Revision 3 of the service bulletin specifies repeating the inspection during each subsequent engine change for each aft engine mount. This proposed AD does not specify a repetitive inspection but instead specifies in paragraph (n), ``Parts Installation,'' that no person may install an engine on any airplane unless the center link assembly of the aft engine mount is found to be installed correctly.

Revision 3 of the service bulletin also specifies that adding permanent part marks on the center link assembly and the hanger fitting ends the need for the repetitive inspections. As noted above, this proposed AD would not include a repetitive inspection requirement. In addition, because the affected parts are rotable, the repetitive inspections referred to in the service bulletin would be terminated only as long as the engine stays on the airplane.

Changes to Existing AD

This proposed AD would retain the requirements of AD 20030301. Since AD 20030301 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:
Revised Paragraph Identifiers
Corresponding requirement in Requirement in AD 20030301 this proposed AD Paragraph (a)........................... Paragraph (f).
Paragraph (b)........................... Paragraph (g).
Paragraph (c)........................... Paragraph (h).
Paragraph (d)........................... Paragraph (i).
Paragraph (e)........................... Paragraph (m).

Paragraph (f)........................... Paragraph (n).

We have also removed Note 1 of the existing AD and renumbered subsequent notes accordingly. We have also revised Note 2 and Note 3 of the existing AD (Note 1 and Note 2 of this proposed AD) to provide a more uptodate definition of a general visual inspection and a detailed inspection.

Boeing Commercial Airplanes has received a DOA. We have revised paragraph (i) of this AD (paragraph (d) of AD 20030301) to delegate the authority to approve an alternative method of compliance for any repair required by this proposed AD to an Authorized Representative for the Boeing Commercial Airplanes DOA rather than a Designated Engineering Representative (DER). We have also simplified paragraph (i) of this AD by referring to the ``Alternative Methods of Compliance (AMOCs)'' paragraph (o) of this proposed AD for repair methods, which includes a reference to the DOA.

Costs of Compliance

There are about 1,277 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 500 airplanes of U.S. registry. The average labor rate is $80 per work hour. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.
Estimated Costs Cost per Action Work hours Parts airplane Fleet cost Maintenance records review (required by AD 20030301)...... 1 $0 $80 $40,000 Inspection for correct installation of center link assembly 1 0 80 40,000 (new proposed action)...................................... 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. [[Page 64570]]

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 proposed 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.

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 39AIRWORTHINESS 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 removing amendment 3913025 (68 FR 4367, January 29, 2003) and adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA20081118; Directorate Identifier 2007NM 318AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by December 15, 2008.
Affected ADs
(b) This AD supersedes AD 20030301.
Applicability
(c) This AD applies to all Boeing Model 737600, 700, 700C, 800, and 900 series airplanes, certificated in any category. Unsafe Condition
(d) This AD results 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. We are issuing this AD 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.
Compliance
(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Restatement of the Requirements of AD 20030301
Review of Maintenance Records
(f) Within 90 days after February 13, 2003 (the effective date of AD 20030301), review the airplane maintenance records to determine whether either engine has been removed since the airplane's date of manufacture. If neither engine has been removed since the airplane's date of manufacture, no further action is required by this paragraph; however paragraph (n) of this AD continues to apply.
Inspection To Determine if Center Link Assembly Is Installed Correctly (g) For any installed engine that is found to have been removed from the airplane since the airplane's date of manufacture: Within 90 days after February 13, 2003, do a onetime general visual inspection to determine if the center link assembly of the aft engine mount is installed correctly, per the Accomplishment Instructions of Boeing Alert Service Bulletin 73771A1462, Revision 1, dated November 7, 2002; or Revision 3, dated May 20, 2004. If the center link assembly is installed correctly, as specified in the service bulletin, no further action is required by paragraph (g), (h), or (i) of this AD for that engine; however paragraph (n) of this AD continues to apply.

Note 1: For the purposes of this AD, a general visual inspection is: ``A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.''
Followon and Corrective Actions
(h) For any center link assembly that is found installed incorrectly during the inspection required by paragraph (g) of this

FOR FURTHER INFORMATION CONTACT

Allen Rauschendorfer, Aerospace Engineer, Airframe Branch, ANM120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057 3356; telephone (425) 9176432; fax (425) 9176590.