AD 99-21-32

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 series airplanes, that requires a one-time inspection to measure clearance and detect interference between the elevator cable pulley and the shroud frame of the ventral stairway, and modification of the shroud frame of the ventral stairway. This amendment is prompted by reports of pitch oscillation of several Model MD-90-30 series airplanes. The actions specified by this AD are intended to prevent interference between the elevator cable pulley and the shroud frame of the ventral stairway, which could result in pitch oscillation of the airplane, and consequent damage to the elevator cable pulley and reduced controllability of the airplane.

Final rule.

99-21-32 MCDONNELL DOUGLAS: Amendment 39-11378. Docket 98-NM-340-AD. \n\n\tApplicability: Model MD-90-30 series airplanes, as listed in McDonnell Douglas Service Bulletin No. MD90-27-026, dated September 30, 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 (c) 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 interference between the elevator cable pulley and the shroud frame of the ventral stairway, which could result in pitch oscillation of the airplane, and consequent damage to the elevator cable pulley and reduced controllability of the airplane, accomplish the following: \n\nInspection \n\t(a)\tWithin 12 months after the effective date of this AD, perform a one-time general visual inspection to measure clearance and detect interference between the elevator cable pulley and the shroud frame of the ventral stairway in accordance with Phase 1 of McDonnell Douglas Service Bulletin No. MD90-27-026, dated September 30, 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\t(1)\tIf clearance is greater than or equal to 0.5 inch, and if no interference is detected: Within 18 months after performing the inspection, accomplish the requirements of paragraph (b) of this AD. \n\n\t\t(2)\tIf clearance is less than 0.5 inch, or if any interference is detected: Prior to further flight, accomplish the requirements of paragraph (b) of this AD. \n\nModification \n\t(b)\tModify the shroud frame of the ventral stairway in accordance with Phase 2 of McDonnell Douglas Service Bulletin No. MD90-27-026, dated September 30, 1998. \n\nAlternative Methods of Compliance \n\t(c)\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 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\nSpecial Flight Permits \n\t(d)\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\nIncorporation by Reference \n\t(e)\tThe inspection and modification shall be done in accordance with McDonnell Douglas Service Bulletin No. MD90-27-026, dated September 30, 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(f)\tThis amendment becomes effective on November 24, 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 MD-90-30 series airplanes was published in the Federal Register on February 9, 1999 (64 FR 6259). That action proposed to require a one-time inspection to measure clearance and detect interference between the elevator cable pulley and the shroud frame of the ventral stairway, and modification of the shroud frame of the ventral stairway. \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 of the Proposal \n\n\tSeveral commenters support the proposed rule. \n\nRequest to Shorten Compliance Time \n\n\tOne commenter requests that the proposed 12-month compliance time for accomplishment of the inspection specified in paragraph (a) of the proposed AD beshortened to 90 days. The commenter asserts that the proposed compliance time is too long in consideration of the flight critical nature of the unsafe condition. Based on the proposed compliance time, administrative procedure time to publish the final rule, and a possible "delayed" effective date, the commenter states that it could be 3 years or more before an operator must correct this unsafe condition, which is an unacceptable amount of time. \n\n\tThe FAA does not concur. In developing an appropriate compliance time, the FAA considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the inspection. Further, the proposed compliance time was arrived at with operator, manufacturer, and FAA concurrence. In consideration of all of these factors, the FAA determined that the compliance time, as proposed, represents an appropriate interval in which the inspection can be accomplished in a timely manner within the fleet and stillmaintain an adequate level of safety. Operators are always permitted to accomplish the requirements of an AD at a time earlier than that specified as the compliance time; therefore, if an operator elects to accomplish the inspection prior to 12 months after the effective date of this AD, it is that operator's prerogative to do so. If additional data are presented that would justify a shorter compliance time, the FAA may consider further rulemaking on this issue. \n\nRequest to Shorten the Effective Date \n\n\tOne commenter requests that the maximum time from issuance to the effective date be no more than 30 days. The commenter suggests that the proposed compliance time may be unnecessarily extended by adding in the administrative procedures time to publish the final rule in the Federal Register. \n\n\tThe FAA does not concur with the commenter's request. The Administrative Procedure Act (APA) requires that Federal agencies provide at least 30 days after publication of a final rule in the Federal Register before making it effective, unless "good cause" can be found not to do so. Under the APA, the basis for this finding is similar to the basis for a finding of good cause to dispense with notice and comment procedures in issuing rules. In the case of certain AD's, the nature of the action may be of such urgency that for the FAA to take any additional time to provide notice and opportunity for prior public comment would be impracticable; in those cases, the FAA finds good cause for making the rule effective in less than 30 days. In the case of this AD action, however, the FAA did not consider that the addressed unsafe condition was of such a critical nature that time could not be afforded for notice and the opportunity for the public to comment on the rule. It follows then, that there is no basis for finding good cause for making this rule effective in less than 30 days. For domestic final rules following notice, the FAA assigns an effective date of 35 days afterpublication. \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 as proposed with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 58 airplanes of the affected design in the worldwide fleet. The FAA estimates that 58 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 1 work hour per airplane to accomplish the required inspection, at an average labor rate of $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 $3,480, or $60 per airplane. \n\n\tIt will take approximately 2 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $6,960, or $120 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 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\tAirtransportation, 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: