[Federal Register Volume 76, Number 105 (Wednesday, June 1, 2011)]
[Rules and Regulations]
[Pages 31454-31456]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-13434]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM445; Special Conditions No. 25-429-SC]


Special Conditions: Gulfstream Model GVI Airplane; Automatic 
Speed Protection for Design Dive Speed

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued 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. These design features 
include a high speed protection system. 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 1, 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.
    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

[[Page 31455]]

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 Gulfstream Model GVI airplane 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). The 
applicable airworthiness regulations do not contain adequate or 
appropriate safety standards for this design feature. These special 
conditions are identical or nearly identical to those previously 
required for type certification of other airplane models.

Discussion

    Gulfstream proposes to reduce the speed margin between 
VC and VD required by Sec.  25.335(b), based on 
the incorporation of a high speed protection system in the GVI flight 
control laws. The GVI 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).
    Section 25.335(b)(1) is an analytical envelope condition which was 
originally adopted in Part 4b of the Civil Air Regulations to provide 
an acceptable speed margin between design cruise speed and design dive 
speed. Freedom from flutter and the airframe design loads are affected 
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 all potential 
overspeed conditions, including non-symmetric ones.
    To establish that all potential overspeed conditions are enveloped, 
the applicant would demonstrate that the dive speed will not be 
exceeded during pilot-induced or gust-induced upsets in non-symmetric 
attitudes.
    In addition, the high speed protection system in the GVI must have 
a high level of reliability.

Discussion of Comments

    Notice of proposed special conditions No. 25-11-04-SC for 
Gulfstream GVI airplanes was published in the Federal Register on 
February 16, 2011 (76 FR 8917). One supportive comment was received.
    On March 29, 2011, Advisory Circular (AC) 25-7B, Flight Test Guide 
for Certification of Transport Category Airplanes, was issued. This 
revision supersedes the reference to AC 25-7A, Change 1, in special 
condition 2 of the proposed special conditions. Therefore, the 
reference to AC 25-7A, Change 1, section 32, paragraphs c.(3)(i) and 
(iii) has been updated to AC 25-7B, section 32, paragraph c.3(a) and 
(c), and the title of the AC has been included. Except for the updated 
AC reference in special condition 2, 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.
    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 
reliable or conservative aerodynamic data are used.
    (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. Control 
application, up to full authority, is made to try to maintain this new 
flight path. Twenty seconds after initiating the upset, manual recovery 
is made at a load factor of 1.5 g (0.5 acceleration increment), or a 
greater load factor that is automatically applied by the system with 
the pilot's pitch control neutral. Power, as specified in Sec.  
25.175(b)(1)(iv), is assumed until recovery is initiated, at which time 
power reduction and the use of pilot controlled drag devices may be 
used.
    (b) From a speed below VC/MC, with power 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 control authority 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 high speed warning system by application of a load factor of 1.5g 
(0.5 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. 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. The applicant must also demonstrate that the speed margin, 
established as above, will not be exceeded in inadvertent or gust 
induced upsets resulting in initiation of the dive from non-symmetric 
attitudes, unless the airplane is protected by the flight control laws 
from getting into non-symmetric upset conditions. The upset maneuvers 
described in AC 25-7B, Flight Test Guide for Certification of Transport 
Category Airplanes, section 32, paragraphs c.3(a) and (c) may be used 
to comply with this requirement.
    3. Any failure of the high speed protection system that would 
affect the speed margin determined by paragraphs 1. and 2. must be 
improbable (occur at a rate less than 10-\5\ per flight 
hour).
    4. 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

[[Page 31456]]

must be reduced to a value that maintains a speed margin between 
VMO/MMO and VD/MD that is 
consistent with showing compliance with Sec.  25.335(b) without the 
benefit of the high speed protection system.
    5. 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 4., 
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 Renton, Washington, on May 24, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-13434 Filed 5-31-11; 8:45 am]
BILLING CODE 4910-13-P