05-23054. Airworthiness Directives; Boeing Model 767-300 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 767-300 series airplanes. This AD requires replacing the frequency converters used to supply power for medical and galley utility outlets with modified frequency converters, and related actions. This AD results from a report indicating that a hard short circuit condition between the output of certain frequency converters and their downstream circuit breakers will produce a continuous output current that could cause the undersized output wiring to overheat when the frequency converters fail to shut off. We are issuing this AD to prevent overheating of the output wiring of the frequency converters, which could result in the failure of a wire bundle and consequent adverse effects on other systems sharing the affected wire bundle.

DATES:

Effective December 28, 2005.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of December 28, 2005.

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:

Binh Tran, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, 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 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 767-300 series airplanes. That NPRM was published in the Federal Register on March 17, 2005 (70 FR 12986). That NPRM proposed to require replacing the frequency converters used to supply power for medical outlets with modified frequency converters, and related actions.

Comments

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

Request To Revise Date of Referenced Service Bulletin

One commenter, the manufacturer, requests that we revise the release date of the service bulletin referenced in the NPRM. The commenter states that the correct reference is Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003.

We agree. We inadvertently referenced the incorrect release date of Boeing Service Bulletin 767-25-0334, Revision 1. Therefore, we have revised paragraphs (c) and (f) of this AD to include the correct release date.

Request To Clarify Use of Frequency Converters

The same commenter requests that we revise the “Summary” and “Relevant Service Information” sections of the NPRM to specify that the affected frequency converters are also used for supplying power to galley utility outlets.

We agree. We have revised the “Summary” section and paragraph (f) of this AD to clarify that the affected frequency converters are used to supply power to “* * * medical and galley utility outlets * * *.” However, since the “Relevant Service Information” section of the preamble does not reappear in the final rule, we have not made that change.

Request To Use Alternative Method of Compliance (AMOC)

A second commenter, an operator, requests that we include an option to remove and deactivate the affected frequency converters and wiring, instead of replacing the affected frequency converters. The commenter states that it is not currently using the medical outlets and has removed the affected frequency converters from its airplanes. The commenter also states that, if the medical outlets are later reactivated, the NPRM should require installing modified frequency converters.

We agree that removing and deactivating the affected frequency converters is adequate for addressing the unsafe condition of this AD. We have moved the proposed requirement to replace the affected frequency converters to new paragraph (f)(1) of this supplemental NPRM and have added new paragraph (f)(2) to this supplemental NPRM, which gives operators the option of deactivating the affected frequency converters. Before a deactivated frequency convert can be re-installed on an airplane, paragraph (f)(2) also would require modifying the affected frequency converters in accordance with Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003.

Request To Reference Parts Manufacturer Approval (PMA) Parts

A third commenter requests that we identify the model and part number of the affected frequency converters in the NPRM. The commenter states that the parts manufacturer of the affected frequency converters produces parts both as an original equipment manufacturer (OEM) supplier and as a direct seller under a PMA. The commenter asserts that, since parts manufacturers are encouraged to use different part numbers for PMA and OEM parts, a PMA part identical to the OEM part, but having a different part number, might be installed on an airplane. The commenter requests that the NPRM account for any PMA parts that might contain the same deficiencies as an OEM part and be installed in its place.

We do not concur with the commenter's request. Our available information indicates that any existing PMA frequency converter installed on any affected airplane retains the OEM original part number and, therefore, would be required to be removed in accordance with the Boeing service bulletin referenced in this AD as the appropriate source of service information. Once the existing parts are removed, the operator must replace it with the part numbers specified in the service bulletin in order to be in compliance with this AD. No change to the final rule is necessary in this regard.

Regarding the commenter's request to address PMA part numbers in ADs, in general, the Transport Airplane Directorate currently is in the process of reviewing this issue as it applies to transport category airplanes. Once we have thoroughly examined all aspects of this issue and have made a final determination, we will consider whether our policy regarding addressing PMA parts in ADs needs to be revised. We consider that to delay this AD action would be inappropriate, since we have determined that an unsafe condition exists and that replacement of certain parts must be accomplished to ensure continued safety. Therefore, no change has been made to the final rule in this regard.

Conclusion

We have carefully reviewed the available data, including the comments that have been 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 55 airplanes of the affected design in the worldwide fleet. This AD affects about 54 airplanes of U.S. registry. The actions in this AD take about 1 work hour per frequency converter, at an average labor rate of $65 per work hour. There are about 2 frequency converters per airplane. Based on these figures, the estimated cost of the AD for U.S. operators is $7,020, or $130 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):

2005-24-04 Boeing: Amendment 39-14384. Docket No. FAA-2005-20629; Directorate Identifier 2004-NM-266-AD.

Effective Date

(a) This AD becomes effective December 28, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 767-300 series airplanes, certificated in any category; as identified in Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003.

Unsafe Condition

(d) This AD was prompted by a report indicating that a hard short circuit condition between the output of certain frequency converters and their downstream circuit breakers will produce a continuous output current that could cause the undersized output wiring to overheat when the frequency converters fail to shut off. We are issuing this AD to prevent overheating of the output wiring of the frequency converters, which could result in the failure of a wire bundle and consequent adverse effects on other systems sharing the affected wire bundle.

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.

Replace Frequency Converters

(f) Within 18 months after the effective date of this AD, do the actions specified in either paragraph (f)(1) or (f)(2) of this AD.

(1) Replace the frequency converters used to supply power for medical and galley utility outlets with modified frequency converters, and do any related actions, by doing all of the actions specified in the Accomplishment Instructions of Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003.

(2) Remove and deactivate the frequency converters used to supply power for medical and galley utility outlets, and cap and stow the frequency converter wire bundles, in accordance with B.1. through B.6. of the Accomplishment Instructions of Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003. As of the effective date of this AD, no person may install a frequency converter that has been removed and deactivated in accordance with this paragraph, unless it is modified in accordance with the Accomplishment Instructions of the service bulletin.

Credit for Previous Service Bulletin

(g) Actions done before the effective date of this AD in accordance with Boeing Service Bulletin 767-25-0334, dated November 7, 2002, are acceptable for compliance with the requirements of paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

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

Material Incorporated by Reference

(i) You must use Boeing Service Bulletin 767-25-0334, Revision 1, dated June 19, 2003, 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/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on November 10, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.