[Federal Register Volume 62, Number 9 (Tuesday, January 14, 1997)]
[Proposed Rules]
[Pages 1859-1861]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-813]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-60-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Industrie Model A310 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 series 
airplanes. This proposal would require repetitive inspections to detect 
discrepancies or damage of the steady bearing assemblies of the flap 
transmission system, and replacement of any discrepant or damaged 
assembly with a new, like assembly. This proposal also would require 
eventual replacement of all the steady bearing assemblies with new, 
improved assemblies, which would terminate the repetitive inspection 
requirement. This proposal is prompted by reports of cracking of the 
hardened steel inner race, and broken or missing inner races of the 
steady bearing assemblies. The actions specified by the proposed AD are 
intended to prevent such discrepancies and damage of the shafts of the 
steady bearing assemblies, which could cause the shafts to fail; 
failure of the steady bearing shafts during a subsequent asymmetric 
stop could result in an uncommanded asymmetric retraction of the flap, 
and subsequent reduced controllability of the airplane.

DATES: Comments must be received by February 24, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 1860]]

Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-60-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: Tom Groves, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1503; 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 96-NM-60-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. 96-NM-60-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Direction General 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 series 
airplanes. The DGAC advises that it has received reports indicating 
that some steady bearings of the flap transmission system on these 
airplanes have been found with cracking of the hardened steel inner 
race, or a broken or missing inner race. The DGAC also advises that it 
has received reports indicating that the spherical part of a steady 
bearing assembly was found to be detached from its mounting flange. The 
cause of these discrepancies is believed to be a design deficiency in 
the bearing seal that, in certain circumstances, may result in the loss 
of grease from the bearings.
    Such discrepancies and damage of the steady bearing assemblies 
could weaken the shaft and lead to failure of the shaft in the event of 
a subsequent asymmetric flap drive failure. Failure of a steady bearing 
in that situation could result in an uncommanded asymmetric retraction 
of the flap, and subsequent reduced controllability of the airplane.

Explanation of Relevant Service Information

    Airbus has issued Service Bulletin A310-27-2067, Revision 1, dated 
January 5, 1995, which describes procedures for repetitive visual 
inspections to detect damage or discrepancies of the steady bearing 
assemblies of the flap transmission system. The service bulletin also 
provides instructions for replacement of damaged assemblies with new, 
like assemblies. The DGAC classified this service bulletin as mandatory 
and issued French airworthiness directive (CN) 95-073-178(B), dated 
April 26, 1995, in order to assure the continued airworthiness of these 
airplanes in France.
    Airbus also issued Service Bulletin A310-27-2074, dated November 
18, 1994, which describes procedures for replacement of the steady 
bearing assemblies with new, improved assemblies. The improved assembly 
is equipped with integral sealing for both the ball bearing and the 
spherical bearing, which will improve the service life of the bearing 
assemblies. The service bulletin also describes procedures to install 
special spherical spacers for steady bearing assembly positions FIN 
5486 and FIN 5529 in order to keep the seal lips within the flange. 
(This Airbus service bulletin references Lucas Liebherr Service 
Bulletin 551A-27-M551-03, Revision 1, dated February 13, 1995, as an 
additional source of service information.) The DGAC has approved the 
technical content of this service bulletin.

FAA's Conclusions

    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.

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 repetitive visual 
inspections to detect any discrepancy or damage to the steady bearing 
assemblies of the flap transmission system, and replacement of any 
damaged or discrepant assembly with a new, like assembly. The proposed 
AD also would require eventual replacement of all steady bearing 
assemblies with the new, improved assemblies, which would terminate the 
repetitive inspection requirement. The actions would be required to be 
accomplished in accordance with the service bulletins described 
previously.

Differences Between the Proposal and the Related French CN

    Operators should note that, this proposal would differ from the 
parallel French CN, referenced previously, in that this proposed rule 
would require the accomplishment of a terminating action (replacement 
of the steady bearing assemblies with new, like assemblies) for the 
repetitive inspections. The French CN provides for that action only as 
optional.
    Mandating the terminating action is based on the FAA's 
determination that long term continued operational safety will be 
better assured by design changes to remove the source of the problem, 
rather than by repetitive inspections. Long term inspections may not be

[[Page 1861]]

providing the degree of safety assurance necessary for the transport 
airplane fleet. This, coupled with a better understanding of the human 
factors associated with numerous continual inspections, has led the FAA 
to consider placing less emphasis on inspections and more emphasis on 
design improvements. The proposed requirement to accomplish the 
terminating action is in consonance with these considerations.

Cost Impact

    The FAA estimates that 26 Airbus Model A310 series airplanes of 
U.S. registry would be affected by this proposed AD, that it would take 
approximately 15 work hours per airplane to accomplish the proposed 
inspections, and that the average labor rate is $60 per work hour. 
Based on these figures, the cost impact of the proposed inspection on 
U.S. operators is estimated to be $23,400, or $900 per airplane, per 
inspection cycle.
    It would take approximately 8 work hours per airplane to accomplish 
the proposed replacement, at an average labor rate of $60 per work 
hour. Required parts would cost approximately $16,872 per airplane. 
Based on these figures, the cost impact of the proposed replacement on 
U.S. operators is estimated to be $451,152, or $17,352 per airplane.
    The cost impact figures discussed above are 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 96-NM-60-AD.

    Applicability: Model A310 series airplanes, on which Airbus 
Modification 10962 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 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 failure of the flap transmission shaft due to damaged 
steady bearing assemblies, which could cause an uncommanded 
asymmetric retraction of the flap, and result in reduced 
controllability of the airplane, accomplish the following:
    (a) Prior to the accumulation of 2,000 total landings or within 
500 flight hours after the effective date of this AD, whichever 
occurs later: Perform a visual inspection to detect damage or any 
discrepancy of the steady bearing assemblies of the flap 
transmission system, in accordance with Airbus Service Bulletin 
A310-27-2067, Revision 1, dated January 5, 1995.
    (1) If no damage or discrepancy is detected: Repeat the 
inspection thereafter at intervals not to exceed 2,000 landings, 
until the requirements of paragraph (b) of this AD are accomplished.
    (2) If any damage or discrepancy is detected and the groove 
depth of the shaft is less than 1 mm (.04 inch): Prior to the 
accumulation of 50 landings after detection of this discrepancy, 
replace the steady bearing assembly with a new, like assembly in 
accordance with Airbus Service Bulletin A310-27-2067, Revision 1, 
dated January 5, 1995.
    (3) If any damage or discrepancy is detected and the groove 
depth on the shaft is 1 mm or more: Prior to further flight, replace 
the steady bearing assembly with a new, like assembly, in accordance 
with Airbus Service Bulletin A310-27-2067, Revision 1, dated January 
5, 1995.
    (b) Within 5 years after the effective date of this AD, replace 
all steady bearing assemblies of the flap transmission system with 
new, improved assemblies, in accordance with Airbus A310-27-2074, 
dated November 18, 1994. Accomplishment of the replacement 
constitutes terminating action for the requirements of this AD.

    Note 2: Airbus Service Bulletin A310-27-2074 references Lucas 
Liebherr Service Bulletin 551A-27-M551-03 as an additional source of 
service information for replacement of the steady bearing assemblies 
with the new, improved assemblies.

    (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 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.

    (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 January 7, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-813 Filed 1-13-97; 8:45 am]
BILLING CODE 4910-13-U