Unknown. Final special conditions; amendment

4,277 words·~19 min read·/register/2025/05/23/2025-09414·

A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

--- schema: federal-register doc_type: fedreg source_file: FR-2025-05-23.xml --- 90 99 Friday, May 23, 2025 Contents Agriculture Agriculture Department See Forest Service NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals, 22056-22057 2025-09250 2025-09252 Army Army Department NOTICES Requests for Nominations: Advisory Committee on Arlington National Cemetery, 22068-22069 2025-09348 Census Bureau Census Bureau NOTICES Agency Information Collection Activities;

Proposals, Submissions, and Approvals: Current Population Survey, School Enrollment Supplement, 22059-22060 2025-09265 Civil Rights Civil Rights Commission NOTICES Hearings, Meetings, Proceedings, etc.: Ohio Advisory Committee, 22058-22059 2025-09308 Wyoming Advisory Committee, 22059 2025-09309 Commerce Commerce Department See Census Bureau See International Trade Administration See National Oceanic and Atmospheric Administration See Patent and Trademark Office Committee for Purchase Committee for Purchase From People Who Are Blind or Severely Disabled NOTICES Procurement List;

Additions and Deletions, 22064-22066 2025-09314 2025-09315 Consumer Product Consumer Product Safety Commission NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: National Electronic Injury Surveillance System and Follow-up Activities for Product Related Injuries, 22066-22068 2025-09251 Defense Department Defense Department See Army Department NOTICES Arms Sales, 22069-22077 2025-09345 2025-09346 2025-09347 2025-09350 Non-Foreign Overseas Per Diem Rates, 22077-22080 2025-09317 Election Election Assistance Commission NOTICES Technical Guidelines Development Committee;

Vacancy, 22080 2025-09336 Energy Department Energy Department See Federal Energy Regulatory Commission NOTICES Change in Control: Louisiana LNG Infrastructure LLC, 22082-22083 2025-09289 Importation or Exportation of Liquified Natural Gas or Electric Energy; Applications, Authorizations, etc.: NFE Altamira FLNG, S. de R.L. de C.V., 22080-22082 2025-09291 Environmental Protection Environmental Protection Agency RULES Final Authorization of State Hazardous Waste Management Program:

Alabama, 22016-22021 2025-09302 Mississippi, 22013-22016 2025-09304 PROPOSED RULES Air Quality State Implementation Plans; Approvals and Promulgations: Oregon; Lane Regional Air Protection Agency, Outdoor Burning, 22051-22054 2025-09324 Texas and Oklahoma; Texas Regional Haze Plans for the First and Second Implementation Periods and Five-Year Progress Report; Oklahoma Regional Haze Plan for the First Implementation Period, 22166-22198 2025-09293 Vermont; Regional Haze State Implementation Plan for the Second Implementation Period, 22033-22051 2025-09274 Final Authorization of State Hazardous Waste Management Program:

Alabama, 22055 2025-09301 Mississippi, 22054-22055 2025-09303 NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Contractor Conflicts of Interest, 22087-22088 2025-09276 Contractor Cumulative Claim and Reconciliation Renewal, 22093-22094 2025-09275 Cross-State Air Pollution Rule and Texas SO2 Trading Programs, 22091-22092 2025-09300 Hazardous Remediation Waste Management Requirements Contaminated Media, 22088 2025-09298 National Emission Standards for Hazardous Air Pollutants for Pesticide Active Ingredient Production, 22092-22093 2025-09292 NOx SIP Call, 22089-22090 2025-09299 Approved State Primacy Program for the State of California, 22088-22089 2025-09273 Environmental Impact Statements;

Availability, etc., 22093 2025-09311 Revision of Approved State Primacy Program for the State of Hawaii, 22090-22091 2025-09277 Export Import Export-Import Bank NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Application for Credit Guarantee Facility and Long-Term Direct Loan or Guarantee, 22094 2025-09322 Report of Premiums Payable for Financial Institutions Only, 22094-22095 2025-09323 Federal Aviation Federal Aviation Administration RULES Special Conditions:

The Boeing Company Model 777-9 Airplane; Operation Without Normal Electrical Power, 22005-22007 2025-09414 Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures; Miscellaneous Amendments, 22007-22012 2025-09283 2025-09284 PROPOSED RULES Airspace Designations and Reporting Points: Nantucket, MA, 22031-22033 2025-09285 Airworthiness Directives: Airbus Helicopters, 22028-22031 2025-09095 NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals:

Infrastructure Investment and Jobs Act Competitive Grant Project Information, 22151-22152 2025-09248 Pilot Certification Unmanned Aircraft Systems, 22146 2025-09268 Operating Limitations: Newark Liberty International Airport, Interim Order Establishing Targeted Scheduling Limits, 22147-22150 2025-09376 Petition for Exemption; Summary: Brunner Aerospace LLC, 22150-22151 2025-09286 Helicopter Wildlife Services, 22145 2025-09287 Muskox Ministries, 22145-22146 2025-09307 Northeast Unmanned Aviation Research Alliance, 22146-22147 2025-09312 Federal Communications Federal Communications Commission RULES FM Terrestrial Digital Audio Broadcasting Systems, 22021-22023 2025-09278 NOTICES Hearings, Meetings, Proceedings, etc.:

Communications Security, Reliability, and Interoperability Council, 22095 2025-09280 Federal Deposit Federal Deposit Insurance Corporation NOTICES Meetings; Sunshine Act, 22095 2025-09384 Federal Election Federal Election Commission NOTICES Meetings; Sunshine Act, 22095-22096 2025-09415 Federal Energy Federal Energy Regulatory Commission NOTICES Combined Filings, 22083-22087 2025-09332 2025-09333 Designation of Commission Staff as Non-Decisional: American Efficient, LLC, Modern Energy Group LLC, MIH LLC et al., 22083 2025-09326 Environmental Assessments;

Availability, etc.: Distrigas of Massachusetts LLC, Bog Compressor Project, 22085 2025-09330 Licenses; Exemptions, Applications, Amendments, etc.: PacifiCorp, 22084-22085 2025-09327 Federal Highway Federal Highway Administration NOTICES Environmental Impact Statements; Availability, etc.: Virginia, 22152-22156 2025-09288 Federal Railroad Federal Railroad Administration NOTICES Petition for Waiver of Compliance, 22156-22157 2025-09282 Federal Reserve Federal Reserve System NOTICES Change in Bank Control:

Acquisitions of Shares of a Bank or Bank Holding Company, 22096 2025-09344 Proposals to Engage in or to Acquire Companies Engaged in Permissible Nonbanking Activities; Correction, 22096 2025-09342 Financial Crimes Financial Crimes Enforcement Network NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Reports of Transactions with Foreign Financial Agencies, 22157-22163 2025-09310 Forest Forest Service NOTICES Hearings, Meetings, Proceedings, etc.:

Flathead Resource Advisory Committee, 22057-22058 2025-07052 Geological Geological Survey NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Comprehensive Test Ban Treaty, 22109-22110 2025-09249 Health and Human Health and Human Services Department See Health Resources and Services Administration See National Institutes of Health Health Resources Health Resources and Services Administration NOTICES Emergency Medical Services for Children Innovation and Improvement Center, 22096-22097 2025-09294 National Vaccine Injury Compensation Program:

List of Petitions Received, 22097-22099 2025-09295 Homeland Homeland Security Department See U.S. Customs and Border Protection Interior Interior Department See Geological Survey See Land Management Bureau See Office of Natural Resources Revenue Internal Revenue Internal Revenue Service NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Disclosure of Returns and Return Information to Designee of Taxpayer, 22163 2025-09263 International Trade Adm International Trade Administration NOTICES Antidumping or Countervailing Duty Investigations, Orders, or Reviews:

Welded Stainless Steel Pressure Pipe from the Socialist Republic of Vietnam, 22060-22062 2025-09319 International Trade Com International Trade Commission NOTICES Investigations; Determinations, Modifications, and Rulings, etc.: Certain Balloon Dilation Devices, Systems, and Components Thereof, 22116-22117 2025-09340 Nonfat Milk Solids; Competitive Conditions for the United States and Major Foreign Suppliers, 22113-22115 2025-09339 Refined Brown Aluminum Oxide from China, 22113 2025-09355 Steel Threaded Rod from China, 22115-22116 2025-09354 Labor Department Labor Department NOTICES Agency Information Collection Activities;

Proposals, Submissions, and Approvals: Main Fan Operation and Inspection (I-A, II-A, III, and V-A Mines), 22117-22118 2025-09269 Marine Terminal Operations and Longshoring Standards, 22117 2025-09358 Land Land Management Bureau NOTICES Plats of Survey: New Mexico, 22110 2025-09306 Wyoming, 22110-22111 2025-09359 National Institute National Institutes of Health NOTICES Hearings, Meetings, Proceedings, etc.: Center for Scientific Review, 22099-22102 2025-09267 2025-09271 2025-09272 National Heart, Lung, And Blood Institute, 22100 2025-09270 National Oceanic National Oceanic and Atmospheric Administration RULES International Fisheries:

Pacific Tuna Fisheries; Fishing Restrictions for Tropical Tuna in the Eastern Pacific Ocean for 2025 and Beyond, 22023-22027 2025-09281 NOTICES Hearings, Meetings, Proceedings, etc.: Mid-Atlantic Fishery Management Council, 22062-22063 2025-09262 Permits; Applications, Issuances, etc.: Endangered and Threatened Species; File No. 24016, 22062 2025-09325 Marine Mammals; File No. 28931, 22063 2025-09296 Nuclear Regulatory Nuclear Regulatory Commission NOTICES Meetings; Sunshine Act, 22118 2025-09423 Permits;

Applications, Issuances, etc.: Long Mott Energy, LLC; Long Mott Generating Station, 22118-22119 2025-07730 Natural Resources Office of Natural Resources Revenue NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals: Indian Oil and Gas Valuation, 22111-22112 2025-09266 Patent Patent and Trademark Office NOTICES Agency Information Collection Activities; Proposals, Submissions, and Approvals, 22063-22064 2025-09357 Personnel Personnel Management Office PROPOSED RULES Improving Performance, Accountability and Responsiveness in the Civil Service, 22028 2025-09356 Postal Regulatory Postal Regulatory Commission NOTICES New Postal Products, 22119-22120 2025-09335 Postal Service Postal Service RULES Domestic Mail Manual;

Incorporation by Reference, 22012-22013 2025-09351 International Mail Manual; Incorporation by Reference, 22012 2025-09353 Securities Securities and Exchange Commission NOTICES Application: Global X Venture Fund, et al., 22130 2025-09264 Consolidated Tape Association: Consolidated Tape Association Plan and Restated Consolidated Quotation Plan, 22128-22130 2025-09260 Joint Industry Plan: Collection, Consolidation and Dissemination of Quotation and Transaction Information for Nasdaq-Listed Securities Traded on Exchanges on an Unlisted Trading Privileges Basis, 22140-22141 2025-09261 Self-Regulatory Organizations;

Proposed Rule Changes: Cboe BZX Exchange, Inc., 22127-22128, 22130-22131, 22139-22142 2025-09253 2025-09254 2025-09255 2025-09256 2025-09258 NYSE Arca, Inc., 22120-22127, 22132-22139 2025-09257 2025-09259 Small Business Small Business Administration NOTICES Disaster Declaration: Illinois, 22142-22143 2025-09329 Surrender of License of Small Business Investment Company: High Street Capital IV SBIC, LP, 22143 2025-09331 Surface Transportation Surface Transportation Board NOTICES Acquisition of Control:

ISQ Bus BIDCO, Inc. et al.; A and S Transportation Inc. et al., 22143-22144 2025-09334 Transportation Department Transportation Department See Federal Aviation Administration See Federal Highway Administration See Federal Railroad Administration Treasury Treasury Department See Financial Crimes Enforcement Network See Internal Revenue Service Customs U.S. Customs and Border Protection NOTICES Final Determination: Biomedix Selec-3 Multiple Drop Intravenous Product, 22102-22105 2025-09320 Meeting Tables, 22105-22107 2025-09318 Platform Software, 22107-22109 2025-09321 Veteran Affairs Veterans Affairs Department NOTICES Agency Information Collection Activities;

Proposals, Submissions, and Approvals: Program of Comprehensive Assistance for Family Caregivers Decision Appeal Form, 22163-22164 2025-09328 Separate Parts In This Issue Part II Environmental Protection Agency, 22166-22198 2025-09293 Reader Aids Consult the Reader Aids section at the end of this issue for phone numbers, online resources, finding aids, and notice of recently enacted public laws. To subscribe to the Federal Register Table of Contents electronic mailing list, go to https://public.govdelivery.com/accounts/USGPOOFR/subscriber/new, enter your e-mail address, then follow the instructions to join, leave, or manage your subscription. 90 99 Friday, May 23, 2025 Rules and Regulations DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 25 [Docket No.

FAA-2021-0894; Special Conditions No. 25-791A-SC] Special Conditions: The Boeing Company Model 777-9 Airplane; Operation Without Normal Electrical Power AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final special conditions; amendment. SUMMARY: These special conditions are issued for the Boeing Company (Boeing) Model 777-9 series airplane. This airplane will have a novel or unusual design feature when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes.

This design feature is electrical and electronic systems that perform critical functions, the loss of which could be catastrophic to the airplane. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for this design feature. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. DATES:

Effective June 23, 2025. FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, Electrical Systems, AIR-626A, Technical Policy Branch, Policy and Standards Division, Aircraft Certification Service, Federal Aviation Administration, 2200 South 216th Street, Des Moines, Washington 98198; telephone 206-231-3160; email; *nazih.khaouly@faa.gov.* SUPPLEMENTARY INFORMATION: Background On September 30, 2018, Boeing applied for an amendment to Type Certificate No. T00001SE to include the new Model 777-9 series airplane.

The Boeing Model 777-9 airplane, which is a derivative of the Boeing Model 777 airplane currently approved under Type Certificate No. T00001SE, is a twin-engine, transport category airplane with seating for 495 passengers, and a maximum takeoff weight of 775,000 lbs. On September 29, 2021, special conditions (No. 25-791-SC) were issued for this design feature and became effective on October 4, 2021 (86 FR 54588, Oct. 4, 2021). Type Certification Basis Under the provisions of title 14, Code of Federal Regulations (14 CFR) 21.101, Boeing must show that the Model 777-9 series airplane meets the applicable provisions of the regulations listed in Type Certificate No.

T00001SE, or the applicable regulations in effect on the date of application for the change, except for earlier amendments as agreed upon by the FAA. If the Administrator finds that the applicable airworthiness regulations ( *e.g.,* 14 CFR part 25) do not contain adequate or appropriate safety standards for the Boeing Model 777-9 series airplane because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16. Special conditions are initially applicable to the model for which they are issued.

Should the type certificate for that model be amended later to include any other model that incorporates the same novel or unusual design feature, or should any other model already included on the same type certificate be modified to incorporate the same novel or unusual design feature, these special conditions would also apply to the other model under § 21.101. In addition to the applicable airworthiness regulations and special conditions, the Boeing Model 777-9 series airplane must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the noise-certification requirements of 14 CFR part 36.

The FAA issues special conditions, as defined in 14 CFR 11.19, in accordance with § 11.38, and they become part of the type certification basis under § 21.101. Novel or Unusual Design Features The Boeing Model 777-9 series airplane will incorporate the following novel or unusual design feature: Electrical and electronic systems that perform critical functions, the loss of which may result in loss of flight controls and other critical systems and may be catastrophic to the airplane.

Discussion The Boeing Model 777-9 series airplane has a fly-by-wire flight control system that requires a continuous source of electrical power in order to maintain an operable flight control system. Section 25.1351(d), “Operation without normal electrical power,” requires safe operation in visual flight rule

(VFR)conditions for at least 5 minutes after the loss of normal electrical power excluding the battery. This rule is structured around a traditional design using mechanical control cables and linkages for flight control. These manual controls allow the crew to maintain aerodynamic control of the airplane for an indefinite period of time after loss of all electrical power. Under these conditions, a mechanical flight control system provides the crew with the ability to fly the airplane while attempting to identify the cause of the electrical failure, restart engine(s) if necessary, and attempt to re-establish some of the electrical power generation capability. A critical assumption in § 25.1351(d) is that the airplane is in VFR conditions at the time of the failure. This is not a valid assumption in today's airline operating environment where airplanes fly much of the time in instrument meteorological conditions

(IMC)on air traffic control defined flight paths. Another assumption in the existing rule is that the loss of all normal electrical power is the result of the loss of all engines. The 5-minute period in the rule is to allow at least one engine to be restarted following an all-engine power loss in order to continue the flight to a safe landing. However, service experience on airplane models with similar electrical power system architecture as the Boeing Model 777-9 airplane has shown that at least the temporary loss of all electrical power for causes other than all-engine failure is not extremely improbable. To maintain the same level of safety envisioned by the existing rule with traditional mechanical flight controls, the Boeing Model 777-9 series airplane design must not be time-limited in its operation under all reasonably foreseeable conditions, including loss of all normal sources of engine or auxiliary power unit (APU)-generated electrical power. Unless Boeing can show that the non-restorable loss of the engine and APU power sources is extremely improbable, Boeing must demonstrate that the airplanes can maintain safe flight and landing (including steering and braking on the ground for airplanes using steer/brake-by-wire and/or fly-by-wire speed brake panels) with the use of its emergency/alternate electrical power systems. These electrical power systems, or the minimum restorable electrical power sources, must be able to power loads that are essential for continued safe flight and landing, including those required for the maximum length of approved flight diversion. The FAA is amending two paragraphs from the original special conditions. Those paragraphs are (d)(2) and (e)(4). Paragraph (d)(2) of the original special conditions states that the operating limitations section of the airplane flight manual

(AFM)must incorporate non-normal procedures that direct the pilot to take appropriate actions to activate the APU after loss of normal engine-driven generated electrical power. The FAA is requiring that these non-normal procedures be incorporated in the AFM instead of requiring them to be in the operating limitations section of the AFM. Paragraph (e)(4) of the original special conditions states that the airplane must provide adequate indication of loss of normal electrical power to direct the pilot to the non-normal procedures, and the operating limitations section of the AFM must incorporate non-normal procedures that will direct the pilot to take appropriate actions. As in paragraph (d)(2), the FAA is requiring that these non-normal procedures be incorporated in the AFM instead of specifying the particular section of the AFM that these procedures need to reside. These are to remedy an oversight that occurred during the issuance of the original special conditions where the FAA inadvertently required the non-normal procedures to be in the limitations section of the AFM. The FAA found that this requirement is inconsistent with similarly issued special conditions for other transport category airplanes. The Boeing 777-9 electrical power system does not require pilot activation of the APU after loss of normal engine-driven generated electrical power. Paragraph

(d)does not apply to designs that do not rely on the APU for an alternate source of power. The intent of paragraphs (d)(2) and (e)(4) is to ensure that non-normal procedures that provide instructions to the pilot to take appropriate action are incorporated into the AFM. These procedures are more appropriate for the operating procedures section of the AFM and were not intended to be an operating limitation. The special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing airworthiness standards. Discussion of Comments To provide the public with an opportunity to comment on this amendment, the FAA issued Notice of Proposed Special Conditions No. 25-791-SC for the Boeing Company Model 777-9 series airplane, which was published in the **Federal Register** on August 2, 2024 (89 FR 63111). The FAA received responses from two commenters. An individual requested that the FAA not issue this amendment, stating that the company should not receive special treatment. The FAA's special conditions process is established by regulation and is available to all applicants. FAA made no change as a result of this comment. The Air Line Pilots Association

(ALPA)commented that after reviewing the FAA's proposal to change two paragraphs of this special condition, ALPA does not support design features which increase the psychological and workload burden on flightcrew to recover the supply of the electrical generation and distribution system to the aircraft through manual activation of the APU, in addition to the required multiple start attempt to the engines. The FAA does not agree that the special conditions, as now amended, require design features that would increase the psychological and workload burden on the flightcrew in order to recover the supply electrical generation and distribution system to the aircraft. Special conditions are issued by the FAA when a proposed aircraft, aircraft engine, or propeller incorporates a design feature that is novel or unusual, *i.e.,* it was not envisaged by the existing design regulations. Aircraft were originally designed using mechanical cables and linkages to control flight surfaces. Modern aircraft use fly-by-wire designs to incorporate enhanced flight envelope protections to increase safety over the earlier mechanical flight control designs. The FAA's generally-applicable design standard for operation of transport airplanes that lack electrical power, 14 CFR 25.1351, envisaged mechanical flight control systems, therefore the FAA issues special conditions to address modern fly-by-wire aircraft designs. Boeing 777-9 Special Conditions No. 25-791-SC, as originally issued, includes procedures for pilot manual activation of the APU after loss of normal engine-driven generated electrical power. This procedure is performed by the pilot, while the flight controls are operating on battery power to ensure APU electrical power is available for the flight controls until engine-driven electrical power is restored. Therefore, these revised special conditions do not change the flightcrew burden but instead remove the prior requirement that the procedure be in the Limitations section of the airplane flight manual (AFM). Activation of the APU after loss of normal engine-driven generated electrical power is a non-normal pilot procedure, which is properly in the procedures rather than limitations section. Therefore, this amendment only changes the location in the AFM for this procedure from the Limitations section to the Non-Normal section and removes the requirement for the procedure to be in the Limitation section. The FAA has also restored the statement that these special conditions are in lieu of 14 CFR 25.1351(d); this statement was inadvertently left out of the notice but was part of the original special conditions. The special conditions are adopted as proposed with the edit as mentioned above. Applicability As discussed above, these special conditions, as amended, are applicable to the model for which they are issued. Should the type certificate for that model be amended later to include any other model that incorporates the same novel or unusual design feature, or should any other model already included on the same type certificate be modified to incorporate the same novel or unusual design feature, these special conditions would apply to the other model as well. Conclusion This action affects only a certain novel or unusual design feature on one model series of airplane. It is not a rule of general applicability. List of Subjects in 14 CFR Part 25 Aircraft, Aviation safety, Reporting and recordkeeping requirements. Authority Citation The authority citation for these special conditions is as follows: Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 44704. The Special Conditions Accordingly, the Federal Aviation Administration

(FAA)issues the following special conditions, as amended, as part of the type certification basis for The Boeing Company Model 777-9 series airplanes. In lieu of 14 CFR 25.1351(d), the following special conditions apply:

(a)The applicant must show by test or a combination of test and analysis that the airplane is capable of continued safe flight and landing with all normal electrical power sources inoperative, as prescribed by paragraphs (a)(1) and (a)(2), below. For purposes of these special conditions, normal sources of electrical power generation do not include any alternate power sources such as the battery, ram air turbine, or independent power systems such as the flight control permanent magnet generating system. In showing capability for continued safe flight and landing, the applicant must account for systems capability, effects on crew workload and operating conditions, and the physiological needs of the flightcrew and passengers for the longest diversion time for which the applicant is seeking approval.

(1)In showing compliance with this requirement, the applicant must account for common-cause failures, cascading failures, and zonal physical threats.

(2)The applicant may consider the ability to restore operation of portions of the electrical power generation and distribution system if it can be shown that unrecoverable loss of those portions of the system is extremely improbable. The design must provide an alternative source of electrical power for the time required to restore the minimum electrical power generation capability required for safe flight and landing. The applicant may exclude unrecoverable loss of all engines when showing compliance with this requirement.

(b)Regardless of any electrical generation and distribution system recovery capability shown under paragraph

(a)of these special conditions, sufficient electrical system capability must be provided to:

(1)Allow time to descend, with all engines inoperative, at the speed that provides the best glide distance, from the maximum operating altitude to the top of the engine restart envelope; and

(2)Subsequently allow multiple start attempts of the engines and auxiliary power unit (APU). The design must provide this capability in addition to the electrical capability required by existing part 25 requirements related to operation with all engines inoperative.

(c)The airplane emergency electrical power system must be designed to supply:

(1)Electrical power required for immediate safety, which must continue to operate without the need for crew action following the loss of the normal electrical power, for a duration sufficient to allow reconfiguration to provide a non-time-limited source of electrical power.

(2)Electrical power required for continued safe flight and landing for the maximum diversion time.

(d)If the applicant uses APU-generated electrical power to satisfy the requirements of these special conditions, and if reaching a suitable runway for landing is beyond the capacity of the battery systems, then the APU must be able to be started under any foreseeable flight condition prior to the depletion of the battery or the restoration of normal electrical power, whichever occurs first. Flight test must demonstrate this capability at the most critical condition.

(1)The applicant must show that the APU will provide adequate electrical power for continued safe flight and landing.

(2)The airplane flight manual

(AFM)must incorporate non-normal procedures that direct the pilot to take appropriate actions to activate the APU after loss of normal engine-driven generated electrical power.

(e)As part of showing compliance with these special conditions, the tests to demonstrate loss of all normal electrical power must also take into account the following:

(1)The assumption that the failure condition occurs during night instrument meteorological conditions

(IMC)at the most critical phase of the flight, relative to the worst possible electrical power distribution and equipment-loads-demand condition.

(2)After the un-restorable loss of normal engine generator power, the airplane engine restart capability is provided, and operations continued in IMC.

(3)The airplane is demonstrated to be capable of continued safe flight and landing. The length of time must be computed based on the maximum diversion time capability for which the airplane is being certified. The applicant must account for airspeed reductions resulting from the associated failure or failures.

(4)The airplane must provide adequate indication of loss of normal electrical power to direct the pilot to the non-normal procedures, and the AFM must incorporate non-normal procedures that will direct the pilot to take appropriate actions. Issued in in Kansas City, Missouri, on May 20, 2025. Patrick R. Mullen, Manager, Technical Policy Branch, Policy and Standards Division, Aircraft Certification Service. [FR Doc. 2025-09414 Filed 5-22-25; 8:45 am]

Connectionstraces to 3

Traces to 3 documents

CFR

U.S. Code