Airworthiness Directives; The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER Series Airplanes

AGENCY:

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

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

The FAA is revising an earlier NPRM for an airworthiness directive (AD) that applies to all Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. The original NPRM would have superseded an existing AD that currently requires reviewing the airplane maintenance records to determine whether an engine has been removed from the airplane since the airplane was manufactured. For airplanes on which an engine has been removed, the existing AD also requires an inspection of the aft engine mount to determine if the center link assembly is correctly installed, and follow-on actions if necessary. The original NPRM proposed to require the same actions for airplanes on which the engine has not been previously removed. The original NPRM resulted from reports indicating that operators found that the center link assembly for the aft engine mount was reversed on several airplanes that had not had an engine removed since delivery. This new action revises the original NPRM by expanding the applicability to include Model 737-900ER airplanes. We are proposing this supplemental NPRM to prevent increased structural loads on the aft engine mount, which could result in failure of the aft engine mount and consequent separation of the engine from the airplane.

ADDRESSES:

We must receive comments on this supplemental NPRM by February 25, 2011.

DATES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: 202-493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com . You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

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

FOR FURTHER INFORMATION CONTACT:

Alan Pohl, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6450; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2008-1118; Directorate Identifier 2007-NM-318-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with a notice of proposed rulemaking (NPRM) for an AD (the “original NPRM”) to supersede AD 2003-03-01, Amendment 39-13025 (68 FR 4367, January 29, 2003). The original NPRM applied to all Model 737-600, -700, -700C, -800, and -900 series airplanes. The original NPRM was published in the Federal Register on October 30, 2008 (73 FR 64568). The original NPRM would have superseded an existing AD that currently requires reviewing the airplane maintenance records to determine whether an engine has been removed from the airplane since the airplane was manufactured. For airplanes on which an engine has been removed, the existing AD also requires an inspection of the aft engine mount to determine if the center link assembly is correctly installed, and follow-on actions if necessary. The original NPRM proposed to require the same actions for airplanes on which the engine has not been previously removed.

Actions Since Original NPRM Was Issued

Since we issued the original NPRM, the manufacturer has informed us that Model 737-900ER airplanes should be included in the applicability of the supplemental NPRM. Model 737-900ER airplanes were not being produced in May 2004 when Revision 3, dated May 20, 2004, of Boeing Alert Service Bulletin 737-71A1462, was issued. (Revision 3 was referred to as an appropriate source of service information for accomplishing the proposed actions in the original NPRM.) Following production it was determined that the affected aft engine mount is interchangeable with Model 737-900ER airplanes; however, those airplanes were inspected in production to ensure that the center link was properly installed. Therefore, the requirements in the existing AD do not apply to those airplanes. However, since we are including airplanes on which the engines have been removed since production, we have added Model 737-900ER airplanes to the applicability section of this supplemental NPRM.

Comments

We have considered the following comments on the original NPRM.

Request for Exemption From AD Requirements

American Airlines (AA) asks that all operators that have performed the actions specified in Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004, be exempt from repeating maintenance actions in accordance with the original NPRM for a maintenance program that is already in place and proven effective. AA states that it has exceeded the requirements of AD 2003-03-01 by inspecting both engine aft mount center link assemblies, regardless of the stipulation in the existing AD, which limited the inspection requirement to engines removed since the airplane date of manufacture. AA adds that the inspections revealed that none of its installed or spare engines had incorrectly installed aft mount center link assemblies. AA notes that it is doing Part 2 of the Accomplishment Instructions of the service bulletin at every engine shop visit, and has implemented maintenance task documentation to verify the proper aft mount center link configuration at every engine change. AA concludes that it has not accepted delivery of any additional Model 737 airplanes since the release of the existing AD and Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004.

We acknowledge the commenter's request. Actions done in accordance with Boeing Alert Service Bulletin 737-71A1462, Revision 3, before the effective date of this AD are acceptable for compliance with the AD, as indicated by the phrase “unless the actions have already been done” in paragraph (f) of this AD. We have made no change to the supplemental NPRM in this regard.

Request To Change Paragraph (d)

Boeing asks that paragraph (d) of the original NPRM be changed to indicate that the center link assembly for the aft engine mount was reversed on one airplane that had not had an engine removed since delivery. Boeing is aware of only one such report.

We do not agree with the commenter. We have received another report indicating that some airplanes were found with the engine mounts installed incorrectly on engines that had not been removed since airplane delivery. Therefore, we have not changed paragraph (d) of the NPRM (paragraph (e) of the supplemental NPRM).

Request To Change Paragraph (n)

Boeing asks that paragraph (n) of the original NPRM be changed to clarify parts not affected by the “Parts Installation” paragraph by including the permanent part marking on the center link assembly, as specified in Part 2 of the Work Instructions of Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004. Boeing states that this change would be equivalent to an existing alternative method of compliance (AMOC) for AD 2003-03-01, requiring the installation of marked engine mounts, as specified in the approved section of Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004.

We agree with the commenter for the reasons provided. We have changed paragraph (n) of the supplemental NPRM to include permanent part marking on the center link assembly, as specified in Part 2 of the Work Instructions of Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004.

Request To Clarify Requirements in Paragraph (n)

Japan Airlines (JAL) asks for clarification whether the requirement in paragraph (n) of the original NPRM applies only to airplanes affected by Boeing Alert Service Bulletin 737-71A1462, Revision 3, dated May 20, 2004; or to all Model 737-600, -700, -700C, -800, and -900 series airplanes. JAL states that if the requirement in paragraph (n) applies to all Model 737NG (next generation) airplanes then a change should be made to paragraph (n) of the supplemental NPRM for clarification.

We acknowledge the commenter's concern and provide the following clarification. As noted under “Actions Since Original NPRM Was Issued,” we have added Model 737-900ER airplanes to the applicability section of this supplemental NPRM; therefore, the requirement in paragraph (n) of the supplemental NPRM applies to all Model 737NG airplanes. No change to paragraph (n) of the supplemental NPRM is necessary.

Request To Change Paragraphs (i) and (o)

CFM International states that the acronym CFMI is not accurate and recommends using CFM International (CFM) throughout the NPRM.

We agree that the correct acronym should be used in the supplemental NPRM and in future rulemaking. However, CFMI is not referred to anywhere in this supplemental NPRM; therefore, no change is necessary.

CFM also asks that paragraphs (i) and (o) of the original NPRM be changed to include the Engine and Propeller Directorate, Engine Certification Office (ECO), as an approved source for obtaining repair procedures. CFM states that the engine mounting lugs and adjacent engine turbine rear frame are under the responsibility of CFM as part of the engine type certificate. CFM notes that it is in charge of approval of repairs by delegation of both engine authorities, which are the FAA and European Aviation Safety Agency (EASA); CFM is a joint certification. CFM adds that for any part problems it contacts the ECO, in Burlington, Massachusetts, and the EASA Engine Certification Office, in Cologne, Germany. In light of this, CFM does not recommend the parts be repaired under approval of a Boeing Representative.

We partially agree with the commenter for the reasons provided. We agree that the appropriate office for approval of certain repairs specified in the original NPRM is the ECO. Paragraph (i) of the original NPRM is a restatement of the requirements in AD 2003-03-01. However, paragraph (i) of the supplemental NPRM does refer to paragraph (o) of the supplemental NPRM for AMOC approval. We have changed paragraph (o) of this supplemental NPRM to allow for certain AMOC approvals by the ECO.

Explanation of Additional Changes Made to This Supplemental NPRM

We have changed this supplemental NPRM to identify the legal name of the manufacturer as published in the most recent type certificate data sheet for the affected airplane models.

We have added a new paragraph (d) to this supplemental NPRM to provide the Air Transport Association (ATA) of America subject code 71: Powerplant. This code is added to make this supplemental NPRM parallel with other new AD actions. We have reidentified subsequent paragraphs accordingly.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

Certain changes discussed above expand the scope of the original NPRM; therefore, we have determined that it is necessary to reopen the comment period to provide additional opportunity for public comment on this supplemental NPRM.

Explanation of Change to Costs of Compliance

Since issuance of the original NPRM, we have increased the labor rate in the Costs of Compliance from $80 per work hour to $85 per work hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate.

Costs of Compliance

There are about 1,846 airplanes of the affected design in the worldwide fleet. We estimate that 854 airplanes of U.S. registry would be affected by this proposed AD. There are no new requirements in this proposed AD; however, we have expanded the applicability as noted under “Actions Since Original NPRM Was Issued.” The current costs for this proposed AD are recalculated for the convenience of affected operators, as follows:

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 proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the 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 supplemental NPRM 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

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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.