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, 747-100B, 747-100B SUD, 747-200B, 747-200F, 747-300, 747SP, and 747SR series airplanes was published in the Federal Register on January 2, 2002 (67 FR 38). That action proposed to require one-time inspections for cracking in certain upper deck floor beams and follow-on actions. \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\nSupportive Comment \n\n\tOne commenter agrees with the proposed rule. \n\nRequest To Withdraw Proposed Rule \n\n\tOne commenter is concerned with the continuing trend to issue Airworthiness Directives (ADs) that overlap or are in close proximity to other ADs, based on isolated reports of minor structural cracks. The commenter provided the AD numbers for ADs that require inspections and repair of the same structure specified in this proposed rule. The commenter notes that the Boeing 747 Maintenance Program requires visual inspections of the upper deck floor beam of the fuselage frame interface, in addition to those inspections required by the previously issued ADs. The commenter adds that the few reports of upper chord cracking of the floor beam can be adequately detected by the maintenance program inspections before an unsafe condition could develop. \n\n\tAlthough the commenter does not make any specific request, the FAA infers that the commenter wants to withdraw the proposed rule. We acknowledge that Boeing Model 747 series airplanes have an extensive service life and that numerous inspections have been performed as part of the FAA-approved 747 maintenance program. (All operators are required to maintain their airplanes in accordance with an FAA-approved maintenance program as required for continued airworthiness.)However, we find that the subject inspections in the maintenance program do not adequately address certain in-service difficulties and thus do not adequately address the identified unsafe condition. Additionally, we do not agree that the cited ADs already require inspections and repair of the same structure specified in this final rule. Therefore, the FAA has determined that the proposed rule is appropriate and warranted. \n\nExclude Certain Flight Cycles \n\n\tOne commenter states that the service bulletin referenced in the proposed rule specifies the exclusion of flight cycles with a cabin pressure differential of 2.0 pounds per square inch (psi) or less. The commenter asks that this exclusion be added to the final rule. \n\n\tWe agree with the commenter in that this exclusion is specified in the referenced service bulletin. Paragraph (a) of this final rule has been changed to exclude flight cycles with a cabin pressure differential of 2.0 psi or less, as stated above. \n\nReduce Applicability \n\n\tOne commenter asks that all references to Boeing Model 747-200F series airplanes be deleted from the proposed rule. The commenter states that the service bulletin referenced in the proposed rule adds the same inspection of the upper deck floor beams required by AD 98-09-17 for Model 747-200F series airplanes. \n\n\tWe agree with the commenter. AD 98-09-17, amendment 39-10498 (63 FR 20311, April 24, 1998), is applicable to Boeing Model 747-200F and -200C series airplanes. That AD requires repetitive inspections or a one-time inspection to detect cracking of certain areas of the upper deck floor beams; and corrective actions, if necessary. Therefore, we have deleted all references to Model 747-200F from this final rule. \n\nAllow Permanent Repairs Specified in Service Information \n\n\tOne commenter states that paragraph (c) of the proposed rule would require repair of any crack found during the proposed inspections either by a temporary repair, per the referenced service bulletin, or by accomplishing an approved permanent repair. The commenter adds that Note 3 of the proposed rule states that the referenced service bulletin does not contain instructions for permanent repairs; however, page 29 of the service bulletin does contain permanent repair instructions. The commenter notes that paragraph (c)(2) of the proposed rule should be changed to allow permanent repairs to be done per the service bulletin. \n\n\tWe agree with the commenter that the referenced service bulletin does contain permanent repair instructions for floor beam web, strap, and frame cracks, but not upper chord cracks. Therefore, paragraph (c)(2) of this final rule has been changed to specify repair according to the service bulletin, unless the service bulletin specifies contacting the manufacturer. Also, Note 3 has been removed from this final rule and subsequent notes have been renumbered accordingly. \n\nChange Certain Wording \n\n\tOne commenter asks that the wording specified in paragraphs (c)(1)(i), (c)(1)(ii), and (d) of the proposed rule be changed. The commenter states that the words "temporary repair" should be changed to "time-limited repair." The commenter notes that, since a time-limited repair must be replaced with a permanent repair within 18 months or 1,500 flight cycles, this change would ensure that a permanent repair would be installed before the modification is done. The commenter adds that the word "repair" specified in paragraph (d) of the proposed rule should be changed to "permanent repair." \n\n\tWe agree with the commenter. The term "time-limited" repair should be used instead of "temporary" repair, for clarity. We also agree that the post-modification inspection threshold should begin after installation of a permanent repair. Paragraphs (c)(1)(i), (c)(1)(ii), and (d) of this final rule have been changed accordingly. \n\nChange Cost Impact \n\n\tOne commenter asks that the Cost Impact section of the proposed rule be changed. The commenter states that it will take 8 work hours to accomplish the initial inspections, but an additional 22 work hours to gain access and close up in order to accomplish the inspections. The commenter adds that the 24 work hours necessary to accomplish the modification are in addition to the hours for the inspections, and for gaining access and close up. \n\n\tWe do not agree to change the work hours for the initial inspections. The number of work hours necessary to accomplish the inspections, specified as 8 in the cost impact information, is consistent with the service bulletin. This number represents the time necessary to perform only the inspections actually required by this AD. The FAA recognizes that, in accomplishing the requirements of any AD, operators may incur "incidental" costs in addition to the "direct" costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. \n\n\tWe agree that adding the words "in addition to the inspection" to the 24 work hours for the modification will provide clarification. The cost impact section has been changed accordingly. \n\nChange Paragraph (d) of the Proposed Rule \n\n\tOne commenter asks that paragraph (d) of the proposed rule be changed. The commenter reiterates the requirements in paragraph (d) of the proposed rule and suggests alternatives to that paragraph as follows: 1. Issue the proposed rule only after the referenced service bulletin is revised to include post-modification/repair instructions; 2. Specifically define the inspection requirements and include them in paragraph (d); or 3. Omit paragraph (d) from the proposed rule, and, if necessary, issue a revised or new AD after the service bulletin has been revised. \n\n\tWe do not agree with the commenter.Alternative 1. would delay issuance of the proposed rule, which would not address the unsafe condition in a timely manner. At this time, we do not have the necessary data to incorporate alternative 2. When the manufacturer revises its service bulletin to include post-modification inspections, we can consider approving it as an alternative method of compliance (AMOC) to the final rule. Regarding alternative 3., we have determined that post-modification inspections should be addressed in this final rule; therefore, paragraph (d) of this final rule will not be omitted. \n\nReference Revised Service Information \n\n\tOne commenter asks that the FAA reference the revised service bulletin that will be issued later, rather than the current issue referenced in the proposed rule. The commenter states that there are inconsistencies and minor errors in the referenced service bulletin. \n\n\tWhile we acknowledge the commenter's statements about the accuracy of certain wording in the accomplishmentinstructions of the service bulletin, we do not concur with the request to reference a service bulletin that has not yet been issued or reviewed and approved by us. The airplane manufacturer is aware of the discrepancies in the service bulletin instructions and may issue a revision of the service bulletin in the future. However, considering the criticality of the unsafe condition noted previously, we find it would be inappropriate to delay the issuance of this AD until a revised service bulletin is available. No change to the final rule is necessary in this regard. \n\nChange Certain Sections in the Preamble \n\n\tOne commenter asks that the sentence in the Summary section of the proposed rule be changed from "This action is intended to address the identified unsafe condition," to "This action is intended to address the identified potential unsafe condition." The commenter also asks that the sentence be changed in the Explanation of Requirements of Proposed Rule section. The commenter states that while a severed upper chord of the upper floor beam would pose an unsafe condition, a chord that has not cracked, but at some time may crack, poses a "potential" unsafe condition. \n\n\tWe acknowledge but do not agree with the commenter's request. The sentence in the Summary section specifies that the action is intended to address the identified unsafe condition. The final rule is necessary to find and fix cracking in certain upper deck floor beams, which is not a "potential" unsafe condition. Additionally, the Explanation of Requirements of Proposed Rule section is not restated in this final rule. No change to the final rule is necessary in this regard. \n\nReduce Compliance Time \n\n\tOne commenter asks that the compliance time specified in paragraph (a)(1) of the proposed rule be reduced. The commenter states that paragraph (a)(1) of the proposed rule specifies the inspection of airplanes with 22,000 flight cycles or less be accomplished within 1,500 flight cycles after theeffective date of the AD. The commenter notes that the inspection could occur as late as 23,500 flight cycles and adds that paragraph (a)(2) of the proposed rule requires that the inspections be accomplished on airplanes with more than 22,000 flight cycles within 500 flight cycles. The commenter suggests that paragraph (a)(1) of the proposed rule be changed to require the inspection of airplanes within 22,000 flight cycles or less to be accomplished within 1,500 flight cycles after the effective date of the AD, but no later than 22,500 flight cycles. \n\n\tWe do not agree with the commenter. The commenter provides no data to justify its statement that the proposed compliance time should be changed in the manner suggested. In developing an appropriate compliance time for this AD, we considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessaryto perform the inspections. We find that the compliance time required by paragraph (a)(1) of the final rule is an appropriate interval for affected airplanes to continue to operate without compromising safety. No change to the final rule is necessary in this regard. \n\nAllow Operators To Change Method of Inspection \n\n\tOne commenter (the airplane manufacturer) asks that, to avoid confusion, the instructions specified in paragraph (d) of the proposed rule should be changed to allow for operators to change the method of inspection. The commenter suggests that, instead of "Repeat the inspection within * * *" as specified in paragraphs (d)(1) and (d)(2) of the proposed rule, the wording be changed to "Conduct the next inspection within * * *" The commenter states that this wording seems to imply that the operator must continue with the same inspection method. \n\n\tWe do not agree with the commenter that the wording specified in paragraph (d) of the final rule obligates the operator to continue using the same inspection method. However, if the commenter needs further clarification, the clarification can be made in a future revision to the service bulletin. The FAA may then consider approving the bulletin as an AMOC to the final rule. No change to the final rule is necessary in this regard. \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 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\nCost Impact \n\n\tThere are approximately 539 airplanes of the affected design in the worldwide fleet. The FAA estimates that 168 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 8 work hours per airplane to accomplish the initial inspections, at the average labor rate of $60 perwork hour. Based on these figures, the cost impact of these required inspections on U.S. operators is estimated to be $80,640, or $480 per airplane. \n\n\tIt will take approximately 24 work hours per airplane to accomplish the modification or permanent repair, in addition to the inspection, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the required modification or repair on U.S. operators is estimated to be $241,920 or $1,440 per airplane. \n\n\tIt will take approximately 8 work hours per airplane to accomplish the post-modification/repair inspections, at the average labor rate of $60 per work hour. Based on these figures, the cost impact of the required post-modification/repair inspections on U.S. operators is estimated to be $80,640 or $480 per airplane, per inspection cycle. \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. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132. \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. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amendedby adding the following new airworthiness directive: