The FAA proposed to amend 14 CFR part 39 with an AD for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. That action, published in the Federal Register on March 23, 2005 (70 FR 14589), proposed to require doing a one-time high-frequency eddy current inspection and repetitive detailed inspections for cracks in the frame web of main entry door number 1; and repairing the door frame web if necessary. That action also proposed to provide for optional terminating action for the repetitive inspections. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD. \n\nRequest To Include Optional Inspection \n\n\tOne commenter requests that we include an option for Group 3 airplanes in paragraph (f) of the proposed AD to perform an open-hole high-frequency eddy current (HFEC) inspection every 3,000 flight cycles instead of a detailed inspection every 1,500 flight cycles. The commenter states that the manufacturer has found this optional inspection to be structurally acceptable. \n\n\tWe agree with the commenter that performing an HFEC inspection every 3,000 flight cycles would provide an equivalent level of safety as intended by this AD. However, the repetitive detailed inspection requirement is actually specified in paragraph (g) of the proposed AD, not paragraph (f). Therefore, we have revised paragraph (g) of the final rule, for Group 3 airplanes only, to include an option to perform a surface HFEC inspection of the frame web between the upper door sill and door stop number 8 for cracks every 3,000 flight cycles in accordance with the method referenced in Figure 3 or Figure 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin (ASB) 747- 53A2508, dated August 19, 2004. \n\nRequest To Revise Frame Inner Chord Inspection Requirement \n\n\tOne commenter requests that we delete paragraph (j) of the proposed AD or revise it to state that when the frame inner chord is being replaced concurrently with the required frame web repairs, the open- hole HFEC inspection of the frame inner chord is not required. The commenter states that the intent of paragraph (j) should be that when the frame inner chord is being replaced, there is no need to inspect the existing fastener holes in the chord because the chord is a new part. The commenter refers to the applicable Boeing Structural Repair Manual (SRM) and Boeing ASB 747-53A2508 to support this contention. \n\n\tWe agree with this request. Open-hole HFEC inspection of the frame inner chord is a conditional inspection included in the repair procedures specified in paragraph (h) of this AD. However, AD 91-11-01, amendment 39-6997 (dated May 15, 1991), referenced in paragraph (j) of the proposed AD, only requires inspecting the frame inner chord, while AD 90-06-06, amendment 39-6490 (datedMarch 7, 1990), actually requires replacing the frame inner chord. Therefore, we have concluded that paragraph (j) of the proposed AD should have referred to AD 90-06-06, rather than AD 91-11-01, regarding concurrent replacement of the frame inner chord. We have revised paragraph (j) of the final rule to reflect the commenter's request and to correctly refer to AD 90-06-06. Further, to ensure that there is no confusion about the HFEC inspection, we also revised paragraph (h) of the final rule to include a reference to an "open-hole" HFEC inspection. \n\nRequest To Clarify Use of Structural Repair Manual \n\n\tThe same commenter requests that paragraph (h) of the proposed AD be clarified. The commenter asserts that paragraph (h) should be revised to state that the Boeing SRM meets the intent of the proposed AD. Further, the commenter requests that we clarify the statement "For a repair method to be approved, the approval must specifically reference this AD." The commenter feels that paragraph (h) as written might lead to confusion. \n\n\tWe agree with the commenter that the Boeing SRM procedures specified in the service bulletin are appropriate sources of service information for the required repairs. We also agree with the commenter that the statement "For a repair method to be approved, the approval must specifically reference this AD" applies only when the service bulletin advises the operators to contact Boeing for repair procedures, because that statement relates only to damage that is not addressed by the SRM repair procedures. To make it clear that any repair that is done in accordance with the SRM requires no further FAA approval, we have added Note 1 after paragraph (h) of the final rule, which states that the service bulletin "references the Boeing structural repair manual as an additional source of service information to comply with the intent of paragraph (h) this AD." \n\nRelated Rulemaking \n\n\tWe have determined that certain detailed inspections requiredby paragraph (f) of AD 2005-20-30, amendment 39-14327 (70 FR 59252, October 12, 2005), or paragraph (f) of AD 2005-08-01, amendment 39- 14053 (70 FR 18290, April 11, 2005), are considered acceptable for accomplishing the repetitive detailed inspections required for Group 1 and Group 2 airplanes by paragraph (g)(1) of this AD or for Group 3 airplanes by paragraph (g)(2)(i) of this AD. Therefore, to give credit for accomplishing the corresponding actions described in AD 2005-20-30 and AD 2005-08-01, we have retitled and reidentified paragraph (j) as paragraph (j)(1), and inserted new paragraph (j)(2) in the final rule. \n\nExplanation of Editorial Corrections to Proposed AD \n\n\tWe have made certain minor changes to punctuation, spelling and other mechanical elements of the proposed AD. These changes do not affect the technical content of the final rule. \n\nClarification of Alternative Method of Compliance (AMOC) Paragraph \n\n\tWe have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies. \n\nExplanation of Change Made to This AD \n\n\tWe have simplified paragraph (h) of this AD by referring to the "Alternative Methods of Compliance (AMOCs)" paragraph of this AD for repair methods. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comments that have been submitted, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCosts of Compliance \n\n\tThere are about 274 airplanes of the affected design in the worldwide fleet. This AD will affect about 140 airplanes of U.S. registry. The following table, using an estimated labor rate of $65 per work hour, provides the estimated costs for U.S. operators to comply with this AD. \n\n\nAirplanes \nNumber of airplanes \nWork hours \nCost per airplane \nFleet cost \nGroup 1 (left and right side HFEC inspection) \n119 \n2 \n$130 \n$15,470. \nGroup 1 (left and right side detailed inspection) \n119 \n2 \n130, per inspection cycle\n15,470, per inspection cycle. \nGroup 2 (left side HFEC inspection) \n16 \n1 \n65 . \n1,040. \nGroup 2 (left side detailed inspection) \n16 \n1 \n65, per inspection cycle \n1,040, per inspection cycle. \nGroup 3 (left and right side HFEC inspection) \n5 \n2 \n130 \n650. \nGroup 3 (left and right side detailed inspection) \n5 \n2 \n130, per inspection cycle\n650, per inspection cycle. \n\n\nAuthority for This Rulemaking \n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority. \n\n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, "General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\tWe have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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. \n\n\tFor the reasons discussed above, I certify that this AD: \n\n\t(1) Is not a "significant regulatory action" under Executive Order 12866; \n\n\t(2) Isnot a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\n\t(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. \n\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation. \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\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. 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\n2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):