03-17. Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes, that requires replacement of the existing fueling float switch and conduit assemblies in the main and center fuel tanks with new, improved assemblies. The actions specified by this AD are intended to prevent fluid contamination inside the fueling float switch or chafing of the wiring to the in-tank conduit, which could generate an ignition source and consequent fire and explosion in the fuel tank. This action is intended to address the identified unsafe condition.

DATES:

Effective February 10, 2003.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 10, 2003.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

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:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes was published in the Federal Register on August 20, 2002 (67 FR 53893). That action proposed to require replacement of the existing fueling float switch and conduit assemblies in the main and center fuel tanks with new, improved assemblies.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Request To Add Revised Service Information

One commenter, the manufacturer, asks that Boeing Alert Service Bulletin 737-28A1142, Revision 2, dated November 26, 2002, be added to the proposed AD as another source of service information for accomplishment of the specified actions. Boeing Alert Service Bulletin 737-28A1142, dated February 7, 2002, was referenced in the proposed AD as the appropriate source of service information for accomplishment of the actions.

The FAA agrees with the commenter. We have reviewed and approved Boeing Alert Service Bulletin 737-28A1142, Revision 2, dated November 26, 2002. We find that the changes incorporated in Revision 2 of the service bulletin are not substantive, meaning that airplanes modified per the original issue of the service bulletin are not subject to any additional work under Revision 2 of the service bulletin. Therefore, we have revised paragraph (a) of this final rule to refer to Revision 2 of the service bulletin as the appropriate source of service information for the actions in that paragraph. In addition, we have added a new paragraph (b) to this final rule (and reordered subsequent paragraphs accordingly) to give credit for replacements accomplished before the effective date of this AD according to the original issue of the service bulletin.

Request To Change Number of Airplanes Affected

The same commenter asks that the number of affected airplanes that is specified in the Cost Impact section of the proposed AD be changed. The commenter provided supporting data which confirms that the number of airplanes in the worldwide fleet is 927, and the number of U.S.-registered airplanes is 421.

We agree with the commenter, as we inadvertently specified the incorrect numbers of affected airplanes in the proposed AD. We have changed the Cost Impact section in this final rule to reflect the correct numbers of airplanes.

Request To Change Work Hours

One commenter states that the man hours specified in the Cost Impact section of the proposed AD are conservative, and notes that the actual man hours will be higher and will increase the out-of-service time for its airplanes.

Although the commenter does not request a change, we infer that the commenter would like the number of work hours specified in the Cost Impact section to be increased.

We do not agree to change the work hours for the replacements. The number of work hours necessary to accomplish the replacements, as specified in the Cost Impact section, is consistent with the service bulletin. The number represents the time necessary to perform only the replacements actually required by this AD. We recognize that, in accomplishing the requirements of any 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 close up, planning time, or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. Therefore, no change is made to the final rule in this regard.

Explanation of Change to Final Rule

We have changed the compliance time terminology specified in paragraphs (a)(1), (a)(2), and (a)(3) of the proposed AD from flight cycles to flight hours in the final rule. We inadvertently used the term “flight cycles,” in the proposed AD; however, the referenced service bulletin specifies “flight hours,” and the proposed AD also should have specified “flight hours.”

Conclusion

After careful review of the available data, we have determined that air safety and the public interest require the adoption of the rule with the changes previously described. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 927 airplanes of the affected design in the worldwide fleet. The FAA estimates that 421 airplane of U.S. registry will be affected by this AD.

It will take approximately 56 work hours per airplane to accomplish the replacement in the two main fuel tanks, as specified in Work Page I, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the work hours for this required replacement on U.S. operators is estimated to be $1,414,560, or $3,360 per airplane.

It will take approximately 23 work hours per airplane to accomplish the replacement in the center fuel tank, as specified in Work Package II, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the work hours per this required replacement on U.S. operators is estimated to be $580,980, or $1,380 per airplane.

The kit required to accomplish the replacement in all three fuel tanks will cost approximately $5,116 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

2002-26-18 Boeing: Amendment 39-13006. Docket 2002-NM-44-AD.

Applicability: Model 737-600, -700, -700C, -800, and -900 series airplanes; certificated in any category; as listed in Boeing Alert Service Bulletin 737-28A1142, Revision 2, dated November 26, 2002.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent fluid contamination inside the fueling float switch or changing of the wiring to the in-tank conduit, which could generate an ignition source and consequent fire and explosion in the fuel tank, accomplish the following:

Replacement

(a) Replace the existing fueling float switch and conduit assemblies in the main and center fuel tanks with new, improved assemblies (includes a new float switch and a new conduit assembly with a liner system inside the conduit), at the applicable time specified in paragraph (a)(1), (a)(2), or (a)(3) of this AD, per Work Packages I and II of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1142, Revision 2, dated November 26, 2002.

Note 2:

Due to the lack of sleeving on the existing electrical wire installations of the center fuel tank, it is recommended that Work Package II be completed before Work Package I.

(1) For airplanes that have accumulated fewer than 5,000 total flight hours as of the effective date of this AD: Within 2 years after the effective date of this AD.

(2) For airplanes that have accumulated 5,000 total flight hours or more, but fewer than 10,000 total flight hours as of the effective date of this AD: Within 1 year after the effective date of this AD.

(3) For airplanes that have accumulated 10,000 total flight hours or more as of the effective date of this AD: Within 180 days after the effective date of this AD.

(b) Replacements done before the effective date of this AD per Boeing Alert Service Bulletin 737-28A1142, dated February 7, 2002, are considered acceptable for compliance with paragraph (a) of this AD.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airport Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requests of this AD can be accomplished.

Incorporation by Reference

(e) Unless otherwise specified in this AD, the replacement shall be done in accordance with Boeing Alert Service Bulletin 737-28A1142, Revision 2, dated November 26, 2002. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Effective Date

(f) This amendment becomes effective on February 10, 2003.

Issued in Renton, Washington, on December 26, 2002.

Charles D. Huber,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.