[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 

[[Page 56272]]
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