AD 2003-22-08

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 and -11F airplanes, that requires a one-time inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, and follow-on and corrective actions if necessary. This action is necessary to prevent such corrosion, which could result in structural damage and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2003-22-08 McDonnell Douglas: Amendment 39-13356. Docket 2002-NM-06- AD. \n\n\tApplicability: Model MD-11 and -11F airplanes, as listed in Boeing Service Bulletin MD11-55-023, dated November 28, 2001; certificated in any category. \n\n\tNote 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent corrosion of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer, which could result in structural damage and consequent reduced controllability of the airplane, accomplish the following: \n\nOne-Time Inspection/ Follow-on and Corrective Actions \n\n\t(a) Within 18 months or 6,000 flight hours after the effective date of this AD, whichever is later: Do a one-time detailed inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, per Boeing Service Bulletin MD11-55-023, including Appendix A, dated November 28, 2001. Before further flight, do the actions required by paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this AD, as applicable. \n\n\tNote 2: For the purposes of this AD, a detailed inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\n\t(1) If no corrosion is found: Clean, seal, and tape the barrel nut holes per Figure 4 of the service bulletin. \n\n\t(2) If corrosion is found that does not exceed the limits specified in Figure 2 of the service bulletin: Remove and retain the barrel nuts and bolts, remove the corrosion of the barrel nut hole, seal and tape the holes per Figure 4 of the service bulletin, and reinstall the barrel nuts and bolts per Figure 2 of the service bulletin. \n\n\t(3) If corrosion is found that does not exceed 0.060 inch on the barrel nut bottom: Remove and retain the barrel nuts and bolts, remove the corrosion, fabricate and install bushings, seal and tape the holes per Figure 4 of the service bulletin, and reinstall the barrel nuts and bolts per Figure 2 of the service bulletin. \n\n\t(4) If corrosion is found in the barrel nut bearing area, and/or corrosion exceeds the dimensional limits for each hole specified in Figure 2 of service bulletin: Repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA. \n\nAlternative Methods of Compliance \n\n\t(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO. \n\n\tNote 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\nSpecial Flight Permit \n\n\t(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(d) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin MD11-55-023, including Appendix A, dated November 28, 2001. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW, Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(e) This amendment becomes effective on December 8, 2003.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 and -11F airplanes was published in the Federal Register on May 29, 2003 (68 FR 32001). That action proposed to require a one-time inspection of the barrel nut holes of the upper spar caps and skin panel of the horizontal stabilizer for corrosion, and follow-on and corrective actions if necessary. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comment received. \n\nRequest To Extend Compliance Time \n\n\tThe commenter requests that the compliance time for the proposed one-time inspection be extended from 18 months to 36 months, and that the proposed AD be revised to include a new revision to the referenced service bulletin. The commenter states that it has inspected over 10 percent of its fleet, during which all three corrosion conditions were found. Finding these conditions caused the commenter to do a more extensive inspection. To accomplish the more extensive inspection, the commenter asserts that it takes an average of 1,650 work hours per airplane, and approximately 5,000 work hours for earlier manufactured airplanes. In light of the more extensive inspection, the commenter states that a compliance time of 36 months would be more realistic. \n\n\tIn addition, the commenter states that the manufacturer is revising Boeing Service Bulletin MD11-55-023 (which was referenced as the appropriate source of service information for the actions specified in the proposed AD) to incorporate a more extensive inspection along with an extended compliance time. The recommended compliance time for the more extensive inspection (Phase II) would be at the next scheduled heavy maintenance check or within 6 years after the Phase I inspection (specified in the proposedAD). Therefore, the commenter asserts that the proposed AD should be revised to include the new service bulletin revision for accomplishment of the more extensive inspection. \n\n\tFrom these statements, the FAA infers that the commenter is requesting that the proposed AD also be revised to include a more extensive inspection for which they are requesting an extended compliance time. We do not agree that the 18-month compliance time should be extended or that a more extensive inspection should be added to the proposed AD. We have determined that the required inspection is sufficient to ensure an adequate level of safety for the transport fleet. We have coordinated this issue with the manufacturer and have determined that the 18-month compliance time is appropriate for the inspection method specified in this final rule. However, we may consider additional rulemaking to mandate a more extensive inspection and compliance time once the manufacturer has issued, and we have reviewed and approved, a revision of the service bulletin incorporating such an inspection. No change has been made to this final rule in this regard. \n\n\tWe note that the commenter has been proactive in accomplishing a more thorough inspection than was specified in the proposed AD. Under the provisions of paragraph (b) of this final rule, we may consider requests for alternative methods of compliance or adjustments to the compliance time if data are submitted to substantiate that such methods or adjustments would provide an acceptable level of safety. \n\nConclusion \n\n\tAfter careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nChanges to 14 CFR Part 39/Effect on the AD \n\n\tOn July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. However, for clarity and consistency in this final rule, we have retained the language of the NPRM regarding that material. \n\nChange to Labor Rate Estimate \n\n\tWe have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate. \n\nCost Impact \n\n\tThere are approximately 191 airplanes of the affected design in the worldwide fleet. The FAA estimates that 66 airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the required inspection, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $25,740, or $390 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\nAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n2. Section 39.13 is amended by adding the following new airworthiness directive: