[Federal Register Volume 64, Number 148 (Tuesday, August 3, 1999)]
[Proposed Rules]
[Pages 42054-42056]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-19808]


-----------------------------------------------------------------------

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.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Aerospatiale Model ATR72 
series airplanes. This proposal would require 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. 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 
ensure that fatigue cracking of certain structural elements are 
detected and corrected; such fatigue cracking could adversely affect 
the structural integrity of these airplanes.

DATES: Comments must be received by September 17, 1999.

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.
    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, 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-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, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 97-NM-273-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, has notified the FAA that an unsafe 
condition may exist on Aerospatiale Model ATR72 series airplanes. The 
DGAC advises that analysis of fatigue test data has revealed that 
certain inspections must be performed at specific intervals to preclude 
fatigue cracking in certain areas of the airplane. Additionally, 
certain life limits must be imposed for various components on these 
airplanes to preclude the onset of fatigue cracking in those 
components.
    Fatigue cracking of certain structural elements, if not detected 
and corrected in a timely manner, could adversely affect the structural 
integrity of these airplanes.

Description of Service Information

    Aerospatiale has issued ATR72 Maintenance Planning Document (MPD), 
``Time Limits,'' Revision 1, dated February 1996, which includes the 
following:
    1. Life limit times for certain structural components or parts of 
the nose landing gear, the main landing gear, the main landing gear 
support structure, engine components, and various equipment. And
    2. Structural inspection times to detect fatigue cracking of 
certain Structural Significant Items (SSI's).

[[Page 42055]]

    Performing the specified structural inspections will identify 
fatigue cracking, and revising the component life limits will preclude 
the onset of fatigue cracking of certain structural elements of the 
airplane.
    The French DGAC has classified Revision 1 of the Time Limits 
section of the Aerospatiale Model ATR72 Maintenance Planning Document, 
dated February 1996, as mandatory, and has issued French airworthiness 
directive 95-105-026(B), dated May 24, 1995, 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 French DGAC has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the French 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.

Description of the 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 a revision to the 
Airworthiness Limitations Section of the Instructions for Continued 
Airworthiness [Aerospatiale refers to this as the maintenance planning 
document (MPD)] to incorporate inspections to detect fatigue cracking 
of certain SSI's. The proposed AD also would revise life limits for 
certain equipment and various components that are specified in the Time 
Limits section of the ATR72 Airworthiness Limitations of the 
Maintenance Planning Document, dated February 15, 1996.

Explanation of Action Taken by the FAA

    In accordance with airworthiness standards requiring ``damage 
tolerance assessments'' [reference current section 1529 of parts 23, 
25, 27, and 29 of the Federal Aviation Regulations (FAR); section 4 of 
parts 33 and 35 of the FAR; section 82 of part 31 of the FAR; and the 
Appendices referenced in those sections], all products certificated to 
comply with those sections must have Instructions for Continued 
Airworthiness (or, for some products, maintenance manuals), that 
include an Airworthiness Limitations Section. That section must set 
forth:
     Mandatory replacement times for structural components,
     Structural inspection intervals, and
     Related approved structural inspection procedures 
necessary to show compliance with the damage-tolerance requirements.
    Compliance with the terms specified in the Airworthiness 
Limitations Sections is required by sections 43.16 (for persons 
maintaining products) and 91.403 (for operators) of the FAR.
    In order to require compliance with these inspection intervals and 
life limits, the FAA must engage in rulemaking, namely the issuance of 
an AD. For products certificated to comply with the referenced part 25 
requirements, it is within the authority of the FAA to issue an AD 
requiring a revision to the Airworthiness Limitations Section that 
includes reduced life limits, or new or different structural inspection 
requirements. These revisions then are mandatory for operators under 
section 91.403(c) of the FAR, which prohibits operation of an airplane 
for which Airworthiness Limitations have been issued unless the 
inspection intervals specified in those limitations have been complied 
with.
    Once that document is revised, as required, and the AD has been 
fully complied with, the life limit or structural inspection change 
remains enforceable as a part of the Airworthiness Limitations. (This 
is analogous to AD's that require changes to the Limitations Section of 
the Airplane Flight Manual.)
    Requiring a revision of the Airworthiness Limitations, rather than 
requiring individual inspections, 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 AD, in one place within the operator's 
maintenance program, thereby reducing the risk of non-compliance 
because of oversight or confusion.

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 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:


[[Page 42056]]


    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:
    (a) Within 30 days after the effective date of this AD, revise 
the Airworthiness Limitations Section of the Instructions for 
Continued Airworthiness in accordance with Section 9, ``Time 
Limits,'' of the ATR72 Maintenance Planning Document, Revision 1, 
dated February 1996. This may be accomplished by inserting a copy of 
Section 9, ``Time Limits,'' of the ATR72 Maintenance Planning 
Document, Revision 1, dated February 1996, into the Airworthiness 
Limitations Section of the Instructions for Continued Airworthiness.
    (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.
    (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.

    (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 directives 95-105-026 (B), dated May 24, 1995.

    Issued in Renton, Washington, on July 27, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-19808 Filed 8-2-99; 8:45 am]
BILLING CODE 4910-13-U