AD 2009-11-02

This AD becomes effective June 23, 2009.

The Docket Operations office is located at Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.

Stephen K. Sheely, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: stephen.k.sheely@faa.gov; telephone (781) 238-7750; fax (781) 238-7199.

The FAA proposed to amend 14 CFR part 39 with a proposed AD. The proposed AD applies to CFM International S.A. CFM56-2, CFM56-3, CFM56-5A, CFM56-5B, CFM56-5C, and CFM56-7B series turbofan engines with certain P/N and SN HPC 4-9 spools installed. We published the proposed AD in the Federal Register on November 26, 2008 (73 FR 71951). That action proposed to require removing certain HPC 4-9 spools that have a P/N and SN listed in Table 1 of this AD before accumulating 8,900 cycles since repair at PTLLC or within 1,100 cycles from the effective date of this AD, whichever occurs later.

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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

Three commenters, the Air Transport Association (ATA), United Airlines, and CFM International, point out a typographical error in the SN for a 4-9 spool, P/N 1590M29G01. They state that the Special Airworthiness Information Bulletin (SAIB) NE-08-17 shows SN GWNFY924 for that P/N and the proposed rule shows SN GWNFY824 for the same P/N.

We agree. Serial number GWNFY924 is the correct SN. We changed Table 1, P/N 1590M29G01 SN “GWNFY824,” to “GWNFY924” in this AD.

One commenter, the ATA, suggests the proposed AD doesn't show a clear relationship between its requirements and those contained in SAIB NE-08-17. The ATA suggests we provide a clarification and a better understanding of why we wrote SAIB NE-08-17 and the proposed rule. The ATA also asks if the recommendations or the hardware listed in SAIB NE-08-17 is still in effect.

We partially agree. The proposed AD specifies the same twenty-six 4-9 spools as SAIB NE-08-17. Special Airworthiness Information Bulletin NE-08-17 still provides recommendations for dispositioning other parts listed in that SAIB. However, we don't require removing the hardware listed in SAIB NE-08-17, other than the 4-9 spools. We didn't change the AD.

One commenter, CFM International, asks us to delete “Seal tooth plasma overspray between the seal teeth, which is not permitted by the engine overhaul manual, and” from the Discussion Section. CFM International states that the overhaul manual does allow plasma overspray between the seal teeth.

We agree that the overhaul manual allows plasma overspray between the seal teeth. However, the Discussion Section is not included in the AD. We didn't change the AD.

One commenter, Japan Airlines, states that we include a prohibition for installing the affected 4-9 spools, but we don't specify what to do with the 4-9 spools removed as specified in the proposed AD. They ask us to provide instructions to disposition the removed 4-9 spools.

We don't agree. The proposed rule requires removing from service, certain 4-9 spools, which removes the unsafe condition. The included installation prohibition resolves our remaining regulatory concerns. How operators recycle metal is beyond the scope of an AD, so long as the excluded part doesn't find its way back into service. We didn't change the AD.

One commenter, the Boeing Company, asks us to clarify the compliance times for removing the affected 4-9 spools. Boeing suggests that, as written, the compliance times of “before accumulating 8,900 cycles-since-repair at PTLLC or within 1,100 cycles after the effective date of this AD,” could allow up to 10,000 cycles to accumulate on an engine before an operator has to take corrective action.

We agree. That is what we intended. We didn't change the AD.

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.

We estimate that this AD will affect 26 engines installed on airplanes of U.S. registry. We also estimate that it will take about 410 work-hours per engine to perform the required actions, and that the average labor rate is $80 per work-hour. Required parts will cost about $227,500 per engine. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $6,767,800.

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.

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 summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive: