Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes, 4419-4423 [E7-1396]

Download as PDF Federal Register / Vol. 72, No. 20 / Wednesday, January 31, 2007 / Rules and Regulations Issued in Renton, Washington, on January 23, 2007. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E7–1394 Filed 1–30–07; 8:45 am] Airframe Branch, ANM–120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 917–6430; fax (425) 917–6590. SUPPLEMENTARY INFORMATION: BILLING CODE 4910–13–P Examining the Docket You may examine the airworthiness directive (AD) docket on the Internet at https://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 (800) 647–5227) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section. DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2006–24496; Directorate Identifier 2005–NM–141–AD; Amendment 39–14914; AD 2007–03–03] RIN 2120–AA64 Airworthiness Directives; Boeing Model 737–100, –200, –200C, –300, –400, and –500 Series Airplanes Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Final rule. mstockstill on PROD1PC62 with RULES AGENCY: SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737–100, –200, –200C, –300, –400, and –500 series airplanes. This AD requires repetitive inspections to detect cracks in the vertical beam webs of the body station (BS) 178 bulkhead, and corrective actions if necessary. This AD also requires a terminating modification for the repetitive inspections. This AD results from reports of numerous cracks in the vertical beam webs. We are issuing this AD to prevent fatigue cracks in certain vertical beam webs, which could result in loss of structural integrity of the BS 178 bulkhead, and consequently could impair the operation of the control cables for the elevators, speed brakes, and landing gear, or could cause the loss of cabin pressure. DATES: This AD becomes effective March 7, 2007. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of March 7, 2007. ADDRESSES: You may examine the AD docket on the Internet at https:// 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: Howard Hall, Aerospace Engineer, VerDate Aug<31>2005 15:06 Jan 30, 2007 Jkt 211001 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 737–100, –200, –200C, –300, –400, and –500 series airplanes. That NPRM was published in the Federal Register on April 18, 2006 (71 FR 19835). That NPRM proposed to require repetitive inspections to detect cracks in the vertical beam webs of the body station (BS) 178 bulkhead, and corrective actions if necessary. That NPRM also proposed to require a terminating modification for the repetitive inspections. Comments We provided the public the opportunity to participate in the development of this AD. We have considered the comments received. Request To Extend Compliance Time Threshold Continental Airlines (Continental) requests that the threshold for the compliance times specified in Table 1 of the NPRM be aligned with the compliance times specified in ADs 2000–05–29, amendment 39–11639 (65 FR 14834, March 20, 2000), and 2001– 02–01, amendment 39–12085 (66 FR 7576, January 24, 2001). Continental states that this will reduce the economic impact on operators from doing early inspections and will encourage operators to terminate those ADs at 20,000 total flight cycles as opposed to doing repetitive inspections. We do not agree. Continental provided no technical justification for revising the inspection threshold. In developing an appropriate compliance time for this action, we considered the safety implications and normal maintenance schedules for the timely accomplishment of the inspections. In PO 00000 Frm 00009 Fmt 4700 Sfmt 4700 4419 consideration of these items, as well as the reports of numerous cracks in the vertical beam webs in service, we have determined that the compliance times specified in Table 1 of this AD will ensure an acceptable level of safety and allow the inspections to be done during scheduled maintenance intervals for most affected operators. However, according to the provisions of paragraph (m) of the AD, we may approve requests to adjust the compliance time if the request includes data that substantiate that the new compliance time would provide an acceptable level of safety. Request To Include an Additional Grace Period The Air Transport Association (ATA), on behalf of one of its members, United Airlines (United), requests that the compliance time specified in paragraph (f)(2) of the NPRM be revised to reflect the intention of Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005 (referred to in the NPRM as the appropriate source of service information for accomplishing the repetitive inspections and terminating preventative modification). United proposes that all airplanes should have a minimum of 4,500 flight cycles after the effective date of the AD to do the initial inspection required by paragraph (f) of the NPRM. United also states that Boeing Service Bulletin 737–53A1225, dated October 19, 2000, specifies an interval of 12,000 flight cycles for the repetitive high frequency eddy current (HFEC) inspections. Without a grace period, United points out that operators doing those inspections would be grounded as of the effective date of the AD. We agree and have revised paragraph (f)(2) of this AD to provide a grace period of 4,500 flight cycles after the effective date of this AD. Request To Include Certain Airplanes in Compliance Time Table Boeing requests that we revise Table 1, ‘‘Compliance Times,’’ of the NPRM to address airplanes inspected in accordance with Boeing Service Bulletin 737–53A1225, Revision 1. We do not agree. Operators are given credit for actions previously done by means of the phrase in paragraph (e) of this AD that states, ‘‘unless the actions have already been done.’’ Therefore, in the case of this AD, if the required inspection specified in Boeing Service Bulletin 737–53A1225, Revision 1, has been done before the effective date of this AD, this AD does not require that it be repeated. In addition, if the required inspection specified in Boeing Service Bulletin 737–53A1225, Revision E:\FR\FM\31JAR1.SGM 31JAR1 4420 Federal Register / Vol. 72, No. 20 / Wednesday, January 31, 2007 / Rules and Regulations mstockstill on PROD1PC62 with RULES 1, has not been done before the effective date of this AD, this AD requires that inspection to be done at the applicable time specified in Table 1. We have made no change to the final rule in this regard. Requests To Allow the Use of Boeing BOECOM M–7200–01–00546 KLM Engineering & Maintenance (KLM), Southwest Airlines (Southwest), and United request that the procedures specified in Boeing BOECOM M–7200– 01–00546, dated March 1, 2001 (referred to in paragraph (j) of the NPRM) be allowed to be used after the effective date of the AD as an acceptable method of compliance with the preventative modification specified in paragraph (i) of the NPRM. Southwest states that BOECOM M–7200–01–00546 describes procedures for fabricating replacement parts, which would result in a significant cost savings to operators. United states that it has modified the majority of its fleet using instructions equivalent to those contained BOECOM M–7200–01–00546. KLM states that it has modified a majority of its fleet using Boeing Service Bulletin 737–53A1173, Revision 4, dated September 19, 2002 (Revision 3 of Boeing Service Bulletin 737–53A1173 is referred to in paragraph (k) of the NPRM as the appropriate source of service information for accomplishing the preventative modification), together with the instructions specified in BOECOM M– 7200–01–00546. United and KLM would like to continue modifying their fleets using the same instructions. In addition, Boeing requests that the description of acceptable actions in paragraph (j) of the NPRM be revised to include procedures done in accordance with Boeing BOECOM M–7200–01– 00546 and approved by Boeing and the FAA after March 1, 2001. We partially agree. We agree that doing the replacement or modification specified in Boeing BOECOM M–7200– 01–00546, dated March 1, 2001, may be an acceptable means of compliance with the requirements of paragraph (j) of this AD. However, it is not likely that replacement or modification in accordance with BOECOM M–7200–01– 00546 can be done without deviations that require further FAA approval. It has been our experience that work done in accordance with BOECOM M–7200–01– 00546 has nearly always required deviations. As noted in BOECOM M– 7200–01–00546, to obtain approval for using the BOECOM, the operator must provide an Authorized Representative (AR) for the Boeing Commercial Airplanes Delegation Option Authorization Organization with the VerDate Aug<31>2005 15:06 Jan 30, 2007 Jkt 211001 airplane identification, the details of the proposed replacement, and any deviations. Therefore, we have determined that operators who use the BOECOM procedures after the effective date of this AD must get them approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (m) of this AD. We have made no change to the final rule in this regard. Request To Remove Option To Repair Boeing requests that the word ‘‘repair’’ in paragraph (i) of the NPRM and in the ‘‘Relevant Service Information’’ section of the NPRM be deleted. Boeing did not provide a justification. We agree. We have re-reviewed Boeing Service Bulletin 737–53A1225, Revision 1. In several places in Parts II through IV of the Accomplishment Instructions, the service bulletin states, ‘‘Repair or change the vertical beam * * * Refer to Figure 25 * * *.’’ Figure 25 refers to ‘‘replacement’’ procedures; however, it does not refer to a repair procedure. Therefore, we have deleted ‘‘repair or’’ in paragraph (i) of this AD. We have made no change to the AD in regard to the ‘‘Relevant Service Information’’ section, because that section of the NPRM does not reappear in the final rule. Request To Allow Repair Plans Approved Previously Southwest requests that paragraph (j) of the NPRM be revised to allow certain repair plans approved by an AR for the Boeing Commercial Airplanes Delegation Option Authorization Organization or a Boeing Designated Engineering Representative (DER) before the release of Boeing BOECOM M–7200–01–00546, dated March 1, 2001, as an acceptable method of compliance with the preventative modification specified in paragraph (i) of the NPRM. Southwest states that it has installed thicker vertical beam webs with such approval on some of its airplanes before the issuance of Boeing BOECOM M–7200–01–00546, dated March 1, 2001. We do not agree with Southwest to revise paragraph (j) of this AD. Southwest did not provide sufficient data for us to determine if these earlier repairs are equivalent to those specified in Boeing BOECOM M–7200–01–00546, dated March 1, 2001. It is possible that the review and approval of earlier repairs may not have taken into account the latest information that was used to develop the BOECOM. However, if a particular repair is shown to be PO 00000 Frm 00010 Fmt 4700 Sfmt 4700 equivalent to that specified in the BOECOM, paragraph (m) of the AD provides operators the opportunity to apply for an AMOC to address this type of repair. Request for Clarification Southwest requests that paragraph (j) of the NPRM be revised to clarify that it is not necessary to replace certain stiffeners per step 4 of Boeing BOECOM M–7200–01–00546, if the existing holes can be oversized and a new identical fastener can be installed with an acceptable edge distance. Step 4 indicates that certain stiffeners must be replaced because they are offset by the thickness of the new webs. Southwest believes that the intent of that step is to eliminate detrimental fastener oversizing and short edge distances that can result from the offset. We do not agree with Southwest to revise paragraph (j) of this AD. Southwest did not provide any specific limits nor define any acceptable combinations of maximum over-sizing of fasteners and/or minimum fastener edge distance. Therefore, we are unable to provide approval at this time. However, under the provisions of paragraph (m) of this AD, we may consider requests for approval of an AMOC if sufficient data are submitted to substantiate that such a design change would provide an acceptable level of safety. Request To Delete Concurrent Requirements Delta Air Lines (Delta) requests that the concurrent requirements of paragraphs (k) and (l) of the NPRM be deleted, and to continue to allow the requirements specified in paragraph (c) of ADs 2000–05–29 and 2001–02–01 to be done separately. Delta notes that the ‘‘Effect of Accomplishing Concurrent Requirements’’ section in the preamble of the NPRM states, ‘‘We realize that the concurrent requirements of this proposed AD will force some operators to do the preventative modifications required by AD 2001–02–01 early and to do the optional preventative modification specified in AD 2000–05– 29. However, accomplishing the applicable preventative modifications together is necessary to avoid repeated disassembly and re-assembly of common parts, which increases the likelihood of additional assembly errors.’’ Delta states that the timing of doing the preventative modification is an economic and operational decision, which is properly at the discretion of the operators, not a subject for an AD. We partially agree. We do not agree with Delta that the concurrent E:\FR\FM\31JAR1.SGM 31JAR1 Federal Register / Vol. 72, No. 20 / Wednesday, January 31, 2007 / Rules and Regulations requirements be deleted. We determined that mandating the previous optional preventative modification specified in AD 2000–05–29 in this AD will better ensure long-term continued operational safety of the affected airplanes by removing the source of the problem, rather than by repetitive inspections. Long-term inspections may not provide the degree of safety necessary for the affected airplanes. This, coupled with our understanding of the human factor errors associated with numerous repetitive inspections, has led us to consider placing less emphasis on special procedures and more emphasis on design improvements. The preventative modification required by paragraph (l) of this AD is consistent with these considerations. Additionally, accomplishing the modifications concurrently provides the most effective installation of these modifications and will avoid repeated disassembly and reassembly of common parts of critical structure, which increases the likelihood of additional assembly errors. Boeing also has provided us with data supporting our determination. We somewhat agree with Delta to allow the requirements specified in paragraph (c) of ADs 2000–05–29 and 2001–02–01 to be done separately. It is acceptable to do the preventative modifications required by AD 2001–02– 01 before the requirements of paragraph (i) of this AD. However, paragraphs (k) and (l) of the NPRM state, ‘‘Concurrently with the requirements of paragraph (i) of this AD * * *.’’ Therefore, we have revised those paragraphs to clarify that the concurrent requirements must be done ‘‘before or concurrently with the requirements of paragraph (i) of this AD.’’ For clarification purposes, we also removed the phrase ‘‘unless already done before the effective date of this AD’’ from paragraph (k) of this AD. mstockstill on PROD1PC62 with RULES Request To Supersede AD 2000–05–29 The ATA, on behalf of one of its members, Delta, requests that AD 2000– 05–29 be superseded or revised to avoid conflicting requirements. Delta states that this should be done if its request in the ‘‘Request To Delete Concurrent Requirements’’ section of this AD is not feasible. We do not agree. Paragraph (k) of this AD mandates the previously optional preventative modification specified in paragraph (c) of AD 2000–05–29. A mandatory requirement takes precedence over an optional action. Therefore, we find that no conflict exists between the requirements of this AD and AD 2000–05–29. VerDate Aug<31>2005 15:06 Jan 30, 2007 Jkt 211001 In addition, we considered superseding ADs 2000–05–29 and AD 2001–02–01 when developing the NPRM. We determined that doing so would have made this AD more complex and would have increased the consequent workload associated with revising maintenance record entries, because this AD does not affect all requirements of those ADs. This AD only affects paragraph (c) of those ADs. Therefore, we determined that a less burdensome approach for operators was not to supersede those existing ADs. Request To Address Certain Airplanes If the concurrent requirements of the NPRM are kept, Delta further requests that Boeing be tasked to address airplanes on which the replacement of the forward pressure bulkhead web has been done and on which the modification of the vertical beam has not been done. We do not agree. We have determined that the procedures specified in the Accomplishment Instructions of Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005, adequately address all affected airplanes. Although the information mentioned by Delta may be helpful, the procedures specified in the service bulletin are adequate. Therefore, we find it inappropriate to task Boeing to revise the service bulletin and to delay the issuance of this AD. However, if additional data are presented that would justify additional actions, we may consider further rulemaking on this issue. Requests To Allow AMOCs Approved Previously Southwest requests that paragraphs (k) and (l) of the NPRM be revised to allow AMOCs approved previously in accordance with ADs 2000–05–29 and 2001–02–01, respectively. Southwest wants to avoid any issues as to whether or not those AMOCs must be resubmitted to us for approval. Continental requests that paragraph (k) of the NPRM be revised to refer to Boeing Service Bulletin 737–53A1173, Revision 4, dated September 19, 2002. Continental states that Revision 4 included several corrections and work flow improvements. We partially agree with both Southwest and Continental. We agree that approved AMOCs to paragraph (c) of ADs 2000–05–29 and 2001–02–01 that are done before or concurrently with the requirements of paragraph (i) of this AD are acceptable as AMOCs for the corresponding provisions of paragraphs (k) and (l) of this AD, respectively. Boeing Service Bulletin 737–53A1173, Revision 4, is one of those AMOCs. We PO 00000 Frm 00011 Fmt 4700 Sfmt 4700 4421 do not agree with the commenters that the paragraphs (k) and (l) should be revised in regard to AMOCs. The appropriate paragraph to revise is paragraph (m) of this AD, which is the AMOC paragraph. Therefore, we have revised paragraph (m) accordingly. Request To Revise AMOC Paragraph Boeing requests that paragraph (m)(3) of the NPRM be changed to allow AR approval of modifications as well as repairs. We agree and have revised paragraph (m)(3) of this AD accordingly. Requests To Revise Costs of Compliance The ATA, on behalf of two of its members, U.S. Airways and United, requests that the Costs of Compliance section in the preamble of the NPRM account for the work required to gain access, reassemble, complete postmodification checkouts, close access, etc. associated with the proposed inspection and preventative modification. U.S. Airways states that these actions represent an increase of almost 40 percent above and beyond the 240 work hours specified in the NPRM. United states that the proposed inspection and preventative modification are not normally accessed at any routine maintenance visit. We do not agree. The Costs of Compliance section describes only the direct costs of the specific actions required by this AD. Based on the best data available, the manufacturer provided the number of work hours (240 for preventative modification; 4 for each inspection) necessary to do the required actions. This number represents the time necessary to perform only the actions actually required by this AD. We recognize that, in doing the actions required by an AD, operators may incur incidental costs in addition to the direct costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and close up, time necessary for planning, or time necessitated by other administrative actions. Those incidental costs, which may vary significantly among operators, are almost impossible to calculate. Therefore, we have made no change to this AD in this regard. Request To Correct Typographical Error Boeing requests that a typographical error be fixed in paragraph (h) of the NPRM. The reference to ‘‘paragraph (1) of this AD’’ should be changed to ‘‘paragraph (m) of this AD.’’ We agree and have changed paragraph (h) of this AD accordingly. E:\FR\FM\31JAR1.SGM 31JAR1 4422 Federal Register / Vol. 72, No. 20 / Wednesday, January 31, 2007 / Rules and Regulations Conclusion We have carefully reviewed the available data, including the comments 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 3,132 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. ESTIMATED COSTS Action Work hours Inspection, per inspection cycle. Preventative modification. Average labor rate per hour Parts Cost per airplane $320, per inspection cycle. Between $20,160 and $32,820, depending on configuration. 4 $80 None .................. 240 80 Between $960 and $13,620, depending on kit purchased. (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. 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; mstockstill on PROD1PC62 with RULES 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. PART 39—AIRWORTHINESS DIRECTIVES VerDate Aug<31>2005 15:06 Jan 30, 2007 Jkt 211001 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: I 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD): 2007–03–03 Boeing: Amendment 39–14914. Docket No. FAA–2006–24496; Directorate Identifier 2005–NM–141–AD. Frm 00012 Fmt 4700 1,172 (720 airplanes have had the preventative modification incorporated). $375,040, per inspection cycle. Between $9,112,320 and $14,834,640. Effective Date (a) This AD becomes effective March 7, 2007. Affected ADs (b) None. Applicability (c) This AD applies to Boeing Model 737– 100, –200, –200C, –300, –400, and –500 series airplanes, certificated in any category; as identified in Boeing Service Bulletin 737– 53A1225, Revision 1, dated April 14, 2005. Unsafe Condition (d) This AD results from reports of numerous cracks in the vertical beam webs. We are issuing this AD to prevent fatigue cracks in certain vertical beam webs, which could result in loss of structural integrity of the body station (BS) 178 bulkhead, and consequently could impair the operation of the control cables for the elevators, speed brakes, and landing gear, or could cause the loss of cabin pressure. (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. Repetitive Inspections [Amended] I PO 00000 1,172 ................. Fleet cost Compliance I § 39.13 Number of U.S.registered airplanes Sfmt 4700 (f) At the applicable times specified in Table 1 of this AD, do a high frequency eddy current (HFEC) inspection and detailed inspection to detect cracks in the BS 178 vertical beam webs, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005. E:\FR\FM\31JAR1.SGM 31JAR1 Federal Register / Vol. 72, No. 20 / Wednesday, January 31, 2007 / Rules and Regulations 4423 TABLE 1.—COMPLIANCE TIMES For airplanes on which— Inspect— And repeat the HFEC and detailed inspections thereafter at— (1) An HFEC or a detailed inspection specified in Boeing Service Bulletin 737–53A1225, dated October 19, 2000, has not been done as of the effective date of this AD. (2) An HFEC or detailed inspection specified in Boeing Service Bulletin 737–53A1225, dated October 19, 2000, has been done before the effective date of this AD. Before the accumulation of 15,000 total flight cycles, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later. Within 6,000 flight cycles since the last HFEC inspection, within 1,200 flight cycles since the last detailed inspection, or within 4,500 flight cycles after the effective date of this AD, whichever occurs later. Intervals not to exceed 6,000 flight cycles. Corrective Actions (g) If any crack is detected during any inspection required by paragraph (f) of this AD, before further flight, repair or replace the vertical beam web and associated parts with a new vertical beam web, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005, except as provided by paragraph (h) of this AD. (h) If any damage is beyond the scope of the service bulletin or structural repair manual, before further flight, repair the damaged vertical beam web in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or using a method approved in accordance with paragraph (m) of this AD. mstockstill on PROD1PC62 with RULES Terminating Preventative Modification (i) Before the accumulation of 50,000 total flight cycles, or within 25,000 flight cycles after the effective date of this AD, whichever occurs later, replace the vertical beams at buttock lines (BL) 5.7 and 17.0 of the BS 178 bulkhead, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005. Accomplishing the replacement ends the repetitive inspections required by paragraph (f) of this AD. (j) Actions done before the effective date of this AD in accordance with Boeing BOECOM M–7200–01–00546, dated March 1, 2001, are acceptable for compliance with the requirements of paragraph (i) of this AD. Prior to or Concurrent Requirements (k) For Group 1 airplanes identified in Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005: Before or concurrently with the requirements of paragraph (i) of this AD, do the preventative modifications of the center web, vertical chords, and side chord areas, including the side chord areas at water line 207, of the forward pressure bulkhead, specified in paragraph (c) of AD 2000–05–29, amendment 39–11639 (reference Boeing Alert Service Bulletin 737–53A1173, Revision 3, dated May 6, 1999). (l) For Group 2 airplanes identified in Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005: Before or concurrently with the requirements of paragraph (i) of this AD, but no later than the time specified in AD 2001–02–01, amendment 39–12085, do the preventative modifications of the vertical and side chord VerDate Aug<31>2005 15:06 Jan 30, 2007 Jkt 211001 areas of the forward pressure bulkhead required by paragraph (c) of AD 2001–02–01 (reference Boeing Alert Service Bulletin 737– 53A1208, dated May 6, 1999). Alternative Methods of Compliance (AMOCs) (m)(1) The Manager, Seattle ACO, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. (2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office. (3) An AMOC that provides an acceptable level of safety may be used for any replacement or repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a replacement or repair method to be approved, the replacement or repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. (4) Approved AMOCs to paragraph (c) of AD 2000–05–29 done before or concurrently with the requirements of paragraph (i) of this AD are approved as AMOCs for the corresponding provisions of paragraph (k) of this AD. (5) Approved AMOCs to paragraph (c) of AD 2001–02–01 done before or concurrently with the requirements of paragraph (i) of this AD are approved as AMOCs for the corresponding provisions of paragraph (l) of this AD. Material Incorporated by Reference (n) You must use Boeing Service Bulletin 737–53A1225, Revision 1, dated April 14, 2005, 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 https://dms.dot.gov; or at the PO 00000 Frm 00013 Fmt 4700 Sfmt 4700 Intervals not to exceed 6,000 flight cycles. National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741–6030, or go to https:// www.archives.gov/federal_register/ code_of_federal_regulations/ ibr_locations.html. Issued in Renton, Washington, on January 19, 2007. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E7–1396 Filed 1–30–07; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF HOMELAND SECURITY Bureau of Customs and Border Protection DEPARTMENT OF THE TREASURY 19 CFR Parts 113, 141, and 151 [CBP Dec. 07–02] RIN 1505–AB57 Conditional Release Period and CBP Bond Obligations for Food, Drugs, Devices, and Cosmetics Customs and Border Protection, Department of Homeland Security; Department of the Treasury. ACTION: Final rule. AGENCIES: SUMMARY: This document amends the Customs and Border Protection (CBP) regulations to clarify the responsibilities of importers of food, drugs, devices, and cosmetics under the basic CBP importation bond and to provide a reasonable period of time to allow the Food and Drug Administration (FDA) to perform its enforcement functions with respect to these covered articles. The amendments include a provision for a specific conditional release period of 30 days for any food, drug, device, or cosmetic which has been released under bond and for which admissibility is to be determined under the provisions of E:\FR\FM\31JAR1.SGM 31JAR1

Agencies

[Federal Register Volume 72, Number 20 (Wednesday, January 31, 2007)]
[Rules and Regulations]
[Pages 4419-4423]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-1396]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24496; Directorate Identifier 2005-NM-141-AD;
Amendment 39-14914; AD 2007-03-03]
RIN 2120-AA64

Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series
airplanes. This AD requires repetitive inspections to detect cracks in
the vertical beam webs of the body station (BS) 178 bulkhead, and
corrective actions if necessary. This AD also requires a terminating
modification for the repetitive inspections. This AD results from
reports of numerous cracks in the vertical beam webs. We are issuing
this AD to prevent fatigue cracks in certain vertical beam webs, which
could result in loss of structural integrity of the BS 178 bulkhead,
and consequently could impair the operation of the control cables for
the elevators, speed brakes, and landing gear, or could cause the loss
of cabin pressure.

DATES: This AD becomes effective March 7, 2007.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in the AD as of March 7,
2007.

ADDRESSES: You may examine the AD docket on the Internet at https://
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: Howard Hall, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425)
917-6430; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (AD) docket on the
Internet at https://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 (800) 647-5227) 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
737-100, -200, -200C, -300, -400, and -500 series airplanes. That NPRM
was published in the Federal Register on April 18, 2006 (71 FR 19835).
That NPRM proposed to require repetitive inspections to detect cracks
in the vertical beam webs of the body station (BS) 178 bulkhead, and
corrective actions if necessary. That NPRM also proposed to require a
terminating modification for the repetitive inspections.

Comments

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

Request To Extend Compliance Time Threshold

Continental Airlines (Continental) requests that the threshold for
the compliance times specified in Table 1 of the NPRM be aligned with
the compliance times specified in ADs 2000-05-29, amendment 39-11639
(65 FR 14834, March 20, 2000), and 2001-02-01, amendment 39-12085 (66
FR 7576, January 24, 2001). Continental states that this will reduce
the economic impact on operators from doing early inspections and will
encourage operators to terminate those ADs at 20,000 total flight
cycles as opposed to doing repetitive inspections.
We do not agree. Continental provided no technical justification
for revising the inspection threshold. In developing an appropriate
compliance time for this action, we considered the safety implications
and normal maintenance schedules for the timely accomplishment of the
inspections. In consideration of these items, as well as the reports of
numerous cracks in the vertical beam webs in service, we have
determined that the compliance times specified in Table 1 of this AD
will ensure an acceptable level of safety and allow the inspections to
be done during scheduled maintenance intervals for most affected
operators. However, according to the provisions of paragraph (m) of the
AD, we may approve requests to adjust the compliance time if the
request includes data that substantiate that the new compliance time
would provide an acceptable level of safety.

Request To Include an Additional Grace Period

The Air Transport Association (ATA), on behalf of one of its
members, United Airlines (United), requests that the compliance time
specified in paragraph (f)(2) of the NPRM be revised to reflect the
intention of Boeing Service Bulletin 737-53A1225, Revision 1, dated
April 14, 2005 (referred to in the NPRM as the appropriate source of
service information for accomplishing the repetitive inspections and
terminating preventative modification). United proposes that all
airplanes should have a minimum of 4,500 flight cycles after the
effective date of the AD to do the initial inspection required by
paragraph (f) of the NPRM. United also states that Boeing Service
Bulletin 737-53A1225, dated October 19, 2000, specifies an interval of
12,000 flight cycles for the repetitive high frequency eddy current
(HFEC) inspections. Without a grace period, United points out that
operators doing those inspections would be grounded as of the effective
date of the AD.
We agree and have revised paragraph (f)(2) of this AD to provide a
grace period of 4,500 flight cycles after the effective date of this
AD.

Request To Include Certain Airplanes in Compliance Time Table

Boeing requests that we revise Table 1, ``Compliance Times,'' of
the NPRM to address airplanes inspected in accordance with Boeing
Service Bulletin 737-53A1225, Revision 1.
We do not agree. Operators are given credit for actions previously
done by means of the phrase in paragraph (e) of this AD that states,
``unless the actions have already been done.'' Therefore, in the case
of this AD, if the required inspection specified in Boeing Service
Bulletin 737-53A1225, Revision 1, has been done before the effective
date of this AD, this AD does not require that it be repeated. In
addition, if the required inspection specified in Boeing Service
Bulletin 737-53A1225, Revision

[[Page 4420]]

1, has not been done before the effective date of this AD, this AD
requires that inspection to be done at the applicable time specified in
Table 1. We have made no change to the final rule in this regard.

Requests To Allow the Use of Boeing BOECOM M-7200-01-00546

KLM Engineering & Maintenance (KLM), Southwest Airlines
(Southwest), and United request that the procedures specified in Boeing
BOECOM M-7200-01-00546, dated March 1, 2001 (referred to in paragraph
(j) of the NPRM) be allowed to be used after the effective date of the
AD as an acceptable method of compliance with the preventative
modification specified in paragraph (i) of the NPRM. Southwest states
that BOECOM M-7200-01-00546 describes procedures for fabricating
replacement parts, which would result in a significant cost savings to
operators. United states that it has modified the majority of its fleet
using instructions equivalent to those contained BOECOM M-7200-01-
00546. KLM states that it has modified a majority of its fleet using
Boeing Service Bulletin 737-53A1173, Revision 4, dated September 19,
2002 (Revision 3 of Boeing Service Bulletin 737-53A1173 is referred to
in paragraph (k) of the NPRM as the appropriate source of service
information for accomplishing the preventative modification), together
with the instructions specified in BOECOM M-7200-01-00546. United and
KLM would like to continue modifying their fleets using the same
instructions. In addition, Boeing requests that the description of
acceptable actions in paragraph (j) of the NPRM be revised to include
procedures done in accordance with Boeing BOECOM M-7200-01-00546 and
approved by Boeing and the FAA after March 1, 2001.
We partially agree. We agree that doing the replacement or
modification specified in Boeing BOECOM M-7200-01-00546, dated March 1,
2001, may be an acceptable means of compliance with the requirements of
paragraph (j) of this AD. However, it is not likely that replacement or
modification in accordance with BOECOM M-7200-01-00546 can be done
without deviations that require further FAA approval. It has been our
experience that work done in accordance with BOECOM M-7200-01-00546 has
nearly always required deviations. As noted in BOECOM M-7200-01-00546,
to obtain approval for using the BOECOM, the operator must provide an
Authorized Representative (AR) for the Boeing Commercial Airplanes
Delegation Option Authorization Organization with the airplane
identification, the details of the proposed replacement, and any
deviations. Therefore, we have determined that operators who use the
BOECOM procedures after the effective date of this AD must get them
approved as an alternative method of compliance (AMOC) in accordance
with the procedures specified in paragraph (m) of this AD. We have made
no change to the final rule in this regard.

Request To Remove Option To Repair

Boeing requests that the word ``repair'' in paragraph (i) of the
NPRM and in the ``Relevant Service Information'' section of the NPRM be
deleted. Boeing did not provide a justification.
We agree. We have re-reviewed Boeing Service Bulletin 737-53A1225,
Revision 1. In several places in Parts II through IV of the
Accomplishment Instructions, the service bulletin states, ``Repair or
change the vertical beam * * * Refer to Figure 25 * * *.'' Figure 25
refers to ``replacement'' procedures; however, it does not refer to a
repair procedure. Therefore, we have deleted ``repair or'' in paragraph
(i) of this AD. We have made no change to the AD in regard to the
``Relevant Service Information'' section, because that section of the
NPRM does not reappear in the final rule.

Request To Allow Repair Plans Approved Previously

Southwest requests that paragraph (j) of the NPRM be revised to
allow certain repair plans approved by an AR for the Boeing Commercial
Airplanes Delegation Option Authorization Organization or a Boeing
Designated Engineering Representative (DER) before the release of
Boeing BOECOM M-7200-01-00546, dated March 1, 2001, as an acceptable
method of compliance with the preventative modification specified in
paragraph (i) of the NPRM. Southwest states that it has installed
thicker vertical beam webs with such approval on some of its airplanes
before the issuance of Boeing BOECOM M-7200-01-00546, dated March 1,
2001.
We do not agree with Southwest to revise paragraph (j) of this AD.
Southwest did not provide sufficient data for us to determine if these
earlier repairs are equivalent to those specified in Boeing BOECOM M-
7200-01-00546, dated March 1, 2001. It is possible that the review and
approval of earlier repairs may not have taken into account the latest
information that was used to develop the BOECOM. However, if a
particular repair is shown to be equivalent to that specified in the
BOECOM, paragraph (m) of the AD provides operators the opportunity to
apply for an AMOC to address this type of repair.

Request for Clarification

Southwest requests that paragraph (j) of the NPRM be revised to
clarify that it is not necessary to replace certain stiffeners per step
4 of Boeing BOECOM M-7200-01-00546, if the existing holes can be
oversized and a new identical fastener can be installed with an
acceptable edge distance. Step 4 indicates that certain stiffeners must
be replaced because they are offset by the thickness of the new webs.
Southwest believes that the intent of that step is to eliminate
detrimental fastener over-sizing and short edge distances that can
result from the offset.
We do not agree with Southwest to revise paragraph (j) of this AD.
Southwest did not provide any specific limits nor define any acceptable
combinations of maximum over-sizing of fasteners and/or minimum
fastener edge distance. Therefore, we are unable to provide approval at
this time. However, under the provisions of paragraph (m) of this AD,
we may consider requests for approval of an AMOC if sufficient data are
submitted to substantiate that such a design change would provide an
acceptable level of safety.

Request To Delete Concurrent Requirements

Delta Air Lines (Delta) requests that the concurrent requirements
of paragraphs (k) and (l) of the NPRM be deleted, and to continue to
allow the requirements specified in paragraph (c) of ADs 2000-05-29 and
2001-02-01 to be done separately. Delta notes that the ``Effect of
Accomplishing Concurrent Requirements'' section in the preamble of the
NPRM states, ``We realize that the concurrent requirements of this
proposed AD will force some operators to do the preventative
modifications required by AD 2001-02-01 early and to do the optional
preventative modification specified in AD 2000-05-29. However,
accomplishing the applicable preventative modifications together is
necessary to avoid repeated disassembly and re-assembly of common
parts, which increases the likelihood of additional assembly errors.''
Delta states that the timing of doing the preventative modification is
an economic and operational decision, which is properly at the
discretion of the operators, not a subject for an AD.
We partially agree. We do not agree with Delta that the concurrent

[[Page 4421]]

requirements be deleted. We determined that mandating the previous
optional preventative modification specified in AD 2000-05-29 in this
AD will better ensure long-term continued operational safety of the
affected airplanes by removing the source of the problem, rather than
by repetitive inspections. Long-term inspections may not provide the
degree of safety necessary for the affected airplanes. This, coupled
with our understanding of the human factor errors associated with
numerous repetitive inspections, has led us to consider placing less
emphasis on special procedures and more emphasis on design
improvements. The preventative modification required by paragraph (l)
of this AD is consistent with these considerations. Additionally,
accomplishing the modifications concurrently provides the most
effective installation of these modifications and will avoid repeated
disassembly and re-assembly of common parts of critical structure,
which increases the likelihood of additional assembly errors. Boeing
also has provided us with data supporting our determination.
We somewhat agree with Delta to allow the requirements specified in
paragraph (c) of ADs 2000-05-29 and 2001-02-01 to be done separately.
It is acceptable to do the preventative modifications required by AD
2001-02-01 before the requirements of paragraph (i) of this AD.
However, paragraphs (k) and (l) of the NPRM state, ``Concurrently with
the requirements of paragraph (i) of this AD * * *.'' Therefore, we
have revised those paragraphs to clarify that the concurrent
requirements must be done ``before or concurrently with the
requirements of paragraph (i) of this AD.'' For clarification purposes,
we also removed the phrase ``unless already done before the effective
date of this AD'' from paragraph (k) of this AD.

Request To Supersede AD 2000-05-29

The ATA, on behalf of one of its members, Delta, requests that AD
2000-05-29 be superseded or revised to avoid conflicting requirements.
Delta states that this should be done if its request in the ``Request
To Delete Concurrent Requirements'' section of this AD is not feasible.
We do not agree. Paragraph (k) of this AD mandates the previously
optional preventative modification specified in paragraph (c) of AD
2000-05-29. A mandatory requirement takes precedence over an optional
action. Therefore, we find that no conflict exists between the
requirements of this AD and AD 2000-05-29.
In addition, we considered superseding ADs 2000-05-29 and AD 2001-
02-01 when developing the NPRM. We determined that doing so would have
made this AD more complex and would have increased the consequent
workload associated with revising maintenance record entries, because
this AD does not affect all requirements of those ADs. This AD only
affects paragraph (c) of those ADs. Therefore, we determined that a
less burdensome approach for operators was not to supersede those
existing ADs.

Request To Address Certain Airplanes

If the concurrent requirements of the NPRM are kept, Delta further
requests that Boeing be tasked to address airplanes on which the
replacement of the forward pressure bulkhead web has been done and on
which the modification of the vertical beam has not been done.
We do not agree. We have determined that the procedures specified
in the Accomplishment Instructions of Boeing Service Bulletin 737-
53A1225, Revision 1, dated April 14, 2005, adequately address all
affected airplanes. Although the information mentioned by Delta may be
helpful, the procedures specified in the service bulletin are adequate.
Therefore, we find it inappropriate to task Boeing to revise the
service bulletin and to delay the issuance of this AD. However, if
additional data are presented that would justify additional actions, we
may consider further rulemaking on this issue.

Requests To Allow AMOCs Approved Previously

Southwest requests that paragraphs (k) and (l) of the NPRM be
revised to allow AMOCs approved previously in accordance with ADs 2000-
05-29 and 2001-02-01, respectively. Southwest wants to avoid any issues
as to whether or not those AMOCs must be resubmitted to us for
approval.
Continental requests that paragraph (k) of the NPRM be revised to
refer to Boeing Service Bulletin 737-53A1173, Revision 4, dated
September 19, 2002. Continental states that Revision 4 included several
corrections and work flow improvements.
We partially agree with both Southwest and Continental. We agree
that approved AMOCs to paragraph (c) of ADs 2000-05-29 and 2001-02-01
that are done before or concurrently with the requirements of paragraph
(i) of this AD are acceptable as AMOCs for the corresponding provisions
of paragraphs (k) and (l) of this AD, respectively. Boeing Service
Bulletin 737-53A1173, Revision 4, is one of those AMOCs. We do not
agree with the commenters that the paragraphs (k) and (l) should be
revised in regard to AMOCs. The appropriate paragraph to revise is
paragraph (m) of this AD, which is the AMOC paragraph. Therefore, we
have revised paragraph (m) accordingly.

Request To Revise AMOC Paragraph

Boeing requests that paragraph (m)(3) of the NPRM be changed to
allow AR approval of modifications as well as repairs.
We agree and have revised paragraph (m)(3) of this AD accordingly.

Requests To Revise Costs of Compliance

The ATA, on behalf of two of its members, U.S. Airways and United,
requests that the Costs of Compliance section in the preamble of the
NPRM account for the work required to gain access, reassemble, complete
post-modification checkouts, close access, etc. associated with the
proposed inspection and preventative modification. U.S. Airways states
that these actions represent an increase of almost 40 percent above and
beyond the 240 work hours specified in the NPRM. United states that the
proposed inspection and preventative modification are not normally
accessed at any routine maintenance visit.
We do not agree. The Costs of Compliance section describes only the
direct costs of the specific actions required by this AD. Based on the
best data available, the manufacturer provided the number of work hours
(240 for preventative modification; 4 for each inspection) necessary to
do the required actions. This number represents the time necessary to
perform only the actions actually required by this AD. We recognize
that, in doing the actions required by an AD, operators may incur
incidental costs in addition to the direct costs. The cost analysis in
AD rulemaking actions, however, typically does not include incidental
costs such as the time required to gain access and close up, time
necessary for planning, or time necessitated by other administrative
actions. Those incidental costs, which may vary significantly among
operators, are almost impossible to calculate. Therefore, we have made
no change to this AD in this regard.

Request To Correct Typographical Error

Boeing requests that a typographical error be fixed in paragraph
(h) of the NPRM. The reference to ``paragraph (1) of this AD'' should
be changed to ``paragraph (m) of this AD.''
We agree and have changed paragraph (h) of this AD accordingly.

[[Page 4422]]

Conclusion

We have carefully reviewed the available data, including the
comments 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 3,132 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.

Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of U.S.-
Action Work hours Average labor rate per hour Parts Cost per airplane registered Fleet cost
airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection, per inspection 4 $80 None.............. $320, per 1,172............ $375,040, per
cycle. inspection cycle. inspection
cycle.
Preventative modification...... 240 80 Between $960 and Between $20,160 1,172 (720 Between
$13,620, and $32,820, airplanes have $9,112,320 and
depending on kit depending on had the $14,834,640.
purchased. configuration. preventative
modification
incorporated).
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

0
Accordingly, under the authority delegated to me by the Administrator,
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

0
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by
adding the following new airworthiness directive (AD):

2007-03-03 Boeing: Amendment 39-14914. Docket No. FAA-2006-24496;
Directorate Identifier 2005-NM-141-AD.

Effective Date

(a) This AD becomes effective March 7, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-100, -200, -200C, -300,
-400, and -500 series airplanes, certificated in any category; as
identified in Boeing Service Bulletin 737-53A1225, Revision 1, dated
April 14, 2005.

Unsafe Condition

(d) This AD results from reports of numerous cracks in the
vertical beam webs. We are issuing this AD to prevent fatigue cracks
in certain vertical beam webs, which could result in loss of
structural integrity of the body station (BS) 178 bulkhead, and
consequently could impair the operation of the control cables for
the elevators, speed brakes, and landing gear, or could cause the
loss of cabin pressure.

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.

Repetitive Inspections

(f) At the applicable times specified in Table 1 of this AD, do
a high frequency eddy current (HFEC) inspection and detailed
inspection to detect cracks in the BS 178 vertical beam webs, in
accordance with the Accomplishment Instructions of Boeing Service
Bulletin 737-53A1225, Revision 1, dated April 14, 2005.

[[Page 4423]]

Table 1.--Compliance Times
------------------------------------------------------------------------
And repeat the HFEC
and detailed
For airplanes on which-- Inspect-- inspections
thereafter at--
------------------------------------------------------------------------
(1) An HFEC or a detailed Before the Intervals not to
inspection specified in accumulation of exceed 6,000 flight
Boeing Service Bulletin 737- 15,000 total flight cycles.
53A1225, dated October 19, cycles, or within
2000, has not been done as 4,500 flight cycles
of the effective date of after the effective
this AD. date of this AD,
whichever occurs
later.
(2) An HFEC or detailed Within 6,000 flight Intervals not to
inspection specified in cycles since the exceed 6,000 flight
Boeing Service Bulletin 737- last HFEC cycles.
53A1225, dated October 19, inspection, within
2000, has been done before 1,200 flight cycles
the effective date of this since the last
AD. detailed
inspection, or
within 4,500 flight
cycles after the
effective date of
this AD, whichever
occurs later.
------------------------------------------------------------------------

Corrective Actions

(g) If any crack is detected during any inspection required by
paragraph (f) of this AD, before further flight, repair or replace
the vertical beam web and associated parts with a new vertical beam
web, in accordance with the Accomplishment Instructions of Boeing
Service Bulletin 737-53A1225, Revision 1, dated April 14, 2005,
except as provided by paragraph (h) of this AD.
(h) If any damage is beyond the scope of the service bulletin or
structural repair manual, before further flight, repair the damaged
vertical beam web in accordance with a method approved by the
Manager, Seattle Aircraft Certification Office (ACO), FAA; or using
a method approved in accordance with paragraph (m) of this AD.

Terminating Preventative Modification

(i) Before the accumulation of 50,000 total flight cycles, or
within 25,000 flight cycles after the effective date of this AD,
whichever occurs later, replace the vertical beams at buttock lines
(BL) 5.7 and 17.0 of the BS 178 bulkhead, in accordance with the
Accomplishment Instructions of Boeing Service Bulletin 737-53A1225,
Revision 1, dated April 14, 2005. Accomplishing the replacement ends
the repetitive inspections required by paragraph (f) of this AD.
(j) Actions done before the effective date of this AD in
accordance with Boeing BOECOM M-7200-01-00546, dated March 1, 2001,
are acceptable for compliance with the requirements of paragraph (i)
of this AD.

Prior to or Concurrent Requirements

(k) For Group 1 airplanes identified in Boeing Service Bulletin
737-53A1225, Revision 1, dated April 14, 2005: Before or
concurrently with the requirements of paragraph (i) of this AD, do
the preventative modifications of the center web, vertical chords,
and side chord areas, including the side chord areas at water line
207, of the forward pressure bulkhead, specified in paragraph (c) of
AD 2000-05-29, amendment 39-11639 (reference Boeing Alert Service
Bulletin 737-53A1173, Revision 3, dated May 6, 1999).
(l) For Group 2 airplanes identified in Boeing Service Bulletin
737-53A1225, Revision 1, dated April 14, 2005: Before or
concurrently with the requirements of paragraph (i) of this AD, but
no later than the time specified in AD 2001-02-01, amendment 39-
12085, do the preventative modifications of the vertical and side
chord areas of the forward pressure bulkhead required by paragraph
(c) of AD 2001-02-01 (reference Boeing Alert Service Bulletin 737-
53A1208, dated May 6, 1999).

Alternative Methods of Compliance (AMOCs)

(m)(1) The Manager, Seattle ACO, FAA, has the authority to
approve AMOCs for this AD, if requested in accordance with the
procedures found in 14 CFR 39.19.
(2) Before using any AMOC approved in accordance with Sec.
39.19 on any airplane to which the AMOC applies, notify the
appropriate principal inspector in the FAA Flight Standards
Certificate Holding District Office.
(3) An AMOC that provides an acceptable level of safety may be
used for any replacement or repair required by this AD, if it is
approved by an Authorized Representative for the Boeing Commercial
Airplanes Delegation Option Authorization Organization who has been
authorized by the Manager, Seattle ACO, to make those findings. For
a replacement or repair method to be approved, the replacement or
repair must meet the certification basis of the airplane, and the
approval must specifically refer to this AD.
(4) Approved AMOCs to paragraph (c) of AD 2000-05-29 done before
or concurrently with the requirements of paragraph (i) of this AD
are approved as AMOCs for the corresponding provisions of paragraph
(k) of this AD.
(5) Approved AMOCs to paragraph (c) of AD 2001-02-01 done before
or concurrently with the requirements of paragraph (i) of this AD
are approved as AMOCs for the corresponding provisions of paragraph
(l) of this AD.

Material Incorporated by Reference

(n) You must use Boeing Service Bulletin 737-53A1225, Revision
1, dated April 14, 2005, 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 https://dms.dot.gov; or
at the National Archives and Records Administration (NARA). For
information on the availability of this material at the NARA, call
(202) 741-6030, or go to https://www.archives.gov/federal_register/
code_of_federal_regulations/ibr_locations.html.

Issued in Renton, Washington, on January 19, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-1396 Filed 1-30-07; 8:45 am]
BILLING CODE 4910-13-P

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