[Federal Register Volume 60, Number 216 (Wednesday, November 8, 1995)]
[Proposed Rules]
[Pages 56271-56274]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-27648]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-66-AD]
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 supersedure of an existing
airworthiness directive (AD), applicable to all Airbus Model A310
series airplanes, that currently requires inspections to detect cracks
in the area of the shock absorber attachment at the top of the barrel
at the main landing gear (MLG), a measurement of the gap between the
barrel and the shock absorber attachment; and corrective action, if
necessary. That AD was prompted by a report of the rupture of the aft
hinge arm of the left MLG barrel. This action would require a
measurement of the gap between the washer and barrel of the MLG, eddy
current inspections to detect cracking of the MLG barrel, correction of
any discrepancy, and accomplishment
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of certain other follow-on actions. Terminating actions would also be
provided by this proposal. The actions specified by the proposed AD are
intended to prevent collapse of the MLG.
DATES: Comments must be received by December 19, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-66-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; and Messier Services, 45635 Willow Pond Plaza,
Sterling, Virginia 20164. This information may be examined at the FAA,
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,
Washington.
FOR FURTHER INFORMATION CONTACT: Phil Forde, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-2146; 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-66-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-66-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On December 3, 1991, the FAA issued AD 91-22-52, amendment 39-8119
(57 FR 5372, February 14, 1992), applicable to all Airbus Model A310
series airplanes. That AD requires repetitive inspections of the main
landing gear (MLG) to detect cracks in the area of the shock absorber
attachment at the top of the barrel, and repair, if necessary; and a
measurement of the gap between the barrel and the shock absorber
attachment, and corrective action, if necessary. That action was
prompted by a report of the rupture of the aft hinge arm of the left
MLG barrel. The requirements of that AD are intended to prevent the
collapse of the MLG.
Description of New Service Information
Since the issuance of that AD, Messier Bugatti has issued Airbus
A310 Service Bulletin 470-32-726, Revision 2, dated February 8, 1994.
This service bulletin describes procedures for:
1. Performing a measurement of the gap between the washer and
barrel of the MLG;
2. Coating the MLG barrel and shock absorber connecting rod nut
with a rubber sealant, for certain airplanes;
3. Performing a gap recovery procedure, and visual inspections to
detect cracks of the MLG barrel, if the gap is equal to or greater than
1 mm (0.04 in.);
4. Replacing the barrel with a modified barrel, if any crack is
detected, which eliminates the need for further inspections;
5. Removing the rubber sealant;
6. Performing an eddy current inspection to detect cracks of the
MLG barrel; and
7. Performing repetitive gap measurements, repetitive eddy current
and visual inspections; or installing a new bushing and replacement of
the bronze washer, if no cracks are detected following accomplishment
of the eddy current inspection, which terminates the need for
repetitive inspections.
Accomplishment of the installation of a new bushing and replacement
of the bronze washer, or the replacement of the barrel with a modified
barrel will positively address the unsafe condition identified as the
collapse of the MLG.
The Direction Generale de l'Aviation Civile (DGAC), which is the
airworthiness authority for France, classified Messier Bugatti Airbus
A310 Service Bulletin 470-32-726, Revision 2, as mandatory and issued
French airworthiness directive (CN) 91-234-127(B)R2, dated December 22,
1993, in order to assure the continued airworthiness of these airplanes
in France.
Description of the Proposed AD
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.
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 supersede AD 91-22-52 to
completely revise the required actions.
Paragraph (a) of the proposed AD would require a measurement of the
gap between the washer and barrel of the main landing gear (MLG).
Paragraph (b) of the proposed AD specifies actions that would be
required if the gap measurement is within certain limits. These actions
entail either no action, for certain airplanes; or coating the MLG
barrel and shock absorber connecting rod nut with a rubber sealant, for
other airplanes.
Paragraph (c) of the proposed AD specifies actions that would be
required if the gap measurement is outside of certain limits. These
actions entail performing a gap recovery procedure and conducting
repetitive visual inspections to detect cracks of the MLG barrel.
Paragraph (d) of the proposed AD would require eddy current
inspections to detect cracking of the MLG barrel. If no cracking is
detected, operators would be required to perform various follow-on
actions, which include repetitive gap measurements, eddy current
inspections, and visual inspections; installation of a new bushing and
[[Page 56273]]
replacement of the bronze washer with a stainless steel washer would
terminate these actions. If cracking is detected, the barrel would be
required to be replaced with a modified barrel, which would terminate
any further action required by the AD.
The proposed actions would be required to be accomplished in
accordance with the Messier Bugatti Airbus A310 service bulletin
described previously.
Differences Between the Proposed AD and Referenced Service Bulletin
The FAA has determined that installation of a new bushing on crack-
free barrel having no oxidation of the cadmium plating may not ensure
that the cadmium plating would not degrade and allow stress corrosion
to occur. Table No. 3 of the referenced Messier Bugatti Airbus A310
service bulletin recommends that these new bushing be installed at the
next overhaul. However, the FAA finds that, since overhaul schedules
vary from operator to operator, the next overhaul for some operators
may not occur for several years. Therefore, operators should note that
the requirements of paragraph (d) of the proposed AD would differ from
the recommendations of the service bulletin in that, in lieu of that
bushing installation, it would require either repetitive gap
measurements and eddy current inspections at intervals not to exceed 2
years, or installation of a new bushing and replacement of the bronze
washer at the upper part of the MLG barrel with a stainless steel
washer (which would terminate further inspections).
Economic Impact
The FAA estimates that 18 airplanes of U.S. registry would be
affected by this proposed AD.
To accomplish the proposed gap measurements, visual inspections,
and other follow-on actions would require approximately 5 work hours
per airplane, at an average labor rate of $60 per work hour. Based on
these figures, the total cost impact of these proposed actions on U.S.
operators is estimated to be $5,400, or $300 per airplane, per cycle.
To accomplish the proposed eddy current inspections would
requireapproximately 8 work hours per airplane, at an average labor
rate of $60 per work hour. Based on these figures, the total cost
impact of these proposed inspections on U.S. operators is estimated to
be $8,640, or $480 per airplane, per inspection cycle.
Based on the figures discussed above, the total cost impact of this
AD on U.S. operators is estimated to be $14,040, or $780 per airplane,
per cycle. This total cost impact figure 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 removing amendment 39-8119 (57 FR
5372, February 14, 1992), and by adding a new airworthiness directive
(AD), to read as follows:
Airbus Industrie: Docket 95-NM-66-AD. Supersedes AD 91-22-52,
Amendment 39-8119.
Applicability: Model A310 series airplanes on which Airbus
Modification 1033 (reference Airbus Service Bulletin A310-32-2066,
Revision 1, dated January 30, 1992) 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 use the authority
provided in paragraph (e) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent collapse of the main landing gear (MLG), accomplish
the following:
(a) Perform a measurement of the gap between the washer and
barrel at the times specified in paragraph (a)(1) or (a)(2) of this
AD, as applicable, in accordance with Messier Bugatti Airbus A310
Service Bulletin 470-32-726, Revision 2, dated February 8, 1994.
(1) For airplanes equipped with MLG barrels applicable to Table
No. 1 of the service bulletin: Perform the measurement within 8 days
after the effective date of this AD.
(2) For airplanes equipped with MLG barrels applicable to Table
No. 2 of the service bulletin: Perform the measurement within 3
months after the effective date of this AD.
(b) If the gap measurement is less than 1 mm (0.04 in.):
Accomplish either paragraph (b)(1) or (b)(2) of this AD, as
applicable.
(1) For airplanes equipped with MLG barrels applicable to Table
No. 1 of the service bulletin: No further action is required by this
paragraph for those airplanes.
(2) For airplanes equipped with MLG barrels applicable to Table
No. 2 of the service bulletin: Prior to further flight, coat the MLG
barrel and shock absorber connecting rod nut with a rubber sealant
in accordance with Messier Bugatti Airbus A310 Service Bulletin 470-
32-726, Revision 2, dated February 8, 1994.
(c) If the gap is equal to or greater than 1 mm (0.04 in.):
Accomplish paragraphs (c)(1), (c)(2), and (c)(3) of this AD, as
applicable, in accordance with Messier Bugatti Airbus A310 Service
Bulletin 470-32-726, Revision 2, dated February 8, 1994.
[[Page 56274]]
(1) For all airplanes: Within 15 days after accomplishing the
measurement required by paragraph (a) of this AD, perform a gap
recovery procedure in accordance with paragraph 2.B.(5) of the
Accomplishment Instructions of the service bulletin.
(2) For airplanes equipped with MLG barrels applicable to Table
No. 2 of the service bulletin: Prior to further flight after
accomplishing the gap recovery procedure required by paragraph
(c)(1) of this AD, coat the MLG barrel and connecting rod nut with a
rubber sealant in accordance with the service bulletin.
(3) For all airplanes: Within 15 days after accomplishing the
measurement required by paragraph (a) of this AD, perform a visual
inspection to detect cracks of the MLG barrel, in accordance with
paragraph 2.B.1 of the Accomplishment Instructions of the service
bulletin.
(i) If no crack is detected: Repeat the visual inspection
thereafter at intervals not to exceed 7 days until the eddy current
inspection required by paragraph (d) of this AD is accomplished.
(ii) If any crack is detected: Prior to further flight, replace
the MLG barrel with a barrel that has been modified in accordance
with Messier Bugatti Service Bulletin 470-32-640, dated July 11,
1988, and Messier Bugatti Service Bulletin 470-32-763, dated
February 28, 1994. Accomplishment of this replacement shall be done
in accordance with Messier Bugatti Airbus A310 Service Bulletin 470-
32-726, Revision 2, dated February 8, 1994. After accomplishment of
this replacement, no further action is required by this AD.
(d) Except as provided by paragraph (c)(3)(ii) of this AD (MLG
barrel replacement): Following accomplishment of either paragraph
(b) or (c) of this AD, and at the applicable times specified in
Table No. 1 and Table No. 2 of Messier Bugatti Airbus A310 Service
Bulletin 470-32-726, Revision 2, dated February 8, 1994, remove the
rubber sealant and perform an eddy current inspection to detect
cracks of the MLG barrel in accordance with Table No. 3 of that
service bulletin.
(1) If no crack is detected: At the times specified in Table No.
3 of the service bulletin, perform the various follow-on actions in
accordance with the service bulletin. (The follow-on actions include
repetitive gap measurements, repetitive eddy current and visual
inspections, installation of a new bushing, and replacement of the
bronze washer with a stainless steel washer.)
(i) However, in lieu of installing a new bushing on crack-free
barrels having no oxidation of the cadmium plating at the next
overhaul, as specified in the service bulletin, operators must
either repeat the gap measurement and eddy current inspection at
intervals not to exceed 2 years, or install a new bushing and
replace the bronze washer at the upper part of the MLG barrel with a
stainless steel washer, in accordance with the service bulletin.
(ii) After accomplishment of the installation of a new bushing
(reference Messier Bugatti Service Bulletin 470-32-640) and the
replacement of the bronze washer (reference Messier Bugatti Service
Bulletin 470-32-763), no further action is required by this AD.
(2) If any crack is detected: Prior to further flight, replace
the barrel with a barrel that has been modified in accordance with
Messier Bugatti Service Bulletin 470-32-640, dated July 11, 1988,
and Messier Bugatti Service Bulletin 470-32-763, dated February 28,
1994. Accomplishment of this replacement shall be done in accordance
with the Messier Bugatti Airbus A310 Service Bulletin 470-32-726,
Revision 2, dated February 8, 1994. After accomplishment of this
replacement, no further action is required by this AD.
(e) 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 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(f) 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 November 2, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-27648 Filed 11-7-95; 8:45 am]
BILLING CODE 4910-13-U
