[Federal Register Volume 63, Number 113 (Friday, June 12, 1998)]
[Proposed Rules]
[Pages 32152-32154]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-15676]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-146-AD]
RIN 2120-AA64


Airworthiness Directives; Aerospatiale Model ATR42 and 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 ATR42 
and ATR72 series airplanes. This proposal would require one-time 
inspections to verify the correct shape of the stiffeners for the upper 
engine cowl and to detect wear of the aft upper fittings of the rear 
engine mounts, and corrective actions, if necessary. 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 wear (scratches or grooving) of 
the aft upper fittings of the rear engine mount, and consequent reduced 
structural integrity of the engine mounts.

DATES: Comments must be received by July 13, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-146-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

[[Page 32153]]

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-146-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-146-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 ATR42 and ATR72 
series airplanes. The DGAC advises that it has received reports 
indicating that wear (scratches or grooving) was found between the aft 
upper fittings of the rear engine mount and the stiffener of the upper 
engine cowl. Investigation revealed that the stiffener of the upper 
engine cowl, which protects the aft upper fittings, was not shaped 
properly during manufacturing, which caused interference between the 
engine mount and the stiffener. Installation of these misshapen 
stiffeners could result in wear of the aft upper fittings of the rear 
engine mount. Such wear, if not corrected, could result in reduced 
structural integrity of the engine mounts.

Explanation of Relevant Service Information

    The manufacturer has issued Avions de Transport Regional Service 
Bulletins ATR42-54-0019 (for Model ATR42 series airplanes) and ATR72-
54-1011 (for Model ATR72 series airplanes), both dated March 9, 1998. 
These service bulletins describe procedures for a one-time visual 
inspection to verify the correct shape of the stiffeners for the upper 
left and right engine cowls; and a one-time detailed visual inspection 
to detect wear (scratches or grooving) of the aft upper fittings of the 
left- and right-hand rear engine mounts; and corrective actions, if 
necessary. The corrective actions include modification of the stiffener 
or replacement with a new stiffener, and repair of the aft upper 
fittings. Accomplishment of the actions specified in the service 
bulletins is intended to adequately address the identified unsafe 
condition. The DGAC classified these service bulletins as mandatory and 
issued French airworthiness directives 98-069-073(B) (for Model ATR42 
series airplanes), dated February 11, 1998; and 98-071-035(B) (for 
Model ATR72 series airplanes), dated February 11, 1998, as revised by 
Erratum 98-071-35(B), dated February 25, 1998, in order to assure the 
continued airworthiness of these airplanes in France.

FAA's Conclusions

    These airplane models are manufactured in France and are 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.

Differences Between Proposed Rule and Service Bulletin

    Operators should note that, although the service bulletins specify 
that the manufacturer may be contacted for disposition of certain wear 
conditions, this proposal would require the repair of those conditions 
to be accomplished in accordance with a method approved by the FAA.

Cost Impact

    The FAA estimates that 152 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 15 work 
hours 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 
$136,800, or $900 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:

Aerospatiale: Docket 98-NM-146-AD.

    Applicability: Model ATR42 and Model ATR72 series airplanes, as 
listed in Avions

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de Transport Regional Service Bulletins ATR42-54-0019 (for Model 
ATR42 series airplanes) and ATR72-54-1011 (for Model ATR72 series 
airplanes), both dated March 9, 1998; 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 prevent wear (scratches or grooving) of the aft upper 
fittings of the rear engine mount, and consequent reduced structural 
integrity of the engine mounts, accomplish the following:
    (a) Within 10 months after the effective date of this AD, 
perform a one-time visual inspection of the stiffeners for the upper 
left and right engine cowls to ensure the stiffeners have the 
correct lower edge profile, in accordance with the Accomplishment 
Instructions of Avions de Transport Regional Service Bulletin ATR42-
54-0019 or ATR72-54-1011, both dated March 9, 1998, as applicable.
    (1) If the lower edge profile of the stiffener meets the 
specifications of the applicable service bulletin, no further action 
is required by this paragraph.
    (2) If the lower edge profile of the stiffener does not meet the 
specifications of the applicable service bulletin, prior to further 
flight, modify or replace the stiffener with a new stiffener in 
accordance with the applicable service bulletin.
    (b) Within 10 months after the effective date of this AD, 
perform a one-time detailed visual inspection for wear (scratches or 
grooving) of the aft upper fittings of the left-and right-hand rear 
engine mounts, in accordance with Avions de Transport Regional 
Service Bulletin ATR42-54-0019 (for Model ATR42 series airplanes) or 
ATR72-54-1011 (for Model ATR72 series airplanes), both dated March 
9, 1998, as applicable.
    (1) If no wear is detected, no further action is required by 
this paragraph.
    (2) If any wear is detected that cannot be removed with a Type I 
or II blend-out as described in the applicable service bulletin, 
prior to further flight, repair in accordance with a method approved 
by the Manager, International Branch, ANM-116, FAA, Transport 
Airplane Directorate.
    (3) If any wear other than that specified in paragraph (b)(2) of 
this AD is detected, prior to further flight, repair in accordance 
with the Accomplishment Instructions of the applicable service 
bulletin.
    (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, 8-069-073(B) (for Model ATR42 series 
airplanes), dated February 11, 1998, and 98-071-035(B) (for Model 
ATR72 series airplanes), dated February 11, 1998, as revised by 
Erratum 98-071-35(B), dated February 25, 1998.

    Issued in Renton, Washington, on June 5, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-15676 Filed 6-11-98; 8:45 am]
BILLING CODE 4910-13-U