AD 99-24-04 — Aircraft-logs.com

99-24-04 McDonnell Douglas: Amendment 39-11428. Docket 99-NM-05-AD. \n\n\tApplicability: Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD-83), and DC-9-87 (MD-87) series airplanes, and Model MD-88 airplanes; as listed in McDonnell Douglas Service Bulletin MD80-53-201, Revision 02, dated July 20, 1998; 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 failure of certain Hi-Lok pin fasteners and subsequent gouging of the aft pressure bulkhead tee, which could result in fatigue cracking and reduced structural integrity of the airplane, accomplish the following: \n\nInspection \n\n\t(a) Within 48 months after the effective date of this AD, perform a one-time general visual inspection to determine whether self-aligning nuts are installed at certain locations of the aft pressure bulkhead tee, in accordance with McDonnell Douglas Service Bulletin MD80-53-201, Revision 02, dated July 20, 1998, as revised by Information Notice MD90-53-201 R02, dated October 21, 1998. \n\n\tNote 2: For the purposes of this AD, a general visual inspection is defined as "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked." \n\n\t(1) If all nuts installed are self-aligning, no further action is required by this AD. \n\n\t(2) If any nut is determined to be non-self-aligning, prior to further flight, remove the existing nut and perform a one-time visual inspection to detect gouges in the aft pressure bulkhead tee on station Y=1338.000 and longeron end fitting, as applicable, in accordance with the service bulletin. \n\n\t(i) If no gouge is detected, prior to further flight, install new self-aligning nuts in accordance with the service bulletin. \n\n\t(ii) If any gouge is detected that is within the repair limits specified in the service bulletin, prior to further flight, repair the gouge and install new self-aligning nuts inaccordance with the service bulletin. \n\n\t(iii) If any gouge is detected that is outside the repair limits specified in the service bulletin, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. \n\n\tNote 3: Inspections, and repair of the aft pressure bulkhead tee longeron end fittings prior to the effective date of this AD, in accordance with McDonnell Douglas Service Bulletin MD80-53-201, dated July 6, 1988, or Revision 1, dated March 22, 1991, are considered acceptable for compliance with the actions required by paragraph (a) of this AD. \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 4: 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 Permits \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) Except as provided by paragraph (a)(2)(iii) of this AD, the actions shall be done in accordance with McDonnell Douglas Service Bulletin MD80-53-201, Revision 02, dated July 20, 1998. 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 The Boeing Company, Douglas Products Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Dept. C1-L51 (2-60). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(e) This amendment becomes effective on December 27, 1999.

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 DC-9-80 series airplanes and Model MD-88 airplanes was published in the Federal Register on February 2, 1999 (64 FR 8530). That action proposed to require a one-time visual inspection to determine whether self-aligning nuts are installed at certain locations of the aft pressure bulkhead tee; 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 comments received. \n\nSupport for the Proposal \n\n\tAll commenters support the objectives of the proposal, however, some of the commenters request several changes. \n\nRequests To Extend the Compliance Time \n\n\tSeveral commenters request that the proposed compliance time be revised from the proposed 24months to 48 months. \n\n\tOne of the commenters states that a 48-month compliance time will allow accomplishment of the actions required by the proposed AD "in conjunction with an extended maintenance visit." The commenter also states that no discrepancies were found during inspections of the subject area during accomplishment of Corrosion Prevention and Control Program (CPCP) tasks. Additionally, no discrepancies were found during recent inspections of self-aligning bolts on out-of-service airplanes. \n\n\tTwo commenters state that replacement of the self-aligning nuts and fasteners will require removal of the lavatory or engine. If non-self-aligning nuts are found and both engines must be removed, the commenters state that accomplishment of the replacement within the 24-month proposed compliance time could significantly disrupt aircraft availability. \n\n\tOne commenter points out that the service bulletin recommends a compliance time of at the operator's earliest practical maintenance period. The commenter states that it does not schedule engine or lavatory removal during a 24-month interval maintenance visit. The commenter also states that the fastener failure in the subject area would be detected during inspections accomplished as part of the routine maintenance program. These inspections are generally accomplished at 48-months intervals. Gouges on the tee would be detected during the inspection mandated by AD 96-16-04, amendment 39-9704 (61 FR 39860, July 31, 1996). The commenter states that, due to these thorough inspections that are routinely accomplished on its fleet, it does not believe that the requirements of the proposed AD should be an airworthiness concern. \n\n\tThe FAA partially concurs. The FAA's intent was that the inspection be conducted during a regularly scheduled heavy maintenance visit for the majority of the affected fleet, when the airplanes would be located at a base where special equipment and trained personnel would be readily available, if necessary. Based on the information supplied by the commenters, the FAA now recognizes that 48 months corresponds more closely to the interval representative of most of the affected operators' normal maintenance schedules. Paragraph (a) of the final rule has been revised to reflect a compliance time of 48 months. The FAA does not consider that this extension will adversely affect safety. However, the FAA does not concur with the commenter that the requirements of this AD are not an airworthiness concern. The FAA finds that the requirements of this AD are necessary to address an identified unsafe condition, as discussed in the preamble of the proposed AD. \n\nRequest To Reference a Certain Information Notice \n\n\tOne commenter requests that the proposed AD reference McDonnell Douglas Information Notice MD80-53-201 R02, dated October 21, 1998. The FAA concurs. The information notice clarifies information for parts for the SB09530201-7 kit that was inadvertently omitted on Revision 02 of Service Bulletin MD80-53-201, which is utilized in accomplishing the corrective actions required by paragraph (a)(2) of this AD. Therefore, the FAA has revised paragraph (a) of the final rule accordingly. \n\nRequest To Reference Earlier Versions of Referenced Service Bulletin \n\n\tOne commenter requests that the FAA allow accomplishment of the proposed requirements in accordance with McDonnell Douglas Service Bulletin MD80-53-201, dated July 6, 1988, and Revision 1, dated March 22, 1991, in addition to Revision 02, dated July 20, 1998. The FAA concurs. The FAA points out that NOTE 2 of the proposed AD, which is retained in the final rule, states "inspections, and repair of the aft pressure bulkhead tee longeron end fittings prior to the effective date of this AD, in accordance with McDonnell Douglas Service Bulletin MD80-53-201, dated July 6, 1988, or Revision 1, dated March 22, 1991, are considered acceptable for compliance with the actions required by paragraph (a) of this AD." Therefore, no change to the final rule is necessary. \n\nRequests To Revise Corrective Action in Paragraph (a)(2) of the Proposal \n\n\tTwo commenters request that paragraph (a)(2) of the proposed AD be revised to read "if incorrect nuts are installed at longeron fittings 19, 22, and 29, inspect fitting for gouges and repair or replace fitting per service bulletin 53-201." The commenters state that at longersons 19, 22, and 29, if non-self-aligning nuts are installed, the longeron end fitting would be gouged and not the tee fitting. \n\n\tThe FAA concurs with the commenters request that paragraph (a)(2) of the final rule be revised to require inspection of the bulkhead tee and/or longeron end fittings for gouges. The FAA's intent, as indicated under the header of "Explanation of Requirements of Proposed Rule" in the preamble of the proposed AD, was that "the proposed AD would require accomplishment of the actions specified in the service bulletin * * *" Therefore, the FAA has revised paragraph (a)(2) of the final rule to read "if any nut is determined to be non-self-aligning, prior to further flight, remove the existing nut and perform a one-time visual inspection to detect gouges in the aft pressure bulkhead tee on station Y=1338.000 and longeron end fitting, as applicable, in accordance with the service bulletin." \n\nRequest To Allow Approval of Repairs by Designated Engineering Representative \n\n\tOne commenter requests that the proposed AD be revised to include a provision for approval of repairs for gouges beyond the limits of the referenced service bulletin by a Boeing Designated Engineering Representative (DER) instead of the Manager of the Los Angeles Aircraft Certification Office (ACO). The commenter asserts that this provision will result in a more efficient and timely repair approval process. \n\n\tThe FAA does not concur. While DER's are authorized to determine whether a design or repair method complies with a specific requirement, they are not currently authorized to make the discretionary determination as to what the applicable requirement is. However, the FAA has issued a notice (N 8110.72, dated March 30, 1998), which provides guidance for delegating authority to certain type certificate holder structural DER's to approve alternative methods of compliance for AD-required repairs and modifications of individual airplanes. The FAA is currently working with Boeing, Douglas Products Division (DPD), to develop the implementation process for delegation of approval of alternative methods of compliance in accordance with that notice. Once this process is implemented, approval authority for alternative methods of compliance can be delegated without revising the AD. \n\nRequest To Revise Cost Impact \n\n\tOne commenter requests the FAA revise the Cost Impact paragraph. The commenter states that, while its true that the inspections take one hour, significant additional time will be required for removal of the lavatories, sidewall panels, cargo liners, and other components. The commenter also states that the cost estimate does not reflect the time associated with repairs that may require the removal of the engines, replacement of discrepant fasteners, and inspections required upon fastener removal. \n\n\tThe FAA does not concur. The economic analysis of the AD is limited only to the cost of actions actually required by the rule. It does not consider the costs of "on condition" actions, such as repairing a crack if one is detected during a required inspection ("repair, if necessary"). Such "on-condition" repair actions would be required to be accomplished-regardless of AD direction-in order to correct an unsafe condition identified in an airplane and to ensure operation of that airplane in an airworthy condition, as required by the Federal Aviation Regulations. In addition, the FAA recognizes that, in accomplishing the requirements of any 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; planning time; or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. Therefore, no change to the final rule is necessary. \n\nExplanation of Change Made to Proposal \n\n\tThe FAA has clarified the inspection requirement contained in the proposed AD. Whereas the proposal specified a visual inspection, the FAA has revised this final rule to clarify that its intent is to require a general visual inspection. Additionally, a note has been added to the final rule to define that inspection. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determinedthat these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 1,042 airplanes of the affected design in the worldwide fleet. The FAA estimates that 695 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to accomplish the required inspection, and that the average labor rate is $60 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 $41,700, or $60 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. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects 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\n\tTherefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39-AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive:

AD Number	99-24-04	Status	Superseded
Effective Date	December 27, 1999	Issue Date	November 10, 1999
Docket Number	99-NM-05-AD	Amendment	39-11428
Product Type	["Aircraft"]	Product Subtype	["Large Airplane"]
CFR Part	--- - Part 39	CFR Section	N/A
Citation	(Federal Register: November 19, 1999 (Volume 64, Number 223))

Manufacturer(s)	McDonnell Douglas Corporation
Model(s)	DC-9-81 DC-9-82 DC-9-83 DC-9-87 MD-88

AD 99-24-04 SUPERSEDED