Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain IAE V2522-A5, V2524-A5, V2527-A5, V2527E-A5, V2527M-A5, V2530-A5, V2533-A5, V2525-D5, V2528-D5, and V2531-E5 turbofan engines. The NPRM published in the Federal Register on July 21, 2016 (81 FR 47313). The NPRM was prompted by nine IFSDs resulting from premature failure of the No. 3 bearing. This condition, if not corrected, could result in failure of the No. 3 bearing, failure of one or more engines, loss of thrust control, and loss of the airplane. The NPRM proposed to require removal of the No. 3 bearing from service at the next engine shop visit. We are issuing this AD to prevent failure of the No. 3 bearing, failure of one or more engines, loss of thrust control, and loss of the airplane.
Comments
We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment. Boeing supported the NPRM.
Request To Add Terminating Action
MTU Maintenance Hanover GmbH (MTU) requested that IAE Non Modification Service Bulletin (NMSB) V2500-ENG-72-0673, dated June 3, 2016, be added as a terminating action in this AD. MTU also requested IAE NMSB V2500-ENG-72-0673 be included in credit for previous action. They reason that following the issue of IAE NMSB V2500-ENG-72-0671, dated March 22, 2016, IAE released IAE NMSB V2500-ENG-72-0673, which recommends removal of No. 3 bearing serial numbers (S/Ns) identical to those listed in IAE NMSB V2500-ENG-72-0671.
We partially agree. We agree that the removal of the suspect bearing in accordance with IAE NMSB V2500-ENG-72-0673, dated June 3, 2016 would accomplish both the (e)(3) compliance and (f) terminating action requirements of this AD because both IAE service documents reference identical bearing S/Ns.
We disagree that including IAE NMSB V2500-ENG-72-0673 as a terminating action or listing as credit for previous action is necessary since replacement of a bearing S/N per IAE NMSB V2500-ENG-72- 0673, dated June 3, 2016, makes the engine no longer applicable to the AD. We did not change this AD.
Request To Remove Certain Engine Models From Applicability
IAE and MTU request engine models V2525-D5, V2528-D5, and V2531-E5 be removed from the applicability section of this AD. IAE states that the suspect No. 3 bearings referenced by this AD have all been installed in A5 series engines as specified in IAE NMSB V2500-ENG-72- 0671, dated March 22, 2016 and requests alignment with the service instructions in order to provide consistency between the IAE NMSB V2500-ENG-72-0671 and this AD. MTU reasons that the IAE NMSBs V2500- ENG-72-0671 and V2500-ENG-72-0673 do not list V2525-D5, V2528-D5, and V2531-E5 engine models, therefore, this AD should not be applicable to these models.
We disagree. The applicability section of this AD identifies all V2500 engine models of the same type design where the suspect bearing could be installed. This AD further refines the applicability section with identification of specific No. 3 bearing S/Ns listed in IAE NMSB V2500-ENG-72-0671, Appendix 1, dated March 22, 2016. We did not change this AD.
Request To Identify Applicability by Either Engine S/N or Bearing S/N
Cathay Pacific Airways (CPA) requests the applicability section be revised to identify either the engine S/N or the No. 3 bearing S/N listed in IAE NMSB V2500-ENG-72-0671, dated March 22, 2016. CPA suggests that operators might identify engine applicability based on the No. 3 bearing S/N or the engine S/N, as both are listed in IAE NMSB V2500-ENG-72-0671, Appendix 1, dated March 22, 2016.
We disagree. Determining applicability by engine S/N in lieu of the No. 3 bearing S/N is not adequate, as the suspect bearing may have been reinstalled in another engine. We did not change this AD.
ConclusionWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD as proposed.
Related Service Information Under 1 CFR Part 51
We reviewed IAE NMSB V2500-ENG-72-0671, dated March 22, 2016. The NMSB describes procedures for inspecting the MMCD and further actions if metallic debris is found. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
Other Related Service Information
We reviewed IAE NMSB V2500-ENG-72-0673, dated June 3, 2016. The NMSB describes procedures for removal and replacement of the No. 3 bearing.
Costs of Compliance
We estimate that this AD affects 11 engines installed on airplanes of U.S. registry. We estimate that it would take about 1 hour to perform the inspection. The average labor rate is $85 per hour. We estimatethe cost to replace a No. 3 bearing to be $54,510. Based on these figures, we estimate the cost of this AD on U.S. operators to be $600,545.
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:
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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
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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.