[Federal Register Volume 61, Number 90 (Wednesday, May 8, 1996)]
[Proposed Rules]
[Pages 20762-20764]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-11441]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-241-AD]
RIN 2120-AA64
Airworthiness Directives; Airbus 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 of the slat universal joint and steady bearing
assemblies, and replacement of any discrepant assembly with a new, like
assembly. The proposal also would require replacement of all slat
universal joint and steady bearing assemblies with improved assemblies,
which would terminate the repetitive inspections. This proposal is
prompted by reports of broken or missing inner races on the slat
universal joint and steady bearing assemblies of the slat transmission
system. The actions specified by the proposed AD are intended to
prevent cracking of the inner race, which could cause it to break off
and, consequently, allow the slat universal joint and steady bearing
assemblies to become worn; this situation could result in failure of
the shaft of the slat transmission system, and subsequent uncommanded
movement of the associated slat.
DATES: Comments must be received by June 17, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-241-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,
[[Page 20763]]
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-241-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-241-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 series
airplanes. The DGAC advises that it has received reports that, during
maintenance inspections, the inner races were found to be broken or
missing on the slat universal joint and steady bearing assemblies of
the slat transmission system. The existing design can cause these inner
races to be susceptible to cracking. If the inner race cracks, it could
break off, and the slat universal joint and steady bearing assemblies
consequently could become worn. This condition, if not corrected, could
result in failure of the shaft of the slat transmission system, and
subsequent uncommanded movement of the associated slat.
Explanation of Relevant Service Information
Airbus has issued Service Bulletin A310-27-2040, Revision 2, dated
January 5, 1995. The service bulletin describes procedures for
repetitive visual inspections to detect discrepancies of the slat
universal joint and steady bearing assemblies, and replacement of any
discrepancy assembly with a new, like assembly.
The DGAC classified this service bulletin as mandatory and issued
French airworthiness directive (CN) 95-074-179(B), dated April 26,
1995, in order to assure the continued airworthiness of these airplanes
in France.
In addition, Lucas Liebherr has issued Service Bulletin 523-27-
M523-1, dated April 25, 1986, which describes procedures for
replacement of all slat universal joint and steady bearing assemblies
with new improved assemblies. Accomplishment of the replacement will
eliminate the need for the repetitive inspections. The replacement will
improve the reliability of the universal joint assemblies.
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 the Proposed Requirements of the 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 repetitive visual inspections to detect
discrepancies of the slat universal joint and steady bearing
assemblies, and replacement of any discrepany assembly with a new, like
assembly. The proposed AD also would require replacement of all slat
universal joint and steady bearing assemblies with new assemblies,
which would constitute terminating action for the repetitive inspection
requirements. The actions would be required to be accomplished in
accordance with the service bulletins described previously.
Differences Between the Proposal and the Related French AD
This proposed rule would differ from the parallel French
airworthiness directive (CN) 95-074-179(B), in that it would mandate
the accomplishment of the terminating action for the repetitive
inspections. The French airworthiness directive provides that action 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
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.
It would take approximately 5 work hours per airplane to accomplish
the proposed inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the proposed inspection on
U.S. operators is estimated to be $7,800, or $300 per airplane, per
inspection.
It would take approximately 9 work hours per airplane to accomplish
the proposed replacement, at an average labor rate of $60 per work
hour. Required parts would cost approximately $48,108 per airplane.
Based on these figures, the cost impact of the proposed replacement on
U.S. operators is estimated to be $1,264,848, or $48,648 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
[[Page 20764]]
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 USC 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-241-AD
Applicability: Model A310 series airplanes, on which Airbus
Modification 6022 or 6485 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 shaft of the slat transmission system,
and subsequent uncommanded movement of the associated slat,
accomplish the following:
(a) Prior to the accumulation of 2,000 landings or 500 flight
hours after the effective date of this AD, whichever occurs later,
perform a visual inspection to detect discrepancies of the slat
universal joint and steady bearing assemblies, in accordance with
Airbus Service Bulletin A310-27-2040, Revision 2, dated January 5,
1995.
Note 2: Airbus Service Bulletin A310-27-2040 inadvertently
references Lucas/Liebherr Service Bulletin 551A-27-6010 as the
appropriate source for accomplishing the inspection. Lucas/Liebherr
Service Bulletin 551A-27-610 is the appropriate source of
information.
(1) If no discrepancy is found, repeat the inspection thereafter
at intervals not to exceed 2,000 landings.
(2) If any discrepancy is detected and the groove depth on the
shaft is greater than or equal to 1 mm (0.04 in.), prior to further
flight, replace the discrepant bearing assembly with a new, like
assembly, in accordance with the service bulletin. After
replacement, repeat the visual inspection thereafter at intervals
not to exceed 2,000 landings.
(3) If any discrepancy is detected and the groove depth on the
shaft is less than 1 mm (0.04 in.), prior to 50 landings after
accomplishing the initial inspection, replace the discrepant bearing
assembly with a new, like assembly, in accordance with the service
bulletin. After the replacement, repeat the visual inspection
thereafter at intervals not to exceed 2,000 landings.
(b) Within 5 years after the effective date of this AD, replace
the slat universal joint and steady bearing assemblies with new
assemblies, in accordance with Lucas Liebherr Service Bulletin 523-
27-M523-1, dated April 25, 1986. Accomplishment of the replacement
constitutes terminating action for the repetitive inspection
requirements of paragraph (a) of this AD.
(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 May 2, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-11441 Filed 5-7-96; 8:45 am]
BILLING CODE 4910-13-U
