[Federal Register Volume 70, Number 161 (Monday, August 22, 2005)]
[Rules and Regulations]
[Pages 48844-48848]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16518]


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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: [email protected].

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]
BILLING CODE 4910-13-P