AD 2008-04-12

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 767-200, -300, and -300F series airplanes. That AD currently requires reworking the surface of the ground stud bracket of the left and right transformer rectifier units (TRUs) and the airplane structure mounting surface, and measuring the resistance from the bracket to the structure and the ground lugs to the bracket using a bonding meter. This new AD revises the applicability of the existing AD to include additional airplanes and requires, among other actions, installation of a new ground stud bracket using faying surface bonding. This AD results from a report of loss of all direct current (DC) power generation during a flight, due to inadequate electrical ground path between the ground bracket of the TRUs/main battery charger (MBC) and the structure. We are issuing this AD to prevent depletion of the main battery while in flight, resulting from the loss of both TRUs and theMBC, and consequent loss of all DC power, which could impact the safe flight and landing of the airplane due to the loss of function or malfunction of essential/critical systems and displays in the cockpit.

Final rule.

2008-04-12 Boeing: Amendment 39-15384. Docket No. FAA-2007-0203; Directorate Identifier 2007-NM-105-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective April 3, 2008. \n\nAffected ADs \n\n\t(b) This AD supersedes AD 2004-23-14. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 767-200, -300, -300F, and - 400ER series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 767-24A0162, dated May 30, 2006. \n\nUnsafe Condition \n\n\t(d) This AD results from a report of loss of all direct current (DC) power generation during a flight, due to inadequate electrical ground path between the ground bracket of the left and right transformer rectifier unit (TRUs)/main battery charger (MBC) and the structure. We are issuing this AD to prevent depletion of the main battery while in flight, resulting from the loss of both TRUs and the MBC, and consequent loss of all DC power, which could impact the safe flight and landing of the airplane due to the loss of function or malfunction of essential/critical systems and displays in the cockpit. \n\nCompliance \n\n\t(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. \n\nRequirements of AD 2004-23-14 \n\nRework and Measure Resistance \n\n\t(f) For Model 767-200, -300, and -300F series airplanes, as listed in Boeing Alert Service Bulletin 767-24A0119, Revision 2, dated August 19, 2004; on which the actions of Boeing Service Bulletin 767-24-0119, dated May 14, 1998, and/or Revision 1, dated December 16, 1999, have been done: Within 45 days after December 1, 2004 (the effective date of AD 2004-23-14), rework the ground stud bracket of the TRUs and structure mounting surface, and measure the resistance from the bracket to the structure and the grounding lug to the bracket using a bonding meter, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767- 24A0119,Revision 2, dated August 19, 2004, as revised by Boeing Information Notice 767-24A0119 IN 01, dated October 21, 2004, except as provided by paragraph (g) of this AD. \n\t(g) Step 4, Sheet 3 of Figure 1 in the Accomplishment Instructions of the service bulletin only specifies to install one collar with part number (P/N) BACC30M6. However, a collar with P/N BACC30BL6 (as listed in paragraph 2.C., "Parts Necessary For Each Airplane'' of the service bulletin) may be used as an alternative method of compliance (AMOC). \n\nNew Actions Required by This AD \n\nRework, Installation, Measurement, as Applicable \n\n\t(h) For all airplanes: Within 36 months after the effective date of this AD, rework the existing ground stud bracket of the TRUs/MBC, measure the resistance, and install a new ground stud bracket of the TRUs by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 767- 24A0162, dated May 30, 2006. \n\nAMOCs \n\n\t(i)(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. \n\t(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. \n\nMaterial Incorporated by Reference \n\n\t(j) You must use Boeing Alert Service Bulletin 767-24A0119, Revision 2, dated August 19, 2004, as revised by Boeing Information Notice 767-24A0119 IN 01, dated October 21, 2004; and Boeing Alert Service Bulletin 767-24A0162, dated May 30, 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. \n\t(1) The Director of the Federal Register approved the incorporation by reference of Boeing Alert Service Bulletin 767- 24A0162, dated May 30, 2006, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) On December 1, 2004 (69 FR 67043, November 16, 2004), the Director of the Federal Register approved the incorporation by reference of Boeing Alert Service Bulletin 767-24A0119, Revision 2, dated August 19, 2004, as revised by Boeing Information Notice 767- 24A0119 IN 01, dated October 21, 2004. \n\t(3) 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 FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion \n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that supersedes AD 2004-23-14, amendment 39-13869 (69 FR 67043, November 16, 2004). The existing AD applies to certain Boeing Model 767-200, -300, and -300F series airplanes. That NPRM was published in the Federal Register on November 19, 2007 (72 FR 64964). That NPRM proposed to require reworking the surface of the ground stud bracket of the left and right transformer rectifier units (TRUs) and the airplane structure mounting surface, and measuring the resistance from the bracket to the structure and the ground lugs to the bracket using a bonding meter. That NPRM also proposed revising the applicability of the existing AD to include additional airplanes and to require, among other actions, installation of a new ground stud bracket using faying surface bonding. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We considered the comment that has been received on the NPRM. Boeing, the single commenter, supports the NPRM. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comment that has been received, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tThere are 932 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs\n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per airplane\nNumber of U.S.-registered airplanes\nFleet cost\nRework and Measurement (required by AD 2004-23-14)\n1\n$80\n$4\n$84\n262\n$22,008\nNew actions\n1 or 21\n$80\n$208\n$288 or $3681\n412\n$118,656 or $151,6161\n1Depending on the airplane configuration. \n\nAuthority for This Rulemaking \n\n\tTitle 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. \n\tWe 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. \n\nRegulatory Findings \n\n\tWe 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866; \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\t(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. \n\tWe 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. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by removing amendment 39-13869 (69 FR 67043, November 16, 2004) and by adding the following new airworthiness directive (AD):