Discussion \n\n\n\tThe FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain serial-numbered Textron Aviation Inc. (Textron) (type certificate previously held by Cessna Aircraft Company) Model 172N, 172P, 172Q, 172RG, F172N, F172P, FR172K, R172K, 182E, \n\n((Page 63196)) \n\n182F, 182G, 182H, 182J, 182K, 182L, 182M, 182N, 182P, 182Q, 182R, T182, F182P, F182Q, FR182, R182, TR182, 206, P206, P206A, P206B, P206C, P206D, P206E, TP206A, TP206B, TP206C, TP206D, TP206E, U206, U206A, U206B, U206C, U206D, U206E, U206F, U206G, TU206A, TU206B, TU206C, TU206D, TU206E, TU206F, TU206G, 207, 207A, T207, T207A, 210-5 (205), 210-5A (205A), 210B, 210C, 210D, 210E, 210F, and T210F airplanes. The SNPRM published in the Federal Register on May 29, 2020 (85 FR 32308). \n\tThe FAA preceded the SNPRM with a notice of proposed rulemaking (NPRM) that published in the Federal Register on February 1, 2018 (83 FR 4605). The NPRM was prompted by reports of cracks in the lower area of the forward cabin doorpost bulkhead on more than four dozen Textron 100 and 200 airplanes. The NPRM proposed to require repetitively inspecting the lower area of the forward cabin doorposts at the strut attach fitting for cracks and repairing any cracks found by modifying the area with the applicable service kit. The SNPRM proposed to modify the estimated costs of the proposed AD, the repetitive inspection intervals, and the credit allowed for previous actions; clarify the inspection instructions for airplanes with the service kit installed; correct the contact information for obtaining the service information; and add a reporting requirement to collect the inspection results. The SNPRM also changed some of the model designations listed in the applicability in order to match the models as they are listed in the type certificate data sheet. \n\tThe FAA is issuing this AD to detect and address cracking of the wingstrut attach point. The unsafe condition, if not addressed, could result in failure of the wing in operation, which could result in loss of control of the airplane. \n\nComments \n\n\n\tThe FAA gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the SNPRM and the FAA's response to each comment. \n\nSupport for the SNPRM \n\n\n\tPatrick Imperatrice expressed support for the proposed AD. \n\nRequest To Extend or Remove Calendar Compliance Time \n\n\n\tKermit Bunde expressed support for the 1,000-hour time-in-service (TIS) inspection interval but requested the FAA remove the 36-month calendar time inspection interval. The commenter stated that the 36- month interval is too often and that cracking is a function of usage and not only elapsed time. The commenter provided examples of Cessna maintenance actions that have no calendar time limit. \n\tThe FAA disagrees. Both the manufacturer's guidance, which is published in the supplemental inspection documents (SIDs) for certain airplanes, and fleet history support the 36-month interval for inspecting this location. Loading conditions outside of flight, such as ground loads, handling loads, and tie down loads, may also cause cracking at this location. Therefore, the FAA determined the inspection interval of 36 calendar months or 1,000 hours TIS, whichever occurs first, is necessary to address the unsafe condition. The FAA did not change this AD based on this comment. \n\nConclusion \n\n\n\tThe FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Cessna Single Engine Service Bulletin SEB93-5, Revision 2, dated May 29, 2019 (SEB93-5R2) and Cessna Single Engine Service Bulletin SEB95-19, dated December 29, 1995 (SEB95-19). For the applicable model airplanes, the service information contains procedures for repetitively inspecting the lower area of the forward cabin doorposts for cracks and repairing any cracks found by modifying the area with the applicable Cessna service kit. \n\tThis service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. \n\nOther Related Service Information \n\n\n\tThe FAA reviewed Cessna Single Engine Service Kit SK172-147, dated December 29, 1995. This service kit provides instructions to add a channel to each forward cabin doorpost bulkhead. The FAA also reviewed Cessna Single Engine Service Kit SK182-115, dated December 29, 1995; Cessna Single Engine Service Kit SK206-42D, dated May 29, 2019; and Cessna Single Engine Service Kit SK210-156, dated December 29, 1995. For the applicable model airplanes, these service kits provide instructions to add a doubler and a channel to each forward cabin doorpost bulkhead. In addition, the FAA reviewed Cessna Single Engine Service Kit SK207-19A, dated May 29, 2019. The service information contains procedures to reinforce the lower forward doorpost bulkhead and wing strut fitting by adding a doubler and a channel to each forward cabin doorpost bulkhead. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 14,653 airplanes of U.S. registry. \n\tThe FAA estimates 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 ---------------------------------------------------------------------------------------------------------------- Inspect the lower area of the 1.5 work-hours x $85 Not applicable....... $127.50 $1,868,257.50 \n\tforward cabin doorposts for per hour= $127.50. \n\tcracks. Reporting requirement............. 1 work-hour x $85 per Not applicable....... 85 1,245,505 \n\thour = $85. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tThe FAA estimates the following costs to do any necessary repairs that would be required based on the results of the inspection. Reference the applicable Cessna single engine service bulletin for kit applicability. The FAA has no way of determining the number of airplanes that might need this repair. \n\n((Page 63197)) \n\n\n\n\n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per \n\tAction Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Install Cessna Single-Engine Service Kit SK172- 36 work-hours x $85 per hour = $3,415 $6,475 \n\t147. $3,060. Install Cessna Single-Engine Service Kit SK182- 36 work-hours x $85 per hour = 7,490 10,550 \n\t115. $3,060. Install Cessna Single-Engine Service Kit SK206- 36 work-hours x $85 per hour = 3,115 6,175 \n\t42D. $3,060. Install Cessna Single-Engine Service Kit SK207- 36 work-hours x $85 per hour = 4,957 8,017 \n\t19A. $3,060. Install Cessna Single-Engine Service Kit SK210- 36 work-hours x $85 per hour = 7,020 10,080 \n\t156. $3,060. ---------------------------------------------------------------------------------------------------------------- \n\nPaperwork Reduction Act \n\n\n\tA federal agency may not conduct orsponsor, and a person is not required to respond to, nor shall a person be subject to penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB control number. The control number for the collection of information required by this AD is 2120- 0056. Public reporting for this collection of information is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524. \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\tThe FAA is 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 havea 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) Will not affect intrastate aviation in Alaska, and \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\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.