Document Headings

                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
                -                       the number of the CFR title and the number of each part                      the document amends, proposes to amend, or is directly                      related to                    
                -                       the agency docket number / agency internal file number                    
                -                       the RIN which identifies each regulatory action listed in                      the Unified Agenda of Federal Regulatory and Deregulatory                      Actions                    

                    See the                                          Document Drafting Handbook                                        for more details.                  

###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 25
          - [Docket No. FAA-2023-2439; Special Conditions No. 25-852-SC]

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final special conditions; request for comments.

# SUMMARY:

These special conditions are issued for the Gulfstream Aerospace Corporation (Gulfstream) Model GVIII-G700 and GVIII-G800 series airplanes. These airplanes 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 an electronic flight-control system, the functions of which are dependent upon the electrical power-generation and distribution systems, whereby the loss of all electrical power may 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:

This action is effective on Gulfstream on January 30, 2024. Send comments on or before March 15, 2024.

# ADDRESSES:

Send comments identified by Docket No. FAA-2023-2439 using any of the following methods:
      -  Federal eRegulations Portal:                          Go to                          www.regulations.gov                          and follow the online instructions for sending your comments electronically.                    
      -  Mail:                          Send comments to Docket Operations, M-30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room W12-140, West Building Ground Floor, Washington, DC 20590-0001.                    
      -  Hand Delivery or Courier:                          Take comments to Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    
      -  Fax:                          Fax comments to Docket Operations at 202-493-2251.                               ( print page 5761)      
      -  Docket:                          Background documents or comments received may be read at                          www.regulations.gov                          at any time. Follow the online instructions for accessing the docket or go to Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

# FOR FURTHER INFORMATION CONTACT:

                        Dan Poblete, Aircraft Systems, AIR-623, Technical Innovation Policy Branch, Policy and Innovation Division, Aircraft Certification Service, Federal Aviation Administration, 3960 Paramount Boulevard, Suite 100, Lakewood, California 90712; telephone 562-627-5335, fax 562-627-5210; email                         *daniel.d.poblete@faa.gov.*

# SUPPLEMENTARY INFORMATION:

                    The substance of these special conditions has been published in the                     **Federal Register**                     for public comment in several prior instances with no substantive comments received. Therefore, the FAA finds, pursuant to 14 CFR 11.38(b), that new comments are unlikely, and notice and comment prior to this publication are unnecessary.                

## Privacy

                    Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received without change to                     *www.regulations.gov,*                     including any personal information you provide. The FAA will also post a report summarizing each substantive verbal contact received about these special conditions.                

## Confidential Business Information

Confidential Business Information (CBI) is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to these special conditions contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to these special conditions, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and the indicated comments will not be placed in the public docket of these special conditions. Send submissions containing CBI to the individual listed in the For Further Information Contact section above. Comments the FAA receives, which are not specifically designated as CBI, will be placed in the public docket for these special conditions.

## Comments Invited

The FAA invites interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data.

The FAA will consider all comments received by the closing date for comments and will consider comments filed late if it is possible to do so without incurring delay. The FAA may change these special conditions based on the comments received.

## Background

On December 31, 2019, Gulfstream applied for an amendment to Type Certificate No. T00015AT to include the new Model GVIII-G700 and GVIII-G800 series airplanes. These airplanes, which are derivatives of the Model GVI currently approved under Type Certificate No. T00015AT, are twin-engine, transport-category airplanes, with seating for 19 passengers, and a maximum take-off weight of 107,600 pounds (GVIII-G700) and 105,600 pounds (GVIII-G800).

## Type Certification Basis

Under the provisions of title 14, Code of Federal Regulations (14 CFR) 21.101, Gulfstream must show that the Model GVIII-G700 and GVIII-G800 series airplanes meet the applicable provisions of the regulations listed in Type Certificate No. T00015AT, 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 (                    *i.e.,*14 CFR part 25) do not contain adequate or appropriate safety standards for the Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes 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 Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes must comply with the 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 14 CFR 11.38, and they become part of the type certification basis under § 21.101.

## Novel or Unusual Design Features

The Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes will incorporate the following novel or unusual design feature:

This design feature is an electronic flight-control system, the functions of which are dependent upon the electrical power-generation and distribution systems, whereby the loss of all electrical power may be catastrophic to the airplane. These special conditions retain the level of safety offered by § 25.1351(d).

## Discussion

The Gulfstream Aerospace Corporation Model GVIII-G700 and GVIII-G800 airplanes incorporate a fly-by-wire flight-control system that requires a continuous source of electrical power to keep the flight-control system operable. The current regulation, § 25.1351(d), Amendment 25-72, “Operation without normal electrical power,” states that the airplane must be operated safely in visual-flight-rules conditions for a period of not less than five minutes after loss of all normal electrical power. This rule was structured around a traditional design of mechanical control cables for flight control that allowed time for the crew to remedy an electrical failure, start the engine(s) if necessary, and re-establish some or all of the electrical power-generation capability.

                    To maintain the same level of safety associated with traditional designs, the Model GVIII-G700 and GVIII-G800 airplane's design must not be time limited in its operation when the airplane is without its normal source of engine- or auxiliary-power-unit-generated electrical power. Service experience has shown that the loss of all electrical power generated by an airplane's engine generators or auxiliary power unit (APU) is not extremely improbable. Likewise, regulations                           ( print page 5762)                        require the applicant to demonstrate that the airplane has the power required for continued safe flight and landing with the use of its emergency electrical power systems. These emergency electrical power systems must be able to power all loads considered essential for continued safe flight and landing.                

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.

## Applicability

As discussed above, these special conditions are applicable to the Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes. Should Gulfstream apply at a later date for a change to the type certificate to include another model incorporating the same novel or unusual design feature, these special conditions would apply to that model as well.

## Conclusion

This action affects only a certain novel or unusual design feature on Gulfstream Model GVIII-G700 and GVIII-G800 series of airplanes. 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, and 44704.

## The Special Conditions

 Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for Gulfstream Model GVIII-G700 and GVIII-G800 series airplanes.

Because the total loss of normal, generated, electrical power in two-engine airplanes is not extremely improbable, and because the loss of all electrical power may be catastrophic to airplanes equipped with an electronic flight-control system, the following special conditions apply to Gulfstream Model GVIII-G700 and GVIII-G800 airplanes.

(a) In lieu of § 25.1351(d), the following special conditions apply:

(1) Gulfstream 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 (1)(i) and (1)(ii), below. For purposes of these special conditions, normal sources of electrical-power generation do not include 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, Gulfstream 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 Gulfstream is seeking approval.

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

(ii) Gulfstream 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. Gulfstream may exclude unrecoverable loss of all engines when showing compliance with this requirement.

(2) Regardless of electrical-power generation and distribution-system recovery capability shown under special condition (1), above, sufficient electrical-system capability must be provided to:

(i) 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

(ii) 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.

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

(i) 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.

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

(4) 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 tests must demonstrate this capability at the most critical condition.

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

(ii) The airplane flight manual (AFM) must incorporate abnormal procedures that direct the pilot to take appropriate actions to activate the APU after loss of normal engine-driven generated electrical power.

(5) 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:

(i) 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.

(ii) After an unrestorable loss of normal engine-driven generated electrical power, the airplane engine-restart capability is provided, and operations are continued in IMC.

(iii) The airplane is demonstrated to be capable of continued safe flight and landing. The duration of this capability 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.

(iv) The airplane must provide adequate indication of loss of normal electrical power to direct the pilot to the abnormal procedures, and the AFM must incorporate abnormal procedures that will direct the pilot to take appropriate actions.

Issued in Kansas City, Missouri, on January 24, 2024.

Patrick R. Mullen,

Manager, Technical Innovation Policy Branch, Policy and Innovation Division, Aircraft Certification Service.

[FR Doc. 2024-01740 Filed 1-29-24; 8:45 am]

BILLING CODE 4910-13-P