06-4504. Airworthiness Directives; Airbus Model A330-223, -321, -322, and -323 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all Airbus Model A330-223, -321, -322, and -323 airplanes. This AD requires repetitive inspections of the firewall of the lower aft pylon fairing (LAPF), and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive inspections. This AD results from reports of cracking of the LAPF firewall. We are issuing this AD to detect and correct this cracking, which could reduce the effectiveness of the firewall and result in an uncontrolled engine fire.

DATES:

This AD becomes effective June 20, 2006.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of June 20, 2006.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC.

Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

Tim Backman, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to all Airbus Model A330-223, -321, -322, and -323 airplanes. That NPRM was published in the Federal Register on January 4, 2005 (70 FR 317). That NPRM proposed to require repetitive inspections of the firewall of the lower aft pylon fairing (LAPF), and corrective actions if necessary.

Explanation of New Relevant Service Information

Since we issued the NRPM, Airbus has issued Service Bulletin A330-54-3022, dated May 25, 2005. That service bulletin describes procedures for replacing the existing LAPF assemblies with improved parts. Doing this replacement eliminates the need for the inspections that were proposed in the NPRM. Airbus Service Bulletin A330-54-3022 refers to Pratt & Whitney Service Bulletin PW4G-100-54-7, dated July 1, 2005, as an additional source of service information for modifying the LAPF assemblies.

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, has issued French airworthiness directive F-2004-028 R2, dated October 26, 2005. (The NPRM refers to French airworthiness directive F-2004-028 R1, dated September 15, 2004, as the parallel French action.) French airworthiness directive F-2004-028 R2 adds replacement of the LAPF assemblies with improved assemblies as an optional terminating action for the repetitive inspections of the LAPF firewall. Accordingly, we have added a new paragraph (i) to this AD to provide for doing Airbus Service Bulletin A330-54-3022 as an optional terminating action for the repetitive inspections required by this AD. We have also revised various other paragraphs to refer to paragraph (i) of this AD. We have also not included Note 4 of the NPRM in this AD. (Note 4 of the NPRM states that there is no terminating action for the inspections specified in the NPRM.)

Airbus has also issued Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004. (The NPRM refers to Airbus Service Bulletin A330-54-3021, dated February 4, 2004, as the appropriate source of service information for the actions specified in the NPRM.) Revision 01 of the service bulletin adds airplanes with certain serial numbers to the effectivity listing and incorporates various other editorial changes. We have revised paragraphs (f), (g), (h), and (j) of this AD to refer to Airbus Service Bulletin A330-54-3021, Revision 01, as the appropriate source of service information for doing the actions required by those paragraphs. We have also added a new paragraph (k) to give credit for actions done before the effective date of this AD in accordance with the original issue of that service bulletin.

Airbus Service Bulletin A330-54-3021, Revision 01, refers to Pratt & Whitney Alert Service Bulletin PW4G-100-A54-5, currently at Revision 1, dated June 30, 2004, as an additional source of service information. We have revised Note 2 of this AD to acknowledge that the Pratt & Whitney service bulletin is currently at Revision 1.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.

Support for the NPRM

One commenter, the Air Line Pilots Association, supports the NPRM.

Request To Allow Flight With Repaired Crack

Two commenters, Airbus and Pratt & Whitney (P&W, the engine manufacturer), request that we revise the NPRM to allow continued flight (for a limited period of time) with a known crack that exceeds 1.2 inches.

The French airworthiness directive and Airbus Service Bulletin A330-54-3021 provide for stop-drilling and sealing a crack that is longer than 1.2 inches, then repairing the firewall within 500 flight hours. The NPRM would require repair or replacement of the firewall before further flight if any crack longer than 1.2 inches is found. Under “Differences Among Proposed AD, DGAC Action, and Airbus Service Bulletin” in the NPRM, we note that we do not have data showing that the fireproof capability of the firewall is adequate with a crack greater than 1.2 inches long.

Airbus comments that it considers the firewall having a crack greater than 1.2 inches to be adequately fireproof if the crack is stop-drilled and filled with fireproof sealant. Airbus recommends that operation with such a crack be allowed to continue for 500 flight hours, as given in the French airworthiness directive and the referenced service bulletin.

P&W states, based on its knowledge of the LAPF assembly and its engineering judgment, that stop-drilling a crack that is longer than 1.2 inches and filling it with sealant will be adequate to maintain the fire safety and capability of the firewall for up to 500 flight hours. P&W points out that the proposed requirement to repair or replace the firewall before further flight if a crack exceeds 1.2 inches could cause undue hardships for operators. P&W notes that it is not possible to repair the firewall quickly, nor is it possible to replace the firewall in situ. It is also not common for operators to have a spare firewall.

We partially agree with the commenters' request. We agree that the LAPF firewall is a fire barrier and is not intended to carry significant structural loads. Airbus and P&W state that fireproof capability is maintained with a crack longer than 1.2 inches, but neither present test data that substantiate this. Airbus informs us, however, that the fire test was performed on a firewall with an unrepaired 1.2-inch crack, and the test results show that fireproof capability was adequately maintained even without the crack being stop-drilled and sealed. Airbus also notes that there have been no findings of multiple cracks, and the maximum length of any crack was 1.5 inches. Based on these data, and the expected improvement in fireproof capability if the crack is stop-drilled and sealed, we agree to allow continued operation for up to 500 flight hours with a crack between 1.2 inches and 1.5 inches that has been stop-drilled and sealed. However, any crack that exceeds 1.5 inches must be addressed through repair or replacement of the firewall before further flight in accordance with paragraph (h) of this AD, or in accordance with an alternative method of compliance (AMOC) approved in accordance with the procedures specified in paragraph (l) of this AD. We have added a new paragraph (g)(2) to this AD and have reidentified paragraph (g)(2) from the NPRM as paragraph (g)(3) in this AD. We have also revised Note 3 of this AD.

Request To Address Multiple Cracks

Paragraph (g)(1)(ii) of the NPRM states that, during any repeat inspection, if any crack that was previously less than or equal to 1.2 inches long is found to have extended to be greater than 1.2 inches long, or if an additional crack is found, the firewall must be repaired or replaced before further flight. Northwest Airlines (NWA) requests that additional cracks be allowed as long as the total combined length of all cracks is less than 1.2 inches. NWA proposes a scenario in which a 0.25-inch crack is found during the initial inspection, and another 0.25-inch crack is found during a repeat inspection.

We agree with NWA's request. Although Airbus tells us that there have been no findings to date of multiple cracks in service, it is possible that multiple cracks could be found. We have determined that there would be no difference in the level of safety between one crack of 1.2 inches or shorter, and multiple cracks that are a combined total of 1.2 inches or shorter. We have revised paragraph (g)(1) of this AD accordingly.

Request To Clarify Repetitive Inspections of Repaired Firewall

NWA also requests that we revise paragraph (h) of the NPRM to require inspections of repaired firewalls. While paragraph (h) would require that a replaced firewall be inspected within 3,000 flight hours after replacement, that paragraph states no such requirement for repaired firewalls. NWA believes that repaired firewalls should be inspected within 1,000 flight hours after the repair.

We partially agree with the commenter's request. The last sentence of paragraph (h) of the NPRM should have specified inspecting the firewall within 3,000 flight hours after repair or replacement. We inadvertently omitted the words “repair or” before “replacement” in that sentence. However, we do not agree with the commenter's belief that repaired firewalls must be inspected within 1,000 flight hours after the repair. Airbus has confirmed that, for the purposes of this AD, repairing the firewall using the instructions in P&W Alert Service Bulletin PW4G-100-A54-5, in accordance with Airbus Service Bulletin A330-54-3021, Revision 01, restores the repaired firewall to the status of a new firewall of the same part number. Thus, a repaired firewall must be inspected within 3,000 flight hours after repair, just as a replaced firewall of the same part number must be inspected within 3,000 flight hours after replacement, as we specified in paragraph (h) of the NPRM. We find that a compliance time of 3,000 flight hours for the initial inspection after repair will provide an acceptable level of safety. Accordingly, we have revised the last sentence of paragraph (h)(1) of this AD to state, “within 3,000 flight hours after repair or replacement of the LAPF firewall, inspect the firewall in accordance with paragraph (f) of this AD.” We find that this change does not expand the scope of the NPRM because our intent that a repaired firewall must be inspected should have been obvious considering the statement in Note 4 of the NPRM that, “There is no terminating action at this time for the inspections required by this AD.” (As explained previously, we have not included Note 4 of the NPRM in this AD because a terminating action is now available and is provided as an option in paragraph (i) of this AD.)

Request To Correct Compliance Time

Airbus and NWA request that we revise paragraph (g)(1)(i) to change the compliance time from 4,600 flight cycles to 4,600 flight hours. NWA points out that this change will make the NPRM consistent with the French airworthiness directive and the referenced service bulletins.

We agree. A typographical error resulted in the compliance time being specified in flight cycles not flight hours. We find that this change does not expand the scope of the NPRM because the error was obvious; all other compliance times in this AD are stated in terms of flight hours, not flight cycles, and we did not state that we intended to differ in this regard from either the French airworthiness directive or the referenced service bulletins. We have revised paragraph (g)(1)(i) in this AD accordingly.

Request To Revise Inspection Intervals To Match Maintenance Schedule

US Airways requests that we revise the grace period in paragraph (f) of the NPRM from 500 flight hours to 600 flight hours to align with its A-check interval. For the same reason, U.S. Airways requests that we revise the repeat inspection interval for an uncracked firewall from 1,000 flight hours to 1,200 flight hours, and the repeat interval for a cracked firewall from 500 flight hours to 600 flight hours.

We do not agree with US Airways request to extend the grace periods and repetitive intervals in this AD. We have determined that the specified times represent the maximum interval of time allowable for the affected airplanes to continue to safely operate between inspections. Since maintenance schedules vary among operators, revising the grace period and repetitive intervals would not ensure that all operators would be able to inspect their airplanes during a scheduled maintenance visit. We have not changed the AD in this regard.

Explanation of Additional Change to This AD

We have revised Note 1 of this AD to clarify the definition of a detailed inspection.

Clarification of AMOC Paragraph

We have revised paragraph (l) of this AD to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

This AD affects about 20 airplanes of U.S. registry. The required actions will take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the inspections required by this AD for U.S. operators is $2,600, or $130 per airplane, per inspection cycle.

The optional terminating action, if done, will take about 14 work hours per airplane, at an average labor rate of $65 per work hour. Required parts will cost $120,000. Based on these figures, the estimated cost of the optional terminating action provided by this AD is $120,910 per airplane.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect 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.

For the reasons discussed above, I certify that this AD:

(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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2006-10-13 Airbus: Amendment 39-14597. Docket No. FAA-2004-19982; Directorate Identifier 2004-NM-142-AD.

Effective Date

(a) This AD becomes effective June 20, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Airbus Model A330-223, -321, -322, and -323 airplanes; certificated in any category.

Unsafe Condition

(d) This AD results from reports of cracking of the firewall of the lower aft pylon fairing (LAPF). We are issuing this AD to detect and correct this cracking, which could reduce the effectiveness of the firewall and result in an uncontrolled engine fire.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Repetitive Inspections

(f) Prior to the accumulation of 3,000 total flight hours on the LAPF, or within 500 flight hours after the effective date of this AD, whichever is later: Perform a detailed inspection for cracking of the LAPF firewall, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004. If no cracking is found, repeat the inspection thereafter at intervals not to exceed 1,000 flight hours, until paragraph (i) of this AD is accomplished.

Note 1:

For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Note 2:

Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004, refers to Pratt & Whitney Alert Service Bulletin PW4G-100-A54-5, currently at Revision 1, dated June 30, 2004, as an additional source of service information for doing the inspection and corrective actions.

Corrective Actions and Repetitive Inspections (Cracking Found)

(g) If any crack is found during any inspection required by paragraph (f) of this AD, do paragraph (g)(1) or (g)(2) of this AD.

(1) If the crack is less than or equal to 1.2 inches long, or if multiple cracks are found with a combined total length less than or equal to 1.2 inches: Before further flight, stop-drill the crack or cracks and apply sealants, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004, or do paragraph (h) of this AD. If the crack is stop-drilled and sealants applied, then repeat the inspection required by paragraph (f) of this AD at intervals not to exceed 500 flight hours, and do paragraph (g)(1)(i) or (g)(1)(ii) of this AD, as applicable.

(i) During the repeat inspections required by paragraph (g)(1) of this AD, if the existing crack does not extend to be longer than 1.2 inches, and the combined total length of all cracks is less than or equal to 1.2 inches: Within 4,600 flight hours after the crack is initially found, do paragraph (h) of this AD.

(ii) During any repeat inspection required by paragraph (g)(1) of this AD, if any crack that was previously less than or equal to 1.2 inches long is found to have extended to be greater than 1.2 inches long but less than or equal to 1.5 inches long; or if the total length of all cracks is greater than 1.2 inches but less than or equal to 1.5 inches long: Within 500 flight hours, do paragraph (h) of this AD.

(iii) During any repeat inspection required by paragraph (g)(1) of this AD, if any crack that was previously less than or equal to 1.5 inches long is found to have extended to be greater than 1.5 inches long; or if the total length of all cracks is greater than 1.5 inches: Before further flight, do paragraph (h) of this AD.

(2) If the crack is less than or equal to 1.5 inches long, or if multiple cracks are found with a combined total length less than or equal to 1.5 inches: Before further flight, stop-drill the crack or cracks and apply sealants, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004. Then, within 500 flight hours after the stop-drilling and sealing of the crack or cracks, do paragraph (h) of this AD.

(3) If any crack is greater than 1.5 inches long, or if multiple cracks are found with a combined total length greater than 1.5 inches: Before further flight, do paragraph (h) of this AD.

Note 3:

This AD does not allow continued flight with a known crack that is greater than 1.5 inches long or with multiple cracks having a combined total length greater than 1.5 inches.

Repair or Replacement of Firewall

(h) If any crack is found: At the applicable time specified in paragraph (g) of this AD, do paragraph (h)(1) or (h)(2) of this AD.

(1) Repair the LAPF firewall or replace the LAPF firewall with a new firewall, as applicable, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004. Then, within 3,000 flight hours after repair or replacement of the LAPF firewall, inspect the firewall in accordance with paragraph (f) of this AD.

(2) Do paragraph (i) of this AD.

Optional Terminating Action

(i) Replacing the LAPF assembly with an improved LAPF assembly, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A330-54-3022, dated May 25, 2005, terminates the repetitive inspections required by this AD.

Note 4:

Airbus Service Bulletin A330-54-3022 refers to Pratt & Whitney Service Bulletin PW4G-100-54-7, dated July 1, 2005, as an additional source of service information for modifying the LAPF assemblies.

Reporting Requirement

(j) If any crack is found during any inspection required by this AD: Submit a report of the findings to Airbus, Department AI/SE-E5, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Submit the report at the applicable time specified in paragraph (j)(1) or (j)(2) of this AD. The report must include the inspection results, a description of any discrepancies found, the airplane serial number, and the number of landings and flight hours on the airplane. Submitting Appendix 01 of Airbus Service Bulletin A330-54-3021, Revision 01, dated June 16, 2004, is an acceptable means of accomplishing this requirement. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

(1) If the inspection was done after the effective date of this AD: Submit the report within 30 days after the inspection.

(2) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.

Actions Accomplished Previously

(k) Inspections and corrective actions done before the effective date of this AD in accordance with Airbus Service Bulletin A330-54-3021, including Appendix 01, dated February 4, 2004, are acceptable for compliance with the corresponding requirements of paragraphs (f), (g), (h), and (j) of this AD.

Alternative Methods of Compliance (AMOCs)

(1)(l) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(m) French airworthiness directive F-2004-028 R2, dated October 26, 2005, also addresses the subject of this AD.

Material Incorporated by Reference

(n) You must use Airbus Service Bulletin A330-54-3021, Revision 01, including Appendix 01, dated June 16, 2004, to perform the actions that are required by this AD, unless the AD specifies otherwise. If you do the optional terminating action, you must use Airbus Service Bulletin A330-54-3022, dated May 25, 2005, to perform that action. The Director of the Federal Register approved the incorporation by reference of these documents in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on May 8, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.