06-5205. Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD requires replacing the fuel shutoff valve wires and conduit assemblies in the left and right engine strut aft fairing areas. This AD results from a report that an operator discovered many small chafe marks and exposed shield braid on fuel shutoff wires routed through a conduit in the wing. We are issuing this AD to prevent exposed wires that could provide an ignition source in a flammable leakage zone and possibly lead to an uncontrolled fire or explosion.

DATES:

This AD becomes effective July 17, 2006.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of July 17, 2006.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC.

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

FOR FURTHER INFORMATION CONTACT:

Doug Pegors, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (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 street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. That NPRM was published in the Federal Register on March 16, 2005 (70 FR 12815). That NPRM proposed to require replacing the fuel shutoff valve wires and conduit assemblies in the left and right engine strut aft fairing areas.

Explanation of Revised Service Information

Since we issued the NPRM, Boeing revised Special Attention Service Bulletin 737-28-1199, dated September 9, 2004, which was specified in the NPRM as the appropriate source of service information for accomplishing the proposed requirements of this AD. We have reviewed Boeing Special Attention Service Bulletin 737-28-1199, Revision 1, dated December 15, 2005. Service Bulletin 737-28-1199, Revision 1, incorporates information specified in Boeing Information Notice (IN) 737-28-1199 IN 01, dated November 4, 2004, and additional similar changes' although the procedures remain essentially the same. The information and similar changes include revisions to certain part numbers and materials; changes to the step tables and notes in several figures; addition of drawings used in the preparation of the service bulletin; deletion of the reference to Appendix A of the service bulletin; clarification of work instructions; and other changes. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

Comments

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

Support for the AD

Two commenters, the Airline Pilots Association (ALPA), and AirTran Airways, support the proposed AD.

Request To Extend Compliance Time

Four commenters, Continental, KLM Royal Dutch Airlines (KLM), American Airlines, and the Air Transport Association (ATA) on behalf of American Airlines, request that the compliance time of 24 months specified by the NPRM be extended to 36 months or longer. American Airlines requests that the compliance time be extended to 72 months. The commenters contend that the amount of work proposed by the NPRM will not be possible to accomplish within 24 months without considerable extra maintenance activity at great expense and hardship. The commenters assert that revising the compliance time as requested will bring the AD into closer alignment with scheduled heavy maintenance checks and greatly ease this burden.

We agree that an extension of the compliance time could allow closer alignment with scheduled maintenance for some operators; however, extending the compliance time to 72 months would expose the fleet to an unacceptable level of increased risk. We have determined that extending the 24-month compliance time by 12 months will bring this AD into closer alignment with scheduled maintenance without an unacceptable increase in risk to the fleet. Accordingly, we have revised paragraph (f) of the AD to specify a compliance time of 36 months. Further, to obtain even longer compliance times, anyone may request approval of an AMOC as specified in paragraph (h) of this AD, provided data are submitted to demonstrate that an acceptable level of safety will be maintained.

Request for Wiring Diagram Manual Update

One commenter, Continental, requests that Boeing either incorporate the revised wiring configuration specified by the service bulletin into the existing wiring diagram manual or issue a new manual. Continental asserts that a maintenance technician could unintentionally undo the wire configuration specified by the AD if the existing wiring diagram manual is used after this AD has been performed. Continental states that a revised wiring diagram manual is necessary to maintain the wire routing and modification configuration required by this AD.

We agree that it is essential to maintain proper modification configuration. Section K of Service Bulletin 737-28-1199, Revision 1, lists all publications affected by changes to the service bulletin, such as the wiring diagram manual and illustrated parts catalog. These manuals provide all information needed for maintenance personnel to maintain the wiring configuration detailed by the AD; therefore, such manuals must be current. To ensure this, the release of a service bulletin triggers an update of these manuals. We have confirmed with Boeing that all documents referenced in section K of any Boeing service bulletin are updated and available to operators at the time that service bulletin is released; but that it remains the operator's responsibility to ensure that the updated documents are incorporated into the operator's manuals. No change is needed to the AD in this regard.

Request To Identify Wire Bundle

One commenter, Continental, requests that we revise the NPRM to require installing red-colored identification sleeves on the engine fuel shutoff valve wire bundle. Continental contends that such sleeves, labeled “CAUTION” (followed with the service bulletin number “737-28-1199” or the operator's number), should be installed on the wire bundle at intervals of 12 to 24 inches. Continental states that similar red identification sleeves are installed on the 737 CL (Classic) Isolated Fuel Quantity Transmitter (IFQT) wiring.

We do not agree. Identification of the IFQT safe side wiring is necessary to maintain isolation of those wires from other high-power wiring that may be routed in close proximity. However, isolation of the engine fuel shutoff valve wire bundle is not a safety-critical issue. No change is needed to the AD in this regard.

Request To Reissue Service Bulletin

One commenter, Continental, requests that the service bulletin be reissued with a clearer description of the unsafe condition. Continental requests certain language in the service bulletin be changed to read, “The exposure of the wire shield braid could cause electrical arcing in the fuel leakage zone, which could result in an uncontrolled fire and explosion as well as an in-flight engine shutdown.” Continental asserts that this language clarifies the urgency of the unsafe condition and that the service bulletin should therefore be reissued as an alert service bulletin.

We agree that it is desirable to reflect unsafe conditions in service information as clearly as possible, as this would add a sense of urgency to the service information. However, we have revised the AD to refer to Boeing Service Bulletin 737-28-1199, Revision 1, as the appropriate source of service information for accomplishing the required actions of the AD (refer to “Explanation of Changes Made to This AD”). Revision 1 refers to the possibility of engine shutdown and we have determined that adding “alert” to the title of the service bulletin will have no effect upon airplane safety. No change is needed to the AD in this regard.

Request To Revise Costs of Compliance

Two commenters, Continental and ATA, on behalf of its member, American Airlines, state that the Costs of Compliance shown in the NPRM do not correspond with labor estimates provided by the service bulletin. American Airlines states that the service bulletin specifies 77 work hours rather than the 42 work hours estimated by the NPRM, while Continental asserts that the correct figure should be 50 work hours. Though no request was made, we infer that the commenters wish us to increase the number of work hours shown in the Costs of Compliance.

We do not agree with this request. Based on the best data available, the manufacturer provided the number of work hours necessary to do the required actions. This number represents the time necessary to perform only the actions actually required by this AD. We recognize that in doing the actions required by an AD, operators may incur incidental costs in addition to the direct costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and to close up, time necessary for planning, or time necessitated by other administrative actions. While the service bulletin includes an estimate of the cost to access and close up the aft fairing areas of the engine struts in order to perform the required fuel shutoff valve wire and conduit assembly replacements, we do not include those costs in our estimate. We have not changed the AD in this regard; however, we have provided some relief to operators by extending the compliance time, as described earlier.

Explanation of Changes Made to This AD

Service Bulletin 737-28-1199, Revision 1, Paragraph 1.A.—Effectivity, shows changes of airplane operators from the original issue of the service bulletin. Therefore, we have revised paragraph (c) of the AD to refer to Service Bulletin 737-28-1199, Revision 1, to determine the applicability of the AD. No new airplanes have been added.

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

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.

Costs of Compliance

There are about 1,338 airplanes of the affected design in the worldwide fleet. This AD will affect about 529 airplanes of U.S. registry. The required actions will take about 42 work hours per airplane, at an average labor rate of $65 per work hour. Required parts will cost about $2,418 per airplane. Based on these figures, the estimated cost of the AD for U.S. operators is $2,723,292, or $5,148 per airplane.

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 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 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):

2006-12-11 Boeing: Amendment 39-14636. Docket No. FAA-2005-20626; Directorate Identifier 2004-NM-243-AD.

Effective Date

(a) This AD becomes effective July 17, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes; certificated in any category; as listed in Boeing Special Attention Service Bulletin 737-28-1199, Revision 1, dated December 15, 2005.

Unsafe Condition

(d) This AD was prompted by a report that an operator discovered many small chafe marks and exposed shield braid on fuel shutoff valve wires routed through a conduit in the wing. We are issuing this AD to prevent exposed wires that could provide an ignition source in a flammable leakage zone and possibly lead to an uncontrolled fire or explosion.

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.

Parts Replacement

(f) Within 36 months after the effective date of this AD, replace the fuel shutoff valve wires and conduit assemblies in the left and right engine strut aft fairing areas with new fuel shutoff valve wires and conduit assemblies, by accomplishing all the actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-28-1199, Revision 1, dated December 15, 2005.

Actions Accomplished Using Prior Version of Service Information

(g) Actions accomplished before the effective date of this AD in accordance with Special Attention Service Bulletin 737-28-1199, dated September 9, 2004, are considered acceptable for compliance with the applicable action specified in this AD.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office, 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 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Material Incorporated by Reference

(i) You must use Boeing Special Attention Service Bulletin 737-28-1199, Revision 1, dated December 15, 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 May 31, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.