[Federal Register Volume 60, Number 203 (Friday, October 20, 1995)]
[Proposed Rules]
[Pages 54202-54203]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25988]



      
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 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 60, No. 203 / Friday, October 20, 1995 / 
Proposed Rules  

[[Page 54202]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-77-AD]


Airworthiness Directives; Airbus Model A320 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 Model A320 series 
airplanes. This proposal would require replacement of the relays in the 
forward electronics rack of the braking system of the landing gear with 
new relays. This proposal is prompted by reports of loss of the systems 
of the braking/steering control unit (BSCU) on these airplanes due to 
electrical overvoltage of the relays. The actions specified by the 
proposed AD are intended to prevent such electrical overvoltage of the 
relays, which could result in the loss of the BSCU systems, and 
subsequent loss of the antiskid functions and nose wheel steering of 
the airplane.

DATES: Comments must be received by December 4, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-77-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: Charles D. Huber, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (206) 
227-2589; 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 95-NM-77-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. 95-NM-77-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 Airbus Model A320 series 
airplanes. The DGAC advises that it has received several reports of 
loss of the two systems of the braking/steering control unit (BSCU) on 
these airplanes. Investigation revealed that this problem was caused by 
an electrical overvoltage of the relays during the transfer to the 
second system of the BSCU upon the loss of the first system. This 
condition, if not corrected, could result in loss of the BSCU system, 
and subsequent loss of the antiskid functions and nose wheel steering 
of the airplane.
    Airbus has issued Service Bulletin A320-32-1115, Revision 2, dated 
September 21, 1994, which describes procedures for replacement of the 
relays 24 GG and 25 GG in the forward electronics rack 90VU of zone 120 
of the braking system of the landing gear with new relays. This 
replacement will improve the electrical overvoltage protection on the 
braking system. The DGAC classified this service bulletin as mandatory 
and issued French airworthiness directive (CN) 93-163-043 (B), dated 
September 29, 1993, in order to assure the continued airworthiness of 
these airplanes in France.
    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.
    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 replacement of 
certain relays in the forward electronics rack 90VU of the braking 
system of the landing gear with new relays. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.
    The FAA estimates that 87 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take 

[[Page 54203]]
approximately 2 work hours per airplane to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would be supplied by the manufacturer at no cost to the 
operators. Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $10,440, or $120 per 
airplane.
    The total 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.
    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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Airbus Industrie: Docket 95-NM-77-AD.

    Applicability: Model A320 series airplanes on which Airbus 
Modification 23611 (reference Airbus Service Bulletin A320-32-1115) 
has not been installed; 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 use the authority 
provided in paragraph (b) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an electrical overvoltage of the relays, which could 
result in the loss of the braking/steering control unit (BSCU) 
systems, and subsequent loss of the antiskid functions and nose 
wheel steering of the airplane, accomplish the following:
    (a) Within 10 months after the effective date of this AD, 
replace relays 24 GG and 25 GG in the forward electronics rack 90VU 
of zone 120 of the braking system of the landing gear with new 
relays, in accordance with Airbus Service Bulletin A320-32-1115, 
Revision 2, dated September 21, 1994.
    (b) 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.

    (c) 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 October 16, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-25988 Filed 10-19-95; 8:45 am]
BILLING CODE 4910-13-U