AD 97-04-07

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Airbus Model A300-600 and A310 series airplanes, that currently requires repetitive visual inspections and tap tests of the rudder skin panels to detect disbonding; and repairs, if necessary. That AD was prompted by reports of weakening of the bonding material between the core of the rudder and its inner and outer skin, and cracking of the core. This amendment adds repetitive elasticity laminate checker (ELCH) inspections of the rudder in place of the currently required tap tests. It also requires replacement of the rudder with a modified rudder, which will terminate the repetitive inspections. The actions specified by this AD are intended to detect and prevent disbonding of the rudder, which, if not corrected, could reduce the structural integrity of the rudder, and consequently lead to a reduction in its ability to sustain limit loads.

Final rule.

97-04-07 AIRBUS INDUSTRIE: Amendment 39-9931. Docket 96-NM-65-AD. Supersedes AD 90-12-13, Amendment 39-6625.

Applicability: Model A300-600 and A310 series airplanes; certificated in any category; equipped with pre-modification 5844D4829 rudders having the following part numbers:

A5547150000000
A5547150000200
A5547150000400
A5547150000600
A5547150000800
A5547150001000
A5547150001200
A5547150001400

NOTE 1: The pre-modification rudders to which this AD applies were installed at the time of delivery on Model A300-600 and A310 series airplanes specified in the effectivity listings of the Airbus service bulletins that are referenced in this AD. However, such rudders may have been installed after delivery on airplanes other than the ones listed in those service bulletins. Therefore, as specified by the preceding applicability provision, the operator of any Model A300-600 or A310 series airplane equipped with the pre-modified rudder is required to comply with the requirements of this AD.

NOTE 2: 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 (f) 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.

NOTE 3: The requirements of paragraphs (a) and (b) of this AD are restatements of paragraphs A. and B. that appeared in AD 90-12-13, amendment 39-6625. These paragraphs require no additional action by operators who already have initiated the specified actions. (As indicated in both paragraphs, these actions are to continue until the new actions required by this AD are initiated.)

To detect and prevent disbonding which, if not corrected, could reduce the structural integrity of the rudder, and consequently lead to a reduction in its ability to sustain limit loads, accomplish the following:

(a) Visual Inspections (as Required by AD 90-12-13). Within 10 landings after June 20, 1990 (the effective date of AD 90-12-13, amendment 39-6625), perform a visual inspection to detect disbonding of the rudder skin panels, left and right, in accordance with Airbus All Operators' Telex (AOT) 55/90/01, Revision 1, dated April 27, 1990. After the effective date of this AD, perform this inspection in accordance with Airbus Service Bulletin A300-55-6008 (for Airbus Model A300-600 series airplanes), or Airbus Service Bulletin A310- 55-2010 (for Airbus Model A310 series airplanes), both dated December 10, 1990, as applicable.

(1) If no defects are found, repeat the visual inspection thereafter at intervals not to exceed 7 days or 50 landings, whichever occurs first, until the requirements of paragraph (c) of this AD are initiated.

(2) If defects are found, prior to further flight, perform a tap test in accordance with paragraph (b) of this AD.

(b) Tap Tests (as Required by AD 90-12-13). Within 300 landings after June 20, 1990, perform a tap test to determine the extent of the damage, in accordance with Airbus AOT 55/90/01, Revision 1, dated April 27, 1990.

(1) If disbonding is less than 100 square cm, repeat the tap test of the affected area every 28 days or 200 landings, whichever occurs first, until the ELCH inspection requirements of paragraph (d) of this AD are initiated. For any signs of additional rudder skin panel disbonding, perform drilling procedures in accordance with paragraph 4.2.2.3. of the AOT; and thereafter repeat the visual inspection of the rudder skin panels specified in paragraph (a) of this AD, until the ELCH inspection requirements of paragraph (d) of this AD are initiated.

(2) If disbonding is more than 100 square cm, but less than 5,000 square cm, repair in accordance with paragraph 4.2.2.3. of the AOT. Thereafter, repeat the visual inspection of the rudder skin panels in accordance with paragraph (a) of this AD; and perform repetitive tap tests of the repaired areas at the following intervals; until the visual inspection requirements of paragraph (c) of this AD are initiated:

(i) Perform the tap test of the repaired area every 500 landings for disbonding greater than 100 square cm but less than 300 square cm;

(ii) Perform the tap test of the repaired area every 250 landings for disbonding greater than 300 square cm, but less than 1,000 square cm;

(iii) Perform the tap test of the repaired area every 75 landings for disbonding that is greater than 1,000 square cm, but less than 5,000 square cm.

(3) If disbonding is greater than 5,000 square cm, or if a crack is found, prior to further flight, repair in a manner approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.

(c) New Visual Inspection Requirement. Perform a visual inspection of the complete rudder to detect disbonding and cracking of the rudder skin panels, left and right, in accordance with Airbus Service Bulletin A300-55-6008 (for Airbus Model A300-600 series airplanes), or Airbus Service Bulletin A310-55-2010 (for Airbus Model A310 series airplanes), both dated December 10, 1990, as applicable. Initiation of this inspection constitutes terminating action for the requirements of paragraph (a) and specified portions of paragraph (b) of this AD.

(1) Perform the initial inspection at the later of the times specified in paragraph (c)(1)(i) or (c)(1)(ii) of this AD:

(i) Within 7 days or 50 landings afterthe effective date of this AD, whichever is first; or

(ii) Within 7 days or 50 landings, whichever occurs first after the last visual inspection performed in accordance with AD 90-12-13, amendment 39-6625.

(2) If no disbonding or cracking is detected during this inspection accomplish the actions specified in paragraphs (c)(2)(i) and (c)(2)(ii) of this AD:

(i) Repeat the visual inspection at intervals not to exceed 7 days or 50 landings, whichever occurs first, until the initial ELCH inspection is accomplished in accordance with paragraph (d) of this AD. And

(ii) After the initial ELCH inspection required by paragraph (d) of this AD has been accomplished, repeat these visual inspections thereafter at intervals not to exceed 350 landings, in accordance with the applicable service bulletin.

(3) If any disbonding or cracking is detected, prior to further flight, conduct an ELCH inspection of the suspected area for signs of disbonding, and accomplish follow-on actionsin accordance with the Flow Chart, Figure 2, of the applicable service bulletin. If the confirmed extent of disbonding, however, is greater than 400 square cm in Area I, or greater than 800 square cm in Area II, as those areas of the rudder are defined in the applicable service bulletin, prior to further flight, repair and accomplish subsequent inspections in accordance with the requirements of paragraph (d)(3) of this AD.

(d) ELCH Inspections. Within 6 months after the effective date of this AD, conduct an initial elasticity laminate checker (ELCH) inspection of the complete rudder, in accordance with Airbus Service Bulletin A300-55-6008 (for Model A300-600 series airplanes) or Airbus Service Bulletin A310-55-2010 (for Model A310 series airplanes), both dated December 10, 1990, as applicable. Initiation of this inspection constitutes terminating action for the requirements of paragraph (a) and specified portions of paragraph (b) of this AD.

(1) If no disbonding or crackingis detected, repeat the ELCH inspection at intervals not to exceed 2 years or 3,500 landings, whichever occurs first.

(2) If disbonding or cracking is confirmed by ELCH inspection, and the extent of the disbonding is equal to or less than 400 square cm in Area I, or equal to or less than 800 square cm in Area II, as those areas of the rudder are defined in the applicable service bulletin: Prior to further flight, accomplish follow-on actions in accordance with Flow Chart, Figure 2, of the applicable service bulletin.

(3) If disbonding or cracking is confirmed by ELCH inspection, and the extent of the disbonding is greater than 400 square cm in Area I, or greater than 800 square cm in Area II, as those areas of the rudder are defined in the applicable service bulletin: Prior to further flight, accomplish either paragraph (d)(3)(i) or (d)(3)(ii) of this AD:

(i) Repair in a manner approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate.Thereafter, continue to conduct ELCH inspections in a manner and at intervals approved by the Manager, Standardization Branch, ANM-113.

(ii) Replace the rudder in accordance with in accordance with Airbus Service Bulletin A300-55-6010 (for Model A300-600 series airplanes) or Airbus Service Bulletin A310-55 2012 (for Model A310 series airplanes), both dated April 18, 1991, as applicable. After this replacement is accomplished, no further actions are required by this AD.

(e) Terminating Action. Within five years after the effective date of this AD, replace the rudder in accordance with Airbus Service Bulletin A300-55-6010 (for Model A300- 600 series airplanes) or Airbus Service Bulletin A310-55 2012 (for Model A310 series airplanes), both dated April 18, 1991, as applicable. This replacement constitutes terminating action for the inspection requirements of this AD.

(f) 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. 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 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Manager, Standardization Branch, ANM-113.

(g) 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.

(h) The inspections shall be done in accordance with Airbus Service Bulletin A300- 55-6008, dated December 10, 1990 (for Model A300-600 series airplanes); and Airbus Service Bulletin A310-55-2010, dated December 10, 1990 (for Model A310 series airplanes). The rudder replacement shall be done in accordance with Airbus Service Bulletin A300-55-6010, dated April 18, 1991 (for Model A300-600 series airplanes); and Airbus Service Bulletin A310-55 2012, dated April 18, 1991 (for Model A310 series airplanes). 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.

(i) This amendment becomes effective on March 28, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 90-12-13, amendment 39-6625 (55 FR 23190, June 7, 1990), which is applicable to certain Airbus Model A300-600 and A310 series airplanes, was published in the Federal Register on October 23, 1996 (61 FR 54955). The action proposed to continue to require repetitive visual inspections and tap tests of the rudder skin panels to detect disbonding; and repairs, if necessary. It also proposed to add repetitive elasticity laminate checker (ELCH) inspections of the rudder in place of the currently required tap tests. It also proposed to replace the rudder with a modified rudder, which would terminate the repetitive inspections.

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

Support for the Proposal
One commenter supports the proposed AD.

Request to Withdraw the Proposal
Two commenters request that the FAA withdraw the proposed action. These commenters point out that a retrofit campaign was completed in 1993 on all affected airplanes that were equipped with the pre-modification 5844 rudders. In effect, that campaign installed the proposed terminating action on all airplanes. In light of this, these commenters contend that the proposed AD is not necessary.

The FAA does not concur with the commenters' request to withdraw this AD action. The FAA has no evidence that all affected airplanes, worldwide, have been modified with the new rudder. This AD will ensure that any affected airplane that is imported and placed on the U.S. Register in the future, or any airplane that is currently not operating (i.e., is stored) and not equipped with the new rudder, will be inspected and modified in accordance with this AD prior to entering service.

Request to Correct Service Bulletin Information
Two commenters point out an errorin paragraph (d) of the proposal concerning the appropriate source of service information relative to the ELCH inspections required on Model A310 series airplanes. The proposal indicates that the service bulletin number is A310-55-2008; however, the correct number is A310-55-2010.

The FAA acknowledges that typographical error in proposed paragraph (d). The correct service bulletin number was discussed in the preamble to the notice and appeared correctly in all other references to it in the proposed AD. Paragraph (d) of the final rule has been revised to reflect the correct service bulletin number as A310-55-2010.

Conclusion
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 change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
There are approximately 44 Model A310 and Model A300-600 series airplanes of U.S. registry that will be affected by this proposed AD.

The tap tests that are currently required by AD 90-12-13 take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the previously required actions on U.S. operators is estimated to be $10,560, or $240 per airplane, per tap test.

The visual inspections that are currently required by AD 90-12-13 (and retained in this new AD) take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of these inspections on U.S. operators is estimated to be $2,640, or $60 per airplane, per inspection.

Each ELCH inspection required by this new AD action will take approximately 14 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $36,960, or $840 per airplane, per inspection.

The replacement of the rudder that is required by this new AD action will take approximately 42 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. The required parts will be supplied by the manufacturer at no cost to operators. Based on these figures, the cost impact of this required replacement action on U.S. operators is estimated to be $110,880, or $2,520 per airplane.

The cost impact figures discussed above are 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.

Regulatory Impact
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 distributionof 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 U.S.C. 106(g), 40113, 44701.
39.13 - [Amended]
2. Section 39.13 is amended by removing amendment 39-6625 (55 FR 23190, June 7, 1990), and by adding a new airworthiness directive (AD), amendment 39-9931, to read as follows: