[Federal Register Volume 75, Number 246 (Thursday, December 23, 2010)]
[Proposed Rules]
[Pages 80735-80738]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-32236]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM438 Special Conditions No. 25-10-03-SC]
Special Conditions: Gulfstream Model GVI Airplane; High Incidence
Protection
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 GVI
airplane. This airplane will have novel or unusual design features when
compared to the state of technology envisioned in the airworthiness
standards for transport category airplanes associated with the use of
high incidence protection. The applicable airworthiness regulations do
not contain adequate or appropriate safety standards for these design
features. These proposed 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: We must receive your comments by February 7, 2011.
ADDRESSES: You must mail two copies of your comments to: Federal
Aviation Administration, Transport Airplane Directorate, Attn: Rules
Docket (ANM-113), Docket No. NM438, 1601 Lind Avenue, SW., Renton,
Washington 98057-3356. You may deliver two copies to the Transport
Airplane Directorate at the above address. You must mark your comments:
Docket No. NM438. You can inspect comments in the Rules Docket
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT: Joe Jacobsen, FAA, Airplane &
Flightcrew Interface Branch, ANM-111, Transport Standards Staff,
Transport Airplane Directorate, Aircraft Certification Service, 1601
Lind Avenue, SW., Renton, Washington, 98057-3356; telephone (425) 227-
2011; facsimile (425) 227-1320.
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite 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. We ask
that you send us two copies of written comments.
We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning these special conditions. You can inspect the docket before
and after the comment closing date. If you wish to review the docket in
person, go to the address in the ADDRESSES section of this preamble
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal
holidays.
We will consider all comments we receive on or before the closing
date for comments. We will consider comments filed late if it is
possible to do so without incurring expense or delay. We may change
these special conditions based on the comments we receive. If you want
us to acknowledge receipt of your comments on this proposal, include
with your comments a self-addressed, stamped postcard on which you have
written the docket number. We will stamp the date on the postcard and
mail it back to you.
Background
On March 29, 2005, Gulfstream Aerospace Corporation (hereafter
referred to as ``Gulfstream'') applied for an FAA type certificate for
its new Gulfstream Model GVI passenger airplane. Gulfstream later
applied for, and was granted, an extension of time for the type
certificate, which changed the effective application date to September
28, 2006. The Gulfstream Model GVI airplane will be an all-new, two-
engine jet transport airplane with an executive cabin interior. The
maximum takeoff weight will be 99,600 pounds, with a maximum passenger
count of 19 passengers.
Type Certification Basis
Under provisions of Title 14, Code of Federal Regulations (14 CFR)
21.17, Gulfstream must show that the Gulfstream Model GVI airplane
(hereafter referred to as ``the GVI'') meets the applicable provisions
of 14 CFR part 25, as amended by Amendments 25-1 through 25-119, 25-
122, and 25-124. 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 GVI because of a novel
or unusual design feature, special conditions are prescribed under the
provisions of Sec. 21.16.
In addition to complying with the applicable airworthiness
regulations and special conditions, the GVI must
[[Page 80736]]
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 must also issue a finding of regulatory adequacy pursuant to
section 611 of Public Law 92-574, the ``Noise Control Act of 1972.''
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. 21.17(a)(2).
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 features, the special conditions would also apply to the
other model under provisions of Sec. 21.101.
Novel or Unusual Design Features
The GVI is equipped with a novel or unusual design feature: A high
incidence protection system that replaces the stall warning system
during normal operating conditions, prohibits the airplane from
stalling, limits the angle of attack at which the airplane can be flown
during normal low speed operation, and cannot be overridden by the
flight crew. The system's application of this angle of attack limit
impacts the stall speed determination, the stall characteristics, the
stall warning demonstration, and the longitudinal airplane handling
characteristics. The current regulations, including Sec. Sec. 25.103,
25.145, 25.201, 25.203, 25.207 and 25.1323, do not address this type of
protection feature.
Discussion of Proposed Special Conditions
Special conditions are proposed to address this novel or unusual
design feature of the GVI. These special conditions, which include
airplane performance requirements, will establish a level of safety
equivalent to the current regulations for reference stall speeds, stall
warning, stall characteristics, and miscellaneous other minimum
reference speeds.
Applicability
As discussed above, these proposed special conditions are
applicable to the high incidence protection system on the GVI. 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
features, these proposed special conditions would apply to that model
as well.
Conclusion
This action affects only certain novel or unusual design features
of the GVI. It is not a rule of general applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Proposed Special Conditions
Accordingly, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for the GVI airplanes.
1. Definitions. For terminology that does not appear in the
regulations, the following definitions apply to these proposed special
conditions:
(a) Electronic Flight Control System (EFCS)--The electronic and
software command and control elements of the flight control system.
(b) High Incidence Protection Function--An airplane level function
that automatically limits the maximum angle of attack that can be
attained to a value below that at which an aerodynamic stall would
occur.
(c) Alpha-Limit--The maximum angle of attack at which the airplane
stabilizes with the high incidence protection function operating and
the longitudinal control held on its aft stop.
(d) Vmin--The minimum stabilized flight speed in calibrated
airspeed obtained when the airplane is decelerated at an entry rate not
exceeding 1 knot/sec until the longitudinal pilot control is on the aft
stop with the high incidence protection function operating.
(e) Vmin1g--Vmin corrected to 1g conditions. The minimum calibrated
airspeed at which the airplane can develop a lift force normal to the
flight path and equal to its weight when at an angle of attack not
greater than that determined for Vmin.
2. Capability and Reliability of the High Incidence Protection
System--In lieu of Sec. Sec. 25.103, 25.145, 25.201, 25.203, 25.207
and 25.1323 the following special conditions are proposed for
capability and reliability requirements:
(a) It must not be possible during pilot-induced maneuvers to
encounter a stall, and handling characteristics must be acceptable as
required by paragraphs 5 and 6 of this proposed special condition.
(b) The airplane must be protected against stalling due to the
effects of environmental conditions such as windshear and gusts at low
speeds as required by paragraph 7 of this proposed special condition.
(c) The ability of the high incidence protection function to
accommodate any reduction in stalling angle of attack resulting from
flight in the atmospheric icing conditions of 14 CFR part 25, appendix
C, must be verified.
(d) The reliability of the high incidence protection function and
the effects of failures must be acceptable in accordance with Sec.
25.1309.
(e) The high incidence protection function must not impede
maneuvering for pitch angles up to the maximum required for normal
maneuvering including an all-engines operating takeoff plus a suitable
margin to allow for satisfactory speed control.
3. Minimum Steady Flight Speed and Reference Stall Speed--In lieu
of the requirements of Sec. 25.103, the following special condition is
proposed:
(a) Vmin--The minimum steady flight speed, for the airplane
configuration under consideration and with the high incidence
protection function operating, is the final stabilized calibrated
airspeed obtained when the airplane is decelerated at an entry rate not
exceeding 1 knot per second until the longitudinal pilot control is on
its stop.
(b) The minimum steady flight speed, Vmin, must be determined with:
(1) The high incidence protection function operating normally.
(2) Idle thrust.
(3) All combinations of flap settings and landing gear positions.
(4) The weight used when VSR is being used as a factor
to determine compliance with a required performance standard.
(5) The most unfavorable center of gravity allowable.
(6) The airplane trimmed for straight flight at a speed selected by
the applicant, but not less than 1.13 VSR and not greater
than 1.3 VSR.
(7) The settings of the high incidence protection function, stall
warning system, and stall identification system (if applicable) set at
the low angle of attack tolerance limit, unless the production
tolerances are acceptably small so as to produce insignificant changes
in performance determinations.
(c) Vmin1g--Vmin corrected to 1g conditions, which is the minimum
calibrated airspeed at which the airplane can develop a lift force
normal to the flight path and equal to its weight when at an angle of
attack not greater than that determined for Vmin. Vmin1g is defined as
follows:
[[Page 80737]]
[GRAPHIC] [TIFF OMITTED] TP23DE10.004
Where:
nZW = load factor normal to the flight path at
Vmin.
(d) The reference stall speed, VSR, is a calibrated
airspeed selected by the applicant. VSR may not be less than
a 1g stall speed. VSR is expressed as:
[GRAPHIC] [TIFF OMITTED] TP23DE10.005
Where:
VCLMAX is the calibrated airspeed obtained when the load factor-
corrected lift coefficient
[GRAPHIC] [TIFF OMITTED] TP23DE10.006
is first a maximum during the maneuver prescribed in paragraph
3(e)(7) of this special condition.
nZW = Load factor normal to the flight path at
VCLMAX
W = Airplane gross weight;
S = Aerodynamic reference wing area; and
q = Dynamic pressure.
(e) VSR must be determined with the following
conditions:
(1) Engines idling, or, if that resultant thrust causes an
appreciable decrease in stall speed, not more than zero thrust at the
stall speed.
(2) The airplane in other respects (such as flaps and landing gear)
in the condition existing in the test or performance standard in which
VSR is being used.
(3) The weight used when VSR is being used as a factor
to determine compliance with a required performance standard.
(4) The center of gravity position that results in the highest
value of reference stall speed.
(5) The airplane trimmed for straight flight at a speed selected by
the applicant, but not less than 1.13 VSR and not greater
than 1.3 VSR.
(6) The high incidence protection function disabled, or adjusted to
a high enough incidence to allow full development of the maneuver to
the angle of attack corresponding to VSR.
(7) From the stabilized trim condition, apply the longitudinal
control to decelerate the airplane so that the speed reduction does not
exceed one knot per second.
(f) The flight characteristics at the angle of attack corresponding
to VSR must be suitable in the traditional sense at forward
and aft center of gravity in straight and turning flight at IDLE power.
(g) If VSR is chosen equal to VMIN,1g, an
equivalent safety finding to the intent of Sec. 25.103 may be
considered to have been met. The applicant may choose VSR to
be less than VMIN,1g but not less than VS1g if
compensating factors are provided to ensure safe characteristics.
4. Stall Warning
(a) Normal Operation--If the conditions of paragraph 2 of this
proposed special condition are satisfied, a level of safety equivalent
to that intended by Sec. 25.207, Stall warning, will have been met.
(b) Failure Cases--Following failures of the high incidence
protection function not shown to be extremely improbable, if the
function no longer satisfies paragraphs 2(a), 2(b), and 2(c) of this
proposed special condition, stall warning must be provided in
accordance with Sec. 25.207. The stall warning should prevent
inadvertent stall in the following conditions:
(1) Power off straight stall approaches to a speed 5 percent below
the warning onset.
(2) Turning flight stall approaches with at least 1.5g load factor
normal to the flight path at an entry rate of at least 2 knots per
second when recovery is initiated not less than one second after the
warning onset.
5. High Incidence Handling Demonstrations--In lieu of the
requirements of Sec. 25.201, the following special conditions are
proposed:
(a) Maneuvers to the limit of the longitudinal control, in the nose
up direction, must be demonstrated in straight flight and in 30 degree
banked turns under the following conditions:
(1) The high incidence protection function operating normally.
(2) Power off.
(3) At a power level necessary to maintain level flight at 1.5
VSR1, where VSR1 is the reference stall speed
with the flaps in the approach position, the landing gear retracted,
and with the aircraft at its maximum landing weight. The flap position
to be used to determine this power setting is that position in which
the stall speed, VSR1, does not exceed 110% of the stall
speed, VSR0, with the flaps in the most extended landing
position.
(b) In each condition required by paragraph (a) of this section, it
must be possible to meet the applicable requirements of Sec. 25.203
defined in paragraph 6 of this proposed special condition with:
(1) Flaps, landing gear, and deceleration devices in any likely
combination of positions not prohibited.
(2) Deceleration devices include spoilers and other drag devices
when used as air brakes, and thrust reversers. High incidence maneuver
demonstrations with deceleration devices deployed should be carried out
with power off except where power is normally applied during operations
(e.g., use of extended airbrakes during landing).
(3) Representative weights within the range for which certification
is requested.
(4) The most adverse center of gravity.
(5) The airplane trimmed for straight flight at the speed
prescribed in paragraph 3(e)(5) of this proposed special condition.
(6) The settings of the high incidence protection function, stall
warning system, and stall identification system (if applicable) set at
the high angle of attack tolerance limit, unless the production
tolerances are acceptably small so as to produce insignificant changes
in performance determinations.
(c) The following procedures must be used to show compliance with
Sec. 25.203 as amended by paragraph 6 of this proposed special
condition:
(1) Starting at a speed sufficiently above the minimum steady
flight speed to ensure that a steady rate of speed reduction can be
established, apply the longitudinal control so that the speed reduction
does not exceed one knot per second until the control reaches the stop.
(2) The longitudinal control must be maintained at the stop until
the airplane has reached a stabilized flight condition and then
recovered by normal recovery techniques.
(3) The requirements for turning flight maneuver demonstrations
must also be met with accelerated rates of entry to the incidence
limit, up to the maximum rate achievable.
6. Characteristics in High Incidence Maneuvers--In lieu of the
requirements of Sec. 25.203, the following special condition is
proposed:
(a) Throughout maneuvers with a rate of deceleration of not more
than 1 knot per second, both in straight flight and in 30 degree banked
turns, the airplane's characteristics must be as follows:
(1) No abnormal airplane nose-up pitching.
(2) No uncommanded nose-down pitching (which is indicative of
stall). However, reasonable attitude changes associated with
stabilizing the incidence at alpha limit as the longitudinal control
reaches the stop is acceptable. Any reduction of pitch attitude
associated with stabilizing the incidence at the alpha limit should be
achieved smoothly and at a low pitch rate, so it is not likely to be
mistaken for natural stall identification.
[[Page 80738]]
(3) No uncommanded lateral or directional motion, and the pilot
must retain good lateral and directional control by conventional use of
the cockpit controls throughout the maneuver.
(4) The airplane must not exhibit buffeting of a magnitude or
severity that would act as a deterrent to completing the maneuver
specified in Sec. 25.201(a) as amended by this proposed special
condition.
(b) In maneuvers with increased rates of deceleration, some
degradation of characteristics associated with a transient excursion
beyond the stabilized alpha-limit is acceptable. However, the airplane
must not exhibit dangerous characteristics or characteristics that
would deter the pilot from holding the longitudinal control on the aft
stop for a period of time appropriate to the maneuvers.
(c) It must always be possible to reduce incidence by conventional
use of the longitudinal control.
(d) The rate at which the airplane can be maneuvered from trim
speeds associated with scheduled operating speeds, such as
V2 and VREF up to alpha-limit, should not be
unduly damped or significantly slower than can be achieved on
conventionally controlled transport airplanes.
7. Atmospheric Disturbances--Operation of the high incidence
protection function must not adversely affect aircraft control during
expected levels of atmospheric disturbances, nor impede the application
of recovery procedures in case of windshear. Simulator tests and
analysis may be used to evaluate such conditions, but must be validated
by limited flight testing to confirm handling qualities at critical
loading conditions.
8. Longitudinal Control--In lieu of the requirements of Sec.
25.145(a), (a)(1) and (b)(6), the following special conditions are
proposed:
(a) It must be possible, at any point between the trim speed
prescribed in Sec. 25.103(b)(6) as amended by this proposed special
condition and Vmin, to pitch the nose downward so that the acceleration
to this selected trim speed is prompt.
(b) With the landing gear extended, no change in trim control, or
exertion of more than 50 pounds control force (representative of the
maximum short-term force that can be applied readily by one hand) may
be required for the following maneuver: With power off, flaps extended
and the airplane trimmed at 1.3 VSR1, obtain and maintain
airspeeds between Vmin and either 1.6VSR1 or VFE,
whichever is lower.
9. Airspeed Indicating System--In lieu of Sec. 25.1323(c)(1) and
(c)(2), the following special conditions are proposed:
(a) VMO to Vmin with the flaps retracted; and
(b) Vmin to VFE with flaps in the landing position.
Issued in Renton, Washington, on December 13, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2010-32236 Filed 12-22-10; 8:45 am]
BILLING CODE 4910-13-P