If any crack or corrosion is found during any inspection, replace the web panel or contact Boeing for repair instructions and repair before further flight.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under ``Difference Between the Proposed AD and Service Information.'' Difference Between the Proposed AD and Service Information

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

There are about 31 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 1 airplane of U.S. registry. The proposed tests and inspections would take about 3 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for this U.S. operator is $240.

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 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, 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 adding the following new airworthiness directive (AD):
Boeing: Docket No. FAA20070395; Directorate Identifier 2007NM 157AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by February 25, 2008.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Boeing Model 737300 and 400 series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 737571289, dated June 13, 2007. Unsafe Condition
(d) This AD results from several reports indicating that cracks ranging from 0.8 to 8.0 inches long were found on a certain web panel of the main wheel well pressure deck. We are issuing this AD to prevent fatigue cracking in the web panel of the main wheel well pressure deck, which could result in venting and consequent rapid decompression of 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.
[[Page 1848]]
Testing/Inspecting/Investigative and Corrective Actions
(f) Within 6 months after the effective date of this AD: Do a test of the web panel of the main wheel well pressure deck to determine the material type, and do an ultrasonic inspection to determine material thickness, by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737571289, dated June 13, 2007.
(g) For airplanes on which the web thickness or material is found to be discrepant during the test and inspection required by paragraph (f) of this AD, accomplish the applicable actions specified in paragraphs (g)(1) and (g)(2) of this AD at the time specified, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737571289, dated June 13, 2007.
(1) Do all applicable related investigative and corrective actions (including detailed and general visual inspections) before further flight, by doing all the actions specified in the
Accomplishment Instructions of the service bulletin; except as provided by paragraph (h) of this AD. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles until paragraph (g)(2) of this AD has been done.
(2) Within 30 months or 6,000 flight cycles after accomplishing the actions required by paragraph (g)(1) of this AD, whichever is later, replace the web panel in accordance with the Accomplishment Instructions of the service bulletin. Doing this replacement ends the repetitive inspections required by paragraph (g)(1) of this AD. Corrective Actions
(h) If any crack or corrosion is found during any inspection required by paragraph (g)(1) of this AD, and Boeing Special Attention Service Bulletin 737571289, dated June 13, 2007, specifies to contact Boeing for repair instructions: Before further flight, repair according to a method approved in accordance with the procedures specified in paragraph (i) of this AD.
Alternative Methods of Compliance (AMOCs)
(i)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.
(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.
(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on December 21, 2007. Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. E8251 Filed 1908; 8:45 am]
BILLING CODE 491013P

FOR FURTHER INFORMATION CONTACT Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 980573356; telephone (425) 9176447; fax (425) 9176590.