[Federal Register Volume 64, Number 123 (Monday, June 28, 1999)]
[Proposed Rules]
[Pages 34579-34581]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-16334]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-106-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Model A319, A320, and A321 
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 Airbus A319, A320, and 
A321 series airplanes. This proposal would require modification of the 
electro-distributor for the nose wheel steering servo-control. 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 uncommanded nose 
landing gear wheel rotation, due to defective seals in the wheel 
steering selector valve of the hydraulic control unit for the nose 
landing gear, which could result in reduced controllability of the 
airplane.

DATES: Comments must be received by July 28, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-106-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 Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 
Blagnac Cedex, 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 99-NM-106-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. 99-NM-106-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction Gorale de l'Aviation Civile (DGAC), which is the 
airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on certain Airbus Model A319, A320, and A321 series 
airplanes. The DGAC advises that there have been several cases of 
uncommanded nose landing gear wheel rotation on in-service airplanes. 
Such uncommanded rotation was caused by defective seals in the wheel 
steering selector valve of the hydraulic control unit for the nose 
landing gear, which resulted in failure of the nose landing gear wheel 
steering system. The seals

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were found to be extruded due to aging or the absence of a backup ring. 
Uncommanded nose landing gear wheel rotation, if not corrected, could 
result in reduced controllability of the airplane.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A320-32-1197, Revision 01, dated 
February 11, 1999, which describes procedures for modification of the 
electro-distributor for the nose wheel steering servo-control. The 
modification involves replacing the O-ring seals fitted to the electro-
distributor with new ``GREENE TWEED'' seals with a back-up ring. 
Accomplishment of the action specified in the service bulletin is 
intended to adequately address the identified unsafe condition. The 
DGAC classified this service bulletin as mandatory and issued French 
airworthiness directive 1999-124-129(B), dated March 24, 1999, in order 
to assure the continued airworthiness of these airplanes in France.
    Airbus Service Bulletin A320-32-1197 references MESSIER-BUGATTI 
Service Bulletin C24736-32-3166, dated December 4, 1998, as an 
additional source of service information for accomplishment of the 
modification.

FAA's Conclusions

    These airplane models are manufactured in France and are type 
certificated for operation in the United States under the provisions of 
Sec. 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 action specified in the service bulletin described previously.

Cost Impact

    The FAA estimates that 208 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 7 work 
hours per airplane to accomplish the proposed modification, and that 
the average labor rate is $60 per work hour. Required parts would cost 
approximately $335 per airplane. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be 
$157,040, or $755 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:

Airbus Industrie: Docket 99-NM-106-AD.

    Applicability: Model A319, A320, and A321 series airplanes; 
except those airplanes on which Airbus Modification 23740 was 
accomplished during production, and those airplanes on which Airbus 
Service Bulletin A320-32-1197, dated October 9, 1998, or Revision 
01, dated February 11, 1999, has 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 uncommanded nose landing gear wheel rotation, due to 
defective seals in the wheel steering selector valve of the 
hydraulic control unit for the nose landing gear, which could result 
in reduced controllability of the airplane, accomplish the 
following:

Modification

    (a) Within 12 months after the effective date of this AD, modify 
the electro-distributor for the nose wheel steering servo-control in 
accordance with Airbus Industrie Service Bulletin A320-32-1197, 
Revision 01, dated February 11, 1999.

    Note 2: Airbus Service Bulletin A320-32-1197 references MESSIER-
BUGATTI Service Bulletin C24736-32-3166, dated December 4, 1998, as 
an additional source of service information for accomplishment of 
the modification.

    Note 3: Replacement of the by-pass valve in accordance with 
MESSIER-BUGATTI Service Bulletin C24736-32-3126, dated February 15, 
1995, as revised by Change Notice Number 1, dated March 16, 1999, is 
considered acceptable for compliance with the action specified in 
paragraph (a) of this AD.

Spares

    (b) As of the effective date of this AD, no person shall install 
a hydraulic control unit, part number C24736000 or C24736001, on any 
airplane, unless it has been modified in accordance with the actions 
required by paragraph (a) of this AD.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that

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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 4: 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 
Sec. Sec. 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 5: The subject of this AD is addressed in French 
airworthiness directive 1999-124-129(B), dated March 24, 1999.

    Issued in Renton, Washington, on June 22, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-16334 Filed 6-25-99; 8:45 am]
BILLING CODE 4910-13-U