AD 95-16-03

This amendment adopts a new airworthiness directive (AD), applicable to certain Model DC-9 series airplanes and C-9 (military) airplanes, that requires inspection of the driver links of the thrust reverser door to determine whether the driver links are chamfered, an inspection to detect damage of the overcenter links, and follow-on corrective actions, if necessary; and replacement or rework of the driver links. This amendment is prompted by reports of a thrust reverser door that failed to operate properly due to improperly manufactured (missing chamfers on the) driver links. The actions specified by this AD are intended to prevent damage to the overcenter links due to missing chamfers on the driver links, which may result in uncommanded opening of the thrust reverser door, and subsequently, adversely affecting controllability of the airplane.

Final rule.

95-16-03 MCDONNELL DOUGLAS: Amendment 39-9322. Docket 95-NM-36-AD. \n\n\tApplicability: Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes, as listed in McDonnell Douglas DC-9 Alert Service Bulletin A78-67, dated February 27, 1995, 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 use the authority provided in paragraph (e) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment ofthe effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent uncommanded opening of the thrust reverser door, which may adversely affect controllability of the airplane, accomplish the following: \n\n\t(a)\tWithin 3 months after the effective date of this AD, perform a visual inspection of the actuating mechanisms of the upper and lower doors of the thrust reverser on the left and right engines to determine whether the driver links are chamfered, in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A78-67, dated February 27, 1995. \n\n\t\t(1)\tIf all the driver links are chamfered, prior to further flight, perform a visual inspection to detect damage of the overcenter links (including the bearings, races, and attaching hardware), in accordance with the alert service bulletin. \n\n\t\t\t(i)\tIf no damage to the overcenter links is detected, no further action is required by this paragraph. \n\n\t\t\t(ii)\tIf any damage to the overcenter links is detected, prior to further flight, replace the damaged overcenter links with new or serviceable overcenter links in accordance with the alert service bulletin. \n\n\t\t\t(iii)\tIf any damage to the bearings, races, or attaching hardware of the overcenter links is detected, prior to further flight, perform a visual inspection to detect damage of the drive mechanism of the thrust reverser, in accordance with the alert service bulletin. If any damage to the drive mechanism is detected, prior to further flight, repair or replace the damaged parts with new or serviceable parts, in accordance with the Chapter 78 of the DC-9 Overhaul Manual. \n\n\t\t(2)\tIf any driver link is not chamfered, prior to further flight, remove the driver link and perform dimensional and fluorescent penetrant inspections to determine serviceability of the driver link, in accordance with the alert service bulletin. \n\n\t\t\t(i)\tIf the driver link is serviceable, prior to further flight, machine chamfer the driver link, or replace the driver link with a new or serviceable part, in accordance with the alert service bulletin. \n\n\t\t\t(ii)\tIf the driver link is not serviceable, prior to further flight, replace it with a new or serviceable driver link, in accordance with the alert service bulletin. \n\n\t(b)\tWithin 3 months after the effective date of this AD, perform a visual inspection to detect damage of the overcenter links (including the bearings, races, and attaching hardware, in accordance with the McDonnell Douglas DC-9 Alert Service Bulletin A78-67, dated February 27, 1995. \n\n\t\t(1)\tIf no damage to the overcenter links is detected, no further action is required by this paragraph. \n\n\t\t(2)\tIf any damage to the overcenter links is detected, prior to further flight, replace the damaged overcenter links withnew or serviceable overcenter links in accordance with the alert service bulletin. \n\n\t\t(3)\tIf any damage to the bearings, races, or attaching hardware of the overcenter links is detected, prior to further flight, perform a visual inspection to detect damage of the drive mechanism of the thrust reverser, in accordance with the alert service bulletin. If any damage to the drive mechanism is detected, prior to further flight, repair or replace the damaged parts with new or serviceable parts, in accordance with the Chapter 78 of the DC-9 Overhaul Manual. \n\n\t(c)\tWithin 10 days after accomplishing the visual inspection of the driver links of the thrust reverser door to determine whether the driver links are chamfered, as required by paragraph (a) of this AD, submit a report of the inspection results (both positive and negative findings) to the Manager, FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, California 90712; telephone (310) 627-5245; fax (310) 627-5210; Attention: Robert Baitoo. 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(d)\tAs of the effective date of this AD, no person shall install, on any airplane, a driver link or overcenter link that has not been previously inspected, and replaced or reworked, in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A78-67, dated February 27, 1995. \n\n\t(e)\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(f)\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(g)\tCertain actions shall be done in accordance with McDonnell Douglas DC-9 Alert Service Bulletin A78-67, dated February 27, 1995. 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 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, Los Angeles Aircraft Certification Office, Transport Airplane Directorate, 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(h)\tThis amendment becomes effective on September 5, 1995.

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 Model DC-9 series airplanes and C-9 (military) airplanes was published in the Federal Register on April 17, 1995 (60 FR 19188). That action proposed to require a one-time visual inspection of the driver links of the thrust reverser door to determine whether the driver links are chamfered, and a one-time visual inspection to detect damage of the overcenter links, and follow- on corrective actions, if necessary; and replacement or rework of the driver links. \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\n\tOne commenter requests a revision to the proposal to include an option that would allow deactivation of a thrust reverser in accordance with the Minimum Equipment List (MEL). Additionally, the commenter states that if damage limits are required for driver links or overcenter links that are installed on deactivated thrust reversers, then McDonnell Douglas Alert Service Bulletin A78-67 (that is referenced in the proposal as the appropriate source of service information) should be revised to include those limits. The commenter contends that the revised service bulletin should then be referenced in the final rule as the appropriate source of service information. The commenter states that this suggested change would minimize the impact on scheduled service to the public. \n\n\tThe FAA does not concur. The FAA acknowledges that the MEL permits continued operation of an airplane for up to 10 days with a deactivated thrust reverser. However, the FAA's intent in issuing this AD is to remove all defective driver links from the fleet in a timely manner so as to preclude the potential for any further incidents of uncommanded openings of the thrust reverser door after takeoff.Deactivation of the thrust reverser would essentially extend the compliance time of this AD; the FAA considers such extension to be unacceptable since the affected fleet must be purged of the discrepant part in order to ensure safety. Where there are differences between the MEL and the AD, the AD takes precedence; therefore inspection, and any necessary replacement, must be accomplished by affected operators within 3 months, as required by this AD. \n\n\tFurther, the FAA does not concur with the commenter's request that essentially would delay the issuance of this rule until the manufacturer can release a revised service bulletin containing damage limits for driver links and overcenter links that are installed on deactivated thrust reversers. The FAA does not consider that delaying this action until after the release of a revised service bulletin is warranted or appropriate, since, as explained above, the FAA does not concur with the commenter's request to permit flight with a deactivated thrust reverser. \n\n\tThe same commenter also requests a revision to the proposal to include an alternative to the proposed inspections of the links. The commenter states that if no discrepant parts were received then no inspection should be required. Therefore, the commenter suggests including an alternative to permit operators to check shipping records in lieu of performing the inspections. \n\n\tThe FAA does not concur. Discrepant links have the same part number as those links that have chamfers. Therefore, discrepant links would not be identifiable by checking shipping records. \n\n\tTwo commenters request a revision of the 3-month compliance time proposed in paragraphs (a) and (b). One of these commenters requests that the proposed compliance time be extended to 6 months. The other commenter requests that the inspections be allowed to be accomplished during the time of a normally scheduled "C" check. This commenter states that adoption of a compliance time that coincides with operators' "C" checks would minimize interruptions to the operators' regularly scheduled maintenance. \n\n\tThe FAA does not concur. In developing an appropriate compliance time for this action, the FAA considered not only the degree of urgency associated with addressing the subject unsafe condition, but the practical aspects of accomplishing the inspections within an interval of time that parallels normally scheduled maintenance for the majority of affected operators. \n\n\tThe FAA notes that the driver link and overcenter link assemblies of the thrust reverser are commonly referred to as "driver link and overcenter link." Therefore, for purposes of clarification, paragraph (d) of the final rule has been revised to delete the phrase "assembly of a thrust reverser" following the terms "driver link or overcenter link." \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 determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\n\tThere are approximately 892 airplanes of the affected design in the worldwide fleet. The FAA estimates that 557 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 inspections and 10 work hours per airplane to accomplish the required replacement/rework, and that the average labor rate is $60 per work hour. Required replacement/rework parts will cost approximately $4,100 per airplane. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,651,320, or $4,760 per airplane. \n\n\tThe total 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\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\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.\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: