[Federal Register Volume 62, Number 4 (Tuesday, January 7, 1997)]
[Proposed Rules]
[Pages 949-951]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-252]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-143-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Industrie Model 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 Industrie Model 
A320 and A321 series airplanes. This proposal would require replacement 
of two elevator aileron computers (ELAC) with ELAC's that contain new 
software. This proposal is prompted by reports indicating that some of 
these airplanes have experienced uncommanded movements of the ailerons. 
The actions specified by the proposed AD are intended to prevent 
situations, such as uncommanded rolls during turbulent conditions, 
which could lead to reduced controllability of the airplane.

DATES: Comments must be received by February 18, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-143-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 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, 
stamp postcard on which the following statement is made: ``Comments to 
Docket Number 95-NM-143-AD.'' The postcard will be date stamped and 
returned to the commenter.

[[Page 950]]

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-143-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, has notified the FAA that an unsafe 
condition may exist on certain Airbus Industrie Model A320 and A321 
series airplanes. The DGAC advises that it has received reports 
indicating that some of these airplanes have experienced uncommanded 
rolls; flight crews reported these rolls as ranging from 5 degrees to 
30 degrees.
    The flight control system for both airplane models uses fly-by-wire 
technology. There are situations where the sensitivity of the fly-by-
wire design creates safety concerns. Among these situations are:
     When the flaps are set on CONF 3 or CONF FULL and 
turbulence is encountered: The flight crew's responses, coupled with 
the handling characteristics of the airplane, could cause roll 
oscillations.
     When the flaps, during approach, have jammed in the fully-
extended position and CONF 3 is subsequently selected: It becomes 
difficult for the flight crew to maintain the intended flight path.
     When contaminants interfere with proper operation of the 
sidestick transducer unit: A possible consequence is the transmission 
of transient signals from the sidestick to the ELAC. These signals 
could cause the ailerons to ``jerk,'' and result in an uncommanded 
roll, regardless of the automatic pilot mode and the stage of flight.
    All of these situations, if not corrected, could lead to reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    Airbus Industrie has issued Service Bulletin A320-27-1082, dated 
April 25, 1995, which describes procedures for replacing the two ELAC's 
installed in the aft electronic rack 80VU with two ELAC's that have 
been modified. The modifications entail the installation of new 
software identified as ``L69J Standard,'' a program that alters the 
airplane's flying qualities to reduce the risk of encountering 
situations where uncommanded roll and other unsafe conditions are 
likely to occur. [This service bulletin references Sextant Service 
Bulletins 394512-27-014, dated August 11, 1995 (for airplanes on which 
modification 24136P3436 is not installed), and C12370A-27-001, dated 
May 2, 1995 (for airplanes on which modification 24136P3436 is 
installed), as additional sources of procedural service information for 
modification of the ELAC's. Sextant is the supplier of the ELAC's.]
    The DGAC classified the Airbus Industrie service bulletin as 
mandatory and issued French airworthiness direction (C/N) 95-203-
072(B), dated October 11, 1995, as corrected by Erratum, dated November 
8, 1995, in order to assure the continued airworthiness of these 
airplanes in France.

FAA's Conclusions

    This airplane model is manufactured in French 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, the 
proposed AD would require replacement of the two ELAC's installed in 
the aft electronic rack 80VU with two ELAC's that have been modified to 
include L69J Standard software. The actions would be required to be 
accomplished in accordance with the Airbus Industrie service bulletin 
described previously.

Cost Impact

    The FAA estimates that 108 Airbus Industrie Model A320 and A321 
series airplanes of U.S. registry would be affected by this proposed 
AD.
    It would take approximately 3 work hours per airplane to accomplish 
the proposed actions, at an average labor rate of $60 per work hour. 
Required parts would be provided by the manufacturer at no cost to the 
operator. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $19,440, or $180 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), 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-143-AD.

    Applicability:  Model A320 and A321 series airplanes as listed 
in Airbus Industrie Service Bulletin A320-27-1082, dated April 25, 
1995; certificated in any category.


[[Page 951]]


    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 (b) 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 controllability of the airplane, due to 
problems associated with the elevator aileron computer (ELAC), 
accomplish the following:
    (a) Within 1 year after the effective date of this AD, replace 
the ELAC's having part numbers (P/N) 3945122307 and/or P/N 
C12370AAA01 and located in aft electronics rack 80VU, with modified 
ELAC's having P/N 3945122502, in accordance with Airbus Industrie 
Service Bulletin A320-27-1082, dated April 25, 1995.

    Note 2: Airbus Industrie Service Bulletin A320-27-1082 
references Sextant Service Bulletins 394512-27-014, dated August 11, 
1995 (for airplanes on which Airbus Industrie modification 
24136P3436 has not been installed); and C12370A-27-001, dated May 2, 
1995 (for airplanes on which Airbus Industrie modification 
24136P3436 has been installed); as additional sources of procedural 
service information for modification of the ELAC's.

    (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 3: 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 December 31, 1996.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-252 Filed 1-6-97; 8:45 am]
BILLING CODE 4910-13-U