AD 2012-10-03

We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 747 series airplanes. That AD currently requires repetitive inspections for cracks of the fuselage skin lap splice between body station (BS) 400 and BS 520 at stringers S-6L and S-6R, and repair if necessary. This new AD shortens the interval for the repetitive inspections, requires modification for certain airplanes, and requires certain post-modification inspections for other airplanes. This AD was prompted by reports of multiple adjacent cracks on an airplane, and a recent fleet-wide evaluation of widespread fatigue damage of skin lap joints, which indicated the need for revised procedures and reduced compliance times. We are issuing this AD to detect and correct cracking of the fuselage skin lap splice between BS 400 and BS 520 at stringers S-6L and S-6R, which could result in sudden loss of cabin pressurization and the inability of the fuselage to withstand fail-safe loads.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by removing airworthiness directive (AD) 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), and adding the following new AD: \n\n2012-10-03 The Boeing Company: Amendment 39-17052; Docket No. FAA- 2011-0645; Directorate Identifier 2010-NM-009-AD. \n\n(a) Effective Date \n\n\n\tThis airworthiness directive (AD) is effective June 25, 2012. \n\n(b) Affected ADs \n\n\n\tThis AD supersedes AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990). \n\n(c) Applicability \n\n\n\tThis AD applies to The Boeing Company Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes,certificated in any category, as identified in Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. \n\n(d) Subject \n\n\n\tJoint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 53, Fuselage. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by from reports of multiple adjacent cracks on an airplane, and a recent fleet-wide evaluation of widespread fatigue damage of skin lap joints, which indicated the need for revised procedures and reduced compliance times. The Federal Aviation Administration is issuing this AD to detect and correct cracking of the fuselage skin lap splice between body station (BS) 400 and BS 520, at stringers S-6L and S-6R. Such cracking could result in sudden loss of cabin pressurization and the inability of the fuselage to withstand fail-safe loads. \n\n(f) Compliance \n\n\n\tYou are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\n(g) Retained Inspections \n\n\n\tThis paragraph restates the requirements of paragraph A. of AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with revised service information, reduced inspection interval, and added subparagraph. Conduct a close visual or detailed inspection, and a high frequency eddy current (HFEC) inspection, of the fuselage skin lap splice between BS 400 and BS 520, at stringers S-6L and S-6R, for cracking, in accordance with Boeing Alert Service Bulletin 747- 53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009; at the times specified in paragraph (g)(1), (g)(2), or (g)(3) of this AD. After the effective date of this AD, only Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009, may be used. Adequate lighting must be used for this inspection. The eddy current inspections may be conducted without removal of the paint, provided the paint does not interfere with the inspections. Paint must be removed, using an approved chemical stripper, in any situation where the inspector determines that the paint is interfering with the proper functioning of the inspection instrument. \n\t(1) Within the next 100 landings after March 31, 1989 (the effective date of AD 89-05-03, Amendment 39-6146 (54 FR 7397, February 21, 1989), which was superseded by AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990)), for airplanes that have accumulated 16,000 or more landings as of March 31, 1989, unless previously accomplished within the last 4,900 landings. \n\t(2) Within the next 1,000 landings after March 31, 1989, or prior to the accumulation of 16,000 landings, whichever occurs first, for airplanes that have accumulated between 12,000 and 16,000 landings, as of March 31, 1989 (the effective date of AD 89-05-03, Amendment 39-6146 (54 FR 7397, February 21, 1989), which was superseded by AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990)), unless previously accomplished within the last 4,000 landings. \n\t(3) Prior to the accumulation of 13,000 landings for airplanes that have accumulated 12,000 or fewer landings as of March 31, 1989 (the effective date of AD 89-05-03, \n\n((Page 29860)) \n\nAmendment 39-6146 (54 FR 7397, February 21, 1989), which was superseded by AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990)), unless previously accomplished within the last 5,000 landings. \n\t(4) For the purposes of this AD, a detailed inspection is: ''An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.'' \n\n(h) Retained Inspection Compliance Time for SUD-Modified Airplanes \n\n\n\tThisparagraph restates the requirements of paragraph B. of AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with revised service information. On airplanes which have been modified to the stretched-upper-deck configuration, as identified in Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009; the accumulated landing threshold for compliance with paragraph (g) of this AD is measured from the time of the stretched-upper-deck modification. \n\n(i) Retained Repetitive Inspections \n\n\n\tThis paragraph restates the requirements of paragraph C. of AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with revised service information. If no cracking is detected during the inspections required by paragraph (g) of this AD, repeat the inspections required by paragraph (g) of this AD one time at the earlier of the times specified in paragraphs (i)(1) and (i)(2) of this AD. Thereafter repeat the inspections at intervals not to exceed 3,000 landings. \n\t(1) Within 5,000 landings after the last inspection. \n\t(2) Within 3,000 landings after the last inspection, or within 1,000 landings after the effective date of this AD, whichever occurs later. \n\n(j) Retained Repair \n\n\n\tThis paragraph restates the requirements of paragraph D. of AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with revised service information. If cracks are detected during the inspections required by paragraph (g) of this AD, accomplish the repair or preventive modification of the affected lap splice, in accordance with Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009; prior to further pressurized flight. After the effective date of this AD, only Boeing Service Bulletin747-53A2303, Revision 2, dated October 1, 2009, may be used. If cracks are repaired in local areas without accomplishing preventive modification of the entire affected lap area, continue inspections of the unmodified and unrepaired areas of the affected lap splice in accordance with paragraph (i) of this AD. \n\n(k) Retained Inspection Compliance Time for Airplanes With Preventive Modification \n\n\n\tThis paragraph restates the requirements of paragraph E. of AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), with revised service information. For airplanes incorporating the preventive modification, as described in Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990; or Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009; accomplish the inspections required by paragraph (g) of this AD prior to the accumulation of 10,000 landings after the modification and thereafter at intervals not to exceed 5,000 landings. If cracks are found, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD, prior to further pressurized flight. \n\n(l) New Requirement of This AD: Post-Modification Inspections \n\n\n\tFor airplanes on which a protruding head fastener modification has been done in accordance with Boeing Alert Service Bulletin 747- 53A2303, dated June 2, 1988, or Revision 1, dated March 29, 1990: Within 10,000 flight cycles after modification, or within 500 flight cycles after the effective date of this AD, whichever occurs later, do an external HFEC inspection for cracking in the skin around the fasteners in the upper row of the lap joint, in accordance with Part 5 of the Accomplishment Instructions of Boeing Service Bulletin 747- 53A2303, Revision 2, dated October 1, 2009. If any crack is found, before further flight repair in accordance with Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009 (except as required by paragraph (p) of this AD), or do the modification specified in paragraph (n) ofthis AD. Repeat the inspection in affected uncracked areas at intervals not to exceed 500 flight cycles, until the modification specified in paragraph (n) of this AD is done. Accomplishment of the initial inspection and all applicable corrective actions specified in this paragraph terminates the requirements of paragraph (k) of this AD. \n\n(m) New Requirement of This AD: Internal HFEC Inspection \n\n\n\tFor airplanes on which an external doubler repair has been installed as a modification that was done using a method other than that specified in Boeing 747 structural repair manual (SRM) 53-30- 03, Figure 19, 25, 28 or 34: Within 10,000 flight cycles after modification, or within 500 flight cycles after the effective date of this AD, whichever occurs later, do an internal HFEC inspection for cracking in the skin around the fasteners in the upper row of the lap joint, in accordance with Part 5 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. If any crack is found, before further flight repair in accordance with Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009 (except as required by paragraph (p) of this AD), or do the modification specified in paragraph (n) of this AD. Repeat the inspection in affected uncracked areas at intervals not to exceed 500 flight cycles, until the modification specified in paragraph (n) of this AD is done. Accomplishment of the initial inspection and all applicable corrective actions specified in this paragraph terminates the requirements of paragraph (k) of this AD. \n\n(n) New Requirement of This AD: External Doubler Modification \n\n\n\tFor airplanes on which a protruding head fastener modification or a Boeing 747 SRM 53-30-03 repair or modification has been installed that was not done using Boeing 747 SRM 53-30-03, Figure 19, 25, 28, or 34, for the full length of the lap splice: Within 14,000 flight cycles after the first repair or modification was done, orwithin 3,000 flight cycles after the effective date of this AD, whichever occurs later, modify the skin and do all post- modification inspections and repairs, in accordance with Part 3 of the Accomplishment Instructions of Boeing Service Bulletin 747- 53A2303, Revision 2, dated October 1, 2009, except as required by paragraph (o) of this AD. Do the post-modification inspection within 10,000 flight cycles after installation of the modification. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. All applicable repairs must be done before further flight. \n\n(o) Structural Modification \n\n\n\tThe provisions of paragraphs (o)(1) and (o)(2) of this AD apply to airplanes on which no previous modification or repair has been installed in the affected area. \n\t(1) Accomplishment of the structural modification specified in Part 3 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009, satisfies the requirementsof AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 1990), for only the corresponding modification specified in Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988, and Revision 1, dated March 29, 1990; and Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. \n\t(2) After accomplishment of the modification specified in paragraph (o)(1) of this AD, the applicable requirements and compliance times of paragraphs (l) and (m) of this AD apply. \n\n(p) Exception to Service Bulletin Specification \n\n\n\tWhere Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD. \n\n(q) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly \n\n((Page 29861)) \n\nto the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) or other person who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basisof the airplane, and the approval must specifically refer to this AD. \n\t(4) AMOCs approved previously in accordance with AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), are approved as AMOCs for the corresponding provisions of paragraphs (g) and (i) of this AD. AMOCs approved previously in accordance with AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990), are approved as AMOCs for the corresponding provisions of paragraphs (j) and (n) of this AD only if the repair or preventive modification of the affected lap splice was done in accordance with Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009, including Boeing Designated Engineering Representative (DER) or Airworthiness Representative (AR) approvals of deviations to Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. \n\n(r) Related Information \n\n\n\tFor more information about this AD, contact Bill Ashforth, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; telephone 425-917-6432; fax 425-917-6590; email: bill.ashforth@faa.gov. \n\n(s) Material Incorporated by Reference \n\n\n\t(1) You must use the following service information to do the actions required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference (IBR) of the following service information under 5 U.S.C. 552(a) and 1 CFR part 51: \n\t(i) Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988. \n\t(ii) Boeing Alert Service Bulletin 747-53A2303, Revision 1, dated March 29, 1990. \n\t(iii) Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. \n\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; email me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\t(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221. \n\t(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990). That AD applies to the specified products. The NPRM was published in the Federal Register on June 29, 2011 (76 FR 38074). That NPRM proposed to continue to require repetitive inspections for cracks of the fuselage skin lap splice between body station (BS) 400 and BS 520 at stringers S-6L and S-6R, and repair if necessary; and added modification for certain airplanes and certain post-modification inspections for other airplanes. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal (76 FR 38074, June 29, 2011) and the FAA's response to each comment. \n\n((Page 29858)) \n\nRequest To Remove Conflicting Requirement \n\n\n\tBoeing stated that certain compliance times conflict in the proposed AD (76 FR 38074, June 29, 2011). To resolve the conflict, Boeing requested that we remove paragraph (k) from the proposed AD. (Paragraph (k) was retained from AD 90-21-17, Amendment 39-6768 (55 FR 41510, October 12, 1990).) The initial compliance time for the inspections specified in paragraphs (k), (l), and (m) of the proposed AD is 10,000 flight cycles after certain modifications have been done. Boeing noted that the repetitive interval is 5,000 flight cycles for paragraph (k) of the proposed AD--but Boeing Service Bulletin 747- 53A2303, Revision 2, dated October 1, 2009, specifies 500 flight cycles for paragraphs (l) and (m) of the proposed AD. Boeing stated that the preventive modifications include the protruding head fastener modification and the external reinforcement doubler installation (which does not cut the lap). \n\tWe partially agree with the request. We agree that, as written, the compliance times specified in paragraphs (l) and (m) of the proposed AD (76 FR 38074, June 29, 2011) would have conflicted with the compliance time specified in paragraph (k) in the proposed AD, as described by the commenter. But, for airplanes nearing the 5,000-flight-cycle repetitive interval specified in paragraph (k) of the AD on the new effective date, removing paragraph (k) from the AD would allow an unwarranted extension of time to comply, and could compromise the continued safe operation of those airplanes. We have therefore retained paragraph (k) in this AD. We have further determined that, once the applicable inspections specified in paragraph (l) or (m) of the AD have been initiated, the actions in paragraph (k) are no longer necessary. To avoid the conflict described by the commenter, we have revised paragraphs (l) and (m) of this AD to state that their accomplishment terminates the requirements of paragraph (k) of this AD. \n\nRequest To Revise Modification Requirements \n\n\n\tBoeing requested that we revise paragraph (n) of the proposed AD (76 FR 38074, June 29, 2011)to specify separate requirements for the two groups of affected airplanes, so that the proposed AD agrees with the actions specified in Table 2 of paragraph 1.E., ''Compliance,'' of Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. \n\tOne group affected by paragraph (n) of the proposed AD (76 FR 38074, June 29, 2011) is airplanes on which no previous modification or repair has been installed in the affected area. For those airplanes, Boeing requested that we require a structural modification in accordance with Part 3 of Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009, within the compliance time specified in paragraph A. of AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 1990). \n\t(AD 90-06-06, Amendment 39-6490 (55 FR 8374, March 7, 1990), applies to certain Boeing Model 747 series airplanes and requires structural modifications in accordance with Boeing Document D6-35999, dated March 31, 1989. That document in turn refers to Boeing Alert Service Bulletin 747-53A2303, dated June 2, 1988, as another source of guidance for doing that modification.) \n\tBoeing requested no change for the remaining airplanes identified in paragraph (n) of the proposed AD (76 FR 38074, June 29, 2011). \n\tWe partially agree. For the referenced airplanes, this same modification is one of the requirements of AD 90-06-06, Amendment 39- 6490 (55 FR 8374, March 7, 1990). The compliance time for this modification is 23,000 total accumulated flight cycles, or within 4 years after the effective date (April 17, 1990), whichever occurs later. To clarify the ADs' requirements, we have removed those airplanes from paragraph (n) of the NPRM (76 FR 38074, June 29, 2011) and added a new paragraph (o) in this AD, which explains that, for those airplanes, accomplishment of the referenced modification satisfies the corresponding requirement for AD 90-06-06, but post- modification inspections are required. We have re-identified subsequent paragraphs in thisAD accordingly. \n\nRequest To Refer to Service Information for Compliance Data \n\n\n\tBoeing requested that the FAA review the compliance data in the proposed AD (76 FR 38074, June 29, 2011). Boeing noted that the proposed AD repeated all the compliance data as stated in Boeing Service Bulletin 747-53A2303, Revision 2, dated October 1, 2009. Boeing requested that we refer to the compliance table in this service bulletin as the source of all compliance data, except as noted. \n\tReferring to paragraph 1.E., ''Compliance,'' of a service bulletin may be an efficient way to convey compliance time information in an AD, if the compliance times are complex or numerous. But specifying simpler compliance times within an AD--as in paragraphs (l), (m), and (n) in this AD--is also acceptable and enforceable. For requirements retained from a superseded AD--as in paragraphs (g) through (k) in this AD--we routinely restate the existing language from the AD that is being superseded, including the textdescribing the compliance times. We have not changed this AD regarding this issue. \n\nExplanation of Additional Changes to This AD \n\n\n\tThe information in Note 1 of the proposed AD (76 FR 38074, June 29, 2011) has been moved to a new paragraph (g)(4) in this AD. \n\tAs explained in the proposed AD (76 FR 38074, June 29, 2011), paragraph (p) in the proposed AD (paragraph (q) in this final rule) was revised to add delegation of authority to Boeing Commercial Airplanes Organization Designation Authorization (ODA) to approve an alternative method of compliance for any repair required by this AD. We have also changed paragraph (k) of this AD to reflect this change. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM (76 FR 38074, June 29, 2011) for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM (76 FR 38074, June 29, 2011). \n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\n\tThere are about 165 airplanes of the affected design in the worldwide fleet; of these, 64 are U.S.-registered airplanes. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n((Page 29859)) \n\n\n\n\n\n\n\tEstimated Costs -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tAverage labor \n\tAction Work hours rate per hour Parts Cost per airplane Fleet cost -------------------------------------------------------------------------------------------------------------------------------------------------------- Inspection (required by AD 90-21-17, 8....................... $85 $0..................... $680 per inspection $43,520 per inspection \n\tAmendment 39-6768 (55 FR 41510, cycle. cycle. \n\tOctober 12, 1990). Modification (new action)........... Up to 370............... 85 Between $954 and $2,064 Up to $33,514.......... Up to $2,144,896. -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD. \n\nAuthority for This Rulemaking \n\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\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), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) 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\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.