[Federal Register Volume 76, Number 121 (Thursday, June 23, 2011)]
[Rules and Regulations]
[Pages 36870-36871]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-15708]



[[Page 36870]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM441; Special Conditions No. 25-433-SC]


Special Conditions: Gulfstream Model GVI Airplane; Design Roll 
Maneuver Requirement for Electronic Flight Controls

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Gulfstream GVI 
airplane. This airplane will have a novel or unusual design feature 
associated with an electronic flight control system that provides roll 
control of the airplane through pilot inputs to the flight computers. 
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 Date: July 25, 2011.

FOR FURTHER INFORMATION CONTACT: Carl Niedermeyer, FAA, Airframe/Cabin 
Safety Branch, ANM-115, Transport Standards Staff, Transport Airplane 
Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 227-2279; electronic 
mail [email protected].

SUPPLEMENTARY INFORMATION:

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. 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 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 Gulfstream Model GVI airplane is equipped with an electronic 
flight control system that provides roll control of the airplane 
through pilot inputs to the flight computers. The current design roll 
maneuver requirement for structural loads in 14 CFR part 25 is 
inadequate for addressing an airplane with electronic flight controls 
that affect maneuvering. Special conditions are needed to take into 
account the effects of an electronic flight control system.

Discussion

    The GVI is equipped with an electronic flight control system that 
provides roll control of the airplane through pilot inputs to the 
flight computers. Current part 25 airworthiness regulations account for 
``control laws'' for which aileron deflection is proportional to 
control wheel deflection. They do not address any nonlinearities \1\ or 
other effects on aileron and spoiler actuation that may be caused by 
electronic flight controls. Therefore, the FAA considers the flight 
control system to be a novel and unusual feature compared to those 
envisioned when the current regulations were adopted. Since this type 
of system may affect flight loads, and therefore the structural 
capability of the airplane, special conditions are needed to address 
these effects.
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    \1\ A nonlinearity is a situation where output does not change 
in the same proportion as input.
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    These special conditions differ from current requirements in that 
the special conditions require that the roll maneuver result from 
defined movements of the cockpit roll control as opposed to defined 
aileron deflections. Also, these special conditions require an 
additional load condition at design maneuvering speed (VA), 
in which the cockpit roll control is returned to neutral following the 
initial roll input.

Discussion of Comments

    Notice of proposed special conditions No. 25-11-01-SC for 
Gulfstream GVI airplanes was published in the Federal Register on 
February 14, 2011 (76 FR 8319). Only one comment was received, which 
was supportive, so these special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Gulfstream Model GVI 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 features, these 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 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 GVI airplanes.
    In lieu of compliance with Sec.  25.349(a), Gulfstream must comply 
with the following special conditions.
    The following conditions, speeds, and cockpit roll control motions 
(except as the motions may be limited by pilot effort) must be 
considered in combination with an airplane load factor of zero and of 
two-thirds of the positive maneuvering factor used in design. In 
determining the resulting control surface deflections, the torsional 
flexibility of the wing must be

[[Page 36871]]

considered in accordance with Sec.  25.301(b):
    1. Conditions corresponding to steady rolling velocities must be 
investigated. In addition, conditions corresponding to maximum angular 
acceleration must be investigated for airplanes with engines or other 
weight concentrations outboard of the fuselage. For the angular 
acceleration conditions, zero rolling velocity may be assumed in the 
absence of a rational time history investigation of the maneuver.
    2. At VA, sudden movement of the cockpit roll control up 
to the limit is assumed. The position of the cockpit roll control must 
be maintained until a steady roll rate is achieved and then must be 
returned suddenly to the neutral position.
    3. At VC, the cockpit roll control must be moved 
suddenly and maintained so as to achieve a roll rate not less than that 
obtained in paragraph 2.
    4. At VD, the cockpit roll control must be moved 
suddenly and maintained so as to achieve a roll rate not less than one 
third of that obtained in paragraph 2.

    Issued in Renton, Washington, on June 13, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-15708 Filed 6-22-11; 8:45 am]
BILLING CODE 4910-13-P