Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to the specified products. The NPRM published in the Federal Register on April 11, 2013 (78 FR 21571). The NPRM proposed to require removing the cargo liner support; cleaning the aft MEC drip shield gutter; and doing a one-time general visual inspection for disbonded seams, and repair if necessary. The NPRM also proposed to require installing a fiberglass reinforcement overcoat to the top surface of the aft MEC drip shield gutters and installing the cargo liner support. \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 (78 FR 21571, April 11, 2013) and the FAA's response to each comment. \n\nRequest To Clarify Area for Installing Fiberglass Reinforcement Overcoat \n\n\n\tUnited Airlines (UAL), British Airways (BAB), and Boeing askedthat the area for installing the fiberglass reinforcement overcoat, as specified in paragraph (g)(2) of the NPRM (78 FR 21571, April 11, 2013), be changed for clarification. Boeing stated that the description of the area is not accurate. UAL stated that the location for installing the fiberglass reinforcement overcoat ''to the top surface'' of the aft main equipment center (MEC) drip shield gutters, as specified in paragraph (g)(2) of the NPRM, is different than the area specified in Boeing Alert Service Bulletin 747-25A3613, dated June 22, 2012. UAL noted that the referenced service information specifies installing the fiberglass reinforcement overcoat ''to the underside surface'' of the aft MEC drip shield gutters. BAB stated that Figure 4, Sheets 2 and 3 of Boeing Alert Service Bulletin 747-25A3613, dated June 22, 2012, show the installation from underneath the aft MEC drip shield gutter; and added that Figure 4, Step 3, Note (c) specifies to ''Install the prepared BMS 9-3 fiberglass impregnated fabric to the underside of the bonded seams.'' \n\tWe agree with the commenters' requests to clarify the location for installing the fiberglass reinforcement overcoat. Figure 4, Sheets 2 and 3 of Boeing Alert Service Bulletin 747-25A3613, dated June 22, 2012, provide clarity. Therefore, we have changed the SUMMARY section and paragraph (g)(2) of this final rule to specify the location in Figure 4, Step 3, Note (c) for installation of the fiberglass reinforcement overcoat to ''the underside of the bonded seams.'' \n\nRequest To Clarify the Unsafe Condition \n\n\n\tBoeing asked that we clarify the second sentence of the reason for the unsafe condition, as specified in the SUMMARY section and paragraph (e) of the NPRM (78 FR 21571, April 11, 2013), from ''The water flowed from the drip shield through disbonded floor seams into the aft . . .'' to ''The water flowed from the main deck floor panels, through disbonded seams in the aft . . ..'' Boeing stated that, as specified, the description is not accurate based on reports received from operators. \n\tWe agree with the commenter's request for the reason provided. We have clarified the reason for the unsafe condition in the SUMMARY section and paragraph (e) of this final rule accordingly. \n\nRequest To Add a Note Allowing Different Access for Different Structural Configurations \n\n\n\tUAL asked that we include a note specifying that accessing certain areas to accomplish the actions proposed in the NPRM (78 FR 21571, April 11, 2013) may vary due to configuration differences. UAL stated that including such a note would save operators a lot of time dealing with variances in the quantity of fasteners called out in the service information versus those on the airplane. UAL noted that for AD 2012- 15-10, Amendment 39-17139 (77 FR 46943, August 7, 2012), regarding the MEC drip shield, it already has six alternative methods of compliance (AMOCs) due to these variances. \n\tWe agree with the commenter's request. BoeingAlert Service Bulletin 747-25A3613, dated June 22, 2012, does not identify all possible structural configurations of the affected airplanes when gaining access to the repair area. The resulting AMOC requests and review of those requests creates a high volume of work and time, which impacts both operators and the FAA. These deviations do not directly impact the specified corrective actions. \n\tWe have changed the language in the SUMMARY and Costs of Compliance sections, as well as paragraphs (g)(1) and (g)(2) of this final rule, to remove the reference to the cargo liner support. We have also added a sentence to the introductory text of paragraph (g) of this AD to specify that accomplishing paragraphs 3.B.1. and 3.B.4. of the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 25A3613, dated June 22, 2012, is optional. \n\nRequest To Ground All Affected Airplanes \n\n\n\tOne anonymous commenter reiterated the actions proposed by the NPRM (78 FR 21571, April 11, 2013), and stated that he found it troubling that we are asking the public ''(presumably experts)'' to comment on a safety issue with a Boeing design, yet these airplanes have not been grounded until the notice and comment period ends. The commenter added that The Boeing Company must comply with strict FAA guidelines, as outlined by the Federal Aviation Act of 1958 (49 U.S.C. App. 1301 et seq.). The commenter noted that, crucial to this particular airworthiness directive, the FAA encourages the development of ''next wave'' civil aeronautics, new aviation technology, and continued safety enhancements of all domestically flown commercial airplanes. The commenter also added that participation in the notice and comment period is in line with the FAA's mission. The commenter concluded that Congress charges the FAA with promoting safe flight of civil airplanes in air commerce by prescribing regulations for practices, methods, and procedures. \n\tWe infer that the commenter finds we lack sufficient information to determine a compliance time for correcting this unsafe condition before receiving public comment. We also infer the commenter concluded that affected airplanes are exposed to an unacceptably high risk requiring immediate action to remove \n\n((Page 79291)) \n\nthem from service until more information is obtained through public comments. We do not agree. Before posting an NPRM for public comment, we must perform an investigative review of the subject concern or unsafe condition first obtained from operator reports. After gathering this information from operators and the manufacturer, we make a determination on the associated risk of the unsafe condition and coordinate with the manufacturer on a compliance time and corrective action for all affected airplanes. Airplanes are grounded in rare cases where it is determined that the unsafe condition has an immediate risk to public safety. The unsafe condition in this AD does not meet these criteria. \n\tAdditionally, agencies welcomeand consider all relevant rulemaking comments received from the public. The purpose of public participation is more to obtain comments from interested parties, not necessarily ''experts'' in the aviation industry. This is in line with the democratic, legal, and management principles behind good government and effective rulemaking. Further information on these principles can be found on the Internet at http://www.regulations.gov, under ''docs/ Factsheet--Public--Comments--Make--a--Difference.pdf.'' We have made no change to this final rule in this regard. \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 this AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 79 airplanes of U.S. registry. \n\tWe estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Clean gutter, inspect................. 1 work-hour x $85 per $0 $85 $6,715 \n\thour = $85. Install fiberglass reinforcement...... 1 work-hour x $85 per 100 185 14,615 \n\thour = $85. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tWe have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD. \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 betweenthe 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.