AD 98-16-01

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This action requires repetitive inspections to measure for free play (wear on nut assembly) of the horizontal stabilizer actuator assembly, and corrective actions, if necessary. This amendment is prompted by reports of wear of the horizontal stabilizer actuator assembly due to a jackscrew surface finish that was manufactured incorrectly. The actions specified in this AD are intended to prevent excessive free play and wear of the horizontal stabilizer actuator assembly, which could result in a free-floating horizontal stabilizer, and consequent loss of aircraft pitch control.

Final rule; request for comments.

98-16-01 MCDONNELL DOUGLAS: Amendment 39-10676. Docket 98-NM-212-AD. \n\n\tApplicability: Model MD-11 series airplanes, as listed in McDonnell Douglas MD-11 Alert Service Bulletin MD11-27A067, Revision 03, dated June 9, 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 (i) 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.Compliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent excessive play and wear on the horizontal stabilizer actuator assembly, which could result in a free-floating horizontal stabilizer, and consequent loss of aircraft pitch control, accomplish the following: \n\n\tNOTE 2: Where there are differences between the service bulletins and the AD, the AD prevails. \n\n\t(a)\tWithin 30 days after the effective date of this AD: Perform an inspection to measure for free play (wear on nut assembly) of the horizontal stabilizer actuator assembly, left and right sides, in accordance with any of the following McDonnell Douglas service bulletins: \n\nMcDonnell Douglas Service Bulletin MD11-27-067, dated July 31, 1997; \n\nMcDonnell Douglas Service Bulletin MD11-27-067, Revision 01, dated February 24, 1998; \n\nMcDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 02, dated May 18, 1998; or \n\nMcDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 03, dated June 9, 1998. \n\n\t(b)\tFor airplanes that have accumulated 2,000 or more total landings at the time of accomplishment of the inspection required by paragraph (a) of this AD: If any wear is detected during the inspection required by paragraph (a) of this AD, and it is less than or within the limits identified in Table 1, Condition 1, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD, no further action is required by this AD. \n\n\t(c)\tFor airplanes that have accumulated less than 2,000 total landings at the time of accomplishment of the inspection required by paragraph (a) of this AD: If any wear is detected during any inspection required by paragraph (a) of this AD, and it is less than or within the limits identified in Table 1, Condition 1, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD, repeat the inspection required by paragraph (a) of this AD prior to the accumulation of 2,400 total landings. \n\n\t(d)Condition 2. If any wear is detected during any inspection required by paragraph (a) or (c) of this AD, and it is within the limits identified in Table 1, Condition 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD, within 500 landings following accomplishment of the inspection required by paragraph (a) of this AD, accomplish paragraph (d)(1), (d)(2), (d)(3), (d)(4), or (d)(5) of this AD. \n\n\t\t(1)\tOption 1. Replace the actuator assembly with a new actuator assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(2)\tOption 2. Repair the jackscrew assembly of the horizontal stabilizer and install it utilizing the existing nut assembly in accordance with either: \n\n\t\t\t(i)\tA method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; or \n\n\t\t\t(ii)\tOption 2, Procedure 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD.(3)\tOption 3. Repair the jackscrew assembly of the horizontal stabilizer and install it utilizing a new nut assembly in accordance with either: \n\n\t\t\t(i)\tA method approved by the Manager, Los Angeles ACO; or \n\n\t\t\t(ii)\tOption 3, Procedure 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(4)\tOption 4. Replace the nut assembly with a new nut assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. Within 1,500 landings following accomplishment of the replacement, repeat the inspection required by paragraph (a) of this AD. \n\n\t\t(5)\tOption 5. Repeat the inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 500 landings. \n\n\t(e)\tCondition 3. If any wear is detected during the inspection required by paragraph (a) or (c) of this AD, and it is within the limits identified in Table 1, Condition 3, of the Work Instructions of any service bulletin listed in paragraph (a) of thisAD, within 250 landings following accomplishment of the inspection required by paragraph (a) of this AD, accomplish either paragraph (e)(1), (e)(2), (e)(3), (e)(4), or (e)(5) of this AD. \n\n\t\t(1)\tOption 1. Replace the actuator assembly with a new actuator assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(2)\tOption 2. Repair the jackscrew assembly of the horizontal stabilizer and install it utilizing the existing nut assembly in accordance with either: \n\n\t\t\t(i)\tA method approved by the Manager, Los Angeles ACO; or \n\n\t\t\t(ii)\tOption 2, Procedure 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(3)\tOption 3. Repair the jackscrew assembly of the horizontal stabilizer and install it utilizing a new nut assembly in accordance with either: \n\n\t\t\t(i)\tA method approved by the Manager, Los Angeles ACO; or \n\n\t\t\t(ii)\tOption 3, Procedure 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(4)\tOption 4. Replace the nut assembly with a new nut assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. Within 1,500 landings following accomplishment of the replacement, repeat the inspection required by paragraph (a) of this AD. \n\n\t\t(5)\tOption 5. Repeat the inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 250 landings. \n\n\t(f)\tCondition 4. If any wear is detected during the inspection required by paragraph (a) or (c) of this AD, and it is within the limits identified in Table 1, Condition 4, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD, within 100 landings following accomplishment of the inspection required by paragraph (a) of this AD, accomplish paragraph (f)(1), (f)(2), or (f)(3) of this AD. \n\n\t\t(1)\tOption 1. Replace the actuator assembly with a new actuator assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(2)\tOption 3. Repair the jackscrew assembly of the horizontal stabilizer and install it utilizing a new nut assembly in accordance with either: \n\n\t\t\t(i)\tA method approved by the Manager, Los Angeles ACO; or \n\n\t\t\t(ii)\tOption 3, Procedure 2, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD. \n\n\t\t(3)\tOption 4. Replace the nut assembly with a new nut assembly, in accordance with any service bulletin listed in paragraph (a) of this AD. \n\n\t\t\t(i)\tFor airplanes that have accumulated 1,500 or more landings at the time of the last inspection: Within 1,500 landings following accomplishment of the replacement, repeat the inspection required by paragraph (a) of this AD. \n\n\t\t\t(ii)\tFor airplanes that have accumulated less than 1,500 landings at the time of the last inspection: Following accomplishment of the replacement, repeat the inspection required by paragraph (a) of this AD within the number of landings accumulated at the time of the last inspection. \n\n\t(g)\tIf any wear is detected during the inspection required by paragraph (a) or (c) of this AD, and it exceeds the limits identified in Table 1, Condition 4, of the Work Instructions of any service bulletin listed in paragraph (a) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles ACO. \n\n\t(h)\tWithin 10 days after accomplishment of the initial inspection required by paragraph (a) of this AD, submit a report of the inspection results (positive or negative) to the Manager, Los Angeles Aircraft Certification Office, FAA, Transport Airplane Directorate, 3960 Paramount Boulevard, Lakewood, California 90712; fax (562) 627-5210. 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(i)\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 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\n\t(j)\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(k)\tExcept as provided by paragraphs (d)(2)(i), (e)(2)(i), and (g) of this AD, the actions shall be done in accordance with the following service bulletins: \n\nMcDonnell Douglas Service Bulletin MD11-27-067, dated July 31, 1997; \n\nMcDonnell Douglas Service Bulletin MD11-27-067, Revision 01, dated February 24, 1998; \n\nMcDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 02, dated May 18, 1998; or \n\nMcDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 03, dated June 9, 1998. \n\nThis 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(l)\tThis amendment becomes effective onAugust 14, 1998.

The FAA has received numerous reports of the actuator nut assembly of the horizontal stabilizer prematurely wearing out on McDonnell Douglas Model MD-11 series airplanes. In one of these incidents, the nut assembly had completely worn through. The cause of such wear and resultant excessive free play has been attributed to a jackscrew surface finish that was out of design specification tolerance, as a result of a manufacturing process error. If not corrected, this condition, in conjunction with a failure of the opposite side jackscrew assembly, could result in a free-floating horizontal stabilizer, and consequent loss of aircraft pitch control. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved McDonnell Douglas Service Bulletin MD11-27-067, dated July 31, 1997; McDonnell Douglas Service Bulletin MD11-27-067, Revision 01, dated February 24, 1998; McDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 02, dated May 18, 1998; and McDonnell Douglas Alert Service Bulletin MD11-27A067, Revision 03, dated June 9, 1998. These service bulletins describe procedures for repetitive inspections to measure for free play (wear on nut assembly) of the horizontal stabilizer actuator assembly, and corrective actions, if necessary. These corrective actions include replacing the actuator assembly with a new actuator assembly, repairing the jackscrew assembly, and replacing the nut assembly with a new nut assembly. Accomplishment of the actions specified in these service bulletins is intended to adequately address the identified unsafe condition. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD is being issued to prevent excessive free play and wear of the horizontal stabilizer actuator assembly, which could result in a free-floating horizontal stabilizer, and consequent lossof aircraft pitch control. The actions are required to be accomplished in accordance with the service bulletins described previously, except as discussed below. This AD also requires that operators submit a report of the results of the initial inspection required by this AD to the FAA. \n\nDifferences Between Proposed Rule and Service Bulletins \n\n\tOperators should note that although the service bulletins specify that the manufacturer may be contacted for disposition of certain repair/modification conditions, this AD requires the repair of those conditions to be accomplished in accordance with a method approved by the FAA. \n\nDetermination of Rule's Effective Date \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 rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-212-AD." The postcard will be date stamped and returned to the commenter. \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 the preparation of a Federalism Assessment. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, 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 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 adding the following new airworthiness directive: