[Federal Register: March 30, 2005 (Volume 70, Number 60)]
[Proposed Rules]
[Page 16161-16164]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30mr05-22]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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[[Page 16161]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM303; Notice No. 25-05-02-SC]
Special Conditions: Bombardier Aerospace Models BD-700-1A10 and
BD-700-1A11 Global Express Airplanes; Enhanced Flight Visibility System
(EFVS)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed special conditions.
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SUMMARY: This notice proposes special conditions for the Bombardier
Aerospace Models BD-700-1A10 and BD-700-1A11 Global Express airplanes.
These airplanes, as modified by Bombardier Aerospace Corporation, will
have an Enhanced Flight Visibility 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
regulations applicable to pilot compartment view do not contain
adequate or appropriate safety standards for this design feature. These
proposed special conditions contain the additional safety standards
that the Administrator considers necessary to establish a level of
safety equivalent to that provided by the existing airworthiness
standards.
DATES: Comments must be received on or before April 19, 2005.
ADDRESSES: Comments on this proposal may be mailed in duplicate to:
Federal Aviation Administration, Transport Airplane Directorate,
Attention: Rules Docket (ANM-113), Docket No. NM303, 1601 Lind Avenue
SW., Renton, Washington 98055-4056; or delivered in duplicate to the
Transport Airplane Directorate at that address. All comments must be
marked: Docket No. NM303. Comments may be inspected in the Rules Docket
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
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; e-mail: dale.dunford@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites interested persons to participate in this
rulemaking by submitting 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 proposed special conditions. The docket is available
for public inspection 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 notice between 7:30 a.m. and 4 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 the
proposed special conditions in light of the comments we receive.
If you want the FAA to acknowledge receipt of your comments on this
proposal, include with your comments a pre-addressed, stamped postcard
on which the docket number appears. We will stamp the date on the
postcard and mail it back to you.
Background
On February 26, 2003, Bombardier Aerospace, applied for an
amendment to the type certificate to modify Bombardier Model BD-700-
1A10 and BD-700-1A11 Global Express airplanes. The Model BD-700-1A10 is
a transport category airplane certified to carry a maximum of 19
passengers and a minimum of 2 crew members. The Model BD-700-1A11 is a
smaller version of the BD-700-1A10. The modification involves the
installation of an Enhanced Flight Vision System (EFVS). This system
consists of a Thales HUD system, modified to display FLIR imagery, and
a FLIR camera.
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's intent is that the
pilot will be able to use the combination of information seen in the
image and the natural view of the outside seen through the image as
safely and effectively as a Sec. 25.773-compliant pilot compartment
view without an EVS image.
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.
Note: The term ``enhanced vision system (EVS)'' has been
commonly used to refer to a system comprised of a head up display,
imaging sensor(s), and avionics interfaces that displayed the sensor
imagery on the HUD and overlaid it with alpha-numeric and symbolic
flight information. However, the term has also been commonly used in
reference to systems which displayed the sensor imagery, with or
without other flight information, on a head down display. To avoid
confusion, the FAA created the term ``enhanced flight visibility
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 can be
used to determine ``enhanced flight visibility.'' EFVSs can be
considered a subset of systems otherwise labeled EVSs.
[[Page 16162]]
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 25-
180-SC, which approved the use of an EVS on Gulfstream Model G-V
airplanes. These 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 will allow the use of EFVSs for operation below
the Minimum Descent Altitude (MDA) or Decision Height (DH) to meet new
visibility requirements of Sec. 91.175(l). The purpose of this special
condition is not only to address the issue of the ``pilot compartment
view'' as was done by 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, Bombardier Aerospace must
show that the Bombardier Aerospace Model BD-700-1A10 and BD-700-1A11
Global Express airplanes, as modified, comply with the regulations in
the U.S. type certification basis established for those airplanes. The
U.S. type certificate basis for the airplanes is established in
accordance with 14 CFR 21.21, 14 CFR 21.17, and the type certification
application date. The U.S. type certification basis for these model
airplanes is listed in Type Certificate Data Sheet No. T00003NY.
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 Bombardier Global Express
airplanes modified by Bombardier Aerospace because of a novel or
unusual design feature, special conditions are prescribed under the
provisions of 14 CFR 21.16.
Special conditions, as appropriate, are issued in accordance with
14 CFR 11.19 after public notice, as required by 14 CFR 11.38, and
become part of the type certification basis in accordance with 14 CFR
21.101(b)(2).
Special conditions are initially applicable to the model for which
they are issued. Should Bombardier Aerospace apply at a later date 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, these special conditions would also apply to the other
model under the provisions of 14 CFR 21.101(a)(1).
Novel or Unusual Design Features
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 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 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, there need to be safety standards 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.
[[Page 16163]]
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 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 14 CFR 25.1301 and 14 CFR 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
Bombardier Aerospace Models BD-700-1A10 and BD-700-1A11 Global Express
airplanes. Should Bombardier Aerospace apply at a later date 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, these special conditions would apply to that model as well
under the provisions of Sec. 21.101(a)(1).
Conclusion
This action affects only certain novel or unusual design features
on the Bombardier Aerospace Models BD-700-1A10 and BD-700-1A11 Global
Express airplane, as modified by Bombardier Aerospace. 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.
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 Proposed Special Conditions
Accordingly, pursuant to the authority delegated to me by the
Administrator, the FAA proposes the following special conditions as
part of the amended type certification basis for Bombardier Aerospace
Models BD-700-1A10 and BD-700-1A11 Global Express airplanes, modified
by Bombardier Aerospace:
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. 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
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.
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, 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
[[Page 16164]]
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. There may be airplane attitudes or
cross-wind conditions which 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 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 (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. These tasks include the following:
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. Compliance with these special conditions will enable the EFVS to
be used during instrument approaches in accordance with 14 CFR
91.175(l) such that it may be found acceptable for the following
intended functions:
a. Presenting an image that would aid the pilot during a straight-
in instrument approach.
b. Enabling the pilot to determine that the ``enhanced flight
visibility,'' as required by Sec. 91.175(l)(2) for descent and
operation below minimum descent altitude/decision height (MDA)/(DH).
c. Enabling the pilot to use the EFVS imagery 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 touchdown zone elevation.
5. Use of EFVS for instrument approach operations must be in
accordance with the provisions of 14 CFR 91.175(l) and (m). 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 March 23, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-6310 Filed 3-29-05; 8:45 am]
BILLING CODE 4910-13-P