[Federal Register Volume 59, Number 199 (Monday, October 17, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-25582]


[[Page Unknown]]

[Federal Register: October 17, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-145-AD]

 

Airworthiness Directives; Airbus Model A310 and A300-600 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 A310 and 
A300-600 series airplanes. This proposal would require that certain 
flight control computers be modified so that the autopilot will 
disengage whenever the airplane is in the ``go-around'' mode. This 
proposal is prompted by an accident in which the flight crew may have 
attempted a go-around while the airplane was in an out-of-trim 
condition. The actions specified by the proposed AD are intended to 
prevent severely reduced controllability of the airplane due to an out-
of-trim condition between the trimmable horizontal stabilizer and the 
elevator.

DATES: Comments must be received by November 28, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-145-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.
    Information pertaining to this proposed rule may be obtained from 
or examined at the FAA, Transport Airplane Directorate, Rules Docket, 
1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Stephen Slotte, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2797; fax (206) 227-1320.

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 94-NM-145-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. 94-NM-145-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 A310 and A300-600 
series airplanes. The French DGAC advises that a Model A300-600 series 
airplane was recently involved in an accident during which the flight 
crew may have attempted a go-around while the airplane was in an out-
of-trim condition. Investigation into the cause of this out-of-trim 
condition revealed that the flight crew may have attempted to override 
the autopilot while it was engaged in the COMMAND mode. If the airplane 
is in pitch axis, and the autopilot is overridden for prolonged periods 
by the flight crew via manual input from the control column, and if the 
autopilot is subsequently disengaged, the resultant out-of-trim 
condition between the trimmable horizontal stabilizer and the elevator 
could reduce controllability of the airplane.
    Further investigation indicates that the design of Model A300-600 
series airplanes does not provide for disengagement of the autopilot in 
a manner that would allow for manual input from the control column 
without adversely affecting controllability of the airplane. The design 
of Model A310 series airplanes is identical in this respect to Model 
A300-600 series airplanes.
    The French DGAC issued French Airworthiness Directive 94-185-
165(B), dated August 17, 1994, in order to assure the continued 
airworthiness of these airplanes in France. The French AD requires 
modification of FCC's having part numbers (P/N) B216ABM6, B350AAM1, 
B350AAM2, B350AAM3, and B470ABM1 (for Model A310 series airplanes); and 
P/N's B297AAM3, B297AAM4, B297AAM5, and B470AAM1 (for Model A300-600 
series airplanes).
    The French AD references Airbus Service Bulletins A310-22-2036, 
dated December 14, 1993 (for Model A310 series airplanes), and A300-22-
6021, Revision 1, dated December 24, 1993 (for Model A300-600 series 
airplanes), as the appropriate sources of service information to 
accomplish the modification of the FCC's. However, Airbus Service 
Bulletin A310-22-2036, dated December 14, 1993, describes procedures 
for modification of only one of the FCC's, P/N B470ABM1, which is 
installed on Model A310 series airplanes; while Airbus Service Bulletin 
A300-22-6021, Revision 1, dated December 24, 1993, describes procedures 
for modification of only one of the FCC's, P/N B470AAM1, which is 
installed on Model A300-600 series airplanes. Upon accomplishment of 
this software modification, the autopilot will disengage whenever the 
airplane is in the ``go-around'' mode above 400 feet radio altitude and 
whenever the pilot attempts to override the autopilot by exerting a 
certain amount of manual force on the control column.
    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 French DGAC has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the French 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 modification of 
FCC's having P/N's B216ABM6, B350AAM1, B350AAM2, and B350AAM3 (for 
Model A310 series airplanes); and P/N's B297AAM3, B297AAM4, and 
B297AAM5 (for Model A300-600 series airplanes). Since the manufacturer 
has not yet developed a modification for these FCC's, these 
modifications are to be accomplished in accordance with a method 
approved by the FAA.
    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.
    Modification of FCC's having P/N's B470ABM1 (for Model A310 series 
airplanes) and B470AAM1 (for Model A300-600 series airplanes) has been 
addressed in a separate rulemaking action (reference Airworthiness 
Directive Rules Docket Number 94-NM-134-AD). Since the manufacturer has 
advised that an ample number of required parts will be available for 
modification of FCC's having these two part numbers, and in light of 
the degree of urgency associated with the subject unsafe condition, the 
FAA finds that modification of those FCC's must be accomplished sooner 
than the modification of the FCC's addressed in this proposal. That AD 
action also requires a revision to the FAA-approved Airplane Flight 
Manual (AFM) that warns the flight crew to avoid overriding the 
autopilot while the airplane is in the COMMAND mode and cautions the 
flight crew to check the status of the autopilot in the event the 
flight controls respond abnormally.
    The FAA estimates that 15 Model A310 series airplanes and 36 Model 
A300-600 series airplanes of U.S. registry would be affected by this 
proposed AD.
    Since the manufacturer has not yet developed one specific 
modification commensurate with the requirements of this proposal, the 
FAA is unable at this time to provide a specific information as to the 
number of work hours or cost of parts that would be required to 
accomplish the proposed modification. A further problem in developing a 
specific cost estimate is the fact that modification costs are expected 
to vary from operator to operator and from airplane to airplane 
depending upon airplane configuration. The proposed compliance time of 
24 months should provide ample time for the development, approval, and 
installation of an appropriate modification.
    However, based on similar modifications accomplished previously on 
other FCC's installed on other airplane models, the FAA can reasonably 
estimate that the proposed modification may require as few as 2 work 
hours or as many as 50 work hours to accomplish, at an average labor 
rate of $55 per work hour. The cost of required parts could range from 
a negligible amount to as much as $1,500 per airplane. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be between $5,610 ($110 per airplane) and $216,750 ($4,250 
per airplane).
    As indicated earlier in this preamble, the FAA specifically invites 
the submission of comments and other data regarding this economic 
aspect of proposal.
    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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

Airbus Industrie: Docket 94-NM-145-AD.

    Applicability: Model A310 series airplanes equipped with Flight 
Control Computers (FCC) having part number (P/N) B216ABM6, B350AAM1, 
B350AAM2, or B350AAM3; and Model A300-600 series airplanes equipped 
with FCC's having P/N B297AAM3, B297AAM4, or B297AAM5; certificated 
in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent reduced controllability of the airplane, accomplish 
the following:
    (a) Within 24 months after the effective date of this AD, modify 
the FCC's in accordance with a method approved by the Manager, 
Standardization Branch, ANM-113, FAA, Transport Airplane 
Directorate.
    (b) As of 24 months after the effective date of this AD, no 
person shall install an FCC having P/N B216ABM6, B350AAM1, B350AAM2 
or B350AAM3 on any Model A310 series airplane; and P/N B297AAM3, 
B297AAM4, or B297AAM5 on any Model A300-600 series airplane.
    (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: 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 October 7, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-25582 Filed 10-14-94; 8:45 am]
BILLING CODE 4910-13-U