[Federal Register Volume 63, Number 24 (Thursday, February 5, 1998)]
[Proposed Rules]
[Pages 5900-5902]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-2782]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-263-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospatiale Model ATR72 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 Aerospatiale Model ATR72 
series airplanes. This proposal would require a one-time high frequency 
eddy current inspection to detect cracking of the lower fuselage 
structure, and repair, if necessary. This proposal also would require 
modification of certain fastener holes in the lower fuselage structure. 
This proposal is prompted by the issuance of mandatory continuing 
airworthiness information by a foreign civil airworthiness authority. 
The actions specified by the proposed AD are intended to prevent 
reduced structural integrity of the airplane due to fatigue cracking in 
the lower fuselage structure.

DATES: Comments must be received by March 9, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-263-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-263-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-263-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 Aerospatiale Model ATR72 series 
airplanes. The DGAC advises that the results of full-scale fatigue 
testing on a Model ATR72 test article revealed that fatigue cracks may 
develop in the lower

[[Page 5901]]

fuselage structure in the area of the side brace fitting near frame 25. 
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

    Aerospatiale has issued Service Bulletins ATR72-53-1022, Revision 
2, dated February 20, 1995; ATR72-53-1034, Revision 1, dated March 28, 
1995; and ATR72-53-1053, Revision 1, dated March 28, 1995. These 
service bulletins describe procedures for a one-time high frequency 
eddy current inspection to detect cracking of the lower fuselage 
structure; and modification of certain fastener holes in the lower 
fuselage structure in the area of the side brace fitting near frame 25 
on the left- and right-hand sides. Accomplishment of the actions 
specified in these service bulletins is intended to adequately address 
the identified unsafe condition. The DGAC classified these service 
bulletins as mandatory and issued French airworthiness directive 94-
191-022(B), dated August 17, 1994, 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 that the repair of any crack or oversize hole would be required 
to be accomplished in accordance with a method approved by the FAA.

Cost Impact

    The FAA estimates that 7 airplanes of U.S. registry would be 
affected by this proposed AD.
    Accomplishment of the actions specified in Aerospatiale Service 
Bulletin ATR72-53-1022 would take approximately 80 work hours per 
airplane, at an average labor rate of $60 per work hour. Required parts 
would be provided by the manufacturer at no cost to the operators. 
Based on these figures, the cost impact on U.S. operators of the 
actions specified in this service bulletin and proposed by this AD is 
estimated to be $4,800 per airplane.
    Accomplishment of the actions specified in Aerospatiale Service 
Bulletin ATR72-53-1034 would take approximately 65 work hours per 
airplane, at an average labor rate of $60 per work hour. Required parts 
would be provided by the manufacturer at no cost to the operators. 
Based on these figures, the cost impact on U.S. operators of the 
actions specified in this service bulletin and proposed by this AD is 
estimated to be $3,900 per airplane.
    Accomplishment of the actions specified in Aerospatiale Service 
Bulletin ATR72-53-1053 would take approximately 65 work hours per 
airplane, at an average labor rate of $60 per work hour. Required parts 
would be provided by the manufacturer at no cost to the operators. 
Based on these figures, the cost impact on U.S. operators of the 
actions specified in this service bulletin and proposed by this AD is 
estimated to be $3,900 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:

Aerospatiale: Docket 97-NM-263-AD.

    Applicability: Model ATR72 series airplanes on which 
Aerospatiale Modification 2879 or Modification 2628 has not been 
incorporated, 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 reduced structural integrity of the airplane due to 
fatigue cracking in the lower fuselage structure, accomplish the 
following:
    (a) Prior to the accumulation of 17,500 total flight cycles, or 
within 500 flight cycles after the effective date of this AD, 
whichever occurs later: Except as provided in paragraph (b) of this 
AD, perform a one-time high frequency eddy current inspection to 
detect fatigue cracking around the fastener holes in the lower 
fuselage structure in the area of the

[[Page 5902]]

side brace fitting near frame 25 on the left-and right-hand sides, 
and modify crack-free fastener holes, as required by paragraph 
(a)(1) and/or (a)(2) of this AD, as applicable.
    (1) For airplanes on which Aerospatiale Modification 2879 has 
not been installed: Perform the inspection and modification in 
accordance with Aerospatiale Service Bulletin ATR72-53-1022, 
Revision 2, dated February 20, 1995.
    (2) For airplanes on which Aerospatiale Modification 2628 has 
not been installed: Perform the inspection and modifications in 
accordance with Aerospatiale Service Bulletins ATR72-53-1034, 
Revision 1, and ATR72-53-1053, Revision 1, both dated March 28, 
1995.
    (b) If any crack or oversize hole is found during the 
accomplishment of paragraph (a) of this AD, and if any service 
bulletin listed in paragraph (a) of this AD specifies to contact the 
manufacturer for an appropriate corrective action: Prior to further 
flight, repair the discrepancy in accordance with a method approved 
by the Manager, International Branch, ANM-116, FAA, Transport 
Airplane Directorate.
    (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 94-191-022(B), dated August 17, 1994.

    Issued in Renton, Washington, on January 29, 1998.
Darrell M. Pederson,
 Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-2782 Filed 2-4-98; 8:45 am]
BILLING CODE 4910-13-U