[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