AD 99-05-03

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757-200 series airplanes, that requires replacement of the stringer clip(s) with a new stringer clip(s), and modification of the life raft support structure and/or life raft doors, as applicable. This amendment is prompted by a report that certain life raft stowage compartments and certain life raft doors are understrength. The actions specified by this AD are intended to prevent a life raft falling from its stowage compartment, and consequently injuring nearby occupants or delaying or impeding the evacuation of passengers during an emergency landing.

Final rule.

99-05-03 BOEING: Amendment 39-11052. Docket 98-NM-238-AD. \n\n\tApplicability: Model 757-200 series airplanes, as listed in Boeing Service Bulletin 757-25-0180, dated October 9, 1997, 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 (b) 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 a life raft from falling from its stowage compartment, and consequently injuring nearby occupants or delaying or impeding the evacuation of passengers during an emergency landing, accomplish the following: \n\n\t(a)\tWithin 18 months after the effective date of this AD, replace the stringer clip(s) with a new stringer clip(s), and modify the life raft support structure and/or life raft door, as applicable, in accordance with Boeing Service Bulletin 757-25-0180, dated October 9, 1997. \nAlternative Methods of Compliance \n\n\t(b)\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, Seattle Aircraft Certfication 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, Seattle 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 Seattle ACO. \n\nSpecial Flight Permits \n\n\t(c)\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\n\t(d)\tThe replacement and modification shall be done in accordance with Boeing Service Bulletin 757-25-0180, dated October 9, 1997. 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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\n\t(e) This amendment becomes effective on April 5, 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 Boeing Model 757-200 series airplanes was published in the Federal Register on December 17, 1998 (63 FR 69569). That action proposed to require replacement of the stringer clip(s) with a new stringer clip(s), and modification of the life raft support structure and/or life raft doors, as applicable. \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 five comments received. \n\tThree commenters support the proposed rule. Two commenters indicate that they are not affected by the proposed rule. \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.Cost Impact \n\n\tThere are approximately 256 airplanes of the affected design in the worldwide fleet. The FAA estimates that 139 airplanes of U.S. registry will be affected by this AD. \n\n\tFor Groups 1 and 2 airplanes (as specified in the service bulletin), it will take approximately 32 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $4,544 (for Group 1 airplanes) or $4,801 (for Group 2 airplanes) per airplane. Based on these figures, the cost impact of the actions required by this AD on U.S. operators of Groups 1 and 2 airplanes is estimated to be $6,464 (for Group 1 airplanes), or $6,721 (for Group 2 airplanes) per airplane. \n\n\tFor Groups 3 and 4 airplanes, it will take approximately 30 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $3,668 (for Group 3 airplanes) or $3,530 (for Group 4 airplanes) per airplane. Based on these figures, the cost impact of the actions required by this AD on U.S. operators of Groups 3 and 4 airplanes is estimated to be $5,468 (for Group 3 airplanes), or $5,330 (for Group 4 airplanes) per airplane. \n\n\tFor Group 5 airplanes, it will take approximately 6 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $680 per airplane. Based on these figures, the cost impact of the actions required by this AD on this group of U.S. operators is estimated to be $1,040 per airplane. \n\n\tFor Group 6 airplanes, it will take approximately 20 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $2,785 per airplane. Based on these figures, the cost impact of the actions required by this AD on this group of U.S. operators is estimated to be $3,985 per airplane.For Group 7 airplanes, it will take approximately 13 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $1,019 per airplane. Based on these figures, the cost impact of the actions required by this AD on this group of U.S. operators is estimated to be $1,799 per airplane. \n\n\tFor Group 8 airplanes, it will take approximately 15 work hours per airplane to accomplish the required actions, at an average labor rate of $60 per work hour. Required parts will cost approximately $2,187 per airplane. Based on these figures, the cost impact of the actions required by this AD on this group of U.S. operators is estimated to be $3,087 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\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \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\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: