[Federal Register Volume 61, Number 161 (Monday, August 19, 1996)]
[Proposed Rules]
[Pages 42825-42826]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-21010]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-140-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 modification of the pitch 
uncoupling mechanism of both elevators. This proposal is prompted by 
reports of fatigue cracking of the pitch uncoupling mechanism and the 
torque tube of the elevator. Failure of the pitch uncoupling mechanism 
due to fatigue cracking could result in the uncommanded uncoupling of 
the elevators. The actions specified by the proposed AD are intended to 
prevent such fatigue cracking and subsequent uncommanded uncoupling of 
the elevators, which could result in reduced controllability of the 
airplane.

DATES: Comments must be received by September 27, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-140-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: Gary Lium, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1112; fax (206) 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 96-NM-140-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-103, Attention: Rules 
Docket No. 96-NM-140-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 recently notified the FAA that an 
unsafe condition may exist on certain Aerospatiale Model ATR72 series 
airplanes. The DGAC advises that it has received reports indicating 
that fatigue cracks have been found at the junction of the center 
section of the pitch uncoupling mechanism of the elevators, and the 
torque tube that connects the operation of both elevators. Such fatigue 
cracking could cause failure of the elevator coupling mechanism, and 
result in the uncommanded uncoupling of the elevators. This condition, 
if not detected and corrected in a timely manner, could result in 
reduced controllability of the airplane.

Explanation of Relevant Service Information

    Avions de Transport Regional (ATR) has issued Service Bulletin 
ATR72-27-1044, dated March 5, 1996, which describes procedures for 
modifying the pitch uncoupling mechanism of the elevators. Among other 
actions, the modification involves replacing the aluminum flanges of 
the pitch uncoupling mechanism with steel flanges, and reidentifying 
the uncoupling mechanism with a new part number after modification. The 
replacement will prevent fatigue cracking of the pitch uncoupling 
mechanism and the torque tube of the elevators. The DGAC classified 
this service bulletin as mandatory and issued French airworthiness 
directive (CN) 96-019-028(B), dated January 17, 1996, 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 modification of the 
elevator uncoupling mechanism. This action would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Cost Impact

    The FAA estimates that 51 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 55 work 
hours per airplane to accomplish the proposed

[[Page 42826]]

actions, and that the average labor rate is $60 per work hour. The 
required parts would be provided by the manufacturer at not cost to the 
operator. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $168,300, or $3,300 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 96-NM-140-AD.

    Applicability: Model ATR72-101, -102, -201, -202, -211, and -212 
series airplanes on which Modification 4495 or Aerospatiale Service 
Bulletin ATR 72-27-1044 has not been accomplished; 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 uncoupling of the elevators due to failure of the 
elevator coupling mechanism and resultant reduced controllability of 
the airplane, accomplish the following:
    (a) Prior to the accumulation of 12,000 total landings, or 
within 1,000 landings after the effective date of this AD, whichever 
occurs later: Modify the elevator uncoupling mechanism in accordance 
with Aerospatiale Service Bulletin ATR72-27-1044, dated March 5, 
1996.
    (b) As of the effective date of this AD, no person shall install 
a pitch uncoupling mechanism of the elevator, having the following 
part numbers, on any airplane:

S2738194100800
S2738194102895
S2738194102200
S2738194102400
S2738194102800
S2738194103200

    (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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (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.

    Issued in Renton, Washington, on August 12, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-21010 Filed 8-16-96; 8:45 am]
BILLING CODE 4910-13-U