Discussion \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 777 airplanes. The NPRM published in the Federal Register on December 26, 2018 (83 FR 66178). The NPRM was prompted by reports of uncommanded fore/aft movements of the Captain's and First Officer's seats. The NPRM proposed to require an identification of the part number, and if applicable the serial number, of the Captain's and First Officer's seats, and applicable on-condition actions for affected seats. \n\tThe FAA is issuing this AD to address uncommanded fore/aft movement of the Captain's and First Officer's seats. An uncommanded fore/aft seat movement during a critical part of a flight, such as takeoff or landing, could cause a flight control obstruction or unintended flight control input, which could result in the loss of the ability to control 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 NPRM and the FAA's response to each comment. \n\nSupport for the NPRM \n\n\n\tAir Line Pilots Association, International (ALPA), supported the intent of the NPRM. FedEx had no objection to the NPRM. United Airlines agreed with the NPRM. \n\nRequest for Clarification of Service Information \n\n\n\tUnited Airlines asked for clarification regarding what is considered a finding for the determination of Condition 3 (no findings) in Boeing Special Attention Service Bulletin 777-25-0619, Revision 1, dated August 8, 2018 (''BSASB 777-25-0619, Revision 1''). The commenter wanted to know that if the horizontal actuator is found to have part number (P/N) AD8650502 or AD8650503 at Amendment A or Amendment B, is that considered a finding for the determination of Condition 3 (no findings). \n\tThe FAA agrees to provide clarification regarding Condition 3 in BSASB 777-25-0619, Revision 1. According to BSASB 777-25-0619, Revision 1, following the procedures in Part 3 of the Accomplishment Instructions can result in Condition 3 (no findings) or Condition 4 (any findings). If the horizontal actuator is found to have P/N AD8650502 or AD8650503 at Amendment A or Amendment B it is considered a finding \n\n((Page 45896)) \n\nand meets Condition 4 of BSASB 777-25-0619, Revision 1. If the horizontal actuator is found to have a part number other than P/N AD8650502 or AD8650503 at Amendment A or Amendment B, it is consider a no finding and meets Condition 3 of BSASB 777-25-0619, Revision 1. The FAA has not revised this AD in regard to this issue. \n\nRequest for Clarification Regarding Removal of the Nameplate \n\n\n\tAir New Zealand asked if the work instructions in Part 3.B. of Ipeco Service Bulletin 258-25-14, Issue 4, dated January 29, 2018 (''Ipeco SB 258-25-14, Issue 4'') are compliant with the regulations because the instructions are to remove the original nameplate,which would appear to also be the data plate. Air New Zealand stated that because the data plate should only be created and installed by the original equipment manufacturer these instructions appear to create a bogus part. \n\tThe FAA infers the commenter is referring to 14 CFR 21.616, which requires the holder of a technical standard order (TSO) to mark each TSO article in accordance with 14 CFR part 45. FAA Advisory Circular AC 21-25B, Section 8.2.4, provides an acceptable means of compliance for marking modified seating systems. \n\n\n\tSeat modifications accomplished under (14 CFR) part 43 or under the applicable airworthiness regulations must mark the modified article with sufficient data to identify that it has been modified. This may be accomplished by providing a reference to a design approval (e.g., STC number), the modifier's name and address, or reference to other documentation describing the modification. If the modifier cannot substantiate that the article continues to meetthe applicable TSO(s), the modifier must permanently obliterate the TSO marking while retaining all other identifying data. \n\n\n\tIn this case, since the modifier has no access to the substantiation information, he or she cannot substantiate that the article continues to meet the requirements of the applicable TSO. However, the seat has been modified with a design approval (i.e., Ipeco SB 258-25-14, Issue 4) mandated by this AD. Therefore, the instructions provided by the Ipeco SB 258-25-14, Issue 4, are appropriate and do not conflict with FAA regulations or guidance. The FAA has not revised this AD in regard to this issue. \n\nRequest To Revise Estimated Costs \n\n\n\tMartha Viner requested that the estimated costs in the NPRM be revised to include statistical evidence from the harms of the defective parts. The commenter stated that the NPRM does not address the psychological costs of the unsafe condition including, but not limited to, injuries sustained from the defective parts andhow many individuals have been harmed as a result. The commenter did not provide justification for her request. The FAA does not agree with the commenter's request. Because the scope of FAA ADs are limited and technical in nature, the FAA can only provide the actual known costs (labor and materials) for compliance with the requirements of the AD. The FAA has not revised this AD in regard to this issue. \n\nRequest To Revise Estimated Part Costs \n\n\n\tBoeing requested that the parts cost for the replacement of the horizontal actuator be changed from $205 to $7,936.79. The commenter stated that the part manufacturer, Ipeco, provided the parts cost via email. \n\tThe FAA agrees with the commenter's request because Boeing has confirmed the part cost with Ipeco, the part supplier. The FAA has revised the Costs of Compliance section of this final rule accordingly. \n\nRequest To Revise ''Uncommanded Movement'' Wording \n\n\n\tBoeing requested that in all places where ''uncommanded movement''is used in the NPRM that the wording be changed to ''uncommanded horizontal movement.'' The commenter stated that the Captain's and First Officer's seats have both horizontal and vertical powered movement and the service information specified in the proposed AD addresses only the horizontal movement. \n\tThe FAA agrees with the commenter's observation that Captain's and First Officer's seats have both horizontal and vertical powered movement. The FAA does not agree with the commenter's request to change the wording to ''uncommanded horizontal movement'' because ''horizontal movement'' could also mean movement anywhere in the horizontal plane of the airplane on which the seat is installed. The FAA has revised this final rule to replace all instance of the term ''uncommanded movement'' with ''uncommanded fore/aft movement.'' \n\nRequest To Revise Applicability \n\n\n\tGary Chan asked if the FAA is planning to revise the applicability of the proposed AD to include Model 747 airplanes. Thecommenter noted that Ipeco seat part number 3A258 is rotable between Model 747 and Model 777 airplanes. The commenter also pointed out that Boeing has released service information for Model 747 airplanes to address flight deck seat issues. \n\tThe FAA does not agree with the commenter's request to revise the applicability of this AD. The FAA has already issued an NPRM (84 FR 13840, April 8, 2019) to address the identified unsafe condition and parts rotability concern for Boeing Company Model 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747-8F, and 747-8 series airplanes. The FAA has not revised this AD in regard to this issue. \n\nRequest To Extend Compliance Time \n\n\n\tAir New Zealand expressed concern that replacement parts for the horizontal actuator would not be available in time for operators to comply with the 36-month compliance time specified in the proposed AD. The commenter noted that replacing the horizontal actuator with Artus P/N AD8650503 at Amendment C or later was terminating action for the repetitive checks of the horizontal movement system. The commenter stated it contacted Ipeco regarding pricing and parts availability and was advised that there is a 7-month lead time for the parts. The commenter related that Ipeco may not be able to meet the demand for parts when the AD is released. \n\tThe FAA infers that the commenter is requesting the compliance time be extended due to a perceived parts availability issue. The FAA does not agree with the commenter's request. The 36-month compliance time for the required actions was determined taking into consideration the urgency associated with the subject unsafe condition as well as the availability of required parts. The FAA notes that the commenter is considering parts availability for an optional terminating action, which can be done at any time, and does not have to be done within 36 months after the effective date of this AD. However, the FAA will consider requests for approval ofan extension of the compliance time if sufficient data are submitted to substantiate that the new compliance time would provide an acceptable level of safety. The operator can submit a request for an alternative means of compliance (AMOC) using the provisions in paragraph (k) of this AD. The FAA has not revised this AD in regard to this issue. \n\nRequest To Includes Records Review \n\n\n\tDelta Air Lines requested that paragraph (g) of the proposed AD include a provision to allow operators to do a records review to determine which airplanes have the affected seat part numbers installed. The commenter also \n\n((Page 45897)) \n\nrequested that paragraph (h) of the proposed AD be revised to include the statements ''. . . do an inspection to determine the part number, and serial number as applicable, of the Captain's and First Officer's seats . . .'' and ''A review of the airplane maintenance records may be used for the seat inspection if the part number can be conclusively determined from that review.'' \n\tThe commenter stated that the requested changes are in agreement with the language found in BSASB 777-25-0619, Revision 1, which allows maintenance records to be used to determine the part number of the actuator; and the NOTE following step 3.B.2. of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 777-25-0607, Revision 1, dated July 17, 2018 (''BSASB 777-25-0607, Revision 1''). The commenter stated these added statements would provide an equivalent level of safety for operators that do have affected components installed on airplanes affected by this AD but listed outside of the effectivity specified in the Boeing service information. \n\tThe FAA agrees with the commenters' statement that a records review will provide an acceptable means for operators to identify the part numbers of the Captain's and First Officer's seats installed on an airplane. As noted by the commenter, the service information already allows a record review. For clarity, in paragraph (g) of this AD where we specify to do an inspection, the FAA has included the following statement: ''A review of airplane maintenance records is acceptable in lieu of this inspection if the part number and serial number of the Captain's and First Officer's seats can be conclusively determined from that review.'' \n\tHowever, paragraph (h) of this AD has not been revised. While paragraph (g) of this AD requires an inspection to determine the part number and serial number, as applicable, of the Captain's and First Officer's seats, paragraph (h) of this AD specifies accomplishing applicable actions in accordance with the service information, which includes both inspection and records review language. The records review provided in the service information referenced in pargraph (h) of this AD is applicable to all airplanes identified in the applicability of this AD. Therefore, a statement clarifying that a records review is acceptable in lieu of an inspection is not necessary for paragraph (h) of this AD. \n\nRequest To Clarify Procedures in Certain Service Information \n\n\n\tLufthansa stated that it is not possible for its mechanics to do the maintenance log review that is included in Part A, paragraph 1.c., of the Accomplishment Instructions of Ipeco SB 258-25-14, Issue 4. \n\tThe FAA infers that the commenter is requesting that we clarify the procedures in Ipeco SB 258-25-14, Issue 4. Operators only need to do a review of the maintenance logs if the maintenance logs are available. If maintenance logs are not available then operators do the actions in Part A, paragraph 1.b., of Ipeco SB 258-25-14, Issue 4. Also, Part A, paragraph 1.b. and paragraph 1.c. of the Accomplishment Instructions of Ipeco SB 258-25-14, Issue 4, direct maintenance personnel to do the actions in Part E of the Accomplishment Instructions if the horizontal actuator has P/N AD8650503 at Amendment A or Amendment B. The FAA has not revised this AD in regard to this issue. \n\nRequest ToRequire Alternative Actions \n\n\n\tLufthansa remarked that Boeing Special Attention Service Bulletin 777-25-0619, Revision 1, does not include procedures that provide a permanent and acceptable level of safety. The commenter stated that it would have expected a redesign of the horizontal shaft actuator (including the shaft), which would be required to withstand and limit the maximum loads to the horizontal output shaft, and would prevent shafts from failure at any phase of seat operation. The commenter stated that the repetitive inspections would not be effective because shaft failures could occur at any time between inspections. \n\tThe commenter recommended that a more effective solution would be a crew procedure (e.g., a pre-flight inspection of the seat tracks). Furthermore the commenter stated that it would have expected a termination action for modified/compliant airplanes, for example required maintenance documentation amendments. The commenter asked if any maintenance planningdocument item is being prepared that would require repetitive checks for the part number of the horizontal actuator. \n\tThe FAA infers that the commenter is requesting that we require alternative actions to address the unsafe condition than what is proposed in the NPRM. The FAA does not agree with the commenter's request. The FAA has identified the unsafe condition in this final rule as uncommanded fore/aft movement of the Captain's and First Officer's seats. The FAA has determined that the actions required by this AD adequately address the identified unsafe condition, and that the creation of a maintenance planning document item or other service information is not needed. In addition, the FAA notes that a terminating action is detailed in paragraph (j) of this AD. Paragraph (j) of this AD states ''Installation of a serviceable Captain's or First Officer's seat as specified in, and in accordance with, the Accomplishment Instructions of BSASB 777-25-0619, Revision 1, terminates the repetitive checks required by paragraph (h) of this AD for that seat only.'' \n\tA serviceable Captain's or First Officer's seat is defined in Paragraph 3.A of BSASB 777-25-0619, Revision 1. The horizontal actuator with Artus P/N AD8650503 at Amendment C or later is the redesigned horizontal actuator that is designed to withstand the required limit loads. Additionally, according to the BSASB 777-25-0619, Revision 1, in the case that the horizontal actuator part number is not AD8650503 at Amendment C or later, upon inspection and before further flight, the operator has the option to install a power deactivated seat in lieu of the terminating action or until such a time that the horizontal actuator can be serviced in accordance with the appropriate service information. The FAA has not revised this AD in regard to this issue. However, under the provisions of paragraph (k) of this AD, the FAA will consider requests for approval of alternative actions if sufficient data are submitted to substantiate that alternative actions provide an acceptable level of safety. \n\tRegarding the commenter's statement that shaft failures could occur at any time, the FAA infers that the commenter is referring to the 36- month compliance time and the chance that a shaft failure might occur during this time. The FAA notes that in developing an appropriate compliance time, the FAA considered the urgency associated with the subject unsafe condition, the availability of required parts, and the practical aspect of accomplishing the required actions within a period of time that corresponds to the normal scheduled maintenance for most affected operators. In consideration of all of these factors, the FAA has determined that the compliance time, as proposed, represents an appropriate interval. The FAA further notes that the repetitive checks required by this AD adequately address the unsafe condition, though operators also have the option of installing a serviceable seat to terminate \n\n((Page 45898))those repetitive checks, as specified in paragraph (j) of this AD. \n\nRequest To Provide Credit for Previous Actions \n\n\n\tAmerican Airlines requested that a provision be included in the proposed AD to allow operators to receive credit for actions completed prior to the effective date using the procedures in Boeing Special Attention Service Bulletin 777-25-0607, dated January 9, 2014. \n\tThe FAA does not agree with the commenter's request. This AD requires operators to use BSASB 777-25-0607, Revision 1, because it includes seat part numbers that were not included in Boeing Special Attention Service Bulletin 777-25-0607, dated January 9, 2014. The Ipeco service information was revised in support of BSASB 777-25-0607, Revision 1, by updating information included in the Accomplishment Instructions. The FAA has not revised this AD in regard to this issue. \n\nConclusion \n\n\n\tThe FAA reviewed the relevant data, considered the comments received, and determined that air safety and thepublic interest require adopting this final rule with the changes described previously and minor editorial changes. The FAA has determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tThe FAA also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Boeing Special Attention Service Bulletin 777-25- 0607, Revision 1, dated July 17, 2018 (''BSASB 777-25-0607, Revision 1''). The service information describes procedures for identification of the part number, and if applicable the serial number, of the Captain's and First Officer's seats, and for applicable on-condition actions for affected seats. The on-condition actions include an inspection of each seat's fore/aftand vertical manual control levers for looseness, installation of serviceable seats, and a seat functional test after any cable adjustment. \n\tThe FAA also reviewed Boeing Special Attention Service Bulletin 777-25-0619, Revision 1, dated August 8, 2018 (''BSASB 777-25-0619, Revision 1''). The service information describes procedures for a detailed inspection and repetitive checks of the horizontal movement system for the Captain's and First Officer's seats for findings (e.g., evidence of cracks, scores, corrosion, dents, deformation or visible wear; and incorrectly assembled microswitch assemblies, actuators, and limit switches), and applicable on-condition actions. The on-condition actions include clearing the seat tracks of foreign object debris (FOD), overhaul of the horizontal movement system and replacement of the horizontal actuator. The service information also describes procedures for an optional terminating action for the repetitive checks by installing a serviceable Captain'sor First Officer's seat. \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\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 190 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs for Required Actions per Seat -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tAction Labor cost Parts cost Cost per product Cost on U.S. operators -------------------------------------------------------------------------------------------------------------------------------------------------------- Identification, seat............ 1 work-hour x $85 $0 $85..................................... $16,150.per hour = $85. Detailed inspection, horizontal 1 work-hour x $85 0 $85..................................... $16,150. \n\tmovement system. per hour = $85. Checks, horizontal movement 2 work-hour x $85 0 $170 per check cycle.................... $32,300 per check cycle. \n\tsystem. per hour = $170 \n\tper check cycle. -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\n\n\tThe FAA estimates the following costs to do any necessary on- condition actions that would be required. The FAA has no way of determining the number of aircraft that might need these on-condition actions: \n\n\n\tEstimated Costs of On-Condition Actions per Seat * -------------------------------------------------------------------------------------------------------------------------------------------------------- \n\tActionLabor cost Parts cost Cost per product -------------------------------------------------------------------------------------------------------------------------------------------------------- Adjustment, control lever cable....... 1 work-hour x $85 per $0........................................ $85. \n\thour = $85. Overhaul, horizontal movement system.. 11 work-hours x $85 per Up to $5,824.............................. Up to $6,759. \n\thour = $935. Inspection of each seat's fore/aft and 1 work-hour x $85 per $0........................................ $85. \n\tvertical manual control levers. hour = $85. Installation of serviceable seats..... 1 work-hour x $85 per $0........................................ $85. \n\thour = $85. Clearing FOD.......................... 1 work-hour x $85 per $0........................................ $85. \n\thour = $85. Replacement of the horizontal actuator1 work-hour x $85 per $7,937 per actuator....................... $8,022 per actuator. \n\thour = $85, per \n\tactuator. Functional test, adjusted control 1 work-hour x $85 per $0........................................ $85. \n\tlever cable. hour = $85. -------------------------------------------------------------------------------------------------------------------------------------------------------- \n* The estimated cost for tooling to align an affected seat for adjustment of the control lever cable is up to $46,064.\n\n\n\n\tThe FAA has received no definitive data that would enable the agency to provide cost estimates for the optional terminating action for the repetitive checks 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 \n\n((Page 45899)) \n\nrules 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\tThis AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes and associated appliances to the Director of the System Oversight Division. \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) 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.