished prior to the accumulation of 12,000 total 
flight cycles.

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 93-08-15 and 
AD 93-25-13 to continue to require modification of the wing rear spar 
web and cold expansion of certain attachment holes for the forward 
pintle fitting and certain holes at the actuating cylinder anchorage of 
the MLG. The proposed AD would add a requirement for repetitive 
ultrasonic inspections to detect fatigue cracking in certain areas of 
the wing rear spar, and repair of cracking. This proposed AD also would 
provide for optional terminating action for the inspections proposed by 
this AD.

Difference Between Proposed Rule and Service Bulletin

    Operators should note that, although Service Bulletin A320-57-1088 
specifies that the manufacturer may be contacted for a repair if cracks 
are found, this proposal would require the repair of those cracks 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 proposed AD, a repair approved by the FAA 
or the DGAC would be acceptable for compliance with this proposed AD.

Cost Impact

    There are approximately 126 airplanes of U.S. registry that would 
be affected by this proposed AD.
    Subsequent to the issuance of AD 93-08-15 and AD 93-25-13, the FAA 
reviewed the figure it used in calculating the labor rate relevant to 
the required AD activities. In order to account for various 
inflationary costs in the airline industry, the FAA has found it 
appropriate to increase the labor rate used in these calculations from 
$55 per work hour to $60 per work hour. The economic impact 
information, below, has been revised to reflect this increase in the 
specified hourly labor rate.
    It takes approximately 60 work hours per airplane to accomplish the 
modification of the rear spar web of the wing, as required by AD 93-08-
15 and retained in this AD, at an average labor rate of $60 per work 
hour. Based on these figures, the total cost impact of the modification 
on U.S. operators is estimated to be $3,600 per airplane.
    It takes approximately 600 work hours per airplane to accomplish 
the cold expansion of certain holes associated with the MLG, as 
required by AD 93-25-13 and retained in this AD, at an average labor 
rate of $60 per work hour. Required parts are provided by the 
manufacturer at no cost to the operators. Based on these figures, the 
total cost impact of the cold expansion on U.S. operators is estimated 
to be $36,000 per airplane.
    The inspection that is proposed in this AD action would take 
approximately 24 work hours per airplane to accomplish, 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 $181,440, or $1,440 per airplane, per inspection cycle.
    The cost impact figures discussed above are 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.
    Should an operator elect to accomplish the optional terminating 
action specified in this proposed AD, it would take approximately 750 
work hours, at an average labor rate of $60 per work hour. The required 
parts would cost $27,036; $30,595; or $32,727; depending on the 
airplane configuration. Based on these figures, the cost per airplane 
of the optional terminating action proposed by this AD is estimated to 
be $72,036; $75,595; or $77,727.

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 amendments 39-8563 (58 FR 
27923, May 12, 1993) and 39-8777 (59 FR 1903, January 13, 1994) and by 
adding a new airworthiness directive (AD), to read as follows:

Airbus Industrie: Docket 98-NM-99-AD. Supersedes AD 93-08-15, 
Amendment 39-8563; and AD 93-25-13, Amendment 39-8777.

    Applicability: Model A320 series airplanes, certificated in any 
category, except those on which Airbus Modification 24591 (Airbus 
Service Bulletin A320-57-1089, dated December 22, 1996; Revision 01, 
dated April 17, 1997; or Revision 02, dated November 6, 1998) has 
been accomplished.


[[Page 6569]]


    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 (f)(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 in certain areas of the 
rear spar of the wing, which may lead to reduced structural 
integrity of the wing and the main landing gear (MLG), accomplish 
the following:

Restatement of Actions Required by AD 93-08-15

    (a) For airplanes having manufacturer's serial numbers (MSN) 003 
through 008 inclusive, and 010 through 021 inclusive: Prior to the 
accumulation of 12,000 total flight cycles, or within 500 flight 
cycles after June 11, 1993 (the effective date of AD 93-08-15, 
amendment 39-8563), whichever occurs later, modify the inner rear 
spar web of the wing in accordance with Airbus Industrie Service 
Bulletin A320-57-1004, Revision 01, dated September 24, 1992, or 
Revision 02, dated June 14, 1993.

Restatement of Actions Required by AD 93-25-13

    (b) For airplanes having MSN's 002 through 051 inclusive: Prior 
to the accumulation of 12,000 total flight cycles, or within 2,000 
flight cycles after February 14, 1994 (the effective date of AD 93-
25-13, amendment 39-8777), whichever occurs later, accomplish the 
requirements of paragraphs (b)(1) and (b)(2) of this AD in 
accordance with Airbus Industrie Service Bulletin A320-57-1060, 
dated December 8, 1992; or Revision 02, dated December 16, 1994.
    (1) Perform a cold expansion of all the attachment holes for the 
forward pintle fitting of the MLG, except for the holes that are for 
taper-lok bolts.
    (2) Perform a cold expansion of the holes at the actuating 
cylinder anchorage of the MLG.

    Note 2: Accomplishment of the cold expansion in accordance with 
Airbus Service Bulletin A320-57-1060, Revision 01, dated April 26, 
1993, is also acceptable for compliance with the requirements of 
paragraph (b) of this AD.

New Actions Required by This AD

    (c) For all airplanes: Perform an ultrasonic inspection to 
detect cracking of the rear spar of the wing, in accordance with 
Airbus Service Bulletin A320-57-1088, Revision 02, dated July 29, 
1999; at the applicable time specified by paragraph (c)(1) or (c)(2) 
of this AD. Repeat the inspection thereafter at intervals not to 
exceed 3,600 flight cycles.
    (1) For airplanes on which the actions specified by Airbus 
Service Bulletin A320-57-1004, Revision 02, dated June 14, 1993, or 
earlier version; and Airbus Service Bulletin A320-57-1060, Revision 
02, dated December 16, 1994, or earlier version; have been 
accomplished: Perform the inspection of all applicable fastener 
holes within 12,000 flight cycles after accomplishment of the 
service bulletins, or within 750 flight cycles after the effective 
date of this AD, whichever occurs later.
    (2) For airplanes on which the actions specified by Airbus 
Modification 20740 and Airbus Service Bulletin A320-57-1060, 
Revision 02, dated December 16, 1994, or earlier version, have been 
accomplished; or on which Airbus Modifications 20740, 20741, and 
20796 have been accomplished: Perform the inspections at the 
locations and applicable times specified by paragraphs (c)(2)(i) and 
(c)(2)(ii) of this AD.
    (i) Perform the inspection of left and right fastener holes 52 
to 55, 82, 83, 87, and 88; located in the rear spar of the wing; 
prior to the accumulation of 17,300 total flight cycles, or within 
750 flight cycles after the effective date of this AD, whichever 
occurs later. If any cracking is found, prior to further flight, 
accomplish the requirements of paragraph (c)(2)(ii) of this AD.
    (ii) Except as required by paragraph (c)(2)(i) of this AD: 
Perform the inspection of all fastener holes located in the rear 
spar of the wing that are not identified in paragraph (c)(2)(i) of 
this AD prior to the accumulation of 20,000 total flight cycles, or 
within 200 flight cycles after the effective date of this AD, 
whichever occurs later.

    Note 3: Accomplishment of the actions specified by Airbus 
Service Bulletin A320-57-1088, dated September 30, 1996, or Revision 
01, dated September 17, 1997, prior to the effective date of this AD 
is acceptable for compliance with the requirements of the initial 
inspection required by paragraph (c) of this AD.

    (d) If any crack is found during any inspection required by 
paragraph (c) of this AD: Prior to further flight, repair in 
accordance with a method approved by either the Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate; 
or the DGAC (or its delegated agent). For a repair method to be 
approved by the Manager, International Branch, ANM-116, as required 
by this paragraph, the Manager's approval letter must specifically 
reference this AD.

Optional Terminating Action

    (e) Modification of all specified fastener holes in the rear 
spar of the wing in accordance with Airbus Service Bulletin A320-57-
1089, dated December 22, 1996; Revision 01, dated April 17, 1997; or 
Revision 02, dated November 6, 1998; constitutes terminating action 
for the ultrasonic inspections required by this AD. Such 
modification, if accomplished prior to the accumulation of 12,000 
total flight cycles, constitutes terminating action for the actions 
required by paragraphs (a) and (b) of this AD.

Alternative Methods of Compliance

    (f)(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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 93-25-13; amendment 39-8777, are approved as 
alternative methods of compliance with this AD.

    Note 4: 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

    (g) 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 5: The subject of this AD is addressed in French 
airworthiness directive 1999-264-135(B), dated June 30, 1999.


    Issued in Renton, Washington, on February 4, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-3132 Filed 2-9-00; 8:45 am]
BILLING CODE 4910-13-U