AD 2001-11-08

Effective July 16, 2001.

The incorporation by reference of certain publications, as listed in the regulations, is approved by the Director of the Federal Register as of July 16, 2001.

The incorporation by reference of certain other publications, as listed in the regulations, was approved previously by the Director of the Federal Register as of September 16, 1999 (64 FR 47653, September 1, 1999).

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.

Sheila I. Mariano, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2675; fax (425) 227-1181.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 99-18-16, amendment 39-11282 (64 FR 47653, September 1, 1999), applicable to certain Boeing Model 747-400, 757-200, 767-200, and 767-300 series airplanes, was published in the Federal Register on June 15, 2000 (65 FR 37494). That action proposed to continue to require the actions specified in AD 99-18-16, and to add a terminating action for the repetitive checks and tests. That action also proposed to make those requirements applicable to other airplanes on which the defective power supplies may be installed, eliminate the repetitive tests for certain airplanes, and increase the interval for the repetitive tests for certain other airplanes. Additionally, that action also proposed to require replacement of any subject power supply in the WEU or MAWEA with a new, modified, or serviceable power supply. That action was prompted by a report of a MAWEA power supply failure due to inadequate over-voltage protection.

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

One commenter supports the actions specified by the proposed AD. Four other commenters state that they are either not affected by the proposed AD or are in compliance with the proposed actions.

One commenter states that the FAA should determine the number of power supply modules, part number (P/N) 285T0035-201, currently installed on airplanes. If the subject power supply module is found, the FAA should require a fleet check for part numbers and serial numbers before requiring fleetwide preflight checks. If the manufacturer of the subject part (Boeing) could identify which serial numbers were produced and identify the units that have been modified by July 2000, there may be no need to issue an AD. The FAA infers that the commenter is requesting that the proposed AD be withdrawn.

The FAA does not concur that the proposed AD should be withdrawn. The applicability of this AD limits the requirements to only certain airplanes on which the affected P/N is installed. Airplanes not included in the applicability are not subject to preflight checks or the requirements of this AD. Issuance of this AD is necessary to require U.S. operators of airplanes with the affected P/N installed to accomplish the required actions.

One commenter requests that the FAA clarify the terminating action required by the proposed AD. The commenter states that the intent of the proposed AD is to replace all power supplies, P/N 285T0035-201, found on certain Model 747, 757, and 767 series airplanes and those power supplies in stock. After such replacement, no further repetitive checks are required. However, the proposed AD does not provide clear direction to the terminating action. Paragraphs (a) and (b) of the proposed AD require “test and replacement” action per paragraph (c) or (f). If the action in paragraph (c) or (f) is terminated, operators are not required to do the action required by paragraph (d) or (e), which specify repetitive checks (for Model 747-400 and -400F series airplanes not listed in paragraph (a)) and repetitive checks and functional tests (for Model 757 and 767 series airplanes not listed in paragraph (b)). The operator states that, even though it has replaced the subject power supplies, the proposed AD still requires the repetitive checks (as specified in paragraph (d) of the proposed AD), and the repetitive checks and functional tests (as specified in paragraph (e) of the proposed AD). This creates an unintended burden on operators.

The FAA clarifies that the actions required by paragraphs (a), (b), and (c) of this AD in the section, “Partial Restatement of Requirements of AD 99-18-16,” are included for operators that have not already replaced the power supplies. For those operators, the checks and functional tests, as well as the corrective actions, continue to be required by this new AD. The replacement action was not required by AD 99-18-16. However, this new AD requires replacement of any subject power supplies within 1 year after the effective date of this AD, as the terminating action. Paragraphs (c)(1), (c)(2), and (c)(3) of this AD, clearly state that replacement of the subject power supplies constitutes terminating action for the requirements of this AD. In addition, we point out that the actions required by paragraphs (d) and (e) of this AD only apply to airplanes not subject to the requirements of paragraphs (a) and (b). Paragraphs (d) and (e) both specify that replacement action terminates the repetitive checks and tests specified by this AD. The FAA has revised paragraph (f) of this final rule to clarify that such replacement terminates “the requirements of this AD,” rather than “the repetitive inspection requirements of this AD.”

One commenter requests an inspection of the power supply module to identify the P/N installed at the next “A” check or 45 days (after the effective date of this AD), whichever occurs earlier, and repetitive inspections if subject P/N 285T0035-201 is found. The commenter contends that the first action in paragraphs (d) and (e) of the proposed AD is to check the status page of the EICAS for any MAWEA or WEU failures, which assumes that the subject P/N is installed. However, the FAA should clarify those paragraphs to specify that operators first must determine if a subject P/N is installed at the next “A” check or 45 days (after the effective date of this AD), whichever occurs first. If a subject P/N is found, then the proposed AD should require repetitive checks (as specified in paragraphs (d) and (e) of the proposed AD). The commenter adds that there is no assurance that the subject P/N has not been subsequently installed on an airplane that was modified per AD 99-18-16.

The FAA does not concur with the commenter's request to require an additional inspection to determine if a subject P/N is installed. The applicability statement and certain paragraphs of this AD limit the required actions to only certain airplanes equipped with either a WEU or MAWEA power supply having P/N 28T0035-201. Some operators should be able to review their maintenance log books to determine if the subject P/N has been replaced. Therefore, it is not necessary to add an inspection in paragraphs (d) and (e) of this AD to determine if a subject power supply is installed.

Also, the repetitive checks required by paragraphs (d) and (e) of this AD are limited to only certain airplanes equipped with either a WEU or MAWEA power supply having P/N 285T0035-201, other than those airplanes identified in paragraph (a) or (b) of this AD. We have revised paragraphs (d) and (e) of this AD accordingly to clarify any confusion.

We do not agree that operators may have inadvertently installed the subject P/N on a previously modified airplane. We point out that, for airplanes subject to AD 99-18-16, paragraph (g) of that AD specifies that no person shall install a WEU or MAWEA power supply having P/N 285T0035-201 on any airplane as of the effective date of that AD, as specified in paragraph (g)(1) of this AD. Therefore, no change to this AD is necessary in this regard.

Two commenters request changing a paragraph reference in paragraphs (d)(1) and (e)(1) of the proposed AD. The commenters state that the correct paragraph reference for the terminating action required by the proposed AD is paragraph (f) instead of paragraph (e). The FAA concurs with this request and has changed the final rule accordingly.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

There are approximately 1,592 Model 747-400, 747-400F, 757-200, 757-200CB, 757-200PF, 767-200, 767-300, and 767-300F series airplanes of the affected design in the worldwide fleet. The FAA estimates that 802 airplanes of U.S. registry will be affected by this AD.

The repetitive checks and tests required by AD 99-18-16 are currently applicable to approximately 33 U.S.-registered airplanes. The repetitive checks and tests take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required checks and tests on U.S. operators is estimated to be $1,980, or $60 per airplane, per check/test cycle. Because this AD eliminates the currently required repetitive tests for certain airplanes, and increases the repetitive interval for the tests for certain other airplanes, this AD reduces the costs to operators currently subject to AD 99-18-16.

The repetitive checks and tests in this new action are applicable to approximately 769 additional airplanes. Based on the figures discussed above, the new costs to U.S. operators for the repetitive checks and tests imposed by this AD are estimated to be $46,140, or $60 per airplane, per check/test cycle.

For all airplanes subject to this AD, the new replacement action required by this AD takes approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts cost approximately $6,424 per airplane. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $5,296,408, or $6,604 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.

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.

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:

1. The authority citation for part 39 continues to read as follows: