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[Federal Register Volume 90, Number 22 (Tuesday, February 4, 2025)]
[Proposed Rules]
[Pages 8912-8914]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-02214]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2024-2442; Notice No. 25-24-06-SC]

Special Conditions: Gulfstream Aerospace Corporation, Model GVII-
G400 Airplane; Automatic Speed Protection for Design Dive Speed (Dive 
Speed Definition)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Gulfstream 
Aerospace Corporation (Gulfstream) Model GVII-G400 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 a high-speed 
protection system. 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: Send comments on or before March 21, 2025.

ADDRESSES: Send comments identified by Docket No. FAA-2024-2442 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.
    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: Todd Martin, Airframe (P&S) Section, 
AIR-622, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service, Federal Aviation Administration, 2200 
South 216th Street, Des Moines, WA 98198; telephone 206-231-3210; email 
[email protected].

SUPPLEMENTARY INFORMATION:

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 proposed 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.

Privacy

    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in title 
14, Code of Federal Regulations (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 proposed 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 proposed special conditions.

Background

    On June 30, 2020, Gulfstream applied for an amendment to Type 
Certificate No. T00021AT to include the new Model GVII-G400 airplane. 
The Gulfstream Model GVII-G400 airplane, which is a derivative of the 
Model GVII-G500 airplane currently approved under Type Certificate No. 
T00021AT, is a twin-engine, transport-category, business jet, with a 
maximum seating for 19 passengers, and a maximum take-off weight of 
73,500 pounds.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Gulfstream must show that 
the Model GVII-G400 airplane meets the applicable provisions of the 
regulations listed in Type Certificate No. T00021AT, 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 Gulfstream Model GVII-G400 
airplane because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec.  21.16.
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate

[[Page 8913]]

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 Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Gulfstream Model GVII-G400 airplane 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 Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.101.

Novel or Unusual Design Features

    The Gulfstream Model GVII-G400 airplane will incorporate the 
following novel or unusual design feature:
    The GVII-G400 is equipped with a high-speed protection system that 
limits nose down pilot authority at speeds above VC/
MC and prevents the airplane from actually performing the 
maneuver required under Sec.  25.335(b)(1). Gulfstream proposes to 
reduce the margin between VC and VD required by 
Sec.  25.335(b) based on the incorporation of this high-speed 
protection system in the Gulfstream GVII-G400 flight control laws.

Discussion

    Section 25.335(b)(1) is an analytical envelope condition which was 
originally adopted in part 4b of the Civil Air Regulations in order to 
provide an acceptable speed margin between design cruise speed and 
design dive speed. Flutter clearance design speeds and airframe design 
loads are impacted by the design dive speed. While the initial 
condition for the upset specified in the rule is 1g level flight, 
protection is afforded for other inadvertent overspeed conditions as 
well. Section 25.335(b)(1) is intended as a conservative enveloping 
condition for potential overspeed conditions, including non-symmetric 
ones. To establish that potential overspeed conditions are enveloped, 
the applicant must demonstrate that any reduced speed margin based on 
the high-speed protection system will not be exceeded in inadvertent or 
gust induced upsets resulting in initiation of the dive from non-
symmetric attitudes; or that the airplane is protected by the flight 
control laws from getting into non-symmetric upset conditions. The 
applicant must conduct a demonstration that includes a comprehensive 
set of conditions as described below.
    A special condition is proposed in lieu of Sec.  25.335(b)(1). 
Section 25.335(b)(2), which also addresses the design dive speed, is 
applied separately. Advisory Circular 25.335-1A, ``Design Dive Speed,'' 
dated September 29, 2000, provides an acceptable means of compliance to 
Sec.  25.335(b)(2).
    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 
Gulfstream Model GVII-G400 airplane. 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 the certain novel or unusual design 
feature on the Gulfstream Model GVII-G400 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, and 
44704.

The Proposed Special Conditions

    [ssquf] 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 Aerospace Corporation 
Model GVII-G400 airplanes.
    (1) In lieu of compliance with Sec.  25.335(b)(1), if the flight 
control system includes functions that act automatically to initiate 
recovery before the end of the 20 second period specified in Sec.  
25.335(b)(1), VD/MD must be determined from the 
greater of the speeds resulting from conditions (a) and (b) below. The 
speed increase occurring in these maneuvers may be calculated if the 
analysis method and the data used are shown to be reliable. If any non-
overridable automatic feature is included in the high-speed protection 
system (e.g., automatic power reduction or automatic application of 
drag devices), normal operation of these features may be assumed in the 
maneuvers of (a) and (b).
    (a) From an initial condition of stabilized flight at 
VC/MC, the airplane is upset so as to take up a 
new flight path 7.5 degrees below the initial path. Pilot pitch control 
application, up to full authority, is made to try to achieve and 
maintain this new flight path. Twenty seconds after achieving the new 
flight path at or above VC/MC or twenty seconds 
after reaching full control input at or above VC/
MC, whichever occurs first, manual recovery is made at a 
load factor of 1.5 g (0.5 g acceleration increment), or such greater 
load factor that is automatically applied by the system with the 
pilot's pitch control neutral. Initial power setting, as specified in 
Sec.  25.175(b)(1)(iv), is assumed. Pilot reduction of power and/or use 
of drag devices must be delayed until recovery is initiated.
    (b) From any likely level cruise speed up to VC/
MC, with the longitudinal trim and power set to maintain 
stabilized level flight at this speed, the airplane is upset so as to 
accelerate through VC/MC at a flight path 15 
degrees below the initial path (or at the steepest nose down attitude 
that the system will permit with full pitch control input if less than 
15 degrees). The pilot's controls may be in the neutral position after 
reaching VC/MC and before recovery is initiated. 
Recovery may be initiated three seconds after operation of the high-
speed warning device or immediately upon reaching VC/
MC (whichever is higher) by application of a load factor of 
1.5 g (0.5 g acceleration increment), or such greater load factor that 
is automatically applied by the system with the pilot's pitch control 
neutral; power may be reduced simultaneously if not already 
automatically reduced by the high-speed protection system. All other 
means of decelerating the airplane, the use of which are authorized up 
to the highest speed reached in the maneuver, may be used. The interval 
between successive pilot actions must not be less than one second.
    (2) Any failure of the high-speed protection system that would 
affect the speed margin determined by paragraph (1) must be improbable 
(occur at a rate less than 10-5 per flight hour).
    (3) Failures of the system must be annunciated to the pilots, and 
flight manual instructions must be provided to reduce the maximum 
operating speeds, VMO/MMO. The operating speed 
must be reduced to a value that maintains a speed margin between the 
reduced VMO/MMO and the lesser of VDF/
MDF or VD/MD that is consistent with 
the margin determined from

[[Page 8914]]

paragraph (1)(a) and Sec.  25.335(b)(2) without the benefit of the 
high-speed protection system.
    (4) Master minimum equipment list (MMEL) relief for the high-speed 
protection system may be considered by the FAA Flight Operations 
Evaluation Board (FOEB) provided that the flight manual instructions 
indicate reduced maximum operating speeds as described in paragraph 
(3), and that no additional hazards are introduced with the high-speed 
protection system inoperative. In addition, the cockpit display of the 
reduced operating speeds, as well as the overspeed warning for 
exceeding those speeds, must be equivalent to that of the normal 
airplane with the high-speed protection system operative.

    Issued in Kansas City, Missouri, on signature January 30, 2025.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division, 
Aircraft Certification Service.
[FR Doc. 2025-02214 Filed 2-3-25; 8:45 am]
BILLING CODE 4910-13-P
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