Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32717

State and local officials. (See 7 CFR part

3015, subpart V.)

Executive Order 12988

This rule has been reviewed under

Executive Order 12988, Civil Justice

Reform. This rule: (1) Preempts all State

and local laws and regulations that are

inconsistent with this rule; (2) has no

retroactive effect; and (3) does not

require administrative proceedings

before parties may file suit in court

challenging this rule.

Paperwork Reduction Act

In accordance with the Paperwork

Reduction Act of 1995 (44 U.S.C. 3501

et seq.), the information collection or

recordkeeping requirements included in

this rule have been approved by the

Office of Management and Budget

(OMB) under OMB control number

0579–0168.

List of Subjects in 7 CFR Part 301

Agricultural commodities, Plant

diseases and pests, Quarantine,

Reporting and recordkeeping

requirements, Transportation.

Accordingly, we are amending 7 CFR

part 301 as follows:

PART 301—DOMESTIC QUARANTINE

NOTICES

1. The authority citation for part 301

is revised to read as follows:

Authority: 7 U.S.C. 166, 7711, 7712, 7714,

7731, 7735, 7751, 7752, 7753, and 7754; 7

CFR 2.22, 2.80, and 371.3.

Section 301.75–15 also issued under Sec.

204, Title II, Pub. L. 106–113, 113 Stat.

1501A–293; sections 301.75–15 and 301.75–

16 also issued under Sec. 203, Title II, Pub.

L. 106–224, 114 Stat. 400 (7 U.S.C. 1421

note).

2. Section 301.75–1 is amended by

adding a definition of ACC coverage to

read as follows:

§ 301.75–1 Definitions.

ACC coverage. The crop insurance

coverage against Asiatic citrus canker

(ACC) provided under the Florida Fruit

Tree Pilot Crop Insurance Program

authorized by the Federal Crop

Insurance Corporation.

* * * * *

3. In Subpart—Citrus Canker, a new

§ 301.75–16 is added to read as follows:

§ 301.75–16 Payments for the recovery of

lost production income.

Subject to the availability of

appropriated funds, the owner of a

commercial citrus grove may be eligible

to receive payments in accordance with

the provisions of this section to recover

income from production that was lost as

the result of the removal of commercial

citrus trees to control citrus canker.

(a) Eligibility. The owner of a

commercial citrus grove may be eligible

to receive payments to recover income

from production that was lost as the

result of the removal of commercial

citrus trees to control citrus canker if the

trees were removed pursuant to a public

order between 1986 and 1990 or on or

after September 28, 1995.

(b) Calculation of payments. (1) The

owner of a commercial citrus grove who

is eligible under paragraph (a) of this

section to receive payments to recover

lost production income will, upon

approval of an application submitted in

accordance with paragraph (c) of this

section, receive a payment calculated

using the following rates:

Citrus variety Payment

(per acre)

Grapefruit .................................. $3,342

Orange, Valencia, and tangerine .................................... 6,446

Orange, navel (includes early

and midseason oranges) ...... 6,384

Tangelo ..................................... 1,989

Lime .......................................... 6,503

Other or mixed citrus ................ 3,342

(2) Payment adjustments. (i) In cases

where the owner of a commercial citrus

grove had obtained ACC coverage for

trees in his or her grove and received

crop insurance payments following the

destruction of the insured trees, the

payment provided for under paragraph

(b)(1) of this section will be reduced by

the total amount of the crop insurance

payments received by the commercial

citrus grove’s owner for the insured

trees.

(ii) In cases where ACC coverage was

available for trees in a commercial citrus

grove but the owner of the grove had not

obtained ACC coverage for his or her

insurable trees, the per-acre payment

provided for under paragraph (b)(1) of

this section will be reduced by 5

percent.

(c) How to apply for lost production

payments. The form necessary to apply

for lost production payments may be

obtained from any local citrus canker

eradication program office in Florida, or

from the USDA Citrus Canker Project,

6901 West Sunrise Boulevard,

Plantation, FL 33313. The completed

application should be accompanied by a

copy of the public order directing the

destruction of the trees and its

accompanying inventory that describes

the acreage, number, and the variety of

trees removed. Your completed

application must be sent to the USDA

Citrus Canker Eradication Project, Attn:

Lost Production Payments Program, c/o

Division of Plant Industry, 3027 Lake

Alfred Road, Winter Haven, FL 33881.

Claims for losses attributable to the

destruction of trees on or before the

effective date of this rule must be

received on or before August 17, 2001.

Claims for losses attributable to the

destruction of trees after the effective

date of this rule must be received within

60 days after the destruction of the trees.

The Administrator may, on a case-bycase basis, approve the consideration of

late claims when the circumstances

appear, in the opinion of the

Administrator, to warrant such

consideration. However, any request for

consideration of a late claim must be

submitted to the Administrator on or

before July 18, 2002 for trees destroyed

on or before July 18, 2001, and within

1 year after the destruction of the trees

for trees destroyed after July 18, 2001.

Done in Washington, DC, this 12th day of

June 2001.

Bill Hawks,

Under Secretary for Marketing and Regulatory

Programs.

[FR Doc. 01–15320 Filed 6–15–01; 8:45 am]

BILLING CODE 3410–34–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM185; Special Conditions No.

25–180–SC]

Special Conditions: Enhanced Vision

System (EVS) for Gulfstream Model G–

V Airplanes

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Final special conditions.

SUMMARY: These special conditions are

issued for Gulfstream Model G–V

airplanes. These airplanes, as modified

by Gulfstream Aerospace Corporation,

will have novel or unusual design

features associated with 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 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.

EFFECTIVE DATE: June 18, 2001.

FOR FURTHER INFORMATION CONTACT: Dale

Dunford, FAA, Transport Standards

32718 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

Staff, ANM–111, Transport Airplane

Directorate, Aircraft Certification

Service, 1601 Lind Avenue SW.,

Renton, Washington 98055–4056;

telephone (425) 227–2239; fax (425)

227–1100; e-mail:

dale.dunford@faa.gov.

SUPPLEMENTARY INFORMATION

Background

On February 13, 1998, Gulfstream

Aerospace Corporation, 4150 Donald

Douglas Drive, Long Beach, California

90808, applied for a supplemental type

certificate (STC) to modify Gulfstream

Model G–V airplanes. The Model G–V is

a transport category to modify

Gulfstream Model G–V airplanes. The

Model G–V is a transport category

airplane with a maximum takeoff weight

of 90,500 pounds and powered by two

BMW-Rolls Royce Mark BR700–710A1–

10 engines. This airplane operates with

a two-pilot crew and can hold up to 19

passengers.

The modification incorporates the

installation of an Enhanced Vision

System (EVS), consisting of a Honeywell

2020 head-up display (HUD) system

modified to display forward-looking

infrared (FLIR) imagery provided from a

Kollsman FLIR assembly. The FAA has

previously approved the Honeywell

2020 HUD.

The FAA only considered natural

pilot vision for the pilot compartment

view when issuing § 25.773. The

electronic infrared image displayed

between the pilot and the forward

windshield represents a novel or

unusual design feature in the context of

§ 25.773. The projection of electronic

imagery has the potential to enhance the

pilot’s situational awareness. The FAA

needs to evaluate EVS to determine that

the imagery does not adversely affect

the pilot’s outside compartment view.

Although the FAA determined that

the existing regulations are not adequate

for certification of EVS, it believes that

EVS could be certified through

application of appropriate safety

criteria. Therefore, the FAA has

determined that special conditions

should be issued for certification of EVS

to establish an equivalent level of safety

and effectiveness of the pilot

compartment view as intended by the

regulation.

Gulfstream and the FAA conducted

an extensive proof of concept flight

demonstration program and concluded

that the EVS could be certified to

provide an image that would aid the

pilot during an instrument approach for

detecting and identifying the visual

references listed in Title 14, Code of

Federal Regulations (14 CFR

91.175(c)(3)) for descent below decision

height to 100 feet above touchdown.

Conditions permitting, EVS may yield

safety and operational benefits by

providing the pilot with enhanced

situational awareness.

Type Certification Basis

Under the provisions of § 21.101

(‘‘Designation of applicable

regulations’’), Gulfstream Aerospace

Corporation must show that the

Gulfstream Model G–V airplanes, as

changed, comply with the regulations in

the U.S. type certification basis

established for the Model G–V airplane.

The U.S. type certificate basis

established for the Model G–V airplane

is established in accordance with

§ 21.21 (‘‘Issue of type certificate

***’’) and § 21.17 (‘‘Designation of

applicable regulations’’), and the type

certification application date. The U.S.

type certification basis for this model

airplane is listed in Type Certificate

Data Sheet No. A12EA.

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 Gulfstream Model G–

V airplanes modified by Gulfstream

Aerospace Corporation because of a

novel or unusual design feature, special

conditions are prescribed under the

provisions of § 21.16 (‘‘Special

conditions’’).

In addition to the applicable

airworthiness regulations and special

conditions, these Gulfstream Model G–

V airplanes must comply with the fuel

vent and exhaust emission requirements

of part 34 and the noise certification

requirements of part 36.

Special conditions, as appropriate, are

issued in accordance with § 11.19

(‘‘What is a final rule?’’), after public

notice, as required by § 11.38 (‘‘What

public comment procedures does FAA

follow for Special Conditions?’’), and

become part of the type certification

basis in accordance with § 21.101(b)(2).

Special conditions are initially

applicable to the model for which they

are issued. Should Gulfstream

Aerospace Corporation 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 § 21.101(a)(1).

Novel or Unusual Design Features

The Gulfstream EVS project is the first

civil certification of infrared imagery

displayed on a HUD. This EVS is novel

or unusual technology because it places

a raster* infrared image in the center of

the pilot’s regulated ‘‘pilot compartment

view,’’ which must be free of

interference, distortion, and glare that

would adversely affect the performance

of the pilot’s normal duties. (*A ‘‘raster’’

image is comprised of a set of horizontal

lines that continuously sweep across the

display and form a picture on the

display by modulating their intensity

(luminance).) The EVS/HUD system

projects a raster image derived from a

forward-looking infrared (FLIR) camera

onto the display of the Honeywell HUD

2020 system. The EVS image is

displayed with HUD symbology and

overlays the forward outside view.

Operationally, during an instrument

approach, the EVS image is intended to

enhance the pilot’s ability to detect and

identify ‘‘visual references for the

intended runway’’ (see § 91.175(c)(3)),

to continue the approach below

decision height. 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 the pilot can see them

through the window without EVS.

Scene contrast detected by infrared

sensors can be much different than 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,

shapes and patterns of certain visual

references can be recognized in the

infrared image by the pilot, but,

depending on conditions, they can also

appear significantly different to a pilot

in the infrared image than they would

with normal vision.

There is the potential for the image to

improve the pilot’s ability to detect and

identify items of interest. EVS needs to

be evaluated to determine that the

imagery does not adversely affect the

pilot’s ability to see outside the window

through the image. Section 25.773(a)(2)

states:

Each pilot compartment must be free of

glare and reflection that could interfere with

the normal duties of the minimum flight

crew.

A raster image can be more difficult

for the pilot to see through than strokewritten symbols also displayed on the

HUD. 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

Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32719

with the pilot’s view out the window

through the display. However, unlike

stroke symbology, the raster image

illuminates, to some degree, most of the

total display area of the HUD

(approximately 30 degrees horizontally

and 20 degrees vertically) with much

greater potential interference with the

pilot compartment view. The pilot

cannot see around the raster image, but

must see the outside scene through it.

Unlike the pilot’s external view, the

EVS image is a monochrome, twodimensional display. Some, but not all,

of the depth cues found in the natural

view are also found in the imagery. The

quality of the EVS image and the level

of EVS infrared sensor performance

could depend significantly on the

atmospheric and external light source

conditions. Gain settings of the sensor,

and brightness or contrast settings of the

HUD, can significantly affect image

quality. 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 potential for misalignment must be

considered.

Hence, safety standards for each of the

following factors are needed:

• An acceptable degree of

interference of the window or ‘‘window

and HUD’’ view;

• Potential image misalignment;

• Distortion; and

• The potential for pilot confusion or

misleading information.

The FAA did not anticipate the novel

and unusual design features of the EVS

when § 25.773 was issued, and does not

consider the current regulation to be

adequate to address the specific issues

related to an enhanced vision system.

Therefore, the FAA has determined that,

in addition to the requirements of 14

CFR part 25, special conditions are

needed to address requirements

particular to the installation of an EVS.

Discussion

Gulfstream Aerospace Corporation

intends for the EVS to function by

presenting an enhanced view that

would aid the pilot, during the

approach:

• To see and recognize external visual

references that are required by

§ 91.175(c), 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 when

the Runway Visual Range (RVR) is as

low as 1,200 feet, including approaches

to Type I runways. Gulfstream does not

intend, and the FAA does not intend by

these special conditions for the EVS

imagery to be used either as a means of

flight guidance, or as the substitution for

the outside view while maneuvering the

airplane during approach, landing,

rollout, or takeoff.

The criteria of these special

conditions were developed to determine

that this EVS is of the kind and design

appropriate to the following functions:

• Presenting an enhanced view that

would aid the pilot during the

approach.

• Displaying an image that the pilot

can use to detect and identify the

‘‘visual references for the intended

runway’’ required by § 91.175(c)(3) to

continue the approach with vertical

guidance to 100 feet height above

touchdown (HAT).

Depending on the atmospheric

conditions and the particular visual

references that happen to be distinctly

visible and detectable in the EVS image,

these two 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

in the operating regulations (e.g., parts

91, 121, and 135). The EVS does not

change the approach minima prescribed

in the standard instrument approach

procedure being used; published

minima still apply.

The FAA certification of this EVS is

limited as follows:

• The infrared-based EVS image will

not be certified as a means to satisfy the

requirements for descent below 100 feet

HAT.

• The infrared-based EVS image will

not be certified as a means to establish

that flight visibility is consistent with

the visibility condition prescribed in the

standard instrument approach being

used (see § 91.175(c)(2)).

• The EVS imagery, alone, will not be

certified either as flight guidance, or as

a substitution for the outside view for

maneuvering the airplane during

approach, landing, rollout, or takeoff.

• The EVS 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 EVS 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

§ 25.773-compliant pilot compartment

view without an EVS image. This is the

fundamental objective of the special

conditions.

The FAA also intends to apply

certification criteria, not as special

conditions, for compliance with other

Federal Aviation Regulations, including

§ 25.1301 (‘‘Equipment: Function and

installation’’) and § 25.1309

(‘‘Equipment, systems, and

installations’’). These criteria address

certain image characteristics,

installation, demonstration, and system

safety.

Image characteristics criteria include:

• resolution,

• luminance,

• luminance uniformity,

• low level luminance,

• contrast variation,

• display quality,

• display dynamics (for example,

jitter, flicker, update rate, and lag), and

• brightness controls.

Installation criteria address:

• visibility and access to EVS controls,

and

• integration of EVS in the cockpit.

The EVS 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.

Discussion of Comments

Notice of proposed special conditions

No. 25–01–02–SC for Gulfstream Model

G–V airplanes was published in the

Federal Register on March 16, 2001 (66

FR 15203). Eighteen commenters,

including the applicant, responded. A

discussion of the comments follows,

along with the FAA’s disposition of

those comments.

Special Conditions Paragraph 4.

(Intended Function)

Several commenters recommend

withdrawal or revision of paragraph 4.

and provide the following comments in

support of this recommendation.

Two commenters state that it is not

clear why operational restrictions are

specified within the special conditions,

and recommend that all references and

attempts at rulemaking and rule

interpretations of parts 91 and 97 be

withdrawn and removed.

Another commenter states that

paragraph 4. may not be accurate as a

32720 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

categorical statement for the future.

There could be other images developed

in the future that may have greater

capabilities than FLIR; hence, this

statement could be mistakenly

interpreted to rule out any chance of

progress in this area.

One commenter states that the

proposed language is a precedent-setting

prohibition against the reduction of

ceiling and visibility minimums through

EVS usage.

The same commenter also states that

the extensive investments by NASA and

industry to develop commercially viable

and certifiable enhanced and synthetic

vision products to increase the overall

safety are viewed as jeopardized by the

operational restrictions contained

within the proposed special conditions.

Two commenters contend that the use

of EVS to lower landing minimums is

not an issue that is historically

addressed by FAA Aircraft Certification,

but by FAA Flight Standards. Following

some period of operational use, Flight

Standards may or may not see fit to

allow the use of an enhanced vision

image to replace visual contact below

the normal decision height.

Several commenters state that

paragraph 4. is beyond the scope of the

rulemaking and outside the authority

established by § 21.16 in that it

establishes interpretations of operating

rules.

One commenter objects to the use of

the special conditions by the Aircraft

Certification Service to prescribe

operational limits. Approach limits are

codified rather than allowing for growth

of the system into one with reduced

limits.

Another commenter states that the

proposed special conditions set the

overall policy direction for all future

HUD and EVS installations. The

commenter goes on to say that even

though the rule is written as a part 91

only concern, the philosophy will carry

forward and affect part 121 operators as

well.

Three commenters recommend the

following revisions to paragraph 4.:

• Delete the first sentence,

• Replace the reference to ‘‘100 ft.

HAT’’ with ‘‘to an appropriate height

above touchdown,’’

• Add a paragraph 4.c. that states,

‘‘presenting an image that would act as

an independent integrity monitor during

the approach,’’ and

• Revise paragraph 4. to read, ‘‘The

use of EVS will not reduce the ceiling

and visibility minima of the instrument

approach procedure being used, unless

an equivalent level of task performance

and safety required for that reduced

visibility minima can be achieved.’’

The FAA agrees that special

conditions should not establish

interpretations of the operating rules.

The special conditions are not intended

to create, change, restrict, or reinterpret

provisions of the operational rules,

including those related to ceiling and

visibility minima. Special conditions

paragraph 4. is meant to define the

intended function for which this EVS

would be certified, since installed

equipment must be of a type and design

appropriate to its intended function. If

future applicants propose to expand the

intended functions of this or similar

equipment, different special conditions

may be necessary to identify the

appropriate certification criteria for

those intended functions.

The FAA does not agree that

references to operational regulations

should be deleted. Section 91.175(c)(3)

is only mentioned to clarify a function

of the EVS that the pilot may use to

detect and identify ‘‘visual references.’’

The first sentence of special

conditions paragraph 4. is not an

operational restriction. Instead, the

intent of that sentence was to clarify

that the airworthiness approval of EVS

does not reduce or override the

established ceiling and visibility

minima that are legally prescribed in the

standard instrument approach

procedure. In fact, airworthiness

approval of any equipment, whether it

uses a raster image or not, cannot take

precedence over the established

minima. The special condition does not

impose this limitation; it acknowledges

it. When the notice was issued, there

were no published instrument

procedures that prescribed different

minima for operators of EVS-equipped

airplanes.

The FAA agrees that FAA Flight

Standards is responsible for determining

operational requirements. However, it is

also true that the requirements of the

existing operational regulations are

mandatory. Flight Standards may

choose to approve different minima for

operators of EVS-equipped airplanes

either by revising the operational rules

or instrument approach procedures to

specify minima for EVS-equipped

airplanes. As needed, Flight Standards

would also determine in the future

whether different minima would be

applied to operators of airplanes

equipped with this or other EVS

configurations. Therefore, the FAA does

not agree that the first sentence of

special conditions paragraph 4. should

be revised to add the phrase ‘‘unless an

equivalent level of task performance and

safety required for that reduced

visibility minima can be achieved.’’

The FAA also does not agree that the

first sentence of paragraph 4. should be

deleted. However, to clarify the intent of

the first sentence, it is changed to read:

‘‘Compliance with these special

conditions does not affect the

applicability of any of the requirements

in the operating regulations (e.g., parts

91, 121, 135).

The FAA does not agree that the

reference to ‘‘100 feet HAT’’ should be

replaced with ‘‘an appropriate height

above touchdown.’’ Section 91.175(c)(3)

(as well as respective provisions in parts

121 and 135) distinguishes between

visual references required for descent

below decision height and those

required for descent below 100 feet

HAT. The Gulfstream Proof of Concept

(PoC) Flight Test Report recommended

that descent below 100 feet HAT must

not be predicated on EVS imagery alone.

To make such a change as requested

would require separate rulemaking to

change the relevant regulations.

The FAA does not agree that a new

paragraph 4.c. needs to be added to

address the use of the EVS as an

independent monitor. The pilot may use

the EVS image to identify certain visual

references that serve as airplane

position cues. The EVS sensor

performance (i.e., what can be seen and

at what distance) in the actual

atmospheric conditions will affect the

usefulness of the image for the purpose

of verifying airplane position. Special

conditions paragraph 4., with its

subparagraphs, does not explicitly list

the function of ‘‘integrity monitor’’ for

the guidance, but this function is

covered within the dual intended

function of ‘‘presenting an image that

would aid the pilot during the

approach’’ and ‘‘that the pilot can use to

detect and identify the visual

references’’ [§ 91.175(c)(3)]. The EVS

cannot be an independent monitor in

the same sense as the term is normally

used. Normal use of this term is

automatic detection and annunciation of

system performance deviations and

failure conditions.

Clarification of Notice Preamble

(Discussion) and Special Conditions

Paragraph 4

One commenter submitted the

following questions to the FAA docket

for these special conditions. Each

question is followed by an FAA

response which is based on the plain

reading of the regulatory requirements;

specifically, the applicability of the

operational regulations (e.g., parts 91,

121, 135) is the same whether EVS is

installed or not.

Question: Paragraph 4. of the

proposed special conditions states: ‘‘The

Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32721

use of EVS will not reduce the ceiling

and visibility minima of the instrument

approach procedure being used.’’ What

is the purpose of this statement? Is this

a reference to § 91.175(c)(2), and would

this preclude operation below DH or

HAT if the requirements of

§ 91.175(c)(3) were met with EVS alone

but the flight visibility was less than the

visibility prescribed in the approach

being used?

FAA Response: The first sentence of

special conditions paragraph 4. is meant

to clarify that the airworthiness

approval of EVS under part 25 does not

reduce or override the established

ceiling and visibility minima that are

legally prescribed in the standard

instrument approach procedure.

To clarify the intent of the first

sentence, it is changed to read:

‘‘Compliance with these special

conditions does not affect the

applicability of any of the requirements

in the operating regulations (e.g., Parts

91, 121, 135).’’

Question: With respect to item 4(b);

would the pilot be allowed to continue

the approach below a 200 foot HAT to

100 feet, if the EVS detected the

required ‘‘visual references for the

intended runway’’ but the flight

visibility was less than the visibility

prescribed for the approach being used?

FAA Response: As stated previously,

the applicability of the operational

regulations (e.g., parts 91, 121, 135) is

the same whether EVS is installed or

not. Descent and operation below

decision height is not permitted by

§ 91.175 and similar provisions of other

operational parts, as applicable, when

flight visibility is less than prescribed in

the standard instrument approach

procedure being used.

Question: In paragraph eight of the

‘‘Discussion’’ the FAA states: ‘‘However,

the FAA finds that it would not be

appropriate to reduce the ceiling and

visibility minima of the instrument

approach procedure being used based

on the use of EVS.’’ Is this a reference

to § 91.175(c)(2) and would this

preclude a descent below a 200 foot

HAT minimum to 100 feet if the

requirements of § 91.175(c)(3) were met

with the EVS?

FAA Response: This sentence was not

clearly stated. The intent was to say that

compliance with the criteria of these

special conditions does not affect the

applicability of any of the requirements

in the operating regulations (e.g., Parts

91, 121, 135). A descent would be

permitted only if all requirements of

§ 91.175 are met. The first sentence of

special conditions paragraph 4. is

revised accordingly.

Question: Reference paragraph ten of

the ‘‘Discussion’’ section: ‘‘The infraredbased EVS image will not be certified as

a means to satisfy the requirements for

descent below 100 feet HAT.’’ Does this

statement mean that, if the pilot meets

the requirements of § 91.175(c)(3) with

EVS alone at a 200 foot HAT, then he

may descend to a 100 foot HAT?

FAA Response: No, this statement

means that, in order for the pilot to

descend below 100 feet HAT, the

requirements of §§ 91.175(c) and (d)

must be met without the aid of EVS. The

pilot may use EVS below 100 feet HAT,

but the visual references must be

distinctly visible and identifiable with

the naked eye.

Question: If the flight visibility is less

than the prescribed visibility for the

approach being used, but the

requirements of § 91.175(c)(3) at 200 feet

HAT are met, may the approach be

continued to a 100 foot HAT on EVS

alone?

FAA Response: As stated previously,

the applicability of the operational

regulations (e.g., parts 91, 121, 135) is

the same whether EVS is installed or

not. Descent and operation below

decision height is not permitted by

§ 91.175 and similar provisions of other

operational parts, as applicable, when

flight visibility is less than prescribed in

the standard instrument approach

procedure being used.

Descent below the 200 foot decision

height cannot be based on EVS alone.

To use EVS for the descent below

decision height, precision approach

guidance must also be provided on the

HUD. With valid precision approach

guidance provided on the HUD, EVS

may be used to meet the requirements

of § 91.175(c)(3) from the decision

height to 100 feet HAT.

Question: The following example is

provided in an attempt to clarify to all

parties the suggested operating rules.

Situation:

—Part 91 Operator

—Flight Visibility: 0/0

—Published Minima: 200 feet/1⁄2 mile

—EVS: Operational with ‘‘Phase I’’

certification

Note: ‘‘Phase I’’ refers to this certification

program.

In this situation, may the pilot

commence the approach?

FAA Response: Based on the situation

described in the commenter’s question

above, the Part 91 operator can

commence the approach. However, Part

121 and Part 135 operators may not.

Question: At 200 feet the pilot meets

the requirements of § 91.175(c)(3) with

EVS alone, may he continue to 100 feet?

FAA Response: This response is based

on the situation described above by the

commenter. As stated previously, the

applicability of the operational

regulations (e.g., parts 91, 121, 135) is

the same whether EVS is installed or

not. Descent and operation below

decision height is not permitted by

§ 91.175 and similar provisions of other

operational parts, as applicable, when

flight visibility is less than prescribed in

the standard instrument approach

procedure being used.

Descent below the 200-foot decision

height cannot be based on EVS alone.

To use EVS for the descent below

decision height, precision approach

guidance must also be provided on the

HUD. With valid precision approach

guidance provided on the HUD, EVS

may be used to meet the requirements

of § 91.175(c)(3) from the decision

height to 100 feet HAT.

Question: At 100 feet the pilot meets

the requirements of § 91.175(c)(3)

without the aid of EVS, may he continue

to land?

FAA Response: This response is based

on the situation described above by the

commenter. As stated previously, the

applicability of the operational

regulations (e.g., parts 91, 121, 135) is

the same whether EVS is installed or

not. Operation below decision height is

not permitted by § 91.175 and similar

provisions of other operational parts, as

applicable, when flight visibility is less

than prescribed in the standard

instrument approach procedure being

used.

Need for Special Conditions

Part 21 and FAA Order 8110.4B

Several commenters state that the

FAA has failed, in accordance with

§ 21.16 and FAA Handbook 8110.4B, to

justify the need for special conditions.

The commenters state that the existing

regulations (§§ 25.773, 25.1301, and

25.1309) contain the necessary

requirements, and the proposed special

conditions serve no additional purpose.

Two of these commenters recommend

that the special conditions be

withdrawn and paragraphs 1., 2., and 3.

be developed in a method of compliance

issue paper. One of these commenters

states that even if the raster display of

an FLIR image on the HUD is deemed

novel or unusual, regulations are in

place to assure safety.

The FAA disagrees. The legal basis for

the special conditions was carefully

reviewed by the FAA and deemed

appropriate. As discussed in the

preamble of the notice, and these final

special conditions, the FAA issues

special conditions when it determines

that the existing airworthiness standards

do not contain adequate or appropriate

32722 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

safety standards for a novel or unusual

design feature. The regulatory process

for issuing special conditions provides

for public notification and opportunity

for comment on the proposed

certification criteria, and promotes

standardization of new FAA

certification requirements.

The FAA does not agree that § 25.773

is adequate for certification of the EVS.

When the FAA issued § 25.773, it did

not anticipate the display of an

electronic image in the regulated field of

view, and did not account for the

potential of the EVS imagery to help

achieve the safety objectives of the pilot

compartment view. As discussed in the

notice, the EVS image is different from

the natural pilot vision that was

assumed when § 25.773 was issued. The

differences include:

• Image resolution compared to a

pilot’s vision,

• Monochrome image compared to

color vision,

• Fewer cues for depth perception,

and

• The thermal response

characteristics of an infrared sensor

compared to the color discrimination of

pilot vision.

Additionally, the EVS raster image

could potentially interfere with the pilot

view. The raster image covers most of

the combiner at one time, unlike strokewritten HUD symbology, which covers

much less combiner area. Because none

of the regulations referenced by the

commenters contain criteria for

evaluating these issues, the FAA has

determined that those regulations are

inadequate for certification of the EVS.

For these reasons, the FAA determined

that the EVS is novel and unusual with

respect to current airworthiness

regulations, and special conditions are

needed.

One commenter states that the FAA

has failed to provide an adequate

explanation for the basis of the ‘‘novel

and unusual design feature.’’

The special conditions are not merely

a new means of compliance with

§ 25.773, rather they provide a new

requirement and a regulatory path to

certify the EVS and achieve an

equivalent level of safety. The

fundamental requirement contained in

the special conditions, not found in

§ 25.773, is that the combination of what

the pilot sees in the EVS image and

what the pilot sees through and around

the image must be as safe and effective

as the view without the image. The FAA

considers that the level of safety

provided by the special conditions is

equivalent to the level of safety

intended by § 25.773.

Aerospace Standard AS8055

Two commenters state that Aerospace

Standard AS8055 already establishes

standards for EVS and therefore the

special conditions are unnecessary. One

of the commenters states that the FAA

requested industry to recommend

standards for head up displays, which

resulted in the SAE Aerospace Standard

AS8055 that recommends standards for

HUD’s, including raster displays.

The second commenter states that the

basis for the special conditions is

inadequate, and the rationale is one of

opinion. This commenter goes on to say

that the special conditions make no

mention of certain documents (AC

25.773–1, AC 120–28D, SAE AS8055).

The commenter contends that these

documents adequately describe HUD

and EVS design for certification

purposes, without the need for special

conditions.

The FAA does not agree. While the

FAA did request that SAE develop

standards for head up displays, they do

not take the place of airworthiness

regulations or special conditions.

Industry standards, alone, are not

mandatory. The FAA request that SAE

develop these standards does not

contradict the need for special

conditions.

Nevertheless, AS8055 contains

extremely useful industry developed

standards, particularly regarding raster

display quality, that have been adapted

to the fullest possible extent in a

separate means of compliance issue

paper for EVS certification. The current

AS8055 addresses head up displays and

the information presented on them,

including raster imagery, but not

imaging sensors, such as the infrared

camera used in the Gulfstream EVS.

Advisory Circular (AC) 25.773–1

provides criteria for an acceptable

means of compliance with § 25.773, but

does not address the display of

electronic imagery in the regulated pilot

compartment view. The FAA therefore

found no reason to refer to this

document in the notice.

Advisory Circular (AC) 120–28D

provides a means of compliance for

Category III low visibility operations

and certification of equipment designed

for that purpose. The Phase I Gulfstream

EVS is not intended for Category III

operations, and therefore the FAA did

not find a reason to refer to this AC in

the notice.

HUD vs. Raster Imagery

One commenter contends that the

FAA’s main argument revolves around

§ 25.773(a)(2), which states, ‘‘Each pilot

compartment must be free of glare and

reflection that could interfere with the

normal duties of the minimum flight

crew.’’ The commenter further states

that this could equally apply to strokeonly HUD’s which are currently

certified.

Another commenter states that the

notice is in error, since § 25.773 has

been cited and accepted as a means of

compliance for many HUD programs.

A third commenter states that

although § 25.773 does not directly

mention an EVS imagery display, this

regulation, in combination with other

pertinent regulations, contains the

necessary and sufficient requirements

for determining an acceptable pilot

compartment view. The commenter

asserts that these same existing

regulations have been successfully

applied to HUD’s for several years.

The FAA does not agree. Strokewritten HUD symbology and raster

imagery have significantly different

characteristics. As explained in the

notice, stroke-written HUD symbology

illuminates a small fraction of the HUD

combiner area (approximately 20 by 30

degrees) at any one time. The imagery,

on the other hand, can illuminate

almost all of the HUD at one time. The

pilot can see through the relatively large

‘‘unlit spaces’’ between HUD symbols

with very little visual interference, but

the EVS design provides no such spaces

in the raster imagery. Consequently,

depending on the content at any time,

the EVS image might interfere with

much more of the pilot’s view.

Unlike § 25.773, the special

conditions account for this potential

interference by also considering that the

EVS image may also provide useful

information which, in combination with

what the pilot can see through the

image, is as safe and effective as the

pilot’s view without the image.

Military Use of EVS

One commenter states that the EVS

application may be novel and unusual

(that is, for commercial aircraft);

however the technology is not. This

technology, including raster images on a

HUD, has been in use by the military.

The commenter states that special

conditions are premature and the issue

should be studied.

The FAA disagrees. The phrase

‘‘novel or unusual’’ is used in § 21.16 in

the context of existing regulations.

Under the provisions of § 21.16, the

FAA issues special conditions when it

determines existing airworthiness

regulations do not contain adequate

safety standards for a novel or unusual

design feature. The special conditions

are issued to establish a level of safety

Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32723

equivalent to that established in the

existing regulations.

Granted, elements of the EVS have

been in use in the military, even to the

extent of displaying infrared imagery on

a HUD. However, military use of this

technology differs from this civil

application, and the level of safety

required of military systems used in

combat operations differs from what is

required for civil transport airplane

airworthiness. As previously stated in

this document in response to other

comments, certain design features of the

EVS are considered novel or unusual

with respect to the current

airworthiness standards, and the FAA

has determined that special conditions

are needed.

Not Based on Real Data or Analysis

One commenter suggests that the

special conditions be deferred and

modified as necessary so that they are

supported by data and analysis. The

commenter suggests that until that time,

the FAA could make a determination

regarding certification of EVS systems

on a case by case basis.

Another commenter considers the

special conditions to be premature in

that they are based on ‘‘findings’’ that

are not supported by real data or

analysis, and therefore are actually

based on opinions. The commenter

states they participated in the Synthetic

Vision System (SVS) program and that

most of the key elements of the

proposed special conditions are not

supported by the FAA SVS database.

The FAA does not agree that the

special conditions are premature, or that

the criteria for applying the special

conditions for the EVS is not supported

by data and analysis.

The FAA did, in fact, consider the

reported findings of the FAA Synthetic

Vision System Technology

Demonstration program, and the

Gulfstream proof of concept (PoC) flight

test. The large FAA SVS database is

primarily measured sensor performance

with measured atmospheric and scene

conditions. Many of the issues raised

and considered in the FAA SVS

program are addressed in these special

conditions and in a means of

compliance issue paper. As explained in

the notice, and earlier in these final

special conditions in response to other

comments, the electronic EVS image is

different from the pilot’s natural vision

and was not anticipated when § 25.773

was issued, so the FAA determined that

special conditions are needed.

While the FAA believes, based on the

PoC results, that the Gulfstream EVS can

be safely certified, that does not mean

safety standards are unnecessary. The

safety standards covered by the special

conditions are based on issues

investigated during the PoC of the

Gulfstream EVS and the earlier FAA

SVS program.

These special conditions are specific

to the Gulfstream certification project. If

appropriate, different special conditions

may be adopted for future programs

involving similar equipment. The FAA

is making these certification

determinations on a case-by-case basis.

Proof of Concept (PoC) Test Results

One commenter states that the FAA

failed to properly take into account the

results of the FAA proof of concept

program. The test program required two

years and over 200 approaches flown by

FAA selected pilots and specialists, and

the report states that the HUD and the

EVS did not obscure the pilot’s forward

field of view and did not interfere with

the pilot’s view of the runway during

the landing approach.

Another commenter is of the opinion

that the FAA completely ignored the

PoC tests. The commenter states that the

FAA is not justified in issuing the

proposed special conditions since the

results of extensive evaluations during

FAA-mandated PoC flight tests

concluded that the EVS could be

certified and safely used in transport

category operations under existing

airworthiness certification standards.

Another commenter states that the

FAA failed to recognize test results that

show the good faith effort in addressing

the concerns related to safe and effective

use of the EVS. The commenter

contends that the EVS proof-of-concept

tests concluded that the EVS provided

situational awareness, did not obscure

the pilot’s view, and did not interfere

with the pilot’s view of the runway. As

such, it is compliant with the intent of

§ 25.773.

A fourth commenter states that it is

surprising that the notice, which lists

the criteria for issues that must be

addressed for the EVS, makes no

reference to the findings of the PoC

flight test results that conclude these

issues are not a concern.

The FAA does not agree with the

commenters that the PoC test results

were not considered in determining the

need for special conditions. The

purpose of the PoC is to determine what

would be operationally acceptable and

what standards or criteria are needed for

airworthiness approval. It is not the

purpose of the PoC to determine

whether or not the safety standards

must be contained in special conditions.

While the FAA concluded, based on

the PoC results, that the Gulfstream EVS

could be safely certified, it did not

conclude that safety standards were

unnecessary. The safety standards

covered by the special conditions are

not based on deficiencies of the

Gulfstream EVS, but rather on issues

that were investigated during the PoC

and the earlier FAA SVS program.

While the PoC test results show that the

EVS image does not obscure the pilot’s

view, there must be appropriate safety

standards for the impact of the EVS

image on the pilot’s view.

The FAA actions have been consistent

with the PoC process as outlined in

paragraph 10.18 of Advisory Circular

120–28D. As stated earlier, the special

conditions provide a legal avenue to

certify this system.

EVS Enhances Safety and Should Not

Be Delayed

One commenter states that reduced

visibility is a major or contributing

factor in many civil aircraft accidents. If

the pilot could have had the real-time

information provided by EVS, a

significant number of these accidents

could have been avoided. The

commenter asserts that the EVS can save

lives now, and recommends that the

FAA continue to understand and not

delay the benefits of EVS to the air

transportation system.

Another commenter states that new

technology that provides enhanced

aircraft safety should be certified and

deployed in a quick and orderly fashion,

rather than through a long series of

disjointed special conditions. It is the

commenter’s opinion that this is

detrimental both to the FAA and

airlines through unnecessary delays,

and to the traveling public who deserve

improved safety of flight.

A third commenter believes that the

EVS will provide operational safety

improvement. The commenter states

that EVS technology is specifically

aimed at eliminating low-visibility

conditions as a causal factor in civil

aircraft accidents, and that if installed,

the EVS will provide operational

benefits approaching those found in

clear daytime operations, regardless of

weather conditions.

The FAA agrees in part with the

commenters. Indeed, EVS may be able

to improve safety in certain conditions

and phases of flight. The FAA

acknowledges that the EVS image may

improve the pilot’s ability to detect and

identify items of interest. The

application of safety standards through

special conditions does not prevent the

use of EVS in ways that would enhance

safety. The EVS may be used for any

operation or phase of flight where it is

shown to be safe.

32724 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

It has not yet been demonstrated that

the Gulfstream EVS can actually provide

benefits equivalent to conventional clear

daytime operations in all low visibility

conditions. The infrared sensor is

affected by the same visible moisture

that is often the cause of low visibility

conditions. Nevertheless, the actual

operational benefits that the EVS can

provide will be shown in due time with

the accumulation of service experience.

The FAA has not delayed the

certification project, or the safety or

operational benefits that the EVS might

provide. Publication of these final

special conditions has not adversely

impacted the overall certification

program schedule.

Use of Infrared (IR) Imagery To

Establish Visibility

One commenter states that the notice

raises concern that the reported

visibility (visible spectrum) would not

be consistent with the IR visibility

‘‘seen’’ by the EVS, and that this is a

valid operational concern, but not a

certification issue.

The same commenter also states that

the current regulations do not permit

any operator to descend below the

published approach minimums, unless

the visibility is at least that prescribed

in the instrument approach procedure

being used. The commenter says that

the current regulations do not address

electronic aiding, and recommends that

the following statement be added to the

AFM limitations: ‘‘Installation of the

EVS does not constitute approval to

continue an approach below decision

height.’’

The FAA disagrees. The notice

addressed ‘‘flight visibility,’’ not

reported visibility. The two terms are

distinctly different. For descent below

decision height, § 91.175(c)(2) requires

that ‘‘flight visibility,’’ which is the

forward horizontal distance that

unlighted objects can be seen from the

cockpit by day, and lighted objects by

night, be no less than the visibility

prescribed in the standard instrument

approach procedure being used.

The FAA agrees that the requirements

for approach, including flight visibility,

are established by operational

regulations, particularly parts 91, 121,

and 135, and are therefore operational

concerns. However, the requirement

that installed equipment must be of a

type and design to perform its intended

function, defined in special conditions

paragraph 4. for certification purposes,

is a valid airworthiness certification

concern.

The FAA agrees that current

regulations do not address electronic

images in the pilot compartment view

regulated by § 25.773. As stated earlier,

the special conditions are considered

necessary because § 25.773 is not

adequate for the novel or unusual

design features of the EVS. However, the

special conditions do not address

whether operational regulations

adequately address the use of the EVS

and do not create, change, restrict, or

reinterpret the operational

requirements.

The FAA does not agree with the

recommended change to the AFM

limitations, because it appears more

conservative than the FAA concluded is

necessary. One conclusion drawn from

the PoC testing was that the visual

references listed in § 91.175(c)(3) could

be detected and identified in the EVS

image, and that the ability to do this

could be evaluated. The FAA has

revised the first sentence of paragraph 4.

to clarify that the use of EVS does not

affect the applicability of the

operational requirements.

Special Conditions Were Identified Late

in the Program

Two commenters state that the FAA

needs to review processes that were

followed to ensure that FAA personnel

are fully aware of their responsibilities

to raise such concerns early in a

program.

The commenters express the opinion

that the FAA did not follow the

principles of the certification process

improvement effort. The principles

include surfacing issues early in the

program so that they can be resolved

before they have an adverse effect on the

ability of the applicant to certify the

product in accordance with the program

schedule.

The FAA disagrees. Although the

need for special conditions was not

known in the beginning of the program,

the need for special conditions was

identified early enough in the program

to not impact the certification schedule.

The Language in the Notice Is

Damaging to the Development and Use

of EVS

Two commenters express the opinion

that the language and limitations

contained in the notice are prejudicial

against EVS and HUD developments.

One has concerns about the future FAA

response to new safety technologies and

many other proposed safety systems to

meet the goals of the Safer Skies

program.

Another commenter states that the

proposed special conditions do not

accurately represent the Gulfstream EVS

program. The commenter asserts that

the EVS would enhance the ability of

the pilot to see and identify visual

references to continue an approach to a

decision point of 100 feet for Phase I

and 50 feet for Phase II. It is the

commenter’s opinion that the special

conditions create a negative impression

of EVS technology, which further

reflects a biased judgment against EVS

and is contrary to the conclusions

reached under the controlled

evaluations.

The FAA disagrees. The special

conditions are not intended to be a

reference to the product or a

commentary on the product’s success.

Differences between EVS infrared

imagery and natural pilot vision were

described in the preamble of the notice

for the purpose of addressing the

uniqueness of the EVS and the need for

safety standards to address the

differences. That an EVS image has the

potential to interfere or obscure the

pilot’s view does not mean that an EVS

is unacceptable, but that the product

needs to be evaluated with these

potential characteristics in mind to

maintain the level of safety established

by the current airworthiness standards.

The special conditions are not

intended to characterize the Gulfstream

EVS project. The requirements in the

proposed special conditions, and

adopted in these final special

conditions, are intended to provide

safety standards for this EVS to meet,

and to ensure that such a determination

is made during certification, not to

imply that this EVS is unacceptable.

The special conditions address Phase I

of the Gulfstream project, and anything

beyond Phase I will be addressed

outside this rulemaking activity.

The Proposed Special Conditions Are

Too Restrictive on the Use of EVS

One commenter states that the notice

denies the following uses of the EVS:

• As a substitution for the real-world

view,

• As a means to establish that flight

visibility is consistent with the visibility

condition prescribed in the standard

instrument approach being used,

• As a means to reduce the ceiling

and visibility minima of the instrument

approach procedure being used, and

• As a means to satisfy the

requirements for descent below 100 feet

HAT.

Another commenter states that there

could be other images developed in the

future that may have greater capabilities

than FLIR. Paragraph 4. of the proposed

special conditions could be mistakenly

interpreted to rule out any chance of

progress in this area.

The FAA disagrees. The special

conditions do not deny or restrict the

use of EVS. Rather, the language

Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32725

referred to in the comment (and

discussed in the preamble to the notice)

defines what intended functions it is

being certified for and the limits of that

airworthiness certification approval.

Unless found unsafe during any

operation or phase of flight, this would

not limit the use of EVS as a

supplemental device, nor would it

restrict the role of Flight Standards to

authorize the use of EVS.

The first sentence of special

conditions paragraph 4. is not an

operational restriction; instead, it is

meant to clarify that the airworthiness

approval of EVS, itself, does not reduce

or override the established ceiling and

visibility minima prescribed in the

standard instrument approach

procedure. In fact, airworthiness

approval of any equipment, whether it

uses a raster image or not, cannot take

precedence over the established

minima. These special conditions do

not impose this limitation; they

acknowledge it. When the notice was

issued, there were no published

instrument procedures that prescribed

different minima for operators of EVSequipped airplanes.

To clarify the intent of the first

sentence of special conditions

paragraph 4., it is changed to read:

‘‘Compliance with these special

conditions does not affect the

applicability of any of the requirements

in the operating regulations (e.g., parts

91, 121, 135).’’

FAA Flight Standards has the

authority to determine operational

requirements. However, it is also true

that the requirements of the existing

operational regulations are mandatory.

Flight Standards may choose to approve

different minima for operators of EVSequipped airplanes. As needed, Flight

Standards would also determine in the

future whether different minima would

be applied to operators of airplanes

equipped with this or other EVS

configurations.

Clarification Issues

Special Conditions Paragraph 2.a.

One commenter provided the

following comments relative to

paragraph 2.a.:

• ‘‘Burlap overlay’’ is not defined in

the examples provided in paragraph 2.a.

• Use of FLIR, under some

circumstances, may not be desirable or

an improvement over the pilot’s vision,

and may not be appropriate.

• The ability to easily dim and/or

clear the image on the HUD should be

incorporated to permit removal of the

image quickly, if conditions are not

favorable.

FAA clarification of each issue is as

follows:

‘‘Burlap overlay’’ is one example of a

display artifact that has a burlap-like

appearance and was observed during

the PoC flight testing. It could be

distracting to the pilot, make the image

difficult to use, and potentially interfere

with the pilot’s outside view.

The FAA agrees with the commenter

that in some circumstances the EVS

image may not be desirable, and that is

why paragraph 2.c. of the special

conditions requires that a readily

accessible control be provided for the

pilot to immediately deactivate and

reactivate display of the image on

demand.

The FAA agrees with the commenter

that the ability to dim or clear the image

on the HUD should be incorporated, and

that is why paragraph 2.b. of the special

conditions requires effective control of

image brightness, and paragraph 2.c.

requires that a readily accessible control

be provided for the pilot to immediately

deactivate and reactivate display of the

image on demand.

Special Conditions Paragraph 2.f.

One commenter interprets special

conditions paragraph 2.f. to mean that

the EVS image must not affect the

performance of the pilot in the use of

the HUD for previously approved

operations. The commenter assumes

that the EVS image may be removed

during those operations (or phases)

which could be impacted, and states

that the EVS image may need to be

automatically deactivated during certain

phases of flight, perhaps at or prior to

decision height during a low visibility

approach.

The objective of paragraph 2.f. is that

the EVS installation would not

adversely affect the ability of the HUD

to meet any requirement to which it was

originally certified. Whether or not the

EVS image must be removed for some

phases of flight to comply with this

paragraph must be determined on a

case-by-case basis. If there are cases

where removal of the image is required,

automatic means to deactivate the image

would not be required, unless it is

shown that manual procedures to

deactivate the image are inadequate.

Special Conditions Paragraph 3.

The commenter interprets paragraph

3. as follows: ‘‘The EVS image must not

interfere in the pilot’s detection of

traffic, terrain, obstacles, and other

hazards of flight. The assumption is that

objects are recognizable within the EVS

image, or visual objects are still

recognizable through the EVS image.’’

The commenter’s interpretation with

respect to the ability of the pilot to

‘‘see’’ discrete visual items is correct.

For completeness, though, one must

also determine if there are

characteristics that adversely affect the

pilot’s ability to maneuver the airplane

to avoid flight hazards. Excessive image

latency or lag, for example, might have

an adverse effect.

Special Conditions Paragraph 4.a.

One commenter provided the

following comments:

• It is not clear if this rules out the

use of the EVS for taxi and/or takeoff.

• The words seem to indicate that the

evaluation has already been completed

and the special conditions authorize use

during the approach.

• Other potential uses should be

considered (that is, takeoff, taxi, seeing

threatening cloud formations at night).

Special conditions paragraph 4. is

meant to clarify the intended function of

EVS, not to impose operational

limitations. A requirement for

airworthiness certification is that the

system must be of a type and design to

perform its intended function.

The FAA and the applicant agree that

the intended functions listed in

paragraphs 4.a. and 4.b., associated with

approach operations, are the primary

focus of the certification, and for which

the FAA will certify the EVS. However,

there is no intent to restrict use of the

EVS to approach and landing operations

only. The EVS may be used as a

supplemental system for any phase of

flight, including taxi and take-off, when

it is shown to be safe.

A PoC flight test program was

conducted to evaluate what the EVS was

capable of, how it should be used, and

what certification criteria would be

needed. Demonstrations for showing

compliance with the airworthiness

certification requirements will be

accomplished after issuance of the final

special conditions.

Proof of Concept Test

One commenter states that it is

unclear whether a proof of concept

demonstration was conducted and if so,

no results were revealed.

As stated earlier, a PoC demonstration

has already been conducted. The PoC

test report, itself, is proprietary to the

applicant, so the FAA did not provide

it to the public.

Additional Requirements to Proposed

Special Conditions

One commenter states that

consideration should be given to the

following areas in the proposed special

conditions:

32726 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

• Ensure acceptable characteristics

when transitioning from EVS ON to OFF

and vice versa, particularly the ability to

reacquire outside visual references

when EVS is selected OFF during an

instrument approach.

• Evaluate the perception of actual

colors as viewed through the HUD with

the EVS ON.

• Address the effects of power

transients or temporary interruptions.

• Address pilot fatigue or eye strain

while using the EVS.

• Consider EVS dispatch

requirements.

• Paragraph 2.d. should be expanded

to state that the initial certification

should include sufficient testing to

cover the normal range of expected

flight maneuvers for all of the phases of

flight to be certified with the EVS active.

Another commenter states that it may

be desirable to provide the option of a

head down FLIR display when

operations are conducted with a single

HUD.

The FAA agrees, in part, with the

issues raised by the first commenter.

The FAA plans to evaluate these issues

during the certification program, but

does not see the need to revise the

language of the special conditions. FAA

responses to the issues are provided in

the order presented by the commenter.

• Specific standards for acceptable

EVS on/off transitions and color

perception need not be stated. These

factors can be evaluated in the context

of special conditions paragraphs 1. and

2. (including sub-paragraphs).

• The HUD was already certified to

have acceptable responses to power

transients and interruptions. The FAA

does not consider this EVS image, itself,

critical. Based on special conditions

paragraph 2.f., with the EVS

modification, the HUD must continue to

meet the requirements of its original

approval.

• Per special conditions paragraph

2.f., the HUD with the EVS modification

must continue to meet the requirements

of its original approval, including the

eye strain and fatigue criteria of the

HUD issue paper.

• Dispatch requirements are

determined by the FAA Aircraft

Evaluation Group and will not be

specified in the special conditions.

• Software requirements are

addressed, separately, in a means of

compliance issue paper and will not be

addressed in the special conditions.

In response to the second commenter,

the FAA considers that the desirability

of an option to display the EVS image

head down is a matter for the customer

to decide, but is not a safety issue that

would justify a mandatory standard.

Recognize EVS as an Avionics System

With a Broad Base of Experience

The commenter states that the EVS

should be recognized as a system with

an extremely long and broad base of

experience. Many of the issues raised in

the notice are old concerns resolved by

the military in great detail, and at great

cost, including:

• Issues of visual acuity and

cognizant processing.

• Perception of the 3rd dimension is

accomplished through a combination of

relative intensity (brightness), apparent

movement, and size growth with

decreasing distance to items of interest.

• In spite of technical limitations of

older military systems, they were

whole-heartedly embraced as beneficial,

even a poor image is better than no

image. The present technology is better

since it has a larger, more sensitive

detector array.

The FAA did not discount the

military experience when proposing

these special conditions. The ‘‘old

concerns’’ may have been resolved by

the military for the sake of weapon

system design and operational use. The

notice (preamble and special

conditions) raised the issues that

distinguish the EVS image from natural

pilot vision because there are novel or

unusual design features which the

existing rule, § 25.773, does not

adequately address, and to provide

safety standards that can be used to

certify the EVS to the level of safety

required for civil transport category

airplanes.

While acknowledging that there are

some differences between the EVS

image and natural vision, special

conditions provide a way to certify EVS

and maintain the level of safety, based

on the premise that the combination of

what the pilot can see in the image and

what can be seen naturally, while the

image is displayed, must be as safe and

effective as the view without the image

(in the same conditions).

The special conditions were proposed

because of the need for appropriate

safety standards for such systems that

perform required functions previously

done only by natural pilot vision. The

FAA does not suggest, and has no

reason to believe, that that the

Gulfstream EVS is unsafe and cannot

comply with the requirements of the

special conditions.

The special conditions acknowledge

enhanced situational awareness as an

intended function of EVS, where its

safety benefits might be best realized.

Use of the EVS may also be beneficial

during Category I approaches, when the

ceiling and visibility are as prescribed

in the standard instrument approach

procedure. However, its safety benefit,

when used for a Category I approach in

less than prescribed flight visibility, has

yet to be evaluated.

The FAA accepts that the EVS image

can provide some depth cues; however,

unlike EVS, the natural view provides

actual stereoscopic and accommodation

(focus) cues, in addition to depth

perception cues which may be found in

the EVS image. The airworthiness

standard, § 25.773, and the operational

rules, including § 91.175, were written

with natural vision in mind.

The visual acuity (resolution) of the

raster EVS image display also differs

from natural pilot vision. This does not

mean that EVS is unacceptable, only

that it does not match natural vision,

and that safety standards are needed for

the image resolution to be satisfactory

for its intended function, and that it

does not unacceptably interfere with the

pilot’s natural vision.

Notice Implies that Existing Regulations

Do Not Permit the Use of a ‘‘Sensor

Based’’ System

One commenter states that the notice

asserts that the existing regulations do

not permit the use of a ‘‘sensor based’’

system for independent verification that

the primary guidance is accurate.

Another commenter states that there is

no reference in the notice to the PoC test

results that found the EVS suitable for

acting as an independent integrity

monitor for ILS approaches.

The FAA did not say in the notice

that sensor based systems cannot be

used for independent verification of the

primary guidance. Paragraph 4. of the

special conditions does not explicitly

list the function of ‘‘integrity monitor’’

for the guidance, but this function is

covered within the dual intended

function of ‘‘presenting an image that

would aid the pilot during the

approach’’ and ‘‘that the pilot can use to

detect and identify the visual

references’’ (§ 91.175(c)(3)).

The EVS cannot be an independent

monitor in the same sense as the term

is normally used. Normally, use of this

term refers to automatic detection and

annunciation of system performance

deviations and failure conditions. The

pilot may be able to use the EVS image

to identify certain visual references that

serve as airplane position cues. The EVS

sensor performance (i.e., what can be

seen and at what distance) in the actual

atmospheric conditions will affect the

usefulness of the image for the purpose

of verifying airplane position.

Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations 32727

Lack of Understanding of the

Technology and Underlying Physics

One commenter states that the special

conditions delve into the technical

‘‘nitty-gritty’’ of infrared and display

performance with little understanding

of the technology and underlying

physics. The commenter further states

that:

• Infrared sensors are not limited to

the mere sensing of ‘‘heat.’’ The EVS

sensor has been tailored to detect

electromagnetic radiation from the nearIR out to the long-wavelength. This is

technically interesting but not relevant

to the issue at hand.

• Most important is what the system

provides, not the theoretical basis for

infrared operation. With EVS, the pilot

sees the same visual cues, in the same

way, as presented on the HUD in a form

that promotes outside/far-field vision

and facilitates a transition from the IR

image to the real scene.

The FAA agrees, in part, with the

commenter. While the infrared energy

detected by these sensors is primarily

due to ‘‘thermal’’ contrast in the scene,

it is also true that reflected and emitted

infrared energy might be detected.

Because of their spectral response, the

infrared sensors detect contrast in the

scene differently from natural pilot

vision. A scene that shows significant

contrast in the infrared wavelengths

may have less contrast in the visual

wavelengths, and vice versa.

The FAA agrees that the pilot may see

many of the same visual cues with the

EVS that might be seen naturally, but

they are not seen in exactly the same

way. As stated earlier, the cause and

degree of scene contrast can vary

between the infrared image and the

natural view. However, the FAA

acknowledges that the size and spatial

relationships of certain visual

references, particularly lighted objects

such as those listed in § 91.175(c)(3),

may be similar in the image and in the

natural view and therefore may be

identifiable to the pilot.

This is not to say that the EVS

infrared imagery is unacceptable, only

that it is not the same as natural vision,

in a variety of ways. Natural vision was

originally assumed when §§ 25.773 and

91.175 were issued, which, as discussed

earlier, is one basis for the special

conditions. So far, the FAA has not

certified the use of any electronic

imagery displayed in the windshield’s

field of view or imagery generated from

a different part of the electromagnetic

spectrum.

Operational Benefits of EVS

One commenter states that the EVS

could be used at many runway ends

closed for critical take-off and landing

operations due to limited visibility. The

EVS could restore the pilot’s vision and

increase airport capacity.

The full potential for operational

benefits of the EVS will be

demonstrated by the accumulation of

service experience, and will depend on

the FAA Flight Standards’

determination of what operational uses

will be authorized.

That EVS may provide significant

operational benefits is not a factor when

determining the need for safety

standards or special conditions. The

special conditions, alone, will not

restrict the use of EVS for operationally

beneficial purposes.

Requests To Extend Comment Period

One commenter, representing the

interests of airlines and manufacturers,

requests that the comment period be

extended for 30 days. The commenter

states that airlines and manufacturers

must be able to understand the

implications and future impact of the

proposed special conditions and need

the additional time to provide

responsive and constructive comments.

The FAA has decided not to extend

the public comment period. Eighteen

commenters, including this commenter,

were able to provide extensive

comments to the proposed special

conditions during the allotted time.

These special conditions are specific to

the Gulfstream Model G–V EVS project,

and any extension to the public

comment period would adversely delay

certification. There will be additional

opportunities to comment on other

special conditions and rulemaking

related to future EVS certification

projects as they arise.

Request for a Public Meeting

One commenter expresses concern

about the effect this special condition

action will have on the industry-wide

joint effort to improve the certification

process through the use of strong and

trustworthy partnerships, and requests

that the FAA conduct a public hearing

into the process of handling such

further industry developments.

A second commenter requests that the

FAA hold a public hearing to discuss

the special conditions and the rationale

for broader application to products

developed as part of the Safer Skies

program.

The FAA does not agree. The process

of holding a public meeting and dealing

with the result of such a meeting would

unduly delay completion of this

rulemaking and could adversely affect

the applicant’s certification schedule.

The FAA does not believe that such

a meeting would materially serve the

purposes of this rulemaking. A

significant amount of substantive public

comments have already been submitted

that sufficiently characterize objections

and concerns with the special

conditions.

Applicability

As discussed above, these special

conditions are applicable to Gulfstream

Model G–V airplanes modified by

Gulfstream Aerospace. Should

Gulfstream 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 § 21.101(a)(1).

Conclusion

This action affects only certain novel

or unusual design features on the

Gulfstream Model G–V airplanes

modified by Gulfstream 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 Special Conditions

Accordingly, pursuant to the

authority delegated to me by the

Administrator, the following special

conditions are issued as part of the

supplemental type certification basis for

Gulfstream Model G–V airplanes

modified by Gulfstream Aerospace:

1. The EVS imagery on the HUD must

not degrade the safety of flight, nor

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 EVS device

must meet the following requirements:

2.a. The EVS design must minimize

unacceptable display characteristics or

artifacts (for example, 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.

32728 Federal Register / Vol. 66, No. 117 / Monday, June 18, 2001 / Rules and Regulations

2.b. Control of EVS 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.

2.c. A readily accessible control must

be provided that permits the pilot to

immediately deactivate and reactivate

display of the EVS image on demand.

2.d. The EVS image on the HUD must

not impair the pilot’s use of guidance

information nor 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,

and unusual attitude recovery cues.

2.e. The EVS image must be

sufficiently aligned and conformal to

both the external scene and conformal

HUD symbology so as not to be

misleading, cause pilot confusion, or

increase workload.

2.f. A HUD system modified to

display EVS images must continue to

meet all 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 be not be

degraded by the display of the EVS

image. Pilot tasks that must not be

degraded by the EVS image include:

3.a. Detection, accurate identification,

and maneuvering, as necessary, to avoid

traffic, terrain, obstacles, and other

hazards of flight.

3.b. Accurate identification and use of

visual references required for every task

relevant to the phase of flight.

4. Compliance with these special

conditions does not affect the

applicability of any of the requirements

in the operating regulations (e.g., parts

91, 121, 135). The criteria in special

conditions paragraphs 1., 2., and 3. were

developed to determine that this EVS is

of a kind and design appropriate to the

following functions:

4.a. Presenting an image that would

aid the pilot during the approach.

4.b. Displaying an image that the pilot

can use to detect and identify the

‘‘visual references for the intended

runway’’ required by § 91.175(c)(3) to

continue the approach with vertical

guidance to 100 feet height above

touchdown (HAT). Appropriate

limitations must be included in the

Operating Limitations section of the

Airplane Flight Manual to prohibit the

use of the EVS for functions not found

to be acceptable.

Issued in Renton, Washington, on June 8,

2001.

Ali Bahrami,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–15333 Filed 6–15–01; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–319–AD; Amendment

39–12268; AD 2001–12–13]

RIN 2120–AA64

Airworthiness Directives; Empresa

Brasileira de Aeronautica S.A.

(EMBRAER) Model EMB–135 and

EMB–145 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Final rule.

SUMMARY: This amendment adopts a

new airworthiness directive (AD),

applicable to certain EMBRAER Model

EMB–135 and EMB’145 series airplanes,

that requires replacement of certain

brake control units (BCU) with new

units. The actions specified by this AD

are intended to prevent uncommanded

application of 50 percent braking in one

pair of wheels, which could result in the

airplane skidding off the runway. This

action is intended to address the

identified unsafe condition.

DATES: Effective July 23, 2001.

The incorporation by reference of

certain publications listed in the

regulations is approved by the Director

of the Federal Register as of July 23,

2001.

ADDRESSES: The service information

referenced in this AD may be obtained

from Empresa Brasileira de Aeronautica

S.A. (EMBRAER), P.O. Box 343—CEP

12.225, Sao Jose dos Campos—SP,

Brazil. This information may be

examined at the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, Rules Docket,

1601 Lind Avenue, SW., Renton,

Washington; or at the FAA, Atlanta

Aircraft Certification Office, One Crown

Center, 1895 Phoenix Boulevard, suite

450, Atlanta, Georgia; or at the Office of

the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Robert Capezzuto, Aerospace Engineer,

Systems and Flight Test Branch, ACE–

116A, FAA, Atlanta Aircraft

Certification Office, One Crown Center,

1895 Phoenix Boulevard, suite 450,

Atlanta, Georgia 30349; telephone (770)

703–6071; fax (770) 703–6097.

SUPPLEMENTARY INFORMATION: A

proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to

include an airworthiness directive (AD)

that is applicable to certain EMBRAER

Model EMB–135 and EMB’145 series

airplanes was published in the Federal

Register on November 13, 2000 (65 FR

67663). That action proposed to require

replacement of certain brake control

units (BCU) with new units.

Comments

Interested persons have been afforded

an opportunity to participate in the

making of this amendment. Due

consideration has been given to the

single comment received.

Add Service Information

The commenter states that EMBRAER

Service Bulletin 145–32–0060, dated

May 5, 2000, should be included in the

final rule as an additional source of

service information for previous

accomplishment of the specified

actions. EMBRAER Service Bulletin

145–32–0060, Change No. 01, dated

June 6, 2000, was listed as the source of

service information for accomplishment

of the actions specified in the proposed

rule. The commenter states that the

difference between the original issue

and Change No. 01 of the service

bulletin is administrative in nature.

The FAA agrees with the commenter

that the original issue is essentially the

same as Change No. 01 of the service

bulletin. We have added a new Note 2

to the final rule which clarifies that

previous accomplishment of the actions

per the original issue of the service

bulletin meets the requirements of this

final rule.

Conclusion

After careful review of the available

data, including the comment noted

above, the FAA has determined that air

safety and the public interest require the

adoption of the rule with the change

described previously. The FAA has

determined that this change will neither

increase the economic burden on any

operator nor increase the scope of the

AD.

Cost Impact

The FAA estimates that 165 Model

EMB–135 and EMB–145 series airplanes

of U.S. registry will be affected by this

AD. It will take approximately 5 work

hours per airplane (2.5 work hours per