[Federal Register: August 22, 2005 (Volume 70, Number 161)]
[Rules and Regulations]
[Page 48844-48848]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22au05-5]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM324; Special Conditions No. 25-293-SC]
Special Conditions: McDonnell Douglas Model MD-10-10F and MD-10-
30F Airplanes; Enhanced Flight Visibility System (EFVS)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
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[[Page 48845]]
SUMMARY: These special conditions are issued for the McDonnell Douglas
Model MD-10-10F and MD-10-30F airplanes. These airplanes, as modified
by the Federal Express Corporation, will have an advanced 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 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 August 9,
2005. Comments must be received on or before September 21, 2005.
ADDRESSES: Comments on these special conditions may be mailed in
duplicate to: Federal Aviation Administration, Transport Airplane
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM324, 1601 Lind
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate
to the Transport Airplane Directorate at the above address. Comments
must be marked: Docket No. NM324. 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: The FAA has determined that the substance of
these special conditions has previously been subject to the public
comment process. These particular special conditions were recently
issued and only three non-substantive comments were received during the
public comment period. The FAA therefore finds that good cause exists
for making these special conditions effective upon issuance.
Comments Invited
Interested persons are invited to submit such written data, views,
or arguments, as they may desire. Communications should identify the
rules docket number and be submitted in duplicate to the address
specified above. The Administrator will consider all communications
received on or before the closing date for comments. The special
conditions may be changed in light of the comments received. All
comments received will be available in the Rules Docket for examination
by interested persons, both before and after the closing date for
comments. A report summarizing each substantive public contact with FAA
personnel concerning this rulemaking will be filed in the docket.
Persons wishing the FAA to acknowledge receipt of their comments
submitted in response to these special conditions must include with
those comments a self-addressed, stamped postcard on which the
following statement is made: ``Comments to Docket No. NM324''. The
postcard will be date stamped and returned to the commenter.
Background
On May 1, 2004, the Federal Express Corporation applied for a
supplemental type certificate for the installation and operation of a
head-up display (HUD) and an infrared enhanced flight vision system
(EFVS) on McDonnell Douglas Model MD-10-10F and MD-10-30F airplanes.
The original type certificate for the MD-10-10F and MD-10-30F airplanes
is A22WE, revision 7, dated May 24, 2002.
The McDonnell Douglas Model MD-10-10F and MD-10-30F are transport
category cargo-carrying airplanes that operate with a crew of two and
carry no passengers. The model MD-10-10F airplane has a wing span of
155 feet, a length of 181 feet, a maximum takeoff gross weight of
440,000 pounds, is powered by three General Electric CF6-6D or CF6-K
turbofan engines, and has a maximum range of 5,514 nautical miles. The
Model MD-10-30F airplane has a wing span of 165 feet; a length of 182
feet; a maximum takeoff gross weight of 565,000 pounds or 580,000
pounds, depending on the serial number; is powered by three General
Electric CF6-50C2 turbofan engines; and has a maximum range of 6,500
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 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.
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.
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 approved the use of an EVS 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
[[Page 48846]]
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 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 Federal Express
Corporation must show that the McDonnell Douglas Model MD-10-10F and
MD-10-30F airplanes, as modified, comply 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. Sec. 21.21 and 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. A22WE, revision 7, dated May
24, 2005, which covers all variants of the DC-10, MD-10, and MD-11
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 McDonnell Douglas Model MD-10-10F
and MD-10-30F airplanes modified by Federal Express because of a novel
or unusual design feature, special conditions are prescribed under the
provisions of Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the McDonnell Douglas Model MD-10-10F and MD-10-30F
airplanes 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.
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.
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.
Novel or Unusual Design Features
The McDonnell Douglas Model MD-10-10F and MD-10-30F 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 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
flightcrew 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 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 EFVSs and
does not consider Sec. 25.773 to be adequate to address the specific
issues related to such a system. Therefore, the FAA has determined that
special conditions are needed to address the specific issues particular
to the installation and use of an EFVS.
Discussion
The EFVS is intended to function by presenting an enhanced view
during the approach. This enhanced view would help the pilot to see and
recognize external visual references, as required by Sec. 91.175(l),
and to visually monitor
[[Page 48847]]
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 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 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
McDonnell Douglas Model MD-10-10F and MD-10-30F airplanes. Should the
Federal Express Corporation apply at a later date for a supplemental
type certificate to modify any other model included on Type Certificate
No. A22WE 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 McDonnell Douglas Model MD-10-10F and MD-10-30F airplanes modified
by the Federal Express Corporation. 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. For this reason, 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.
0
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Special Conditions
0
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 McDonnell Douglas Model MD-10-10F and
MD-10-30F airplanes modified by the Federal Express 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. 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
[[Page 48848]]
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 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 Sec. 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 there is sufficient
``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
Sec. 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 Sec. 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 August 9, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-16518 Filed 8-19-05; 8:45 am]
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