```

[Federal Register Volume 78, Number 103 (Wednesday, May 29, 2013)]
[Rules and Regulations]
[Pages 32078-32081]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-12605]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0406; Special Conditions No. 25-493-SC]

Special Conditions: Gulfstream Model G280 Airplane, Enhanced 
Flight Vision System (EFVS) With Head-Up Display (HUD)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for the Gulfstream model 
G280 series airplanes. These airplanes, as modified by Gulfstream 
Aerospace Corporation, will have an advanced, enhanced-flight-vision 
system (EFVS). The EFVS is a novel or unusual design feature which 
consists of 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 May 22, 2013. 
We must receive your comments by June 28, 2013.

ADDRESSES: Send comments identified by docket number FAA-2013-0406 
using any of the following methods:
     Federal eRegulations Portal: Go to http://www.regulations.gov/ and follow the online instructions for sending 
your comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC, 20590-0001.
     Hand Delivery or Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE., Washington, DC, between 8 a.m. and 5 p.m., 
Monday through Friday, except federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://www.regulations.gov/, including any personal 
information the commenter provides. Using the search function of the 
docket Web site, anyone can find and read the electronic form of all 
comments received into any FAA docket, including the name of the 
individual sending the comment (or signing the comment for an 
association, business, labor union, etc.). DOT's complete Privacy Act 
Statement can be found in the Federal Register published on April 11, 
2000 (65 FR 19477-19478), as well as at http://DocketsInfo.dot.gov/.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov/ at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE., 
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, 
except federal holidays.

FOR FURTHER INFORMATION CONTACT: Dale Dunford, FAA, Transport Standards 
Staff, ANM-111, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone 
(425) 227-2239 fax (425) 227-1320; email: dale.dunford@faa.gov.

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 
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 4:00 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.

[[Page 32079]]

    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

    Note: The term ``enhanced vision system'' (EVS) in this document 
refers to a system comprised of a head-up display, imaging sensor(s), 
and avionics interfaces that display the sensor imagery on the HUD, and 
which overlay that imagery with alpha-numeric and symbolic flight 
information. However, the term has also been commonly used in reference 
to systems that displayed the sensor imagery, with or without other 
flight information, on a head-down display. For clarity, the FAA 
created the term ``enhanced flight vision system'' (EFVS) to refer to 
certain EVS systems that meet the requirements of the new operational 
rules--in particular, the requirement for a HUD and specified flight 
information--and which can be used to determine ``enhanced flight 
vision.'' An EFVS can be considered a subset of a system otherwise 
labeled EVS.
    On October 21, 2010, Gulfstream Aerospace Corporation applied to 
the FAA, via a G280 STC project, for approval of the installation of an 
Enhanced Flight Vision System (EFVS) with a head up display (HUD). The 
EFVS is also capable of displaying forward-looking infrared (FLIR) 
imagery. The original type certificate for the G280 airplanes is A61NM, 
revision 3, November 5, 2012.
    The Gulfstream Model G280 is a two-crew-member transport business 
jet with a maximum ramp weight of 39,750 lbs and is certified for up to 
19 passengers.
    The electronic infrared image displayed between the pilot and the 
forward windshield represents a novel or unusual design feature in the 
context of 14 CFR 25.773. Section 25.773 was not written in 
anticipation of such technology. The electronic image has the potential 
to enhance the pilot's awareness of the terrain, hazards, and airport 
features. At the same time, the image may partially obscure the pilot's 
direct outside compartment view. Therefore, the FAA needs adequate 
safety standards to evaluate the EFVS to determine that the imagery 
provides the intended visual enhancements without undue interference 
with the pilot's outside compartment view. The FAA intent is that the 
pilot will be able to use a combination of the information seen in the 
image, and the natural view of the outside scene seen through the 
image, as safely and effectively as a pilot compartment view without an 
EVS image, that is compliant with Sec.  25.773.
    Although the FAA has determined that the existing regulations are 
not adequate for certification of EFVSs, it believes that EFVSs could 
be certified through application of appropriate safety criteria. 
Therefore, the FAA has determined that special conditions should be 
issued for certification of EFVS to provide a level of safety 
equivalent to that provided by the standard in Sec.  25.773.
    On January 9, 2004, the FAA published revisions to operational 
rules in 14 CFR parts 1, 91, 121, 125, and 135 to allow aircraft to 
operate below certain altitudes during a straight-in instrument 
approach while using an EFVS to meet visibility requirements.
    Prior to this rule change, the FAA issued Special Conditions No. 
25-180-SC, which applied to an EVS installed on Gulfstream Model G-V 
airplanes. Those special conditions addressed the requirements for the 
pilot compartment view and limited the scope of the intended functions 
permissible under the operational rules at the time. The intended 
function of the EVS imagery was to aid the pilot during the approach, 
and allow the pilot to detect and identify the visual references for 
the intended runway down to 100 feet above the touchdown zone. However, 
the EVS imagery alone was not to be used as a means to satisfy 
visibility requirements below 100 feet.
    The 2004 operational rule change expands the permissible 
application of certain EVSs that are certified to meet the new EFVS 
standards. This rule will allow the use of an EFVS for operation below 
the minimum descent altitude or decision height to meet new visibility 
requirements of Sec.  91.175(l). The purpose of these special 
conditions is not only to address the issue of the ``pilot compartment 
view,'' as was done by Special Conditions No. 25-180-SC, but also to 
define the scope of intended function consistent with Sec.  91.175(l) 
and (m).

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Gulfstream must show that 
the Model G280, as modified, complies with the regulations in the U.S. 
type-certification basis established for those airplanes. The U.S. 
type-certification basis for the airplanes is established in accordance 
with Sec.  21.21 and 21.17, and the type certification application 
date. The U.S. type-certification basis for these airplane models is 
listed in Type Certificate Data Sheet No. A16NM, revision 3, November 
5, 2012, which covers all variants of the Model G280 airplanes.
    In addition, the certification basis includes certain special 
conditions and exemptions that are not relevant to these special 
conditions. Also, if the regulations incorporated by reference do not 
provide adequate standards with respect to the change, the applicant 
must comply with certain regulations in effect on the date of 
application for the change.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 25 as amended) do not contain adequate or 
appropriate safety standards for the Gulfstream Model G280 airplanes, 
modified by the applicant, 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 applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate, to incorporate the same novel or unusual design feature, 
the special conditions would also apply to the other model.
    Special conditions, as defined in Sec.  11.19, are issued in 
accordance with Sec.  11.38 and become part of the type-certification 
basis in accordance with Sec.  21.101.

Novel or Unusual Design Features

    The G280 airplanes will incorporate an EFVS, which is a novel or 
unusual design feature. The EFVS is a novel or unusual design feature 
because it projects a video image derived from a FLIR camera through 
the 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

[[Page 32080]]

detected by natural pilot vision. On a dark night, thermal differences 
of objects which are not detectable by the naked eye are 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 EFVS 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 
flight-crew duties 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 only displays 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 intended to provide a conformal perspective corresponding with 
the outside scene, the system must be able to ensure accurate 
alignment. Therefore, 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 the EFVS 
and does not consider that Sec.  25.773 adequately addresses 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 present an enhanced view during the landing 
approach. This enhanced view would help the pilot see and recognize 
external visual references, as required by Sec.  91.175(l), and to 
visually monitor the integrity of the approach, as described in FAA 
Order 6750.24D (``Instrument Landing System and Ancillary Electronic 
Component Configuration and Performance Requirements,'' dated March 1, 
2000).
    Based on this approved functionality, users would seek to obtain 
operational approval to conduct approaches--including approaches to 
Type I runways--in visibility conditions much lower than those for 
conventional Category I.
    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 aids 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 
14 CFR 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:
    1. The infrared-based EFVS image will not be certified as a means 
to satisfy the requirements for descent below 100 feet height above 
touchdown.
    2. 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.
    3. 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 pilot compartment view without an EVS image 
that is compliant with Sec.  25.773. 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 
Gulfstream Model G280 airplanes. Should

[[Page 32081]]

Gulfstream apply at a later date for a supplemental type certificate to 
modify any other model included on Type Certificate No. A16NM to 
incorporate the same novel or unusual design feature, the special 
conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on Gulfstream Model G280 airplanes. It is not a rule of general 
applicability and it affects only the applicant who applied to the FAA 
for approval of these features on the airplane.

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 Model G280 airplanes 
modified by Gulfstream Aerospace Corporation.
    1. The EFVS imagery on the 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. EFVS design must minimize unacceptable display characteristics 
or artifacts (e.g. noise, ``burlap'' overlay, running water droplets) 
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 advisories, and unusual-attitude 
recovery cues.
    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 and, when 
considered singly or in combination, must not be misleading, cause 
pilot confusion, or increase workload. Some airplane attitudes or 
cross-wind conditions may 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 conformably 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 conformably (for example, ``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 use of the pilot-compartment view must not be degraded by the 
display of the EFVS image. Pilot tasks that 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 for which EFVS has not been found to be 
acceptable.

    Issued in Renton, Washington, on May 22, 2013.
Jeff Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-12605 Filed 5-28-13; 8:45 am]
BILLING CODE 4910-13-P
```