AD 94-17-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-100, -200, -300, and -400 series airplanes, that requires various modifications of certain evacuation ramp/slides. This amendment is prompted by reports of several evacuation ramp/slide malfunctions. The actions specified by this AD are intended to prevent delayed inflation of evacuation ramp/slides, which could delay or impede the evacuation of passengers during an emergency.

Final rule

94-17-09 BOEING: Amendment 39-9004. Docket 93-NM-106-AD.\n \n\tApplicability: Model 747-100, -200, -300, and -400 series airplanes equipped with BFGoodrich evacuation ramp/slides; as listed in BFGoodrich Service Bulletin 7A1418-25-253, dated April 28, 1993, or Revision 2, dated April 15, 1994; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent delayed inflation of evacuation ramp/slides, which could delay or impede the evacuation of passengers during an emergency, accomplish the following: \n\n\t(a)\tWithin 24 months after the effective date of this AD, modify the door 3 offwing evacuation ramp/slide, part number 7A1418-( ), in accordance with the Accomplishment Instructions of BFGoodrich Service Bulletin 7A1418-25-253, dated April 28, 1993; or Revision 2, dated April 15, 1994; as applicable. Accomplishment of the product improvement modifications specified in paragraph 2.G. of the Accomplishment Instructions of the service bulletin is not required by this AD. \n\n\tNOTE 1: Modification of the reservoir assembly (part number 4A3416-1) to the part number 4A3416-3 configuration, as specified in paragraph 2.D.(1) of the service bulletin, is required currently by AD 91-25-02, Amendment 39-8103 (56 FR 63629, December 5, 1991). \n\n\tNOTE 2: BFGoodrich Service Bulletin 7A1418-25-253, Revision 2, dated April 15, 1994, references Boeing Service Bulletin 747-25-3028, dated August 26, 1993, as an additional source of service information for modification of the packboard and girt. \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, 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\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\n\t(d)\tThe modification shall be done in accordance with BFGoodrich Service Bulletin 7A1418-25-253, dated April 28, 1993; or BFGoodrich Service Bulletin 7A1418-25-253, Revision 2, dated April 15, 1994. 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 BFGoodrich Company, Aircraft Evacuation Systems, Sustaining Engineering, D/7916, Phoenix, Arizona 85040. 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(e)\tThis amendment becomes effective on September 21, 1994.

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 747-100, -200, -300, and -400 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on March 15, 1994 (59 FR 11940). That action proposed to require various modifications of certain evacuation ramp/slides. \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 supports the proposed rule. \n\n\tAnother commenter requests that the proposed 24-month compliance time for modification of the ramp/slides be extended to 36 months so that it will coincide with affected operators' scheduled overhauls. The commenter points out that the manufacturer of the subject ramp/slides recommends a compliance time of 36 months. The commenter believes that safety will not be compromised if an extension is allowed. The FAA does not concur with the commenter's request. 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 availability of required parts, the average utilization of the affected fleet, and normal maintenance schedules for timely accomplishment of the modification. The FAA finds that the proposed 24-month compliance time represents the maximum interval of time allowable wherein the modifications can reasonably be accomplished and an acceptable level of safety can be maintained. Further, the FAA took into account the 36-month compliance time recommended by the manufacturer, as well as the number of days required for the rulemaking process; in consideration of these factors, the FAA finds that 24 months after the effective date of this final rule will fall approximately at thesame time for compliance as recommended by the manufacturer. \n\n\tAnother commenter requests that the proposed 24-month compliance time for modification be shortened to 6 months. This commenter believes that a shorter compliance time is necessary for continued safe operation of airplanes equipped with the affected ramp/slides. The FAA does not concur with the commenter's request. As explained above, the FAA considered many factors, including the safety implications, when developing an appropriate compliance time for this AD. After consideration of all the available information, the FAA cannot conclude that a reduction of the proposed compliance time, without prior notice and opportunity for public comment, is warranted. To reduce the compliance time of the AD would necessitate (under the provisions of the Administrative Procedure Act) reissuing the notice, reopening the period for public comment, considering additional comments received, and eventually issuing a final rule; the time required for that process may be as long as four additional months. In comparing the actual compliance date of the final rule after completing such a process to the compliance date of this final rule as issued, the increment in time is minimal. In light of this, and in consideration of the amount of time that has already elapsed since issuance of the original proposal, the FAA has determined that further delay of this final rule action is not appropriate. \n\n\tTwo commenters request that paragraph (a) of the proposed rule be revised to require accomplishment of the modifications specified only in paragraphs 2.C., 2.D.(2), 2.E., and 2.F. of the BFGoodrich service bulletin cited in the AD. The commenters believe that accomplishment of paragraph 2.G. of the service bulletin should be optional, since the modifications included in that paragraph are considered to be product improvements that are not associated with the addressed unsafe condition. One of these commenters, BFGoodrich, states that approximately 40 percent of the slide modification kits were shipped to operators prior to the issuance of the supplemental NPRM, and some operators may not have accomplished the modifications specified in paragraph 2.G. of the service bulletin. The commenter expresses a concern that a requirement to accomplish that paragraph would result in additional costs and unscheduled removal and maintenance actions for operators. \n\n\tThe FAA concurs with the commenters' request, and has revised paragraph (a) of the final rule to specify that accomplishment of the product improvement modifications specified in paragraph 2.G. of the Accomplishment Instructions of the service bulletin is not required by this AD. \n\n\tTwo commenters request that the proposal be revised to cite the latest revision to the BFGoodrich service bulletin specified in the AD and to reference Boeing Service Bulletin 747-25- 3028. The FAA concurs. Since the issuance of the supplemental NPRM, the FAA has reviewed and approved Revision 2 of BFGoodrich Service Bulletin 7A1418-25-253, dated April 15, 1994, which corrects certain typographical errors that appeared in Revision 1 of that service bulletin and references the Boeing service bulletin. The Boeing service bulletin describes procedures for an alternative method of modifying of the packboard and girt. Paragraph (a) of the final rule has been revised to cite the latest revision of the service bulletin as an additional source of service information. Further, "NOTE 2" has been added to paragraph (a) of the final rule to reference Boeing Service Bulletin 747-25-3028 as an additional source of service information for modifying the packboard and girt. \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 1,100 BFGoodrich ramp/slides of the affected design installed on Boeing Model 747-100, -200, -300, and -400 series airplanes in the worldwide fleet. The FAA estimates that 300 of these subject ramp/slides are installed on Boeing Model 747-100, -200, - 300, and -400 series airplanes of U.S. registry that will be affected by this AD. It will take approximately 22 work hours per ramp/slide to accomplish the required actions, at an average labor rate of $55 per work hour. Required parts will be provided by the ramp/slide manufacturer at no cost to operators. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $363,000, or $1,210 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 futureif this AD were not adopted. \n\n\tHowever, the FAA has been advised that 40 percent of the required modification kits have been delivered to airlines having airplanes affected by this AD. From this information, the FAA can assume that 40 percent of the affected fleet already have been modified in accordance with the requirements of this AD. Therefore, the future economic cost impact of this rule on U.S. operators is expected to be 40 percent less than the "total cost impact" figure indicated above. \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\n List 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\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1.\tThe authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. § 39.13 - (Amended) \n\n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: