[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
