[Federal Register Volume 76, Number 121 (Thursday, June 23, 2011)]
[Rules and Regulations]
[Pages 36864-36865]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-15707]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM444; Special Conditions No. 25-435-SC]


Special Conditions: Gulfstream Model GVI Airplane; Operation 
Without Normal Electric Power

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: The Gulfstream GVI airplane will have numerous electrically 
operated systems whose function is needed for continued safe flight and 
landing of the airplane. 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: Effective Date: July 25, 2011.

FOR FURTHER INFORMATION CONTACT: Nazih Khaouly, FAA, Airplane and 
Flight Crew Interface Branch, ANM-111, Transport Standards Staff, 
Transport Airplane Directorate, Aircraft Certification Service, 1601 
Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-
2432; facsimile (425) 227-1320.

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.
    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.
    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).

Novel or Unusual Design Features

    The GVI incorporates an electronic flight control system that 
requires a continuous source of electrical power in order to keep the 
system operable. Due to rapid improvements in airplane technology, the 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for these design features.

Discussion

    The GVI incorporates an electronic flight control system that 
requires a continuous source of electrical power in order to keep the 
system operable. The criticality of this system is such that their 
failure will either reduce the capability of the airplane or the 
ability of the crew to cope with adverse operating conditions, or 
prevent continued safe flight and landing of the airplane. The 
airworthiness standards of part 25 do not contain adequate or 
appropriate standards for protection of these systems from the adverse 
effects of operation without normal electrical power.
    The current rule, Sec.  25.1351(d), Amendment 25-72, requires safe 
operation under visual flight rules (VFR) conditions for at least five 
minutes after loss of all normal electrical power. This rule was 
structured around traditional airplane designs that used mechanical 
control cables and linkages for flight control. These manual controls 
allowed the crew to maintain aerodynamic control of the airplane for an 
indefinite period of time after loss of all electrical power. Under 
these conditions, the mechanical flight control system provided the 
crew with the ability to fly the airplane while attempting to identify 
the cause of the electrical failure, start the engine(s) if necessary, 
and reestablish some of the electrical power generation capability, if 
possible.
    To maintain the same level of safety associated with traditional 
designs, the GVI must be designed for operation with the normal sources 
of engine and auxiliary power unit (APU) generated electrical power 
inoperative. Service experience has shown that loss of all electrical 
power from the airplane's engine and APU driven generators is not 
extremely improbable. Thus, Gulfstream must demonstrate that the 
airplane is capable of recovering adequate primary electrical power 
generation for safe flight and landing.
    For compliance purposes, a test demonstration of the loss of normal 
engine generator must be established such that:
    1. The failure condition should be assumed to occur during night 
instrument meteorological conditions (IMC) at the most critical phase 
of the flight relative to the electrical power system design and 
distribution of equipment loads on the system.
    2. After the unrestorable loss of normal engine generator power, 
the airplane engine restart capability must

[[Page 36865]]

be provided and operations continued in IMC.
    3. The airplane should be demonstrated to be capable of continuous 
safe flight and landing. The length of time must be computed based on 
the maximum diversion time capability for which the airplane is being 
certified. Consideration for speed reductions resulting from the 
associated failure must be made.
    4. Availability of APU operation should not be considered in 
establishing emergency power system adequacy.

Discussion of Comments

    Notice of proposed special conditions No. 25-11-03-SC for 
Gulfstream GVI airplanes was published in the Federal Register on 
February 14, 2011 (76 FR 8314). Only one comment was received, which 
was supportive, so these special conditions are adopted as proposed.

Applicability

    As discussed above, this special condition is 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, this special 
condition 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 Condition

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the following special condition is issued as part of the 
type certification basis for the Gulfstream GVI airplanes.
    Since the total loss of normal generated electrical power in two-
engine airplanes has not achieved the extremely improbable level, and 
since the loss of all electrical power may be catastrophic to airplanes 
utilizing an electronic flight control system, the following special 
condition is in lieu of 14 CFR 25.1351(d):

    It must be demonstrated by test or a combination of test and 
analysis that the airplane can continue safe flight and landing with 
inoperative normal engine and APU generator electrical power 
(electrical power sources excluding the battery and any other 
standby electrical sources). The airplane operation should be 
considered at the critical phase of flight and include the ability 
to restart the engines and maintain flight for the maximum diversion 
time capability being certified.

    Issued in Renton, Washington, on June 13, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-15707 Filed 6-22-11; 8:45 am]
BILLING CODE 4910-13-P