AD 2001-11-08

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747-400, 757-200, 767-200, and 767-300 series airplanes, that currently requires repetitive checks to detect certain failures in the warning electronic unit (WEU) or modular avionic warning electronic assembly (MAWEA); repetitive tests to detect any failure of tactile, visual, or aural alerts generated by the WEU or MAWEA; and corrective action, if necessary. This amendment makes these requirements applicable to other airplanes on which the defective power supplies may be installed, eliminates the repetitive tests for certain airplanes, and increases the interval for the repetitive tests for certain other airplanes. This amendment also requires replacing any subject power supply in the WEU or MAWEA with a new, modified, or serviceable power supply. The actions specified by this AD are intended to prevent failure of the WEU or MAWEA power supplies, which could result in loss of visual, aural, and tactile alerts to the flightcrew. Absence of such alerts could result in the flightcrew being unaware that an immediate or appropriate action should be taken in the event of an unsafe condition.

Final rule.

2001-11-08 Boeing: Amendment 39-12250. Docket 99-NM-350-AD. Supersedes AD 99-18-16, Amendment 39-11282. \n\n\tApplicability: Model 747-400, 747-400F, 757-200, 757-200CB, 757- 200PF, 767-200, 767-300, and 767-300F series airplanes; equipped with either a warning electronics unit (WEU) or a modular avionics warning electronic assembly (MAWEA) power supply having part number (P/N) 285T0035-201; certificated in any category. \n\n\tNote 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 (h)(1) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair onthe 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. \n\n\tCompliance: Required as indicated, unless accomplished previously.\n \n\tTo prevent failure of the WEU or MAWEA power supplies, which could result in loss of visual, aural, and tactile alerts to the flightcrew (the absence of which could result in the flightcrew being unaware that an immediate or appropriate action should be taken in the event of an unsafe condition), accomplish the following: \n\nPartial Restatement of Requirements of AD 99-18-16 \n\nModel 747-400 Series Airplanes: EICAS Status Page Checks \n\n\t(a) For Model 747-400 and 747-400F series airplanes having line number (L/N) 1121 through 1177 inclusive: Within 15 days after September 16, 1999 (the effective date of AD 99-18-16, amendment 39- 11282), check the status page of the engine indication and crew alerting system (EICAS) for any MAWEA failure. Thereafter, repeat the EICAS status page check before each flight until the requirements of paragraph (c) or (f) of this AD have been accomplished. \n\nModel 757-200, 767-200, and 767-300 Series Airplanes: Checks and Functional Tests \n\n\t(b) For Model 757-200, -200CB, and -200PF series airplanes having L/N 761 through 828 inclusive; and Model 767-200, -300, and - 300F series airplanes having L/N 668 through 723 inclusive: Within 15 days after September 16, 1999, check the status page of the EICAS for any WEU failure; and perform the Work Instructions in Section 3, Part 1, of Boeing Service Bulletin 757-31-0066, Revision 1, dated December 17, 1998, or Revision 2, dated November 18, 1999 (for Model 757-200, -200CB, and -200PF series airplanes); or Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998, or Revision 2, dated November 18, 1999 (for Model 767-200, 767-300, and 767-300F series airplanes); as applicable; to detect loss of any visual, aural, or tactile alert. Thereafter, repeat the EICAS status page check before each flight, and the Work Instructions in Section 3, Part 1, of the applicable service bulletin at intervals not to exceed every"A" check or 45 days, whichever occurs first, until the requirements of paragraph (c) or (f) of this AD have been accomplished. After the effective date of this AD, only Revision 2 of the applicable service bulletin shall be used. \n\nCorrective Action \n\n\t(c) If any failure of the MAWEA or WEU, as applicable, or the loss of any visual, aural, or tactile alert is detected during any test required by either paragraph (a) or (b) of this AD, prior to further flight, accomplish paragraph (c)(1), (c)(2), or (c)(3) of this AD; as applicable. \n\n\t\t(1) For Model 747-400 or -400F series airplanes equipped with a MAWEA power supply having P/N 285T0035-201: Replace the power supplies of the MAWEA with new or modified power supplies having P/N 285T0035-202 Mod A, in accordance with either Boeing Service Bulletin 747-31-2288, dated December 17, 1998, or Revision 1, dated January 28, 1999; or with new, modified, or serviceable power supplies having P/N 285T0035-202 Mod A, P/N 285T0035-10, or P/N 285T0035-11, in accordance with Boeing Service Bulletin 747-31-2288, Revision 2, dated November 18, 1999. Such replacement constitutes terminating action for the requirements of this AD. After the effective date of this AD, only Revision 2 of the applicable service bulletin shall be used. \n\n\tNote 2: Page 59 of Boeing Service Bulletin 747-31-2288, Revision 1, dated January 28, 1999, incorrectly references the Boeing 767 AMM as the appropriate source of service information for accomplishment of the removal and installation of the power supply. However, the correct reference is the Boeing 747 AMM. \n\n\t\t(2) For Model 757-200, -200CB, and -200PF series airplanes equipped with a MAWEA power supply having P/N 285T0035-201: Replace the power supplies of the WEU with new or modified power supplies having P/N 285T0035-202 Mod A, in accordance with Boeing Service Bulletin 757-31-0066, Revision 1, dated December 17, 1998; or with new, modified, or serviceable power supplies having P/N 285T0035-202 Mod A, P/N 285T0035-9, P/N 285T0035-10, or P/N 285T0035-11, in accordance with Boeing Special Attention Service Bulletin 757-31- 0066, Revision 2, dated November 18, 1999. Such replacement constitutes terminating action for the requirements of this AD. After the effective date of this AD, only Revision 2 of the service bulletin shall be used. \n\n\t\t(3) For Model 767-200, -300, and -300F series airplanes: Replace the power supplies of the WEU with new or modified power supplies having P/N 285T0035-202 Mod A, in accordance with Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998; or with new, modified, or serviceable power supplies having P/N 285T0035-202 Mod A, P/N 285T0035-9, P/N 285T0035-10, or P/N 285T0035-11, in accordance with Boeing Special Attention Service Bulletin 767-31- 0106, Revision 2, dated November 18, 1999. Such replacement constitutes terminating action for the requirements of this AD. After the effective date of this AD, only Revision 2 of the applicable service bulletin shall be used. \n\nNew Requirements of This AD \n\n\tNote 3: Boeing Component Service Bulletin 285T0035-31-07, dated December 17, 1998, describes procedures for modifying WEU or MAWEA power supplies having P/N 28T0035-201 to 285T0035-202 Mod A. \n\nRepetitive Checks: Model 747-400 and -400F \n\n\t(d) For Model 747-400 and -400F series airplanes equipped with a MAWEA power supply having P/N 28T0035-201, other than those airplanes identified in paragraph (a) of this AD: At the next "A" check or within 45 days, whichever occurs first, check the status page of the EICAS for any MAWEA failure.\n \n\t\t(1) If no MAWEA failure is detected: Thereafter, repeat the EICAS status page check before each flight, until the requirements of paragraph (f) of this AD are accomplished.\n \n\t\t(2) If any MAWEA failure is detected: Prior to further flight, replace MAWEA power supplies having P/N 285T0035-201 with new or modified power supplies having P/N 285T0035-202 Mod A, or new, modified, or serviceable power supplies having P/N 285T0035-10 or P/ N 285T0035-11; in accordance with Boeing Service Bulletin 747-31- 2288, Revision 2, dated November 18, 1999. Such replacement constitutes terminating action for the requirements of this AD. \n\nRepetitive Checks and Functional Tests: Model 757 and 767 \n\n\t(e) For Model 757-200, 757-200CB, 757-200PF, 767-200, 767-300, and 767-300F series airplanes equipped with a WEU power supply having P/N 28T0035-201, other than those airplanes identified in paragraph (b) of this AD: At the next "A" check or within 45 days, whichever occurs first, check the status page of the EICAS for any WEU failure; and perform the Work Instructions in Section 3, Part 1, of Boeing Special Attention Service Bulletin 757-31-0066, Revision 2, dated November 18, 1999; or BoeingSpecial Attention Service Bulletin 767-31-0106, Revision 2, dated November 18, 1999; as applicable; to detect loss of any visual, aural, or tactile alert. \n\n\t\t(1) If no failure of the WEU or loss of any visual, aural, or tactile alert is detected: Thereafter, repeat the EICAS status page check before each flight, and accomplish the Work Instructions in Section 3, Part 1 of the applicable service bulletin at intervals not to exceed every "A" check or 45 days, whichever occurs first, until the requirements of paragraph (f) of this AD are accomplished.\n \n\t\t(2) If any failure of the WEU or loss of any visual, aural, or tactile alert is detected: Prior to further flight, replace WEU power supplies having P/N 285T0035-201, with new or modified power supplies having P/N 285T0035-202 Mod A; or new, modified, or serviceable power supplies having P/N 285T0035-9, P/N 285T0035-10, or P/N 285T0035-11; in accordance with the applicable service bulletin. Such replacement constitutes terminatingaction for the requirements of this AD. \n\nReplacement \n\n\t(f) Within 1 year after the effective date of this AD, replace WEU or MAWEA power supplies having P/N 285T0035-201, with new or modified power supplies having P/N 285T0035-202 Mod A; or new, modified, or serviceable power supplies having P/N 285T0035-9, P/N 285T0035-10, or P/N 285T0035-11; in accordance with Boeing Service Bulletin 747-31-2288, dated December 17, 1998, Revision 1, dated January 28, 1999, or Revision 2, dated November 18, 1999 (for Model 747-400 and 747-400F series airplanes); Boeing Service Bulletin 757- 31-0066, Revision 1, dated December 17, 1998, or Revision 2, dated November 18, 1999 (for Model 757-200, 757-200CB, and 757-200PF series airplanes); or Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998, or Revision 2, dated November 18, 1999 (for Model 767-200, 767-300, and 767-300F series airplanes); as applicable. After the effective date of this AD, only Revision 2 of the applicableservice bulletin shall be used. Such replacement constitutes terminating action for the requirements of this AD. \n\nSpares \n\n\t(g) As of the date specified in paragraph (g)(1) or (g)(2) of this AD, as applicable, no person shall install a WEU or MAWEA power supply having Boeing P/N 285T0035-201 on any airplane. \n\n\t\t(1) For Model 747-400 series airplanes, line numbers 1121 through 1177 inclusive; Model 757-200, -200CB, and -200PF series airplanes, line numbers 761 through 828 inclusive; and Model 767- 200, 767-300, and -300F series airplanes, line numbers 668 through 723 inclusive: As of September 16, 1999 (the effective date of AD 99-18-16, amendment 39-11282). \n\n\t\t(2) For airplanes other than those identified in paragraph (g)(1) of this AD: As of the effective date of this AD. \n\nAlternative Methods of Compliance \n\n\t(h)\t(1) 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. Operators shall submit their requests through an appropriate FAA Principal Avionics Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\t\t(2) Alternative methods of compliance, approved previously by the FAA in accordance with AD 99-18-16, amendment 39-11282, are approved as alternative methods of compliance with this AD. \n\n\tNote 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(i) 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 requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(j) Except for the EICAS status page checks required by paragraphs (a), (b), (d), (d)(1), (e), and (e)(1) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-31-2288, dated December 17, 1998; Boeing Service Bulletin 747- 31-2288, Revision 1, dated January 28, 1999; Boeing Service Bulletin 747-31-2288, Revision 2, including Appendix A, dated November 18, 1999; Boeing Service Bulletin 757-31-0066, Revision 1, dated December 17, 1998; Boeing Special Attention Service Bulletin 757-31- 0066, Revision 2, including Appendix A, dated November 18, 1999; Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998; or Boeing Special Attention Service Bulletin 767-31-0106, Revision 2, including Appendix A, dated November 18, 1999; as applicable. \n\n\t\t(1) The incorporation by reference of Boeing Service Bulletin 747-31-2288, Revision 2, including Appendix A, dated November 18, 1999; Boeing Special Attention Service Bulletin 757-31-0066, Revision 2, including Appendix A, dated November 18, 1999; and Boeing Special Attention Service Bulletin 767-31-0106, Revision 2, including Appendix A, dated November 18, 1999; is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.\n \n\t\t(2) The incorporation by reference of Boeing Service Bulletin 747-31-2288, dated December 17, 1998; Boeing Service Bulletin 747- 31-2288, Revision 1, dated January 28, 1999; Boeing Service Bulletin 757-31-0066, Revision 1, dated December 17, 1998; and Boeing Service Bulletin 767-31-0106, Revision 1, dated December 17, 1998; was approved previously by the Director of the Federal Register as of September 16, 1999 (64 FR 47653, September 1, 1999). \n\n\t\t(3) 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. \n\nEffective Date \n\n\t(k) This amendment becomes effective on July 16,2001.

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. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nSupport for the Proposed AD \n\n\tOne 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. \n\nRequest To Withdraw the Proposed AD \n\n\tOne 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 needto issue an AD. The FAA infers that the commenter is requesting that the proposed AD be withdrawn. \n\n\tThe 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. \n\nRequest To Clarify the Terminating Action \n\n\tOne 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. \n\n\tThe 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 thisAD," rather than"the repetitive inspection requirements of this AD." \n\nRequest To Add an Inspection Requirement \n\n\tOne 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. \n\n\tThe 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. \n\n\tAlso, 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.\n\n\tWe 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. \n\nRequests To Correct a Paragraph Reference \n\n\tTwo 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. \n\nConclusion \n\n\tAfter 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. \n\nCost Impact \n\n\tThere 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. \n\n\tThe 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. \n\n\tThe 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.\n \n\tFor 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. \n\n\tThe cost impact figures discussed above are based onassumptions 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. \n\nRegulatory Impact \n\n\tThe 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. \n\n\tFor 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. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \nAdoption of the Amendment \n\n\tAccordingly, 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: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows:Authority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by removing 39-11282 (64 FR 47653, September 1, 1999), and by adding a new airworthiness directive (AD), amendment 39-12250, to read as follows: