AD 95-17-05

This amendment adopts a new airworthiness directive (AD), applicable to all Airbus Model A310 series airplanes, that requires inspections to detect loose self-locking nuts and damaged cotter pins on the actuating cylinder to drag strut attachment of the left- and right-hand main landing gear (MLG), and correction of discrepancies. This amendment also provides an optional terminating action for the repetitive inspections. This amendment is prompted by reports of loose nuts and sheared cotter pins found on in-service airplanes. The actions specified by this AD are intended to prevent an undampened free fall of the left- and right-hand MLG, which subsequently could lead to the inability to retract the MLG and damage to other airplane systems.

Final rule.

95-17-05 AIRBUS INDUSTRIE: Amendment 39-9334. Docket 93-NM-121-AD.

Applicability: All Model A310 series airplanes, certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been 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 (d) 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 an undampened free fall of the left- and right-hand main landing gear (MLG), which subsequently could lead to the inability to retract the MLG and damage to other airplane systems, accomplish the following:

(a) Within 60 days after the effective date of this AD, perform an inspection to detect loose self-locking nuts and damaged (sheared or marked) cotter pins on the actuating cylinder to drag strut attachment of the left- and right-hand MLG, in accordance with Messier Bugatti Airbus A310 Service Bulletin 470-32-744, dated March 31, 1993, or Revision 1, dated January 13, 1994; or Airbus Service Bulletin A310-32-2069, Revision 1, dated December 13, 1994. Repeat this inspection thereafter at intervals not to exceed 500 landings.

(1) If no nut is loose or no cotter pin is damaged, prior to further flight, install a new cotter pin, in accordance with the service bulletin. After replacement, continue to repeat the inspection at intervals not to exceed 500 landings.

(2) If any nut is loose or any cotter pin is damaged (sheared or marked), prior to further flight, replace the nut, washer, and cotter pin with a new nut, washer, and cotter pin; and torque tighten the nut; in accordance with the service bulletin. After replacement, continue to repeat the inspection at intervals not to exceed 500 landings.

(b) Within 5 days after accomplishing the requirements of paragraph (a) this AD, report all inspection results, positive or negative, to Messier-Bugatti and Airbus Industrie in accordance with Messier-Bugatti Airbus A310 Service Bulletin 470-32-744, dated March 31, 1993, or Revision 1, dated January 13, 1994. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056.

(c) Modification of the actuating cylinder/drag strut attachment of the MLG, in accordance with Messier Bugatti Airbus A310 Service Bulletin 470-32-760, dated December 31, 1993, as revised by Change Notice 1, dated January 28, 1994; or Airbus Service Bulletin A310- 32-2076, Revision 1, dated December 13, 1994; constitutes terminating action for the repetitive inspection requirements of this AD.

(d) 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.

(e) 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.

(f) The inspection shall be done in accordance in accordance with the following service bulletins, which contain the specified list of effective pages:

Service Bulletin
Referenced and Date

Page Number
Revision Level
Shown on Page
Date
Shown on Page
Messier Bugatti
470-32-744,
March 31, 1993

1-7

Original

March 31, 1993
Messier Bugatti
470-32-744,
Revision 1,
January 13, 1994

1-3, 5-6

4

1

Original

January 13, 1994

March 31, 1993
Airbus
A310-32-2069,
Revision 1,
December 13, 1994

1-6, 8-9, 13

7, 10-12

1

Original

December 13, 1994

July 29, 1993

If accomplished, the modification shallbe done in accordance with Messier Bugatti Airbus A310 Service Bulletin 470-32-760, dated December 31, 1993, as revised by Change Notice 1, dated January 28, 1994; or Airbus Service Bulletin A310-32-2076, Revision 1, dated December 13, 1994, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
1-2, 4-8
1
December 13, 1994
3, 9-11
Original
December 14, 1993

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Messier Services, 45635 Willow Pond Plaza, Sterling, Virginia 20164. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on September 21, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Airbus Model A310 series airplanes was published in the Federal Register on November 19, 1993 (58 FR 61037). That action proposed to require repetitive inspections to detect loose self-locking nuts and damaged cotter pins on the actuating cylinder to drag strut attachment of the left- and right-hand main landing gear (MLG). That action also proposed to require replacement of loose nuts with new washers and new nuts, and torque tightening the nuts; replacement of damaged cotter pins with new cotter pins; and submission of inspection reports.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter supports the proposed rule.

Certain commenters request that the proposed rule be revised to cite the latest revision of Messier Bugatti Airbus A310 Service Bulletin 470-32-744 as an additional source of service information. The FAA concurs. Since the issuance of the proposed rule, Messier Bugatti (the manufacturer of the MLG assembly) has issued Revision 1 of Messier Bugatti Airbus A310 Service Bulletin 470-32-744, dated January 13, 1994. This revised service bulletin is essentially identical to the original version and does not entail any additional work. Therefore, the final rule has been revised to reference Revision 1 of the service bulletin as an additional source of service information.

Three commenters request that the FAA revise the proposal to reference the accomplishment of the modification procedures described in Messier Bugatti Airbus A310 Service Bulletin 470-32-760 as a terminating modification for the repetitive inspection requirements. One of these commenters states that the modification described in this service bulletin includes a new hingepin design that will preclude the previously identified problems.

The FAA concurs. Since issuance of the proposed rule, Messier Bugatti has issued Airbus A310 Service Bulletin 470-32-760, dated December 31, 1993, as revised by Change Notice 1, dated January 28, 1994. This service bulletin describes procedures for modification of the actuating cylinder/drag strut attachment of the MLG. The modification entails modifying the greasing duct to enable simultaneous rotation of the duct and cupel. The modification also entails modifying the anti-warping washer to provide rotation play with the actuating cylinder hinge pin. The modification will eliminate the risk of rupture of the cotter pin. Accomplishment of this modification eliminates the need for the repetitive inspections. Additionally, Airbus has issued Service Bulletin A310-32-2076, Revision 1, dated December 13, 1994, which references this Messier Bugatti service bulletin and is essentially identical to it.

The Direction G n rale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, classified these service bulletins as mandatory. However, the FAA finds that the actions specified in the service bulletins may be provided as an optional terminating modification for the repetitive inspection requirements of the AD. The FAA has determined not to mandate the modification, since the inspection area is easily accessible, the discrepancies can be easily detected, and the inspection is easily performed without the need to remove any intervening structure. The FAA has added a new paragraph (c) to the final rule, which provides for this modification as optional terminating action for the required repetitive inspections.

Additionally, since issuance of the notice, Airbus has issued Service Bulletin A310-32-2069, Revision 1, dated December 13, 1994, which references the Messier Bugatti Airbus A310 Service Bulletin 470-32-744 that was cited in the proposal as the appropriate sourceof service information for procedures to inspect the cotter pins. The Airbus service bulletin is essentially identical to the corresponding Messier Bugatti service bulletin. The DGAC classified these service bulletins as mandatory in order assure the continued airworthiness of these airplanes in France and issued French airworthiness directive 93-039-143(B)R2, dated December 7, 1994, in order to assure the continued airworthiness of these airplanes in France. The FAA has revised the final rule to include these Airbus service bulletins as additional sources of service information.

The FAA has reviewed the requirements of the proposed paragraphs (a)(1) and (a)(2) and has determined that clarification is necessary. The actions proposed in those paragraphs were intended to be parallel to those recommended by the manufacturer in its referenced service bulletin. The intent of these requirements was to require the replacement of any loose nut and/or damaged cotter pin with a new nut,washer, and cotter pin; and to require the installation of a new cotter pin if no loose nut or no damaged cotter pin is found. However, as the proposed AD was worded, operators could incorrectly interpret the requirements as meaning that they must replace a loose nut only with a new nut, and replace a damaged cotter pin only with a new cotter pin. The operators also could incorrectly interpret the wording to mean that the installation of a new cotter pin would not be necessary if a loose nut or damaged cotter pin were found. In light of this, the FAA has determined that the wording of proposed paragraphs (a)(1) and (a)(2) must be revised to clarify its intent. These paragraphs of the final rule contain the clarifying wording.

The FAA has recently reviewed the figures it has used over the past several years in calculating the economic impact of AD activity. In order to account for various inflationary costs in the airline industry, the FAA has determined that it is necessary to increase the labor rate used in these calculations from $55 per work hour to $60 per work hour. The economic impact information, below, has been revised to reflect this increase in the specified hourly labor rate.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

As a result of recent communications with the Air Transport Association (ATA) of America, the FAA has learned that, in general, some operators may misunderstand the legal effect of AD's on airplanes that are identified in the applicability provision of the AD, but that have been altered or repaired in the area addressed by the AD. The FAA points out that all airplanes identified in the applicability provision of an AD are legally subject to the AD. If an airplane has been altered or repaired in the affected area in such a way as to affect compliance with the AD, the owner or operator is required to obtain FAA approval for an alternative method of compliance with the AD, in accordance with the paragraph of each AD that provides for such approvals. A note has been added to this final rule to clarify this long-standing requirement.

The FAA estimates that 21 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $1,260, or $60 per airplane, per inspection cycle.

The total cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Should an operator elect to accomplish the optional terminating action that is provided by this AD action, the number of hours required to accomplish it will be approximately 7 work hours per airplane, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,968 per airplane. Based on these figures, the total cost impact of the optional terminating action on U.S. operators would be $2,388 per airplane.

The regulations adopted herein will 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 final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.
39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive