Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM published in the Federal Register on March 27, 2012 (77 FR 18137). That NPRM proposed to require various repetitive inspections of the MDSCD latch pin fittings, measuring the latch pin, and related investigative and corrective actions if necessary. That NPRM also proposed to require modifying the latch pin fittings and installing new latch pins and latch pin fasteners. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal (77 FR 18137, March 27, 2012) and the FAA's response to each comment. \n\nRequests To Change Applicability \n\n\n\tBoeing and Thai Airways International PCL requested that we limit the applicability of the NPRM (77 FR 18137, March 27, 2012) to airplanes with a Boeing-certified MDSCD instead of airplanes identified in Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011. The commenters requested this change to ensure that airplanes modified in the future to Model 747-400 Boeing Converted Freighter (BCF) with an MDSCD installation are inspected and modified per the intent of Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011. \n\tWe partially agree with changing the applicability. The AD already provides coverage for the future Model 747-400 BCF airplanes with an MDSCD installation. That is, the applicability of the AD specifies Model 747-100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747- 400F, and 747SR series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011. This service information identifies Model 747- 100, 747-200B, 747-200C, 747-200F, 747-300, 747-400, and 747-400F airplanes with an MDSCD installed in production or bya Boeing-approved modification. For clarification, per the Type Certificate Data Sheet (TCDS) for those airplanes, Model 747-400 BCF and 747-400 Special Freighter (SF) airplanes remain as Model 747-400 series airplanes for documentation purposes on the TCDS and with regard to the applicability of ADs. Where Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, specifies ''all'' airplanes, this means past, present, and future airplanes. \n\tHowever, we found that Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, does not currently provide a grace period for airplanes that have been modified with an MDSCD after the initial compliance time of 6 months after the effective date of this AD. Therefore, the initial compliance time specified in paragraph (g) of this AD has been modified to add a grace period for airplanes that are modified with an MDSCD after the effective date of this AD. Additionally, the initial compliance time reference toparagraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011, has been removed from paragraph (g) of this final rule. \n\nRequest To Change Service Information Reference \n\n\n\tBoeing requested that we change the service information reference in paragraphs (g), (h), (i), and (j) of the NPRM (77 FR 18137, March 27, 2012) from Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, \n\n((Page 4048)) \n\n2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011, to Revision 3 of that service information. (Since Revision 3 has not been published, there is no issue date.) Boeing stated that Revision 3 of Boeing Alert Service Bulletin 747- 52A2294 will be a full revision that will ''update the effectivity list of Model 747-400 BCF airplanes,'' and will incorporate changes identified during validation, which was accomplished in March 2012. Boeing stated that Revision 3 of Boeing Alert Service Bulletin 747- 52A2294 will add no new work for airplanes having previously incorporated the actions specified in Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011; or Revision 2, dated December 12, 2011. \n\tWe disagree with referencing Revision 3 of Boeing Alert Service Bulletin 747-52A2294 in this final rule. Boeing has not submitted Revision 3 of Boeing Alert Service Bulletin 747-52A2294 for FAA approval. We consider it inappropriate to delay correcting the identified unsafe condition to wait for this new service information revision. However, after Revision 3 of Boeing Alert Service Bulletin 747-52A2294 is FAA-approved and issued, operators may submit requests for approval of alternative methods of compliance (AMOCs) under the provisions of paragraph (l) of this AD to use Revision 3. We have not changed the final rule in this regard. \n\nRequest To Change Credit for Previous Actions \n\n\n\tBoeing requested that we change paragraph (k) of the NPRM (77 FR 18137, March 27, 2012) to also give credit for actions required by paragraphs (g) and (h) of the NPRM, if those actions were performed before the effective date of the AD using Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011. Boeing stated that this request is related to its request to replace the service information reference in paragraphs (g), (h), (i), and (j) of the NPRM from Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011, to Revision 3 of that service information. \n\tWe partially agree. We agree to provide credit for Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, before its revision by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011. However, since we have not changed the AD to refer to Revision 3 of Boeing Alert Service Bulletin 747-52A2294, we disagree with specifying credit for using Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011. We have changed paragraph (k) of this AD to specify credit for the actions required by paragraphs (g) and (h) of this AD performed before the effective date of this AD using Boeing Alert Service Bulletin 747-52A2294, dated July 8, 2010; or Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, before its revision by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011. \n\nRequest To Change Unsafe Condition Statement \n\n\n\tBoeing requested that we modify the unsafe condition statement in the NPRM (77 FR 18137, March 27, 2012) by removing the reference to brokenlatch pin fittings. Boeing stated that Boeing Alert Service Bulletin 747-52A2294, dated July 8, 2010, was prompted by broken retention bolts and the subsequent migration of the latch pins rather than by the broken latch pin fittings. Boeing also stated that the service information recommends inspecting the latch pin fittings for damage, but that no broken latch pin fittings have been associated with this issue. \n\tWe agree with the commenter's request. We have changed the Summary and paragraph (e) of the AD to state that this AD was prompted by reports of broken and damaged latch pin retention bolts and subsequent migration of the latch pins of the MDSCD. \n\nRequest To Add Federal Aviation Regulation Reference \n\n\n\tBoeing requested that we add a reference to paragraph (b) of section 25.571 of the Federal Aviation Regulations (14 CFR 25.571) to paragraph (l)(3), ''Alternative Methods of Compliance (AMOCs),'' of the NPRM (77 FR 18137, March 27, 2012). Boeing stated that paragraph (b)is the specific paragraph of 14 CFR 25.571, Amendment 45, that requires compliance for the Model 747 airframe beyond the original certification basis. \n\tWe find that clarification is necessary. The reference to section 25.571 of the Federal Aviation Regulations (14 CFR 25.571), Amendment 45, was included inadvertently in paragraph (l)(3) of the NPRM (77 FR 18137, March 27, 2012). Therefore, we have revised paragraph (l)(3) of this final rule to remove the reference to ''14 CFR 25.571, Amendment 45.'' \n\nRequest To Change Compliance Time for Deactivated MDSCDs \n\n\n\tKLM Royal Dutch Airlines (KLM) requested that we add alternative compliance times to the NPRM (77 FR 18137, March 27, 2012) for deactivated MDSCDs. KLM stated that a deactivated MDSCD is much less susceptible to mechanical defects than an activated door. KLM suggested that an initial inspection within 6 months after the effective date of the AD, and a modification as required by paragraph (h) of the NPRM within 48 monthsafter the effective date of the AD, would be sufficient to maintain a safe condition. KLM noted that a similar alternative was made for deactivated main entry doors in paragraph (f) of AD 2007-12-11, Amendment 39-15089 (72 FR 31984, June 11, 2007). \n\tWe agree that a deactivated MDSCD is much less susceptible to mechanical defects than an activated door. We have changed paragraphs (g) and (i) of this AD to reference an exception in new paragraph (j)(3) of this AD, which states that the repetitive inspections required by paragraphs (g) and (i) of this AD are not applicable to a deactivated MDSCD. The initial inspection required by paragraph (g) of this AD and modifications and replacements required by paragraph (h) of this AD are still applicable to a deactivated MDSCD. In addition, when the MDSCD is reactivated, the repetitive inspections required by paragraphs (g) and (i) of this AD are applicable and must be done at intervals not to exceed those specified in paragraph 1.E., ''Compliance,'' of Boeing Alert Service Bulletin 747-52A2294, Revision 1, dated August 16, 2011, as revised by Boeing Alert Service Bulletin 747-52A2294, Revision 2, dated December 12, 2011. \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously and minor editorial changes. We have determined that these minor changes: \n\t(Agr)re consistent with the intent that was proposed in the NPRM (77 FR 18137, March 27, 2012) for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM (77 FR 18137, March 27, 2012). \n\n((Page 4049)) \n\n\n\tWe also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 77 airplanes of U.S. registry. \n\tWe estimate the following coststo comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Detailed inspection, including 4 work-hours x $85 $0 $340 per inspection $26,180 per \n\ttorque check. per hour = $340 cycle. inspection cycle. \n\tper inspection \n\tcycle. Modification..................... 11 work-hours x $85 5,530 $6,465............. $497,805. \n\tper hour = $935. Post-modification detailed 2 work-hours x $85 0 $170 per inspection $13,090 per \n\tinspection. per hour = $170 cycle. inspection cycle. \n\tper inspection \n\tcycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe estimate the following costs to do necessary repairs and replacements that would be required based on the results of the inspection. We have no way of determining the number of aircraft that might need these repairs. \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per \n\tAction Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Repair/replacements (Groups 1 and 2 airplanes) 7 work-hours x $85 per hour = $11,478 $12,073 \n\t$595. Repair/replacements (Group 3 airplanes)....... 7 work-hours x $85 per hour = 12,254 12,849 \n\t$595. ---------------------------------------------------------------------------------------------------------------- \n\nAuthority for This Rulemaking \n\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\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\n\tThis 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\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) 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\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.