AD 2008-08-23

We are adopting a new airworthiness directive (AD) for all Boeing Model 737-200C series airplanes. This AD requires revising the FAA-approved maintenance inspection program to include inspections that will give no less than the required damage tolerance rating for each structural significant item (SSI), doing repetitive inspections to detect cracks of all SSIs, and repairing cracked structure. This AD results from a report of incidents involving fatigue cracking in transport category airplanes that are approaching or have exceeded their design service objective. We are issuing this AD to maintain the continued structural integrity of the entire fleet of Model 737-200C series airplanes.

Final rule.

2008-08-23 Boeing: Amendment 39-15477. Docket No. FAA-2007-29029; Directorate Identifier 2007-NM-175-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective May 27, 2008. \n\nAffected ADs \n\n\t(b) Accomplishing the actions required by paragraph (g) and the initial inspections required by paragraph (h) of this AD ends the requirements of AD 98-11-04 R1, amendment 39-10984, for Model 737- 200C series airplanes only. Operators of Model 737-100 and -200 series airplanes must continue to do the actions required by AD 98- 11-04 R1. \n\nApplicability \n\n\t(c) This AD applies to all Boeing Model 737-200C series airplanes, certificated in any category. \n\nUnsafe Condition \n\n\t(d) This AD results from a report of incidents involving fatigue cracking in transport category airplanes that are approaching or have exceeded their design service objective. We are issuing this AD to maintain the continued structural integrity of the entire fleet of Model 737-200C series airplanes. \n\nCompliance \n\n\t(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nService Information \n\n\t(f) The term "Revision E,'' as used in this AD, means Boeing Document D6-37089, "Supplemental Structural Inspection Document for Model 737-100/200/200C Airplanes,'' Revision E, dated May 2007. \n\nRevision of the FAA-Approved Maintenance Inspection Program \n\n\t(g) At the applicable time specified in Table 1 of this AD, incorporate a revision into the FAA-approved maintenance inspection program that provides no less than the required damage tolerance rating (DTR) for each structural significant item (SSI) listed in Revision E. (The required DTR value for each SSI is listed in Revision E.) The revision to the maintenance inspection program must include and must be implemented in accordance with the procedures in Section 5.0, "Damage Tolerance Rating (DTR) System Application,''and Section 6.0, "SSI Discrepancy Reporting'' of Revision E. Under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056. \n\n\tTable 1.--Compliance Time for Revising Maintenance Inspection Program\n\n\nFor airplanes with SSIs -\nCompliance Time\n(1) Affected by the cargo configuration\nBefore the accumulation of 46,000 total flight cycles, or within 12 months after the effective date of this AD, whichever occurs later\n(2) Not affected by the cargo configuration\nBefore the accumulation of 66,000 total flight cycles, or within 12 months after the effective date of this AD, whichever occurs later.\n\n\nInitial and Repetitive Inspections \n\n\t(h) Except as provided by paragraph (i) of this AD: At the applicable time specified in Table 2 of this AD, do the applicable initial inspections to detect cracksof all SSIs, in accordance with Revision E. Repeat the applicable inspections thereafter at the intervals specified in Section 3.0, "Implementation'' of Revision E. \n\n\tTable 2.--Compliance Time for Initial Inspections \n\n\nFor airplanes with SSIs -\nCompliance Time\n(1) Affected by the cargo configuration\nBefore the accumulation of 46,000 total flight cycles, or within 4,000 flight cycles measured from 12 months after the effective date of this AD, whichever occurs later\n(2) Not affected by the cargo configuration\nBefore the accumulation of 66,000 total flight cycles, or within 4,000 flight cycles measured from 12 months after the effective date of this AD, whichever occurs later.\n\n\t(i) For any SSI that has been repaired or altered before the effective date of this AD such that the repair or design change affects your ability to accomplish the actions required by paragraph (h) of this AD: You must request FAA approval of an alternative method of compliance (AMOC) in accordancewith section 39.17 of the Federal Aviation Regulations (14 CFR 39.17), at the initial compliance time specified in paragraph (h) of the AD; or do the actions specified in paragraphs (i)(1) and (i)(2) of this AD, at the times specified in those paragraphs, as an approved means of compliance with the requirements of paragraph (h) of this AD. \n\t(1) At the initial compliance time specified in paragraph (h) of the AD, identify each repair or design change to that SSI. \n\t(2) Within 12 months after the identification of a repair or design change required by paragraph (i)(1) of this AD, assess the damage tolerance characteristics of each SSI affected by each repair or design change to determine the effectiveness of the applicable SSID inspection for that SSI and if not effective, incorporate a revision into the FAA-approved maintenance inspection program to include a damage-tolerance based alternative inspection program for each affected SSI. Thereafter, inspect the affected structure in accordance with the alternative inspection program. The inspection method and compliance times (i.e., threshold and repeat intervals) of the alternative inspection program must be approved in accordance with the procedures specified in paragraph (l) of this AD. \n\nRepair \n\n\t(j) If any cracked structure is found during any inspection required by paragraph (h) or (i) of this AD, before further flight, repair the cracked structure using a method approved in accordance with the procedures specified in paragraph (l) of this AD. \n\nInspection Program for Transferred Airplanes \n\n\t(k) Before any airplane that is subject to this AD and that has exceeded the applicable compliance times specified in paragraph (h) of this AD can be added to an air carrier's operations specifications, a program for the accomplishment of the inspections required by this AD must be established in accordance with paragraph (k)(1) or (k)(2) of this AD, as applicable. \n\t(1) For airplanes that have been inspected inaccordance with this AD: The inspection of each SSI must be done by the new operator in accordance with the previous operator's schedule and inspection method, or the new operator's schedule and inspection method, at whichever time would result in the earlier accomplishment for that SSI inspection. The compliance time for accomplishment of this inspection must be measured from the last inspection accomplished by the previous operator. After each inspection has been done once, each subsequent inspection must be performed in accordance with the new operator's schedule and inspection method. \n\t(2) For airplanes that have not been inspected in accordance with this AD: The inspection of each SSI required by this AD must be done either before adding the airplane to the air carrier's operations specification, or in accordance with a schedule and an inspection method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. After each inspection has been done once, each subsequent inspection must be done in accordance with the new operator's schedule. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(l)(1) The Manager, Seattle ACO has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \n\t(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. \n\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 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 repair method to be approved, the repair approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(m) You must use Boeing Document D6-37089, "Supplemental Structural Inspection Document for Model 737-100/200/200C Airplanes,'' Revision E, dated May 2007, to do the actions required by this AD, unless the AD specifies otherwise. \n\t(1) The document contains the following errors: \n\t(i) Pages 2.0.3 and 2.0.4, Revision D, of Section 2.0 and pages F-14.5, Revision D, and F-14.6, Revision Blank, of Section 8.2 exist; but are not specified in the List of Effective Pages. \n\t(ii) Pages 7.0.43 through 7.0.46 inclusive of Section 7.0 and pages W.34.1 and W.34.2 of Section 11.1, as specified in the List of Effective Pages, do not exist. \n\t(iii) The List of Effective Pages specifies incorrect revision levels for certain pages; the revision levels specified on each page are correct. \n\t(iv) None of the pages are dated. The issue date for each revision is specified in the Revision Highlights section. \n\t(2) The Director ofthe Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(3) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. \n\t(4) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_ regulations/ibr_locations.html.

Discussion \n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to all Boeing Model 737-200C series airplanes. That NPRM was published in the Federal Register on August 23, 2007 (72 FR 48243). That NPRM proposed to require revising the FAA-approved maintenance inspection program to include inspections that will give no less than the required damage tolerance rating for each structural significant item (SSI), doing repetitive inspections to detect cracks of all SSIs, and repairing cracked structure. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the one commenter. \n\nRequest To Allow Alternative Inspections for Previously Repaired/ Altered Structure \n\n\tBoeing requests that the NPRM be revised to include a provision for alternative inspections when a repair area prohibits operators fromdoing the inspections specified in paragraph (h) of the NPRM. Boeing requests that the initial alternative inspection be done within 12 months after the repair is discovered during the initial inspection required by paragraph (h). Boeing points out that a similar provision was provided in paragraph (e) of AD 98-11-04 R1, amendment 39-10984 (64 FR 987, January 7, 1999). Boeing states that including such a provision will assist operators. \n\tWe agree. We have added a new paragraph (i) to this AD (and reidentified subsequent paragraphs) that provides alternative inspections to those in paragraph (h) of this AD. \n\nRequest To Clarify Certain Sections of the Preamble of the NPRM \n\n\tBoeing requests that certain sections in the preamble of the NPRM be clarified for the following reasons: \n\t1. Boeing states that Advisory Circular (AC) No. 91-56, "Supplemental Structural Inspection Program for Large Transport Category Airplanes,'' dated May 6, 2001, applies to airplanes certified under thefail-safe and fatigue requirements of Civil Air Regulations (CAR) 4b or part 25 of the Federal Aviation Regulations (14 CFR part 25), not damage tolerance structural requirements as stated in the "Issuance of Advisory Circular (AC)'' section. \n\t2. Boeing notes that the "Other Relevant Rulemaking'' section identifies the strut as one of the affected SSIs for Model 737-100, - 200, and -200C series airplanes. Boeing states that those airplanes do not have an engine strut. \n\t3. Boeing states that Boeing Document D6-37089, "Supplemental Structural Inspection Document for Model 737-100/200/200C Airplanes,'' Revision E, dated May 2007 (referred to in the NPRM as the appropriate source of service information for the required actions), does not describe procedures for repairing cracked structure, as specified in the "Relevant Service Information'' section. \n\tWe agree with Boeing that the identified sections could be clarified. For the first two items we agree with Boeing's statements. On thethird item, while the document does not specify individual repair procedures for each specific SSI, it does specify that all repairs must be approved. However, no change has been made to the final rule since the identified sections of the NPRM do not reappear in the final rule. \n\nExplanation of Change to Reported Incidents \n\n\tWe have revised the AD to specify that this AD results from a report of incidents involving fatigue cracking only. \n\nExplanation of Change to Costs of Compliance \n\n\tThe requirements for the baseline structure of Model 737-200C series airplanes are currently described in 14 CFR 121.1109(c)(1) and 129.109(b)(1), not in 14 CFR 121.370(a) and 129.16 as indicated in the third paragraph of the Cost of Compliance section of the NPRM. Therefore, we have revised the Costs of Compliance section of the AD accordingly. \n\nConclusion \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. We 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\tThere are about 49 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs\n\n\nAction\nWork hours\nAverage labor rate per hour\nCost\nNumber of U.S.-registered airplanes\nFleet cost\nRevision of maintenance inspection program\n1,000, per operator (3 U.S. operators)\n$80\n$80,000 per operator\n9\n$240,000 \nInspections\n500 per airplane\n$80\n$40,000, per airplane, per inspection cycle\n9\n$360,000, per inspection cycle\n\n\n\tThe number of work hours, as indicated above, is presented as if the accomplishment of the actions in this AD is to be conducted as "stand alone'' actions. However, in actual practice, these actions for the most part will be done coincidentally or in combination with normally scheduled airplane inspections and other maintenance program tasks. Therefore, the actual number of necessary additional work hours will be minimal in many instances. Additionally, any costs associated with special airplane scheduling will be minimal. \n\tFurther, compliance with this AD will be a means of compliance with the aging airplane safety final rule (AASFR) for the baseline structure of Model 737-200C series airplanes. The AASFR final rule requires certain operators to incorporate damage tolerance inspections into their maintenance inspection programs. These requirements are described in 14 CFR 121.1109(c)(1) and 129.109(b)(1). Accomplishment of the actions required by this AD will meet the requirements of these CFR sections for the baseline structure. The costs for accomplishing the inspection portion of this AD were accounted for in the regulatory evaluation of the AASFR final rule. \n\nAuthority for This Rulemaking \n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. "Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and \n\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by adding the following new AD: