[Federal Register Volume 77, Number 71 (Thursday, April 12, 2012)]
[Rules and Regulations]
[Pages 21861-21864]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-8739]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2012-0352; Special Conditions No. 25-462-SC]
Special Conditions: Boeing, Model 777F; 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 Boeing Model 777F
airplane. This airplane, as modified by the FedEx Express Corporation,
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 March 22,
2012. We must receive your comments by May 14, 2012.
ADDRESSES: Send comments identified by docket number FAA-2012-0352
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; fax 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
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 will consider all comments we receive on or before the closing
date for comments. We may change these special conditions based on the
comments we receive.
Background
On November 17, 2010, the FedEx Express Corporation applied for a
supplemental type certificate for the installation and operation of a
HUD and an EFVS in the Boeing Model 777F. The original type certificate
for the 777F airplanes is T00001SE, Revision 28, dated August 5, 2011.
The Boeing Model 777F is a transport-category, cargo-carrying
airplane that operates with a crew of two. It is powered by two General
Electric GE90-110B1 or GE90-115B turbofan engines, has a maximum gross
takeoff weight of 766,800 pounds, and a maximum range of 4,900 nautical
miles.
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 vision system (EVS) image, and 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
[[Page 21862]]
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 14 CFR 21.101, the FedEx Express
Corporation must show that the Boeing Model 777F, as changed, continues
to meet the applicable provisions of the regulations incorporated by
reference in Type Certificate No. T00001SE 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. T00001SE, Revision 28, dated August 5, 2011, which
covers all variants of the Boeing 777 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 Boeing Model 777F 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 777F 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 Boeing Model 777F 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
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
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.
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
[[Page 21863]]
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.
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:
Resolution
Luminance
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.
Applicability
As discussed above, these special conditions are applicable to the
Boeing Model 777F. Should the FedEx Express Corporation apply at a
later date for a supplemental type certificate to modify any other
model included on Type Certificate No. T00001SE 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 Boeing 777F 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.
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
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 Boeing Model 777F airplanes modified
by the FedEx Express Corporation.
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
[[Page 21864]]
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. 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 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. 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. 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
acceptable.
Issued in Renton, Washington, on March 22, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-8739 Filed 4-11-12; 8:45 am]
BILLING CODE 4910-13-P