Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2016-13-05, Amendment 39-18569 (81 FR 41208, June 24, 2016; corrected 81 FR 42475, June 30, 2016), (``AD 2016-13- 05''). AD 2016-13-05 applied to all GE GE90-76B, GE90-77B, GE90-85B, GE90-90B, and GE90-94B turbofan engines. The NPRM published in the Federal Register on December 19, 2016 (81 FR 91880). The NPRM was prompted by an uncontained failure of the HPC stage 8-10 spool, leading to an airplane fire. The NPRM proposed to require an ECI or USI of the HPC stage 8-10 spool and removing from service those parts that fail inspection. We are issuing this AD to prevent failure of the HPC stage 8-10 spool, uncontained rotor release, damage to the engine, and damage to 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.
Request To Revise Compliance
The Boeing Company (Boeing) and GE requested paragraph (f)(1)(i) be changed to apply to ECIs performed between January 2016 and July 29, 2016. Boeing and GE stated that operators who performed an ECI between January 2016 and July 29, 2016 are in accordance with GE GE90 Service Bulletin (SB) 72-1151, Initial issue or Revision 1.
We agree. Credit should be given for ECIs performed in accordance with GE GE90 SB 72-1151, Initial issue or Revision 1. We added paragraph (f)(2)(iii) to the Compliance section.
Request To Revise Compliance Time
Boeing and GE requested paragraph (f)(1)(ii) be changed to state that if it has been more than 400 cycles since the qualified initial USI inspection, then, inspect within 100 cycles from the effective date of this AD. Boeing and GE stated that this provides the operators with a reasonable amount of time to perform the USI.
We disagree. The date for the initial inspection was based on the effective date of AD 2016-13-05. The USI requirement is unchanged, so the 500 cycle allowance mandated in AD 2016-13-05 is also mandated by this AD. We did not change this AD.
Request To Revise Service Information
Boeing, GE, and Japan Air Lines (JAL) requested updating the Related Information section to reflect the latest version of the GE SB. GE SB 72-1151 was revised to Revision 01 on September 13, 2016 and includes the most recent details and aligns with this AD.
We agree. GE GE90 SB 72-1151, Revision 01, dated September 13, 2016, includes the most recent details, aligns with this AD, and also meets the risk analysis performed. We added GE GE90 SB 72-1151, Revision 01, dated September 13, 2016 and GE GE90 SB 72-1151, Revision 0, dated June 10, 2016 to paragraph (i)(2) of this AD.
Request To Revise Service Information
JAL requested updating paragraph (i)(2) Related Information, to perform an ECI in accordance with future revisions of the service information. JAL also requested updating paragraph (i)(2) Related Information, to add ``and later'' to the revision number relating to Chapter 72-31-08; Special Procedure 003 and 72-00-31 Special Procedure 006 in GE GE90 Engine Manual, GEK100700, Revision 68, dated September 1, 2016.
We disagree. We are only authorized to mandate use of service information that we have reviewed and which are published. Since future revisions of service information are not yet published, we are not authorized to mandate their use. We did not change this AD.
Conclusion
We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM, for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.
We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.
Related Service Information
We reviewed GE GE90 SB 72-1151, Revision 01, dated September 13, 2016. The SB describes procedures for an on-wing USI of the stage 8 web of the stage 8-10 spool. 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.
We also reviewed Chapter 72-31-08, Special Procedures 003; and Chapter 72-00-31, Special Procedures 006, in the GE GE90 Engine Manual, GEK100700, Revision 68, dated
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September 1, 2016. These procedures describe how to perform ECI of the stage 8 aft web of the stage 8-10 spool.
Interim Action
We consider this AD interim action. GE is determining the root cause for the unsafe condition identified in this AD. Once a root cause is determined, we will consider additional rulemaking.
Costs of Compliance
We estimate that this AD affects 54 engines installed on airplanes of U.S. registry.
We estimate the following costs to comply with this AD:
Estimated Costs ----------------------------------------------------------------------------------------------------------------
Cost on U.S.
Action Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Inspection............ 7 work-hours x $85 per $0 $595 per inspection $32,130 per
hour = $595 per cycle. inspection cycle.
inspection cycle. ----------------------------------------------------------------------------------------------------------------
We estimate the following costs to do any necessary replacements that would be required based on the results of the inspection. We have no way of determining the number of engines that might need this replacement:
On-Condition Costs ----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Replacement of spool...................... 0 work-hours x $85 per hour = $0.. $780,000 $780,000 ----------------------------------------------------------------------------------------------------------------
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),
(3) Will not affect intrastate aviation in Alaska to the extent that it justifies making a regulatory distinction, 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.