[Federal Register Volume 65, Number 164 (Wednesday, August 23, 2000)]
[Proposed Rules]
[Pages 51260-51263]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-21463]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-273-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospatiale Model ATR72 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

[[Page 51261]]


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 Aerospatiale Model ATR72 series 
airplanes, that would have required a revision to the Airworthiness 
Limitations Section of the Instructions for Continued Airworthiness to 
incorporate inspections to detect fatigue cracking in certain 
structure, inspection intervals, and life limits for certain 
components. That proposal was prompted by issuance of mandatory 
continuing airworthiness information by a foreign civil airworthiness 
authority. This new action revises the proposed rule to require the 
incorporation of revised and new inspections and life limits. The 
actions specified by this new proposed AD are intended to ensure that 
fatigue cracking of certain structural elements is detected and 
corrected; such fatigue cracking could adversely affect the structural 
integrity of these airplanes.

DATES: Comments must be received by September 18, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-273-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. Comments may be submitted via fax to (425) 227-1232.
    Comments may also be sent via the Internet using the following 
address: [email protected]. Comments sent via fax or the 
Internet must contain ``Docket No. 97-NM-273-AD'' in the subject line 
and need not be submitted in triplicate. Comments sent via the Internet 
as attached electronic files must be formatted in Microsoft Word 97 for 
Windows or ASCII text.
    The service information referenced in the proposed rule may be 
obtained from Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 
03, France. This information may be examined at the FAA, 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.
    Submit comments using the following format:
     Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
     For each issue, state what specific change to the proposed 
AD is being requested.
     Include justification (e.g., reasons or data) for each 
request.
    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-273-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, ANM-114, Attention: Rules Docket No. 97-NM-273-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 
Aerospatiale Model ATR72 series airplanes, was published as a notice of 
proposed rulemaking (NPRM) in the Federal Register on August 3, 1999 
(64 FR 42054). That NPRM would have required a revision to the 
Airworthiness Limitations Section of the Instructions for Continued 
Airworthiness to incorporate inspections to detect fatigue cracking in 
certain structure, inspection intervals, and life limits for certain 
components. That NPRM was prompted by issuance of mandatory continuing 
airworthiness information by a foreign civil airworthiness authority. 
Such fatigue cracking, if not corrected, would adversely affect the 
structural integrity of these airplanes.

Comments

    Due consideration has been given to the comments received in 
response to the NPRM.

Necessity for Rulemaking

    One commenter, an operator, questions the need to issue the 
proposed AD. The commenter notes that a listing of airworthiness 
limitations is required for type certification, as specified by section 
25.1529 of the Federal Aviation Regulations (14 CFR 25.1529) and 
Appendix H, paragraph H25.4. The commenter states that this listing is 
included in its Operations Specifications, and that such specifications 
would never be approved with any airworthiness limitations that were 
beyond the limits specified by the manufacturer. In light of this, the 
commenter considers the actions required by the proposed rule to be 
redundant.
    The FAA infers that the commenter requests that the proposed AD be 
withdrawn. The FAA does not concur. As stated in the NPRM, all products 
certificated to comply with the airworthiness standards requiring 
``damage tolerance assessments'' must have Instructions for Continued 
Airworthiness (or, for some products, maintenance manuals), that 
include an Airworthiness Limitations Section (ALS).
    Based on in-service data or post-certification testing and 
evaluation, the manufacturer may revise the ALS to include new or more 
restrictive life limits and structural inspections, or it may become 
necessary for the FAA to impose new or more restrictive life limits and 
structural inspections, in order to ensure continued structural 
integrity and continued compliance with damage tolerance requirements. 
However, in order to require compliance with these new inspection 
requirements and life limits for previously certificated airplanes, the 
FAA must engage in rulemaking; namely, the issuance of an AD. Because 
loss of structural integrity would constitute an unsafe condition, it 
is appropriate to impose such requirements through the AD process.

[[Page 51262]]

Although prudent operators already may have incorporated the latest 
revisions of the ALS, issuance of this AD ensures that all operators 
take appropriate action to correct the identified unsafe condition.
    The practice of requiring a revision to the ALS, rather than 
requiring individual inspections, has been used for several years and 
is not a novel or unique procedure. Requiring ALS revisions is 
advantageous for operators because it allows them to record AD 
compliance status only once--at the time they make the revision--rather 
than after every inspection. It also has the advantage of keeping all 
airworthiness limitations, whether imposed by original certification or 
by the requirements of an AD, in one place within the operator's 
maintenance program, thereby reducing the risk of non-compliance 
because of oversight or confusion. In addition, for a large fleet of 
airplanes with several small operators, it is possible that operators 
may not receive revisions to the ALS. The AD process ensures that these 
operators are aware of the revisions to the ALS. No change to this 
proposed AD is necessary in this regard.

Request To Include Certification Maintenance Requirements Tasks

    One commenter, the manufacturer, states that the ``Time Limits'' 
section of the Maintenance Planning Document (MPD) also includes 
Certification Maintenance Requirements (CMR) tasks that are applicable 
to the equipment and systems and are necessary to keep the certificated 
airworthiness standard. The commenter suggests adding a paragraph to 
the proposed AD to require accomplishment of the CMR tasks.
    The FAA does not concur. Although the FAA agrees that 
accomplishment of CMR tasks is necessary to maintain these airplanes in 
an airworthy condition, the necessity for those actions is based on 
statistical safety analyses of various airplane systems prior to 
issuance of an airplane Type Certificate (TC). Thus, CMR tasks are 
undertaken for a different purpose than the actions required by this 
AD, and are intended to address a different unsafe condition than is 
addressed in this AD. However, if CMR tasks are added or made more 
restrictive following issuance of the TC, the FAA will consider 
separate rulemaking action to require accomplishment of those 
additional actions. No change to the AD is necessary in this regard.

Revisions to Service Information

    Two commenters advise the FAA that Revision 3 of the ``Time 
Limits'' section of the ATR72 MPD was issued in January 1998, and 
suggest that the proposed AD address the use of the later revision of 
that document. The manufacturer also advises that Revision 4 of the 
``Time Limits'' section for Model ATR72 series airplanes, dated July 
1999, is in the process of review and approval by the appropriate 
airworthiness authorities. The manufacturer suggests delaying issuance 
of the final rule until approval of this latest revision is granted.
    The FAA has received and reviewed the latest revision of the 
service information. Revision 4 differs from Revision 1, dated February 
1996 (which was referenced in the proposed AD as the appropriate source 
of service information), in that it revises certain life limits for 
structural components or parts of the landing gear, engine components, 
and various equipment; and structural inspection times to detect 
fatigue cracking of certain Structural Significant Items; and, for 
Model ATR72-212A series airplanes, adds new life limits and inspection 
thresholds and intervals. The FAA has determined that the actions 
required by this AD must be accomplished in accordance with Revision 4 
of the ``Time Limits'' section of the MPD, and is proposing such in 
this supplemental NPRM. Paragraph (a) of this proposed AD has been 
changed accordingly.

Use of Subsequent Service Information Revisions

    One commenter requests that the FAA revise the proposed AD to refer 
to the current revision of the ``Time Limits'' section of the MPD, ``or 
later approved revisions.'' The commenter suggests that only referring 
to the current revision in the AD may lead to confusion about the 
validity of subsequent revisions.
    The FAA does not concur. To use the phrase ``or later approved 
revisions'' in an AD when referring to future revisions of service 
information violates Office of the Federal Register (OFR) regulations 
regarding approval of materials that are ``incorporated by reference'' 
in rules. The AD may only refer to the service information that was 
submitted and approved by the OFR for ``incorporation by reference.'' 
In order for operators to use later revisions of the service 
information, either the AD must be revised to reference the specific 
later revisions, or the FAA must approve their use as an alternative 
method of compliance with this AD. No change to the AD is necessary in 
this regard.

MPD Section Reference

    Two commenters state that, although the ``Time Limits'' section of 
the MPD is incorrectly referenced in the proposed AD as Section 9, the 
correct reference is Section 13. The FAA acknowledges the correction. 
However, to avoid any confusion in case the section number changes in 
the future, the FAA has removed the reference to the specific section 
of the ``Time Limits'' section in paragraph (a) of this AD.

Conclusion

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

Cost Impact

    There are approximately 173 Aerospatiale Model ATR72 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 39 airplanes of U.S. registry would be affected by this 
proposed AD, that it would take approximately 1 work hour per airplane 
to accomplish the proposed actions, and that the average labor rate is 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators is estimated to be $2,340, or $60 per 
airplane.
    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 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

[[Page 51263]]

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:

Aerospatiale: Docket 97-NM-273-AD.
    Applicability: All Model ATR72 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 (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 ensure continued structural integrity of these airplanes, 
accomplish the following:

Airworthiness Limitations Revision

    (a) Within 30 days after the effective date of this AD, revise 
the Airworthiness Limitations Section of the Instructions for 
Continued Airworthiness by incorporating the ``Time Limits'' section 
of the ATR72 Maintenance Planning Document, Revision 4, dated July 
1999, into the Airworthiness Limitations Section.
    (b) Except as provided in paragraph (c) of this AD: After the 
actions specified in paragraph (a) of this AD have been 
accomplished, no alternative inspections or inspection intervals may 
be approved for the structural elements specified in the documents 
listed in 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 95-105-026 (B), dated May 24, 1995.


    Issued in Renton, Washington, on August 17, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-21463 Filed 8-22-00; 8:45 am]
BILLING CODE 4910-13-U