[Federal Register Volume 76, Number 30 (Monday, February 14, 2011)]
[Rules and Regulations]
[Pages 8278-8281]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-3214]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM443; Special Conditions No. 25-416-SC]


Special Conditions: Gulfstream Model GVI Airplane; Enhanced 
Flight Vision System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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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 a head-up display (HUD) system modified to display 
forward-looking infrared (FLIR) imagery. 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: The effective date of these special conditions is February 3, 
2011. We must receive your comments by March 31, 2011.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM443, 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. NM443. 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: Dale Dunford, 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) 227-2239; facsimile 
(425) 227-1320.

SUPPLEMENTARY INFORMATION: The FAA has determined that the substance of 
these special conditions has been subject to the public-comment process 
in several prior instances with no substantive comments received. The 
FAA therefore finds that good cause exists for making these special 
conditions effective upon issuance.

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 
about 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.

[[Page 8279]]

    We will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.
    If you want us to acknowledge receipt of your comments on these 
special conditions, 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 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 enhanced flight vision system (EFVS) is a novel or unusual 
design feature because it projects a video image derived from a 
forward-looking infrared (FLIR) camera through the head-up display 
(HUD). The EFVS image is projected in the center of the ``pilot 
compartment view,'' which is governed by Sec.  25.773. The image is 
displayed with HUD symbology and overlays the forward outside view. 
Therefore, Sec.  25.773 does not contain appropriate safety standards 
for the EFVS display.
    Operationally, during an instrument approach, the EFVS image is 
intended to enhance the pilot's ability to detect and identify ``visual 
references for the intended runway'' (see Sec.  91.175(l)(3)) to 
continue the approach below decision height or minimum descent 
altitude. Depending on atmospheric conditions and the strength of 
infrared energy emitted and/or reflected from the scene, the pilot can 
see these visual references in the image better than he or she can see 
them through the window without EFVS.
    Scene contrast detected by infrared sensors can be much different 
from that detected by natural pilot vision. On a dark night, thermal 
differences of objects which are not detectable by the naked eye will 
be easily detected by many imaging infrared systems. On the other hand, 
contrasting colors in visual wavelengths may be distinguished by the 
naked eye but not by an imaging infrared system. Where thermal contrast 
in the scene is sufficiently detectable, the pilot can recognize shapes 
and patterns of certain visual references in the infrared image. 
However, depending on conditions, those shapes and patterns in the 
infrared image can appear significantly different than they would with 
normal vision. Considering these factors, the EFVS image needs to be 
evaluated to determine that it can be accurately interpreted by the 
pilot.
    The image may improve the pilot's ability to detect and identify 
items of interest. However, the EFVS needs to be evaluated to determine 
that the imagery allows the pilot to perform the normal duties of the 
flight crew and adequately see outside the window through the image, 
consistent with the safety intent of Sec.  25.773(a)(2).
    Compared to a HUD displaying the EFVS image and symbology, a HUD 
that displays only stroke-written symbols is easier to see through. 
Stroke symbology illuminates a small fraction of the total display area 
of the HUD, leaving much of that area free of reflected light that 
could interfere with the pilot's view out the window through the 
display. However, unlike stroke symbology, the video image illuminates 
most of the total display area of the HUD (approximately 30 degrees 
horizontally and 25 degrees vertically) which is a significant fraction 
of the pilot compartment view. The pilot cannot see around the larger 
illuminated portions of the video image but must see the outside scene 
through it.
    Unlike the pilot's external view, the EFVS image is a monochrome, 
two-dimensional display. Many, but not all, of the depth cues found in 
the natural view are also found in the image. The quality of the EFVS 
image and the level of EFVS infrared sensor performance could depend 
significantly on conditions of the atmospheric and external light 
sources. The pilot needs adequate control of sensor gain and image 
brightness, which can significantly affect image quality and 
transparency (i.e., the ability to see the outside view through the 
image). Certain system characteristics could create distracting and 
confusing display artifacts. Finally, because this is a sensor-based 
system that is intended to provide a conformal perspective 
corresponding with the outside scene, the system must be able to ensure 
accurate alignment.
    Hence, safety standards are needed for each of the following 
factors:

--An acceptable degree of image transparency;
--Image alignment;
--Lack of significant distortion; and
--The potential for pilot confusion or misleading information.

    Section 25.773, ``Pilot Compartment View,'' specifies that ``Each 
pilot compartment must be free of glare and reflection that could 
interfere with the normal duties of the minimum flight crew. * * *'' In 
issuing Sec.  25.773, the FAA did not anticipate the development of 
EFVSs and does not consider Sec.  25.773 to be adequate to address the 
specific issues related to such a system. Therefore, the FAA has 
determined that special conditions are needed to address the specific 
issues particular to the installation and use of an EFVS.

Discussion

    The EFVS is intended to function by presenting an enhanced view 
during the approach. This enhanced view would help the pilot to see and 
recognize external visual references, as required by Sec.  91.175(l), 
and to visually monitor the integrity of the approach, as

[[Page 8280]]

described in FAA Order 6750.24D (``Instrument Landing System and 
Ancillary Electronic Component Configuration and Performance 
Requirements,'' dated March 1, 2000).
    Based on this functionality, users would seek to obtain operational 
approval to conduct approaches, including approaches to Type I runways, 
when the runway visual range is as low as 1,200 feet.
    The purpose of these special conditions is to ensure that the EFVS 
to be installed can perform the following functions:

--Present an enhanced view that would aid the pilot during the 
approach.
--Provide enhanced flight visibility to the pilot that is no less than 
the visibility prescribed in the standard instrument approach 
procedure.
--Display an image that the pilot can use to detect and identify the 
``visual references for the intended runway'' required by Sec.  
91.175(l)(3) to continue the approach with vertical guidance to 100 
feet height above the touchdown zone elevation.

    Depending on the atmospheric conditions and the particular visual 
references that happen to be distinctly visible and detectable in the 
EFVS image, these functions would support its use by the pilot to 
visually monitor the integrity of the approach path.
    Compliance with these special conditions does not affect the 
applicability of any of the requirements of the operating regulations 
(i.e., 14 CFR parts 91, 121, and 135). Furthermore, use of the EFVS 
does not change the approach minima prescribed in the standard 
instrument approach procedure being used; published minima still apply.
    The FAA certification of this EFVS is limited as follows:

--The infrared-based EFVS image will not be certified as a means to 
satisfy the requirements for descent below 100 feet height above 
touchdown (HAT).
--The EFVS may be used as a supplemental device to enhance the pilot's 
situational awareness during any phase of flight or operation in which 
its safe use has been established.

    An EFVS image may provide an enhanced image of the scene that may 
compensate for any reduction in the clear outside view of the visual 
field framed by the HUD combiner. The pilot must be able to use this 
combination of information seen in the image and the natural view of 
the outside scene seen through the image as safely and effectively as 
the pilot would use a Sec.  25.773 compliant pilot compartment view 
without an EVS image. This is the fundamental objective of the special 
conditions.
    The FAA will also apply additional certification criteria, not as 
special conditions, for compliance with related regulatory 
requirements, such as Sec. Sec.  25.1301 and 25.1309. These additional 
criteria address certain image characteristics, installation, 
demonstration, and system safety.
    Image characteristics criteria include the following:

--Resolution,
--Luminance,
--Luminance uniformity,
--Low level luminance,
--Contrast variation,
--Display quality,
--Display dynamics (e.g., jitter, flicker, update rate, and lag), and
--Brightness controls.
    Installation criteria address visibility and access to EFVS 
controls and integration of EFVS in the cockpit.
    The EFVS demonstration criteria address the flight and 
environmental conditions that need to be covered.
    The FAA also intends to apply certification criteria relevant to 
high intensity radiated fields (HIRF) and lightning protection.

Applicability

    As discussed above, these special conditions are applicable to 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 feature, these special conditions would apply to that 
model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on one model of airplane. It is not a rule of general applicability.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances and has been 
derived without substantive change from those previously issued. It is 
unlikely that prior public comment would result in a significant change 
from the substance contained herein. Therefore, the FAA has determined 
that prior public notice and comment are unnecessary, and good cause 
exists for adopting these special conditions upon issuance. The FAA is 
requesting comments to allow interested persons to submit views that 
may not have been submitted in response to the prior opportunities for 
comment described above.

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. Enhanced flight vision system (EFVS) imagery on the head-up 
display (HUD) must not degrade the safety of flight or interfere with 
the effective use of outside visual references for required pilot tasks 
during any phase of flight in which it is to be used.
    2. To avoid unacceptable interference with the safe and effective 
use of the pilot compartment view, the EFVS device must meet the 
following requirements:
    (a) The EFVS design must minimize unacceptable display 
characteristics or artifacts (e.g. noise, ``burlap'' overlay, running 
water droplets, etc.) that obscure the desired image of the scene, 
impair the pilot's ability to detect and identify visual references, 
mask flight hazards, distract the pilot, or otherwise degrade task 
performance or safety.
    (b) Control of EFVS display brightness must be sufficiently 
effective, in dynamically changing background (ambient) lighting 
conditions, to prevent full or partial blooming of the display that 
would distract the pilot, impair the pilot's ability to detect and 
identify visual references, mask flight hazards, or otherwise degrade 
task performance or safety. If automatic control for image brightness 
is not provided, it must be shown that a single manual setting is 
satisfactory for the range of lighting conditions encountered during a 
time-critical, high workload phase of flight (e.g., low visibility 
instrument approach).
    (c) A readily accessible control must be provided that permits the 
pilot to immediately deactivate and reactivate display of the EFVS 
image on demand without removing the pilot's hands from the primary 
flight controls (yoke or equivalent) or thrust control.
    (d) The EFVS image on the HUD must not impair the pilot's use of 
guidance information or degrade the presentation and pilot awareness of 
essential flight information displayed on the HUD, such as alerts, 
airspeed, attitude, altitude and direction, approach guidance, wind 
shear guidance, TCAS resolution

[[Page 8281]]

advisories, unusual attitude recovery cues, etc.
    (e) The EFVS image and the HUD symbols (which are spatially 
referenced to the pitch scale, outside view, and image), must be scaled 
and aligned (i.e., conformal) to the external scene. Also, when 
considered singly or in combination, the EFVS image and HUD symbols 
must not be misleading, cause pilot confusion, or increase workload. It 
should be noted that there may be airplane attitudes or cross-wind 
conditions which cause certain symbols, such as the zero-pitch line or 
flight path vector, to reach field of view limits such that they cannot 
be positioned conformally with the image and external scene. In such 
cases these symbols may be displayed, but with an altered appearance 
which makes the pilot aware that they are no longer displayed 
conformally (e.g., ``ghosting'').
    (f) A HUD system used to display EFVS images must, if previously 
certified, continue to meet all of the requirements of the original 
approval.
    3. The safety and performance of the pilot tasks associated with 
the pilot compartment view must be not be degraded by the display of 
the EFVS image. Pilot tasks which must not be degraded by the EFVS 
image include:
    (a) Detection, accurate identification and maneuvering, as 
necessary, to avoid traffic, terrain, obstacles, and other hazards of 
flight.
    (b) Accurate identification and utilization of visual references 
required for every task relevant to the phase of flight.
    4. Appropriate limitations must be stated in the operating 
limitations section of the airplane flight manual to prohibit the use 
of the EFVS for functions that have not been found to be acceptable.

    Issued in Renton, Washington, on February 3, 2011.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-3214 Filed 2-11-11; 8:45 am]
BILLING CODE 4910-13-P