AD 94-13-07

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This action requires inspections and replacement or reidentification and reinstallation of certain aft engine mount link assemblies. This amendment is prompted by reports of cracking in the aft engine mount link assemblies of airplanes having link assemblies identical to those installed on Model MD-11 series airplanes. The actions specified in this AD are intended to prevent loss of the aft engine mount capability to support engine loads, and possible separation of the engine from the airplane.

Final rule; request for comments.

94-13-07 MCDONNELL DOUGLAS: Amendment 39-8947. Docket 93-NM-168-AD. \n\n\tApplicability: Model MD-11 series airplanes; manufacturer's fuselage numbers 449, 456 through 461 inclusive, 463 through 465 inclusive, 472, 473, 475, 477, 480, 481, 484, 485, 487, 489, 490, 494 through 496 inclusive, 498, 502, 506, 509 through 512 inclusive, 514, 516, 518, 519, 522, 525, 532, 533, 536, 538, 539, 541 through 544 inclusive, and 546; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent the loss of the aft engine mount capability to support engine loads and possible separation of the engine from the airplane, accomplish the following: \n\n\t(a)\tPerform a visual inspection of the aft engine mount link assembly, part numbers 221-0262-501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard) to determine the serial numbers of the links and to identify any suspect link that is installed, in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A71-59, dated December 20, 1993, or Revision 1, dated January 14, 1994, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable. Suspect links are those links having serial numbers WPC0001 through WPC1063 inclusive, or M1064 through M1255 inclusive. If no suspect link is installed, no further action is required by this AD. \n\n\tNOTE 1: Links having serial numbers M1255 and below with the "M" prefix are from the same forging supplier as links having the "WPC" prefix. \n\n\t\t(1)\tFor airplanes equipped with engines that have experienced a high power surge within the last 12 months prior to the effective date of this AD: Perform the inspection within 60 days after the effective date of this AD. \n\n\t\t(2)\tFor airplanes equipped with engines that have not experienced a high power surge within the last 12 months prior to the effective date of this AD: Perform the inspection within 120 days after the effective date of this AD. \n\n\t(b)\tIf any suspect link is found during the inspection required by paragraph (a) of this AD, prior to further flight, remove the suspect link, and perform a fluorescent penetrant inspection and an eddy current inspection to detect cracks or other defects in the suspect link, in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A71-59, dated December 20, 1993, or Revision 1, dated January 14, 1994. \n\n\t\t(1)\tIf any crack or defect is found in the link, prior to further flight, replace it with a link having a serial number that is not within the suspect serial number groups, in accordance with the service bulletin. \n\n\t\t(2)\tIf no crack or defect is found in the link, prior to further flight, replace it with a link having a serial number that is not within the suspect serial number groups, or reidentify and reinstall the uncracked suspect link in accordance with the service bulletin. No further action is required by this AD for that link. \n\n\t(c)\tWithin10 days after accomplishing the inspection required by paragraph (b) of this AD, submit a report of inspection findings, including the information specified in paragraphs (c)(1), (c)(2), and (c)(3) of this AD, to the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate, 3229 East Spring Street, Long Beach, California 90806-2425; fax (310) 988-5210. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\n\t\t(1)\tThe serial number of any suspect link found. \n\n\t\t(2)\tThe manufacturer's fuselage number on which the suspect link was found. \n\n\t\t(3)\tThe results of inspections required by paragraph (b) of this AD. \n\n\t(d)\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(e)\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(f)\tThe actions shall be done in accordance with McDonnell Douglas MD-11 Alert Service Bulletin A71-59, dated December 20, 1993, or McDonnell Douglas MD-11 Alert Service Bulletin A71-59, Revision 1, dated January 14, 1994. This incorporation by reference was approved by the Director of theFederal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from McDonnell Douglas Corporation, P.O. Box 1771, Long Beach, California 90801-1771, Attention: Business Unit Manager, Technical Publications - Technical Administrative Support, C1-L5B. 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, 3229 East Spring Street, Long Beach, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(g)\tThis amendment becomes effective on July 8, 1994.

The FAA has received four reports of cracking in the aft engine mount link assemblies, part numbers 221-0262-501 and 221-0262-503, installed on Airbus Industrie Model A310 and A300-600 series airplanes. Link assemblies having those part numbers are installed in conjunction with Pratt & Whitney (PW) 4000 series engines that are installed on those Airbus models, as well as on McDonnell Douglas Model MD-11 series airplanes. \n\n\tMetallurgical analysis and close examination of the cracked links has indicated a similar mode of cracking among the four cracked links reported. This cracking is the result of physical defects, which were caused during the forging process by one supplier. \n\n\tA link assembly is located at all three positions of the aft engine mount (left outboard, right outboard, and inboard) installed on Model MD-11 series airplanes. Cracks in these aft engine mount link assemblies, if not detected and corrected, could result in loss of the capability of the aft engine mount to support engine loads, and possible separation of the engine from the airplane. \n\n\tThe FAA has reviewed and approved McDonnell Douglas MD-11 Alert Service Bulletin A71-59, dated December 20, 1993, and Revision 1, dated January 14, 1994, which contain general information concerning procedures to inspect for and replace the suspect engine mount links. This service bulletin references Pratt & Whitney Service Bulletin APW4MD11 71-86, dated December 20, 1993, for additional service information. The Pratt & Whitney service bulletin describes procedures for: \n\n\t1.\tA visual inspection of the aft engine mount link assembly, part numbers 221-0262- 501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard) to determine the serial numbers of the links. \n\n\t2.\tRemoval of any suspect link that is found during the visual inspection; a fluorescent penetrant inspection and an eddy current inspection to detect cracks or other defects in the suspect link; and replacement of any cracked or defective suspect link with a link having a serial number that is not within the suspect serial number groups. \n\n\t3.\tReplacement of any suspect link that is not cracked or defective with a link having a serial number that is not within the suspect serial number groups, or reidentification and reinstallation of the uncracked suspect link. \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other Model MD-11 series airplanes of the same type design, this AD is being issued to prevent loss of the capability of the aft engine mount to support engine loads, and possible separation of the engine from the airplane. \n\n\tThis AD requires a visual inspection of the aft engine mount link assembly, part numbers 221-0262-501 and 221-0262-503, at all three link positions (left outboard, right outboard, and inboard) to determine the serial numbers of the links. If any suspect link is found, operators are required to remove the link and perform both a fluorescent penetrant inspection and an eddy current inspection of it to detect cracks and other defects, and to replace any cracked or defective suspect link with a link having a serial number that is not within the suspect serial number groups. If no crack or defect is found in the link, it may either be replaced with a non-suspect link, or reidentified and reinstalled. The actions are required to be accomplished in accordance with the McDonnell Douglas alert service bulletin described previously. \n\n\tThis AD also requires that operators report certain inspection findings to the FAA. \n\n\tThe FAA has initiated a similar rulemaking action that is applicable to Airbus series airplanes on which the suspect links may also be installed. \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 93-NM-168-AD." The postcard will be date stamped and returned to the commenter. \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 the preparation of a Federalism Assessment. \n\n\tThe FAA has determined that this regulation is an emergency regulation and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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 \t39) as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1.\tThe authority citation for part 39 continues to read as follows: \n\nAuthority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. \n\n§ 39.13 - (Amended) \n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: