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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
Docket No. 95-NM-262-AD; Amendment 39-9515; AD 96-04-04
Airworthiness Directives; Airbus Model A340 Series Airplanes
PDF Copy (If Available):
Preamble Information
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
SUMMARY: This amendment adopts a new airworthiness directive (AD), applicable to certain Airbus Model A340 series airplanes. This action requires repetitive inspections to detect corrosion and cracking of the shortening mechanism pins in the main landing gear (MLG), and repair or replacement, if necessary. It also requires replacement of the shortening mechanism pin and retraction mechanism pins; the forward pintle pin; the shortening mechanism bellcrank pin; and the bellcrank subassembly of the shortening mechanism. This amendment is prompted by reports of failure of the shortening mechanism pins due to improper grinding of the chrome plating during manufacture, which led to the initiation of stress corrosion and cracks. The actions specified in this AD are intended to prevent failure of these pins, which could lead to a significant reduction of the shock absorber capability or damage to various components of the MLG, and eventually could lead to the failure of the MLG.
DATES: Effective March 11, 1996.
The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 11, 1996.
Comments for inclusion in the Rules Docket must be received on or before April 23, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-262-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The service information referenced in this AD 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Charles Huber, Aerospace Engineer, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 227-2589; fax (206) 227-1149.
SUPPLEMENTARY INFORMATION: The Direction Générale 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 A340 series airplanes. The DGAC advises that there have been two cases of failure of the shortening mechanism pin of the main landing gear (MLG) assembly on in-service airplanes.
In one case, investigation revealed that the pin had broken into three parts, the chrome plating was detached from the base metal around the breaks, and heavy corrosion was present on all of the fracture surfaces. A metallurgical analysis of the broken pin concluded that the pin fractures were the result of cracks in the pin's chrome plating and subsequent stress corrosion. The cracks in the chrome plating most likely occurred as a result of "grinding abuse" when the pin was ground during manufacture. The subsequent penetration of moisture through the cracks to the base metal initiated the stress corrosion and the local detachment of the chrome plating.
In the second case, investigation revealed that the pin had failed as a result of damage caused by stress corrosion.
The DGAC also advises that similar "grinding abuse" may also be present on some forward pintle pins installed on the main strut and dressings of certain affected airplanes, and on the shortening mechanism bellcrank pins of the bellcrank subassembly of the MLG.
Failure of the shortening mechanism pin on the MLG could result in substantial damage to the shortening mechanism, the shock absorber, and the inner top side of the main fitting. This condition could lead to a significant reduction of the shock absorber capability, and eventually could lead to the failure of the MLG.
Likewise, failure of the forward pintle pins or the shortening mechanism bellcrank pins could also result in damage to the shortening mechanism and/or the surrounding area and components, and eventually could lead to the failure of the MLG.
Airbus Industrie has issued the following service bulletins that contain procedures to address this problem:
1. Airbus Service Bulletin A340-32-4050, dated April 10, 1995; and Revision 1, dated May 17, 1995. These service bulletins describe procedures for conducting repetitive visual inspections to detect cracks and corrosion of the shortening mechanism pins. The inspection procedures also call for a one-time lubricating of the affected shortening mechanism links. The service bulletins also describe procedures for replacement of the shortening mechanism pin and retraction mechanism pins of the MLG (left- and right-hand side) with pins that are properly chrome-plated and not susceptible to problems associated with corrosion. (These service bulletins refer to Messier-Dowty Service Bulletins A33/34-32-29 and A33/34-32-30 for more detailed procedural instructions.)
2. Airbus Service Bulletin A340-32-4058, dated April 10, 1995; and Revision 1, dated May 17, 1995. These service bulletins describe procedures for removing discrepant forward pintle pins and replacing them with new or reworked pintle pins that are not susceptible to the problems associated with corrosion This replacement will ensure the integrity of the affected components of the MLG. (These service bulletins refer to Messier-Dowty Service Bulletins A33/34-32-28 and A33/34-32-32 for more detailed procedural instructions.)
3. Airbus Service Bulletin A340-32-4062, dated May 17, 1995. This service bulletin describes procedures for replacing discrepant shortening mechanism bellcrank pins with new or serviceable pins that are not susceptible to the problems associated with corrosion. It also describes procedures for replacing the bellcrank subassembly of the shortening mechanism of the MLG. These replacements will ensure the integrity of the affected components of the bellcrank and the MLG. (This service bulletin refers to Messier-Dowty Service Bulletins A33-34-32-44 and A33/34-32-45 for more detailed procedural instructions.)
The DGAC classified these service bulletin as mandatory and issued French airworthiness directive (CN) 94-244-012(B)R3, dated July 19, 1995, in order to assure the continued airworthiness of these airplanes in France.
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 21.19) 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, this AD is being issued to prevent failure of the MLG. This AD requires, initially, repetitive visual inspections to detect damage or cracks of the shortening mechanism pivot pin, and replacement, if necessary. It also requires a one-time lubrication (greasing) of the MLG shortening mechanism main links.
This AD also requires replacement of the following items:
1. the shortening mechanism pivot pin, and the retraction mechanism pins of the MLG on the left- and right-hand sides (after these replacements are accomplished, the required repetitive visual inspections are terminated);
2. the forward pintle pin fitted to the MLG;
3. the shortening mechanism bellcrank pin of the MLG; and
4. the bellcrank subassembly of the shortening mechanism of the MLG.
These actions are required to be accomplished in accordance with the service bulletins described previously.
None of the Model A340 series airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future.
Should an affected airplane be imported and placed on the U.S. Register in the future, the following costs could be expected:
Inspection of the shortening mechanism pivot pin would require approximately .5 work hour to accomplish the required actions, at an average labor charge of $60 per work hour. Based on these figures, the cost impact of this inspection requirement would be $30 per airplane per inspection cycle.
Replacement of the shortening mechanism pivot pin and retraction mechanism pins would require approximately 118 work hours per airplane to accomplish, at an average labor charge of $60 per work hour. Based on these figures, the cost impact of this replacement requirement would be $7,080 per airplane.
Replacement of the forward pintle pin would require approximately 92 work hours per airplane to accomplish, at an average labor charge of $60 per work hour. Based on these figures, the cost impact of this replacement requirement would be $5,520 per airplane.
Replacement of the shortening mechanism bellcrank pin and bellcrank subassembly would require approximately 13 work hours per airplane to accomplish, at an average labor charge of $60 per work hour. Based on these figures, the cost impact of this replacement requirement would be $780 per airplane.
Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.
Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 95-NM-262-AD." The postcard will be date stamped and returned to the commenter.
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), 40113, 44701.
§ 39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive:
Regulatory Information
96-04-04 AIRBUS: Amendment 39-9515. Docket 95-NM-262-AD.
Applicability: Model A340 series airplanes; having manufacturer's serial numbers (MSN) 002 through 009 inclusive, 011, 013 through 016 inclusive, 018 through 029 inclusive, 031 through 036 inclusive, or 038; 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 (d) 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 collapse of the main landing gear, accomplish the following:
(a) For airplanes having MSN 005 through 009 inclusive, 011, 013 through 016 inclusive, 018 through 029 inclusive, 031 through 034 inclusive, or 038: Accomplish the requirements of paragraphs (a)(1) and (a)(2) of this AD:
(1) Within 7 days after the effective date of this AD, perform a visual inspection to detect corrosion and cracks of the shortening mechanism (pivot) pins of the main landing gear (MLG), in accordance with Airbus Service Bulletin A340-32-4050, dated April 10, 1995, or Revision 1, dated May 17, 1995.
(i) If no corrosion or cracking is found, repeat the inspection thereafter at intervals not to exceed 7 days.
(ii) If any corrosion or cracking is found, prior to further flight, replace the shortening mechanism pin and the retraction mechanism pin with a new pin in accordance with the service bulletin. Accomplishment of this replacement constitutes terminating action for the repetitive inspections required by paragraph (a)(1)(i) of this AD.
(2) With 7 days after the effective date of this AD, perform a one-time lubrication (greasing) of the MLG shortening mechanism main links in accordance with the service bulletin.
(b) Prior to the accumulation of 1,500 total landings, or within 3 months after the effective date of this AD, whichever occurs later, but no later than 12 months after the effective date of this AD, accomplish the requirements of paragraphs (b)(1), (b)(2), and (b)(3) of this AD, as applicable.
(1) For airplanes having MSN 005 through 009 inclusive, 011, 013 through 016 inclusive, 018 through 029 inclusive, 031 through 034 inclusive, or 038: Replace the shortening mechanism pivot pin, and the retraction mechanism pins of the MLG, left- and right- hand side, in accordance with Airbus Service Bulletin A340-32-4050, dated April 10, 1995, or Revision 1, dated May 17, 1995.
(2) For airplanes having MSN 021 through 029 inclusive, or 031 through 034 inclusive: Replace the forward pintle pins fitted to the MLG in accordance with Airbus Service Bulletin A340-32-4058, dated April 10, 1995, or Revision 1, dated May 17, 1995.
(3) For airplanes having MSN 002 through 009 inclusive, 011, 013 through 016 inclusive, 018 through 029 inclusive, or 031 through 036 inclusive: Replace the shortening mechanism bellcrank pin of the MLG in accordance with Airbus Service Bulletin A340-32-4062, dated May 17, 1995.
(c) For airplanes having MSN 002 through 009 inclusive, 011, 013 through 016 inclusive, 018 through 029 inclusive, or 031 through 036 inclusive: Prior to the accumulation of 7,250 total landings, or within 3 months after the effective date of this AD, whichever occurs later, replace the bellcrank subassembly of the shortening mechanism of the MLG in accordance with Airbus Service Bulletin A340-32-4062, dated May 17, 1995.
(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 actions shall be done in accordance with the following Airbus service bulletins, which contain the following list of effective pages:
| Airbus Service Bulletin and Date | Page Number | Revision Level
Shown on Page | Date
Shown on Page |
A340-32-4050,
April 10, 1995 | 1-15 | (Original) | April 10, 1995 |
A340-32-4050,
Revision 1,
May 17, 1995 | 1, 2, 5, 10
3, 4, 6-9, 11-15 | 1
(Original) | May 17, 1995
April 10, 1995 |
A340-32-4058,
April 10, 1995 | 1-10 | (Original) | April 10, 1995 |
A340-32-4058,
Revision 1,
May 17, 1995 | 1-3, 7-9
4-6, 10 | 1
(Original) | May, 17, 1995
April 10, 1995 |
A340-32-4062
May 17, 1995 | 1-10 | (Original) | May 17, 1995 |
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 Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. 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 March 11, 1996.
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