[Federal Register Volume 77, Number 178 (Thursday, September 13, 2012)]
[Rules and Regulations]
[Pages 56525-56528]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-22468]

Rules and Regulations
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Federal Register / Vol. 77, No. 178 / Thursday, September 13, 2012 / 
Rules and Regulations

[[Page 56525]]


Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2012-0968; Special Conditions No. 25-467-SC]

Special Conditions: Bombardier, Model CL-600-2B16 Airplane (CL-
601-3A, CL-601-3R, and CL-604 Variants); Enhanced Flight Vision System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.


SUMMARY: These special conditions are issued for the Bombardier Model 
CL-600-2B16 airplanes, including variants CL-601-3A, CL-601-3R and CL-
604. This airplane, as modified by Atlantic Aero, Inc., will have a 
novel or unusual design feature associated with an advanced, enhanced 
flight vision system (EFVS). The EFVS 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 September 6, 
2012. We must receive your comments by October 29, 2012.

ADDRESSES: Send comments identified by docket number FAA-2012-0968 
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 98057-3356; telephone 
425-227-2239; facsimile 425-227-1320; email: dale.dunford@faa.gov.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and 
opportunity for prior public comment on, these special conditions are 
impracticable because these procedures would significantly delay 
issuance of the design approval and thus delivery of the affected 
aircraft. In addition, 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 

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 will consider all comments we receive by the closing date for 
comments. We may change these special conditions based on the comments 
we receive.


    On October 7, 2011, Atlantic Aero, Inc., applied for a supplemental 
type certificate (STC) for the installation and operation of a HUD and 
an EFVS in the Bombardier Model CL-600-2B16 (CL-601-3A, CL-601-3R, and 
CL-604 variants). The original type certificate for the CL-600-2B16 is 
A21EA, dated April 30, 1987, and is now at revision 31, dated May 25, 
    The Model CL-600-2B16 is a 22-passenger, transport category 
airplane that operates with a crew of two. It is powered by two General 
Electric engines and has a maximum takeoff weight of 43,100 pounds for 
the CL-601-3A and 3R variants and 47,600 pounds for the CL-604 variant.
    The electronic infrared image displayed between the pilot and the 
forward windshield represents a novel or unusual design feature in the 
context of Title 14, Code of Federal Regulations (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's 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, as seen through the image, as safely and effectively as a pilot 
compartment view without an enhanced

[[Page 56526]]

vision system (EVS) image, and that it 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 EFVSs to provide a level of safety 
equivalent to that provided by the standard in Sec.  25.773.

    Note: The term ``enhanced vision system'' (EVS) in this document 
refers to a system comprised of a head-up display (HUD), imaging 
sensor(s), and avionics interfaces that display the sensor imagery 
on the HUD, and overlay that imagery with alpha-numeric and symbolic 
flight information. However, the term has also been commonly used in 
reference to systems that display 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 visibility.'' An EFVS can be considered a subset 
of a system otherwise labeled EVS.

    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 recent operational rule change expands the permissible 
application of certain EVSs that are certified to meet the new EFVS 
standards. The new rule allows 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 Sec.  21.101, Atlantic Aero, Inc., must 
show that the Bombardier Model CL-600-2B16 (CL-601-3A, CL-601-3R, and 
CL-604 variants), as changed, continues to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. A21EA or the applicable regulations in effect on the 
date of application for the change. The regulations incorporated by 
reference in the type certificate are commonly referred to as the 
``original type certification basis.'' The regulations incorporated by 
reference are listed in Type Certificate Data Sheet No. A21EA, Revision 
31, dated May 25, 2011, which covers all variants of the Bombardier CL-
600-2B16 airplanes. In addition, the certification basis includes 
certain special conditions and exemptions that are not relevant to 
these special conditions.
    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 Bombardier Model CL-600-2B16 
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.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model CL-600-2B16 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 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.  21.101.

Novel or Unusual Design Features

    The Bombardier Model CL-600-2B16 will incorporate the following 
novel or unusual design feature: An EFVS that 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 they can be seen 
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 unaided eye are 
easily detected by many imaging infrared systems. On the other hand, 
contrasting colors in visual wavelengths may be distinguished by the 
unaided 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 
flightcrew 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.

[[Page 56527]]

    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 
    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.


    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, 
    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 
     Provide enhanced flight visibility to the pilot that is no 
less than the visibility prescribed in the standard instrument approach 
     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:
    1. The infrared-based EFVS image will not be certified as a means 
to satisfy the requirements for descent below 100 feet height above 
    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.
    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, as 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:

 Luminance uniformity
 Low-level luminance
 Contrast variation
 Display quality
 Display dynamics (e.g., jitter, flicker, update rate, and lag)
 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.


    As discussed above, these special conditions are applicable to the 
Bombardier Model CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604 
variants). Should Atlantic Aero, Inc., apply at a later date for a 
supplemental type certificate to modify any other model included on 
Type Certificate No. A21EA to incorporate the same novel or unusual 
design feature, the special conditions would apply to that model as 


    This action affects only certain novel or unusual design features 
on one model series of airplanes. It is not a rule of general 
applicability and affects only the applicant who applied to the FAA for 
approval of these features on the airplane.
    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, because a delay would 
significantly affect the certification of the airplane, which is 
imminent, the FAA has determined that prior public notice and comment 
are unnecessary and impracticable, 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 

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 

    The authority citation for these special conditions is as follows:

[[Page 56528]]

    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 Bombardier Model CL-600-2B16 (CL-601-
3A, CL-601-3R, and CL-604 variants) airplanes modified by Atlantic 
Aero, Inc.
    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) 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 
    b. Automatic 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, 
windshear guidance, traffic alert and collision avoidance system (TCAS) 
resolution advisories, or 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. In addition, the 
EFVS image and the HUD symbols, when considered singly or in 
combination, must not be misleading, cause pilot confusion, or increase 
workload. Airplane attitudes or crosswind conditions may cause certain 
symbols (e.g., 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, 
    f. A HUD system used to display EFVS images must, if previously 
certified, continue to meet all of the requirements of the original 
    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 
    b. Accurate identification and utilization of visual references 
required for every task relevant to the phase of flight.
    Use of EFVS for instrument approach operations must be in 
accordance with the provisions of Sec.  91.175(l) and (m) and Sec.  
121.651 where applicable. 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 

    Issued in Renton, Washington, on September 6, 2012.
Ali Bahrami
Manager, Transport Airplane Directorate, Aircraft Certification 
[FR Doc. 2012-22468 Filed 9-12-12; 8:45 am]