AD 97-03-16

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 and MD-11F series airplanes, that currently requires, among other things, repetitive visual inspections to detect discrepancies of the fuel pipe of the fuel transfer system of the tail tank and associated mounting bracket located in the aft fuselage compartment. That AD was prompted by reports of cracking or bending of the fuel pipe mounting support and/or attaching bracket in the aft fuselage compartment due to a fuel pressure surge that caused repetitive loading of this area. This amendment adds a requirement to install a restraint on the tail tank fuel pipe, which would terminate the repetitive visual inspections. The actions specified by this AD are intended to prevent such cracking/bending, which could expose the fuel pipe coupling O-ring. An exposed O-ring could lose its sealing effect and could allow a fuel leak in the aft fuselage compartment, which would present a fire hazard.

Final rule.

97-03-16 MCDONNELL DOUGLAS: Amendment 39-9921. Docket 96-NM-218-AD. Supersedes AD 96-14-07, Amendment 39-9691, which superseded AD 91-24-09, Amendment 39-8095. \n\n\tApplicability: Model MD-11 and MD-11F series airplanes, manufacturer's fuselage numbers 0447 through 0599 inclusive; 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 otherwise 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 (f) 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 the possibility of an in-flight or ground fire due to fuel leaking from the fuel pipe coupling, accomplish the following:\n\nRESTATEMENT OF REQUIREMENTS OF AD 96-14-07, AMENDMENT 39-9691 \n\n\t(a)\tPerform a visual inspection to detect discrepancies (i.e., cracks or deformation) of the fuel pipe of the fuel transfer system of the tail tank and associated mounting bracket located in the aft fuselage compartment; and to verify the correct position of the fuel pipe flange, in accordance with McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996; at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. \n\n\t\t(1)\tFor airplanes on which the modification specified in McDonnell Douglas Service Bulletin 28-22, dated September 24, 1991, has been accomplished; or that have been repaired in accordance with an FAA-approved repair procedure, as specified in paragraph (a)(3) of AD 91-24- 09, amendment 39-8095; or on which the shroud assembly has been replaced with a serviceable part: Prior to the accumulation of 600 flight hours, or within 60 days after July 24, 1996 (the effective date AD 96-14-07, amendment 39-9691), whichever occurs later. \n\n\t\t(2)\tFor airplanes on which the modification specified in McDonnell Douglas Service Bulletin 28-22, dated September 24, 1991, has not been accomplished: Prior to the accumulation of 600 flight hours, or within 60 days since accomplishment of the last visual inspection in accordance with AD 91-24-09, amendment 39-8095; whichever occurs first. \n\n\t(b)\tCONDITION 1. No Discrepancy Found. If no discrepancy is detected during any visual inspection required by paragraph (a) of this AD, accomplish either paragraph (b)(1) or (b)(2) of this AD. \n\n\t\t(1)\tCONDITION 1. OPTION 1. Repeat the visual inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 600 flight hours or 60 days, whichever occurs later. Or \n\n\t\t(2)\tCONDITION 1. OPTION 2. Prior to further flight, install a temporary phenolic support block assembly, shim, clamp, and bracket between the tail tank fuel pipe and station Y=2033.750 bulkhead, in accordance with Condition 1, Option 2, of McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996. Within 6 months after accomplishment of this installation, perform a one-time inspection to verify the correct position of the temporary support block assembly installation in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. \n\n\t\t\t(i)\tIf the assembly is found to be positioned properly, repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months. \n\n\t\t\t(ii)\tIf the assembly is found be improperly positioned, prior to further flight, reposition the fuel pipe in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months. \n\n\t(c)\tCONDITION 2. Discrepancy Found; O-Ring Not Exposed. If any discrepancy is detected, and the fuel pipe is found to be improperly positioned, but the O-ring is not exposed, during any visual inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (c)(1) or (c)(2) of this AD. \n\n\t\t(1)\tCONDITION 2. OPTION 1. Repeat the visual inspection in paragraph (a) of this AD thereafter at intervals not to exceed 600 flight hours or 60 days, whichever occurs later. Or \n\n\t\t(2)\tCONDITION 2. OPTION 2. Prior to further flight, install a temporary phenolic support block assembly, shim, clamp, and bracket between the tail tank fuel pipe and station Y=2033.750 bulkhead; and reposition the fuel pipe assembly, asapplicable; in accordance with Condition 2, Option 2, of McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996. Within 6 months after accomplishment of this installation, perform a one-time inspection to verify the correct position of the temporary support block assembly installation in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. \n\n\t\t\t(i)\tIf the assembly is found to be positioned properly, repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months. \n\n\t\t\t(ii)\tIf the assembly is found to be improperly positioned, prior to further flight, reposition the fuel pipe in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months. \n\n\t(d)\tCONDITION 3. Discrepancy Found; O-Ring Exposed. If any discrepancy is detected, and the fuel pipe is found to be improperly positioned, and the O-ring is exposed, during any visual inspection required by paragraph (a) of this AD, prior to further flight, replace the O-ring with a new O-ring, and install a temporary phenolic support block assembly, shim, clamp, and bracket between the tail tank fuel pipe and station Y=2033.750 bulkhead, in accordance with McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996. Within 6 months after accomplishment of the replacement and installation, perform a one-time inspection to verify the correct position of the temporary support block assembly installation in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. \n\n\t\t(1)\tIf the assembly is found to be positioned properly, repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months. \n\n\t\t(2)\tIf the assembly is found to be improperly positioned, prior to further flight, reposition the fuel pipe in accordance with Figure 2 (Sheet 2 of 3) of the alert service bulletin. Repeat the verification of the correct position of the fuel pipe flange, as specified in paragraph (a) of this AD, thereafter at intervals not to exceed 15 months.\n\n NEW REQUIREMENTS OF THIS AD \n\n\t(e)\tWithin 24 months after the effective date of this AD, install a restraint on the tail tank fuel pipe in accordance with McDonnell Douglas Service Bulletin MD11-28-082, dated July 29, 1996. Accomplishment of the installation constitutes terminating action for the repetitive inspection requirements of this AD. \n\n\t(f)\tAn 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO. \n\n\t(g)\tSpecial 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\n\t(h)\tThe actions shall be done in accordance with McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996; and McDonnell Douglas Service Bulletin MD11-28- 082, dated July 29, 1996. The incorporation by reference of McDonnell Douglas Alert Service Bulletin MD11-28A082, dated May 14, 1996, was approved previously by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51 as of July 24, 1996 (61 FR 35946, July 9, 1996). The incorporation by reference of McDonnell Douglas Service Bulletin MD11-28-082, dated July 29, 1996, is 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 McDonnell Douglas Corporation, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Technical Publications Business Administration, Department 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(i)\tThis amendment becomes effective on March 14, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 96-14-07, amendment 39-9691 (61 FR 35946, July 9, 1996), which is applicable to certain McDonnell Douglas Model MD-11 and MD-11F series airplanes, was published in the Federal Register on November 20, 1996 (61 FR 59036). The action proposed to supersede AD 96-14-07 to continue to require repetitive visual inspections to detect discrepancies (i.e., cracks or deformation) of the fuel pipe of the fuel transfer system of the tail tank and associated mounting bracket located in the aft fuselage compartment and to verify the correct position of the fuel pipe flange, and various follow-on actions. The action also proposed to require installation of a restraint on the tail tank fuel pipe, which would constitute terminating action for the repetitive visual inspection requirements. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\n\tThe commenter supports the proposed rule. \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\nCost Impact \n\n\tThere are approximately 152 McDonnell Douglas Model MD-11 and MD-11F series airplanes of the affected design in the worldwide fleet. The FAA estimates that 42 airplanes of U.S. registry will be affected by this AD. \n\tThe actions that are currently required by AD 96-14-07, and retained in this AD, take approximately 6 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $15,120, or $360 per airplane, per inspection cycle. \n\n\tThe new actions that are required by this new AD will take approximately 3 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $7,560, or $180 per airplane. \n\n\tThe cost impact figures discussed above are 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant thepreparation 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\nAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 - (Amended) \n\n\t2. Section 39.13 is amended by removing amendment 39-9691 (61 FR 35946, July 9, 1996), and by adding a new airworthiness directive (AD), amendment 39-9921, to read as follows: