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 (800) 647-5227) 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 A318- 100 and A319-100 series airplanes; Model A320-111 airplanes; and Model A320-200, A321-100, and A321-200 series airplanes. That NPRM was published in the Federal Register on October 27, 2005 (70 FR 61922). That NPRM proposed to require repetitive detailed inspections of the trimmable horizontal stabilizer actuator (THSA) attachments for proper clearances, and any crack, damage, or metallic particles; related corrective actions if necessary; and a report of the inspection results to the manufacturer.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments received.
Updated Service Information
Since we published the NPRM, we have reviewed Airbus Service Bulletin A320-27-1164, Revision 03, including Appendix 01, dated August 24, 2005. The actions described in this service bulletin are essentially the same as the service bulletin we referenced in the NPRM, Airbus Service Bulletin A320-27-1164, Revision 02, including Appendix 01, dated March 30, 2005, except for some minor procedural changes in the order of some steps and when an operator should submit an inspection report. We have revised paragraph (f) of this AD to update the reference to Revision 03 of the service bulletin, and have added paragraph (h) to this AD to allow credit for previous actions done in accordance with Revision 02 of the service bulletin.
Supportive Comments
Three commenters (Airbus, a pilot representing Spirit Airlines pilots, and the Air Line Pilots Association) support the AD. Air Transport Association (ATA) members "generally support the intent of the rulemaking.''
Request To Extend Compliance Time for Repetitive Inspections
The ATA, on behalf of Northwest Airlines, requests that we extend the repetitive inspection interval from 20 months to approximately 21- 22 months. The ATA states that accomplishing the repetitive inspections of the THSA attachments at intervals of 20 months would put a significant financial and logistical burden on some operators because some operators have heavy maintenance schedules that exceed the 20- month interval. Northwest Airlines, in its comments, also states that it is not aware of any substantiating data that would limit the inspection interval and believes the increase in the inspection interval would not affect the level of safety.We do not agree to increase the inspection interval. The ATA did not provide any substantive data to support an increase. In addition, the manufacturer does not support any increase beyond the 20-month inspection interval, until it completes additional testing. We may consider a request for an alternative method of compliance (AMOC) if data is provided to support such a request. This AD remains unchanged in this regard.
Request To Remove Requirement To Inspect Upper THSA Attachments
The ATA, on behalf of U.S. Airways, states that, if the gap clearance of the lower THSA attachment is within limits, then an inspection of the upper THSA attachment is unnecessary. The ATA contends that if the lower THSA attachment shows no sign of damage, there would be no additional loading on the upper THSA attachment. Further, U.S. Airways notes that if the gap clearance of the lower THSA attachment is incorrect, then the THSA is replaced. Part of the replacement procedures involve inspecting all of the THSA attachments, thus eliminating any safety concerns with the actuator or attachments.
We infer that the ATA requests that we remove the requirement to inspect the upper THSA attachment. We do not agree to remove the inspection requirement for the upper THSA attachment. The designs of both attachments include primary and secondary load paths that operate independently of each other. Therefore, a finding of proper clearance during the lower THSA attachment's inspection is no guarantee that the upper THSA attachment is not damaged. This AD has not changed in this regard.
Request To Allow Credit for Previously Accomplished Inspections
US Airways also requests that we mandate the actions of Airbus Alert Service Bulletin A320-27A1164, dated September 10, 2004, to prevent unnecessary work for operators that have performed lower THSA attachment inspections in accordance with that service bulletin.
We disagree with U.S. Airways' request to mandate the alert service bulletin. However, we agree to allow credit for the alert service bulletin as it applies to the lower THSA attachment. Since the publication of the alert service bulletin and of Airbus Service Bulletin A320-27-1164, Revision 01, including Appendix 01, dated December 17, 2004, it has been found that an inspection of the upper THSA attachment is also necessary. Therefore, the actions in the alert service bulletin and Revision 01 are acceptable only for the lower THSA attachment. The upper THSA attachment must be inspected in accordance with Revision 03, dated August 24, 2005, or have been inspected before the effective date of this AD in accordance with Revision 02, dated March 30, 2005. Paragraph (i) of this AD has been added to allow credit for the lower THSA attachment inspection(s).
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 will affect about 700 airplanes of U.S. registry. The actions will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $45,500, or $65 per airplane, per inspection cycle.
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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):