05-23601. Airworthiness Directives; Boeing Model 737-600, -700, -700C, and -800 Series Airplanes

AGENCY:

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

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. This AD requires replacing the point “D” splice fitting between windows number 1 and 2 with a new splice fitting, performing an eddy current inspection for cracking of the holes in the structure common to the new splice fitting, including doing any related investigative actions; and corrective actions if necessary. This AD results from full-scale fuselage fatigue testing on the splice fitting that failed prior to the design objective on Boeing Model 737-800 series airplanes, and a report of a cracked splice fitting on an operational airplane. We are issuing this AD to prevent cracking of the existing fitting that may result in cracking through the skin and consequent decompression of the flight cabin.

DATES:

This AD becomes effective December 21, 2005.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of December 21, 2005.

We must receive comments on this AD by February 6, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

Sue Lucier, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

We have received a report indicating that during the Model 737-800 series airplanes full-scale fuselage fatigue test, the splice fitting failed prior to the design service objective. Additionally, we have received a report indicating that a cracked splice fitting was found on an airplane with less than 13,500 total flight cycles. This condition, if not corrected, could result in cracking of the existing fitting that may cause cracking through the skin and consequent decompression of the flight cabin.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin (ASB) 737-53A1222, Revision 2, dated October 20, 2005. The ASB describes procedures for replacing the splice fitting between windows number 1 and 2, at point “D” on the windowsill with a new splice fitting, and performing related investigative actions. Those investigative actions include performing an open hole eddy current inspection for cracking of the fastener holes, and a special detailed inspection for cracking of 12 fasteners in the adjacent structure. The ASB also describes procedures for repetitive external detailed inspections of the skin near the six skin fasteners below the splice fitting. The ASB specifies that if cracking is detected, to contact Boeing for further instructions. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to prevent cracking of the existing fitting that may result in cracking through the skin and consequent decompression of the flight cabin. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the AD and the ASB.”

Differences Between the AD and the ASB

Where the ASB specifies contacting Boeing if any cracking is detected, this AD requires that, repair of any cracking be accomplished before further flight, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO).

Although the ASB specifies performing repetitive external detailed inspections of the skin near the six skin fasteners below the splice fitting, this AD does not require those inspections. These differences have been coordinated with the manufacturer.

Interim Action

We consider this AD to be an interim action. We are currently considering requiring repetitive external detailed inspections for cracking of the skin near the six skin fasteners below the splice fitting. However the planned compliance time for accomplishing those inspections would necessitate allowing enough time to provide notice and opportunity for prior public comment on the merits of requiring those inspections.

Similar Models

The splice fitting between windows number 1 and 2, at point “D” on the windowsill, on certain Boeing Model 737-600, -700, -700C series airplanes is identical to the splice fitting on the affected Model 737-800 series airplanes. Therefore, all of these models may be subject to the same unsafe condition.

FAA's Determination of the Effective Date

Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include “Docket No. FAA-2005-23176; Directorate Identifier 2005-NM-220-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Dockets

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

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 the 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 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

Adoption of the Amendment

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

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2005-25-03 Boeing: Amendment 39-14396. Docket No. FAA-2005-23176; Directorate Identifier 2005-NM-220-AD.

Effective Date

(a) This AD becomes effective December 21, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-600, -700, -700C, and -800 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin (ASB) 737-53A1222, Revision 2, dated October 20, 2005.

Unsafe Condition

(d) This AD results from full-scale fuselage fatigue testing on the splice fitting that failed prior to the design objective on Boeing Model 737-800 series airplanes, and a report of a cracked splice fitting on an operational airplane. We are issuing this AD to prevent cracking of the existing fitting that may result in cracking through the skin and consequent decompression of the flight cabin.

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.

Replacing the Splice Fittings

(f) Replace the splice fittings with new splice fittings in accordance with the Accomplishment Instructions of Boeing ASB 737-53A1222, Revision 2, dated October 20, 2005, at the times specified in paragraph (f)(1) or (f)(2) of this AD, as applicable. Before further flight, do any related investigative actions by accomplishing all the applicable actions specified in the Accomplishment Instructions.

(1) For airplanes that have accumulated less than 13,500 total flight cycles as of the effective date of this AD: Replace prior to the accumulation of 13,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later.

(2) For airplanes that have accumulated 13,500 or more total flight cycles as of the effective date of this AD: Replace at the later of the times specified in paragraphs (f)(2)(i) and (f)(2)(ii) of this AD.

(i) Prior the accumulation of 18,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs first.

(ii) Within 90 days after the effective date of this AD.

Corrective Actions

(g) If any cracking is found during any inspection required by this AD, prior to further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or with a method approved in accordance with the procedures specified in paragraph (i) of this AD.

Acceptable Method of Compliance

(h) Replacing the splice fitting before the effective date of this AD in accordance with Boeing Service Bulletin 737-53-1222, dated June 6, 2002; or Boeing ASB 737-53A1222, Revision 1, dated January 30, 2003, is acceptable for compliance with the requirements of paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Seattle ACO, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

(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.

Material Incorporated by Reference

(j) You must use Boeing Alert Service Bulletin 737-53A1222, Revision 2, dated October 20, 2005, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on November 25, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.