59634 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 36

[Docket No. FAA–2000–7958; Notice

No. 00–11]

RIN 2120–AH10

Noise Certification Regulations for

Helicopters

AGENCY: Federal Aviation

Administration (FAA), DOT.

ACTION: Notice of Proposed Rulemaking

(NPRM).

SUMMARY: The Federal Aviation

Administration (FAA) is proposing

changes to the noise certification

regulations for helicopters. These

proposed changes are based on a joint

effort by the FAA, the European Joint

Aviation Authorities (JAA), and

Aviation Rulemaking Advisory

Committee (ARAC), to harmonize the

U.S. noise certification regulations and

the European Joint Aviation

Requirements (JAR) for helicopters.

These proposed changes would provide

nearly uniform noise certification

standards for helicopters certificated in

the United States, the JAA countries,

and other countries that have adopted as

their national regulation either the

United States regulations, the JAA

regulations, or the International Civil

Aviation Organization (ICAO)

standards. The harmonization of the

noise certification standards would

simplify airworthiness approvals for

import and export purposes.

DATES: Comments must be received on

or before January 4, 2001.

ADDRESSES: Address your comments to

the Docket Management System, U.S.

Department of Transportation, Room

Plaza 401, 400 Seventh Street, SW.,

Washington, DC 20590–0001. You must

identify the docket number FAA–2000–

7958 at the beginning of your

comments, and you should submit two

copies of your comments. If you wish to

receive confirmation that FAA received

your comments, include a selfaddressed, stamped postcard.

You may also submit comments

through the Internet to http://

dms.dot.gov. You may review the public

docket containing comments to these

proposed regulations in person in the

Dockets Office between 9 a.m. and 5

p.m., Monday through Friday, except

Federal holidays. The Dockets Office is

on the plaza level of the NASSIF

Building at the Department of

Transportation at the above address.

Also, you may review public dockets on

the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT:

Sandy Liu, AEE–100, Office of

Environment and Energy (AEE), Federal

Aviation Administration, 800

Independence Avenue, SW.,

Washington, DC 20591; telephone (202)

493–4864; facsimile (202) 267–5594; or

email at sandy.liu@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to

participate in this rulemaking by

submitting written comments, data,

views, or arguments. Comments on the

possible environmental, economic,

federalism, or energy-related impact of

the adoption of this proposal are

welcomed. Comments concerning the

proposed implementation and effective

date of the rule are also specifically

requested.

Comments should carry the regulatory

docket or notice number and should be

submitted in triplicate to the Rules

Docket address specified above. All

comments received and a report

summarizing any substantive public

contact with FAA personnel on this

rulemaking will be filed in the docket.

The docket is available for public

inspection both before and after the

closing date for receiving comments.

Before taking any final action on this

proposal, the Administrator will

consider the comments made on or

before the closing date for comments,

and the proposal may be changed in

light of the comments received.

The FAA will acknowledge receipt of

comments if commenters include a selfaddressed, stamped postcard with the

comments. The postcards should be

marked ‘‘Comments to Docket No. FAA–

2000-7958.’’ When the comments are

received by the FAA, the postcards will

be dated, time stamped, and returned to

the commenters.

Availability of Rulemaking Documents

You can get an electronic copy using

the Internet by taking the following

steps:

(1) Go to the search function of the

Department of Transportation’s

electronic Docket Management System

(DMS) web page (http://dms.dot.gov/

search).

(2) On the search page type in the last

four digits of the Docket number shown

at the beginning of this notice. Click on

‘‘search.’’

(3) On the next page, which contains

the Docket summary information for the

Docket you selected, click on the

document number of the item you wish

to view.

You can also get an electronic copy

using the Internet through FAA’s web

page at http://www.faa.gov/avr/arm/

nprm/nprm.htm or the Federal

Register’s web page at http://

www.access.gpo.gov/su_docs/aces/

aces140.html.

You can also get a copy by submitting

a request to the Federal Aviation

Administration, Office of Rulemaking,

ARM–1, 800 Independence Avenue

SW., Washington, DC 20591, or by

calling (202) 267–9680. Make sure to

identify the docket number, notice

number, or amendment number of this

rulemaking.

Background

Statement of the Problem

Various governmental bodies have

developed noise certification

regulations to control noise emissions

from helicopters. The International Civil

Aviation Organization (ICAO) issues ongoing prototypical sets of aircraft noise

standards which member States,

including the United States, are

encouraged to adopt into their

respective national regulations. Many

ICAO member States have adopted the

ICAO standards verbatim. The United

States has adopted into 14 CFR part 36

noise certification regulations that,

although similar to the ICAO standard,

differ substantively with the ICAO

version. A third body, the Joint Aviation

Authorities (JAA), is developing its own

version of the ICAO standards with JAA

member States in Europe. Thus, from a

practical standpoint, three sets of

helicopter noise certification

requirements exist, each controlled by

an independent political entity.

Helicopter manufacturers must

demonstrate compliance with at least

one, and often all three, of the sets of

noise certification regulations when a

helicopter is exported beyond its

country of manufacture and

certification. It has become apparent to

the manufacturers that the differences

among the three versions of the

helicopter noise standards are an

undesirable burden. The manufacturers

have requested that the regulating

agencies harmonize the three sets of

regulations in order to minimize the

costs for demonstrating compliance.

These same aviation certification

authorities, United States, JAA and

ICAO, have previously recognized the

value of harmonizing civil aircraft

certification and operating regulations.

The Administrator of the FAA supports

harmonization and has committed the

FAA to support the harmonization of

the FAA regulations with those of the

JAA and ICAO.

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59635

Current United States Helicopter Noise

Certification Regulations

Under 49 U.S.C. 44715, the

Administrator of the Federal Aviation

Administration is directed to prescribe

‘‘standards to measure aircraft noise and

sonic boom * * * and regulations to

control and abate aircraft noise and

sonic boom.’’ Part 36 of title 14 of the

Code of Federal Regulations (14 CFR)

contains the FAA’s noise standards and

regulations that apply to the issuance of

type certificates, changes in type design,

and airworthiness certificates for

specified classes and categories of

aircraft. Subpart H and appendices H

and J of part 36 contain the

requirements and standards that apply

to helicopters. Appendices H and J of

part 36 specify the test conditions,

procedures, and noise levels required to

demonstrate compliance with

certification requirements for

helicopters. The original helicopter

noise certification standards and

regulations, including appendix H, were

issued on February 5, 1988 (53 FR

3534). On September 16, 1992 (57 FR

42846), the FAA published an

alternative noise certification procedure,

appendix J, for helicopters that do not

exceed 6,000 pounds maximum takeoff

weight.

ICAO Helicopter Noise Certification

Standards

The International Civil Aviation

Organization (ICAO) has also adopted a

set of Standards and Recommended

Practices for aircraft noise certification.

These ICAO standards are similar to the

United States regulations. The ICAO

Annex 16 standards, which have no

legal standing of their own, are intended

to be prototypical regulations upon

which the Contracting States to ICAO

may base their own national regulations.

For helicopters, Chapter 8 of Annex 16

is the approximate equivalent of part 36,

appendix H; Chapter 11 of Annex 16 is

the approximate ICAO equivalent to

part 36, appendix J. The ICAO standards

are issued as International Standards

and Recommended Practices,

Environmental Protection, Annex 16 to

the Convention on International Civil

Aviation, Volume 1, Aircraft Noise.

Joint Aviation Authorities Helicopter

Noise Certification Standards

The civil aviation authorities of

certain European countries have agreed

to common comprehensive and detailed

airworthiness and operating

requirements; these are known as the

Joint Aviation Requirements (JARs). The

JARs are intended to minimize type

certification differences on multinational European ventures and to

facilitate the export and import of

aviation products between European

nations. Aviation authorities of

participating countries recognize the

JARs as an acceptable basis for showing

compliance with their national aviation

codes. The JAA added aircraft noise

certification (JAR 36), including the

helicopter requirements of Subsection D

to the JARs effective May 23, 1997. The

JAA’s JAR 36 study group is tasked with

the technical responsibilities for

overseeing the noise certification

standards. Another group, Abatement of

Nuisances Caused by Air Transport

(ANCAT), created under the auspices of

the European Civil Aviation Conference

(ECAC), oversees the policy interests for

the JAA. The ANCAT previously

decided that the JAR aircraft noise

certification standards does mirror the

standards adopted by ICAO.

Aviation Rulemaking Advisory

Committee (ARAC)

In January 1991, the FAA established

the Aviation Rulemaking Advisory

Committee (ARAC) to serve as a forum

for the FAA to obtain input from outside

the government on major regulatory

issues. The FAA has tasked ARAC with

several noise certification issues. These

issues involve the harmonization of part

36 with JAR 36, the harmonization of

associated guidance material including

equivalent procedures, and

interpretations of the regulations. On

May 3, 1994, the ARAC established the

FAR/JAR Harmonization Working

Group for Helicopters (59 FR 22883).

The Helicopter Harmonization Working

Group (HHWG) is comprised of

helicopter noise certification experts,

and is responsible for addressing tasks

assigned by ARAC. The United States

and European interests are represented

in the HHWG, which includes

representatives of the helicopter

manufacturers and aviation authority

representatives from the FAA and the

JAA/ANCAT. The HHWG is co-chaired

by industry representatives from the

United States and Europe, and meetings

are held alternately in the United States

and Europe.

The HHWG reviewed the helicopter

noise certification provisions of 14 CFR

part 36, subparts A and H, and

appendices H and J, and the

corresponding applicable provisions of

JAR 36 and ICAO Annex 16. Differences

between the regulations were identified

and discussed. The goal of the HHWG

is to harmonize the regulations by

modifying or deleting conflicting

requirements. The HHWG is not

authorized to make recommendations

for the creation of new requirements or

the removal of existing requirements

that are common among the different

sets of regulations. Methods for

resolving the differences were agreed to

and forwarded to each regulatory body

for approval. A recommendation for

amending part 36 was forwarded to the

ARAC. After due consideration

including a meeting open to the public

on August 23, 2000, ARAC agreed to

this recommendation and forwarded, in

the form of a draft NPRM, to the FAA

for consideration.

The overall structure for harmonizing

the Federal Aviation Regulations and

the Joint Aviation Regulations is

described in the JAA/FAA

Harmonization Work Program.

Under the Harmonization Work

Program, the FAA and JAA agreed to

form a Harmonization Working Group to

harmonize the aircraft noise

certification requirements of 14 CFR

part 36 and JAR 36. The Working Group

serves under the auspices of both ARAC

and the JAA’s JAR 36 Study Group. The

JAA has adopted the ICAO noise

certification standards; any

recommended changes to the JARs

resulting from a harmonization process,

must first be acted on and approved by

ICAO before they are considered by the

JAA.

Synopsis of the Proposal

Part 36 of the Federal Aviation

Regulations (14 CFR) contains noise

standards for aircraft type and

airworthiness certification. Subpart H of

part 36 and its related appendices H,

and J prescribe noise levels and test

procedures used for certification of civil

helicopters in the normal, transport,

restricted, or primary category,

including rules governing the issuance

of original, amended, or supplemental

type certificates for helicopters for

which application is made on or after

March 6, 1986.

The FAA is proposing to amend some

of the technical specifications included

in appendices H and J, and proposes a

new definition under § 36.1. No changes

to the applicability of part 36 are

proposed. The proposed changes would

not substantively alter the prescribed

noise limits nor change the relative

stringency of the regulations, i.e., the

relationship between the noise level

limits and the measured noise level of

a given helicopter. These proposed

changes may be categorized as (a)

replacing an existing specification with

a similar ICAO specification; (b) adding

an existing ICAO specification to part 36

where a corresponding part 36

specification does not presently exist; or

(c) removing an existing part 36

59636 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

specification where there is no

corresponding ICAO specification.

The FAA has examined the helicopter

noise certification process and analyzed

how the proposed changes would have

affected previous helicopter noise

certification projects. The cumulative

effect of the proposed changes on a

single certification would not typically

exceed ± 0.1 decibels and would not be

expected to exceed ± 0.3 decibels under

a worst-case combination of conditions.

The FAA has determined that the

proposed changes would not

substantively alter the noise

certification levels or the finding of

compliance of helicopters currently

certificated under either appendix H or

appendix J. Accordingly, the FAA has

determined that these proposed changes

are consistent with the statutory criteria

for amending aircraft noise abatement

regulations.

Section-by-Section Discussion

The following is a section-by-section

discussion of the proposed amendment.

Section 36.1 Applicability and

Definitions.

The FAA is proposing the addition of

a new definition to § 36.1(h)(5) for

‘‘maximum normal operating RPM.’’

This would be defined as ‘‘the highest

rotor speed for each reference procedure

corresponding to the airworthiness limit

imposed by the manufacturer and

approved by the FAA.’’ This term would

cover instances where a tolerance on the

highest rotor speed is specified and

where the rotor speed is automatically

linked with flight condition or can be

changed by pilot action. As shown to

apply to reference section H36.107(b)(5)

and J36.105(c)(2).

Section 36.11 Acoustical Change:

Helicopters.

The proposed change would increase

the maximum takeoff weight limit for

appendix J applicability from 6,000

pounds to 7,000 pounds. The proposed

change reflects a new requirement in the

14 CFR part 27 airworthiness standards

for normal category rotorcraft. The part

27 revision, adopted in Amendment 27–

37 and effective on October 18, 1999,

increases the passenger seat limitation

to nine, update of safety standards and

consequential weight growth.

Subpart H—Helicopters

The proposed change to Subpart H

regarding compliance with appendix J,

is being made to conform to the weight

change described above in the

discussion of § 36.11. The same reasons

for adoption apply to this change.

Subpart O—Operating Limitations and

Information

Subpart O of part 36 specifies

requirements for documentation of

noise levels in an airplane flight manual

or rotorcraft flight manual. The FAA is

proposing to add the word

‘‘Documentation’’ as the first word of

the subpart title to more specifically

identify the subject matter of subpart O.

Proposed section 36.1581(a)(2) would

be amended by changing the reference

from appendix F to appendix G. The

noise certification requirement for

propeller-driven small airplanes were

moved to appendix G in Amendment

36–16 (53 FR 47394, November 22,

1988), and this reference was

overlooked.

A new proposed section 36.1581(a)(3)

would be added to require that

helicopter noise levels be included in

the rotorcraft flight manual. This change

specifies the noise certification

documentation requirements; these

would be similar to requirements for

other types of aircraft. This would

provide uniform noise level

documentation requirements for each

aircraft category and would standardize

documentation procedures. This

amendment is intended to improve

certification tracking and

documentation referencing.

Section H36.3 Reference Test

Conditions

Proposed section H36.3(a)(1) would

add sea level pressure in metric units in

addition to English units already

specified. This would prevent possible

variations in measured data that could

result from differing conversion factors

by applicants using metric units.

Proposed section H36.3(c)(2) would

remove a redundant designation

regarding FAA approval. No substantive

change in the approval process is

intended.

Proposed section H36.3(d) would

delete the reference to rotor speed

because it is an unnecessary parameter

in describing a flight profile. This

reference was included in error.

Proposed section H36.3(d) would add

two new criteria for reference airspeeds:

0.9VNE and 0.45VNE+65 knots.

Currently, the reference airspeeds

specified are limited to either 0.9VH or

0.45VH+65 knots, whichever is less.

[Note: VNE is the never-exceed airspeed, an

airworthiness limitation, imposed by the

manufacturer and approved by the FAA.] The

advent of more powerful engines and

improved gearboxes have resulted in

helicopters that can have a VH airspeed in

excess of the power-on VNE airspeed.

Therefore, new noise certification airspeed

criteria are necessary to be consistent with

technological advances and still

accommodate the airworthiness limitations

imposed for safety. These two new reference

airspeed criteria would serve to satisfy these

advances.

Section H36.3(d) would be amended

as follows:

1. Specifically, change the symbol

‘‘D’’ to be replaced by ‘‘Dr’’ and the

symbol ‘‘J’’ to be replaced by ‘‘Jr’’.

1. Deleting the reference to rotor

speed; it is unnecessary for definition of

flight profile.

2. Adding the word ‘‘reference’’ prior

to the words ‘‘airspeed’’ and ‘‘rotor

speed’’ to indicate that the

specifications are for reference flight

conditions.

Proposed section H36.3(f)(1)(i) would

be amended by changing the approach

profile reference from ‘‘EK’’ to ‘‘ErKr’’,

and changing the angle measure ‘‘6° ±

0.5 °’’ to ‘‘6°,’’ respectively. For a

reference situation, no such tolerances

are necessary.

Proposed section H36.3(f)(1)(ii) would

add test approach angle tolerance limits

between 5.5° and 6.5° that were

removed from section H36.3(f)(1)(i).

This is the appropriate paragraph for

these tolerances.

Section H36.5 Symbols and Units

Proposed section H36.5 would

remove the symbols S, Sr, T, and Tr and

their descriptions in the Flight Profile

Identification-Positions table and

remove the symbols ASr, AT, and ATr

and their meanings in the Flight Profile

Distances table. The typographical

errors; Alr and Anr would be corrected

to ALr and ANr. In addition, the three

new symbols and their descriptions

would be added to the Flight Profile

Identification-Positions table of this

section as follows:

Fr—Position on reference takeoff path

directly above noise measuring Station A.

Gr—Position on reference flyover path

directly above noise measuring Station A.

Hr—Position on reference approach path

directly above noise measuring Station A.

These changes and corrections will

make these tables consistent with

amended Figures H1 and H3 (reference

section H36.205 for proposed changes.

Section H36.101 Noise Certification

Test and Measurement Conditions

Proposed section H36.101(b)(6)(iii)

would remove the paragraph for

additional flight test data to determine

the variation of EPNL with weight for

the takeoff condition. In takeoff, noise

generation is a function of torque

(power) to the rotor systems, not weight,

making the current requirement

unnecessary.

Proposed section H36.101(b)(8)(ii)

would require approach tests to be

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59637

conducted between 90 percent and 105

percent of the rotorcraft’s maximum

certification weight. This change is

needed to make this section consistent

with section H36.101(b)(6)(ii), and

simplifies the rules for the three

conditions. (See §§ H36.101(b)(6)(ii) for

takeoff and flyover).

Proposed section H36.101(b)(8)(iii)

removes the paragraph for additional

flight test data that is used to determine

the variation of EPNL with weight for

the approach condition. In approach,

noise generation is predominantly a

function of complex aeroacoustic

sources associated with main rotor

blade vortex interaction, not weight,

making the current requirement

unnecessary. This would further

harmonize measurement procedures

and streamline certification testing.

Proposed section H36.101(b)(6)

requires at least one flight at, or above,

the noise certification weight for each of

the three flight procedures. The

proposal also removes the requirement

for correction of off-reference weight for

the takeoff and approach procedures.

This paragraph is also being removed

from section H36.205.

Proposed section H36.101(c)(2) would

change the minimum test temperature

from 36°F (2.2°C) to 14°F (¥10°C). The

current 36°F (2.2°C) temperature limit is

unnecessarily restrictive, given that no

higher levels of atmospheric absorption

could be encountered by lowering the

test day temperature. Although there is

a revised minimum test air temperature

limit, the limit for the noise measuring

equipment is unchanged.

Proposed section 36.101(c)(2) would

also specify that the temperature test

window be based on the 10-meter

temperature values and that the 10-

meter temperature and relative

humidity values be used to adjust the

sound propagation path for propagation

path absorption. Noise certification data

collected to date has demonstrated that

EPNL values corrected using

atmospheric data measured at 10 meters

are acoustically identical to those

corrected using averaged temperature

and relative humidity data. The

proposed changes would replace

historically unreliable temperature data

collection.

Proposed section H36.101(c)(3) would

specify allowing the use of only the

relative humidity and ambient

temperature values of the 10-meter

measurement station for allowable

sound attenuation in the one-third

octave band centered at 8 kHz and no

longer require the use of aircraft relative

humidity and ambient temperature

measurements. This change is

supported by years of noise certification

data demonstrating that atmospheric

measurements at 10-meters satisfies

both the sound attenuation and relative

humidity range requirements.

Helicopter noise certification test

experience has shown that relative

humidity measurements at the

helicopter position is difficult and

subject to error given the available

instrumentation and procedures.

Analysis has indicated minimal

differences between humidity measured

at the helicopter position and the 10-

meter measurement position.

Corrections have been no greater than

0.1 dB except under extreme conditions

that otherwise would be considered an

anomalous meteorological condition.

Proposed section H36.101(c)(5) would

specify that tests not be conducted

under anomalous wind or anomalous

meteorological conditions. If these

conditions exist at test sites in a desert

environment, temperature and relative

humidity must be established using

FAA-approved procedures.

Proposed section H36.101(d) would

specify that the helicopter height and

lateral position is determined relative to

the reference flight track, not the

centerline or runway. The differential

global positioning system is acceptable

as an independent method of

determining the position of the

helicopter.

Section H36.103 Takeoff Test

Conditions

Proposed section H36.103(b)(1) would

specify that the takeoff procedure

airspeed be established prior to entering

the 10dB-down time interval of the

climbout as opposed to the current

requirement that the takeoff procedure

airspeed must be established during the

horizontal portion of the takeoff test

procedure. This change more clearly

specifies that the portion of the takeoff

at which the required airspeed must be

maintained; this procedure allows the

pilot to establish and stabilize required

power settings at the time the climb is

started. This proposal would simplify

the pilot workload by requiring one less

parameter (power) that must be

stabilized at the time the climb is stated.

This method is only satisfactory if the

initial 10 dB-down time interval occurs

during the climb portion of the profile.

Proposed section H36.103(b)(3) would

more clearly define gearbox torque

limit. It also adds the alternate of

maximum take-off power. The lower of

the two is used for specifying required

takeoff condition. This change more

closely aligns part 36 with JAR 36

without any substantive change. This

section will no longer contain

paragraphs (i) and (ii); the material is

included in the text of (b)(3) as

described.

Proposed section H36.103(b)(4)would

clarify that portion of the takeoff at

which the required best rate of climb

airspeed, or the lowest airworthiness

approved takeoff speed must be

maintained. This section will no longer

contain paragraphs (i) and (ii); the

material is included in the text of (b)(3)

as described. This change more closely

aligns part 36 with JAR 36 without any

substantive change.

Proposed section H36.103(b)(5) would

define the highest rotor speed used in

takeoff. It also states that the rotor’s

average rpm, rather than instantaneous

rpm is required to be within ±1.0

percent during the 10 dB-down time

interval.

Proposed section H36.103(b)(6) would

add a new alternate allowable altitude

criteria of a wider zenith tolerance in

meters for low altitudes near the start

point. The criteria retains the current

permitted zenith tolerance defined in

degrees throughout the 10 dB-down

time interval. This change more closely

aligns part 36 with JAR 36 without any

substantive change.

Proposed section H36.103 (b)(7)

would add a new paragraph that

requires that a constant takeoff

configuration be maintained, and that

the landing gear may be retracted when

establishing the best rate-of-climb and

corresponding speed as required by the

U.S. airworthiness standards.

Section H36.105 Flyover Test

Conditions

Proposed section H36.105(b) would

specify in detail that an even number of

flights (6 or more) is required to assure

balanced measurement of any

directional effects that may be related to

flight path orientation.

Proposed section H36.105(b)(1) would

add the term ‘‘cruise configuration’’ in

requiring that a constant cruise

configuration be maintained. This

change adopts a commonly understood

term and will minimize

misinterpretation of allowance for

unsteady, variable speed operations

during flyover test conditions.

Proposed section H36.105(c)(1) would

add two alternative flyover airspeed

criteria to the current requirement of

continuous power (VH). The proposed

additional level flyover reference

airspeeds are 90 percent of the neverexceed airspeed, VNE, and 45 percent of

the never-exceed airspeed plus 65 knots;

the least of the three is the required

airspeed. As explained above in section

H36.3(d), the advent of more powerful

engines and improved gearboxes have

resulted in helicopters that can have a

59638 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

VH airspeed in excess of the power-on

VNE airspeed. Therefore, new noise

certification airspeed criteria are

necessary to be consistent with

technological advances but still

accommodate the airworthiness

limitations imposed for safety. These

two new reference airspeed criteria

would serve to satisfy these advances.

This change more closely aligns part 36

with JAR 36 without any substantive

change.

Proposed section H36.105(c)(2) would

define the highest rotor speed used in

flyover. It also states that the rotor’s

average rpm, rather than instantaneous

rpm, is required to be within ± 1.0

percent during the 10 dB-down time

interval.

Section H36.107 Approach Test

Conditions

Proposed section H36.107(b)(3) would

add a new alternate allowable altitude

criteria of a wider zenith tolerance in

meters for low altitudes near the end

point of the approach. The criteria

retains the current permitted zenith

tolerance defined in degrees throughout

the 10 dB-down time interval. This

change more closely aligns part 36 with

JAR 36 without any substantive change.

Proposed section H36.107(b)(5)

defines the highest rotor speed to be

used in approach. It also states that the

rotor’s average rpm, rather than

instantaneous rpm, is required to be

within ±1.0 percent during the 10 dBdown time interval. Thus, each noise

certification condition will be tested at

the highest operating rotor RPM as

specified in the Flight Manual. These

amendments are intended to more

closely replicate actual operating rotor

speed when conducting noise

certification tests.

Proposed section H36.107(b)(6) would

add a new paragraph that requires that

a constant takeoff configuration be

maintained, and that the landing gear

may be retracted when establishing the

best rate-of-climb and corresponding

speed as required by the airworthiness

standards.

Section H36.109 Measurement of

Helicopter Noise Received on the

Ground

Under this proposal, section H36.109

would be revised to reference section

B36.3.

Note: The jet noise harmonization

proposed rule (65 FR 42796, July 11, 2000)

includes a proposal for amending the values

in section B36.3. The proposed change would

also apply to helicopter noise and tests.

Section H36.111 Reporting and

Correcting Measured Data

Proposed section H36.111(c)(2) would

add a permissible EPNL correction for

takeoff flight condition only. The

amount of this allowable correction is

limited. Corrections for duration are

described in sections H36.205(f)(1) and

H36.205(g)(1)(i). This change will

reduce the number of takeoff flights

during testing.

Paragraphs (c)(2)(i) through (iv) are

being re-designated. Paragraph (c)(2)(i)

contains a minor editorial correction.

Paragraph (c)(2)(ii) is revised to include

only the difference between actual and

reference flight paths. This change

eliminates specific application that have

become obsolete by recent technology.

The text of current paragraph (c)(2)(iii)

is deleted; it is no longer needed if the

previous changes are made. The text of

current paragraph (c)(2)(iv) is redesignated (c)(2)(iii) and is revised by

retaining only the reference to H36.205.

Proposed section H36.111(c)(3)

changes the aircraft noise level

threshold that must exceed the

background level in each 1⁄3 octave band

from 5dB to 3dB. This change would

bring appendix H in line with appendix

B for transport category and turbojet

powered airplanes.

Section H36.113 Atmospheric

Attenuation of Sound

Proposed section H36.113(b) would

amend the current external reference to

the revised section B36.7 proposed in

the NPRM for subsonic jet, large

airplanes and subsonic transports.

Section B36.7 describes the method to

calculate atmospheric attenuation rates

and completely documents them within

the regulation under part 36.

Documenting this section within U.S.

regulations follows a similar ICAO

practice and builds the harmonization

between regulations.

Proposed section H36.113(c)(1)(iii) is

revised to specify that the 10-meter

temperature and relative humidity

measurement values be used to adjust

for the sound propagation path

absorption. Noise certification data

collected to date has demonstrated that

EPNL values corrected using

atmospheric data measured at 10 meters

are acoustically identical to those

corrected using averaged temperature

and relative humidity data. There is no

loss in accuracy by avoiding inherent

aircraft measurement inaccuracies.

Section H36.205 Detailed Data

Correction Procedures

Proposed section H36.205(a)(1) is

revised to allow negative value

corrections. Such corrections are

appropriate to accurately account for

any difference between reference and

test conditions. Currently, negative

corrections resulted in no correction

(essentially setting the value to zero).

This change will consider all influences,

whether negative or positive.

Proposed sections H36.205(a)(1)(i)

and H36.205(a)(ii) are revised to specify

corrections based on ‘‘differences’’ from

reference rather than conditions ‘‘greater

than’’ or ‘‘higher than’’ reference. This

change clarifies the requirement.

Proposed section H36.205(a)(1)(iii)

eliminates the correction to the EPNL

calculated from measured data if the test

weight is less than maximum

certification weight. Based on past test

data, such weight effects are difficult to

isolate from other dominant parameters.

Such corrections are unnecessary.

Under this proposal, section

H36.205(a)(2) is deleted. This material is

no longer necessary given the allowance

of negative correction values described

in section H36.205(a)(1).

Proposed section H36.205(a)(3)(iii)

redefines in more accurate descriptive

terms the distances applied for duration

corrections. Instead of ‘‘minimum’’

distances, the existing rule requires that

distances be based on the PNLTM

(maximum PNLT) distance. This is a

more accurate method for correcting for

noise impact since it is based on the

actual noise characteristics (peak PNLT)

rather than a minimum distance along

the flight path.

Proposed section H36.205(a)(3)(iv)

would replace the use of rotor rpm and

test speed with the acoustically accurate

term of Mach number that accounts for

both rpm and test speed effects. This is

a more concise and accurate variable to

apply when addressing the acoustical

effects of cumulative speed.

Proposed section H36.205(b)(ii)(2)

simplifies the takeoff airspeed range by

designating as the minimal boundary

the slowest climb speed allowed under

the airworthiness requirements. The

proposed language also removes the

reference to rotor speed, since rotor

speed is not needed in describing a

flight profile for data correction

purposes. This reference was included

in error.

Proposed section H36.205(b)(3)

removes the minimal distance

description from the paragraph. This

description is no longer needed given

the proposed change to section

H36.205(a)(3)(iii).

Proposed section H36.205(c)(1)

removes text that describes speed

criteria. It is not appropriate in a section

describing data correction because the

criteria are included elsewhere in part

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59639

36. The proposed language also removes

a reference to rotor speed, since rotor

speed is not needed in describing a

flight profile for data correction

purposes.

Proposed section H36.205(d)(2) would

eliminate the requirement that the test

approach procedure be included in the

Flight Manual. Such a procedure is

never used in approach , and if included

in the Flight Manual, could be confused

with approved airworthiness approach

procedures. The proposal also explains

the term ‘‘10 dB down period’’ with ‘‘10

dB-down time interval’’ as the accepted

nomenclature for this specific time

segment. This ‘‘harmonized’’ term is

being adopted in the regulations for jets,

large turboprop, small airplanes, and

helicopters.

Proposed section H36.205(d)(3)

removes the minimal distance

description from the reference to figure

H3. This description is no longer

needed given the proposed change to

section H36.205(a)(3)(iii).

Proposed section H36.205(e)(1)

removes the requirement that only the

advancing blade tip Mach number be

used when making source noise

adjustments. It also adds an alternate

procedure for off-reference tip Mach

number adjustments. The proposal

allows use of a more appropriate source

noise adjustment parameter which

would give results identical to that of

the more complex current procedure

while substantially reducing the amount

of additional flyover passes necessary to

generate statistically valid source noise

sensitivity curves.

Proposed section H36.205(f)(1)(i)

corrects designations of measured

takeoff sound propagation path and

length, ‘‘LrA’’ to ‘‘AL’’ and ‘‘LrA’’ to

‘‘ALr’’ , respectively.

Proposed section H36.205(f)(2)

replaces incorrect designations of

takeoff distances for measured and

reference paths, ‘‘AM’’ to ‘‘AN’’ and

AMr’’ to ‘‘ANr’’ , respectively, and add

‘‘i’’ to the alpha in the second term.

Proposed section H36.205(f)(3)

removes the ‘‘o’’ and ‘‘+’’ symbol from

the equation; they are incorrect.

Proposed corrections for the

designator ‘‘K’’ by flight condition are as

follows: ‘‘Ln’’ to ‘‘Lr’’, ‘‘M’’ to ‘‘N’’,

‘‘Mn’’ to ‘‘Nr’’, and ‘‘N’’ to ‘‘M’’, ‘‘Nr’’

to ‘‘Mr’’, respectively, within the

paragraph text. This change also

corrects a typographical error.

Proposed section H36.205(f)(4)

replaces incorrect designations of

flyover distances for measured and

reference paths, ‘‘AN’’ to ‘‘AM’’ and

‘‘ANr’’ to ‘‘AMr’’ , respectively, and

adds a subscript ‘‘i’’ to the first alpha in

the second term.

Proposed sections H36.205(g)(1)(i),

through (iv) correct the constant value

‘‘¥10’’ to ‘‘¥7.5’’ in front of the log

term in each of the ∆2 equations.

Proposed section H36.205(g)(1)(i)

corrects the term for measured and

reference lengths, ‘‘AT’’ to ‘‘AL’’ and

‘‘ATr’’ to ‘‘ALr’’, respectively within the

∆2 equation and paragraph text.

Proposed section H36.205(g)(1)(ii)

corrects the terms used for measured

and reference lengths, ‘‘AS’’ to ‘‘AN’’

and ‘‘ASr’’ to ‘‘ANr’’, respectively,

within the ∆2 equation and paragraph

text.

Proposed section H36.205(g)(1)(iii)

corrects the terms used for measured

and reference lengths at each of the

flight condition, ‘‘T’’ to ‘‘L’’ , ‘‘Tr’’ to

‘‘Lr’’ , ‘‘S’’ to ‘‘N’’, ‘‘Sr’’ to ‘‘Nr’’, and

‘‘G’’ to ‘‘M’’, ‘‘Gr’’ to ‘‘Mr’’, respectively,

within the paragraph text.

Proposed section H36.205(g)(1)(iv)

corrects the terms used for measured

and reference lengths, ‘‘AG’’ to ‘‘AM’’

and ‘‘AGr’’ to ‘‘AMr’’, respectively

within the ∆2 equation and paragraph

text. All of the corrections in section

H36.205(g)(1) are of previous errors. No

substantive changes are intended.

Figures H1, H2 and H3

Proposed revision to Figure H1

deletes the designation of Positions Tr

since the minimal distance designation

is no longer needed and includes the

height above measurement point in

metric units; see the text of proposed

section H36.205(b)(3) regarding the

takeoff condition.

Proposed revision to Figure H2

repositions the bullet-marker that’s

incorrectly positioned near label G due

to a typographical error. The marker is

repositioned in the proposed revised

graphic image at the intersection of line

Dr–Jr and line A–G.

Proposed revision to Figure H3

deletes the designations of Positions S

and Sr since the minimal distance

designation is no longer needed and

includes the height above measurement

point in metric units; see the text of

section H36.205(d)(3) regarding the

approach condition.

In proposed Figures H1, H2, and H3

the titles of the figures are changed to

reflect the language of this proposal.

The word ‘‘reference’’ would replace the

word ‘‘corrected’’ in each title.

Section H36.305 Noise Levels

Proposed sections H36.305(a)(2)(i)

through (iii) would revise the values for

the noise/weight reduction rate, from

‘‘3.01’’ to ‘‘3.0’’. The proposed text also

removes the phrase ‘‘for maximum

weight of 1,764 pounds or less’’ from

the end of each paragraph and replaces

it with the phrase ‘‘after which the limit

is constant.’’ The existing text was

found to be confusing; this proposed

change would enhance clarity. No

substantive change in the requirements

is intended.

Section J36.1 General

Proposed section J36.1 would increase

the maximum takeoff weight

requirement of appendix J from 6,000

pounds to 7,000 pounds. As explained

previously, Part 27 was amended to

increase the allowable passenger seat

limit to nine; accordingly the weight

limit was increased to 7,000 lbs. This

proposal makes the corresponding

changes in appendix J.

Section J36.3 Reference Test

Conditions.

Proposed section J36.3(c) would

clarify that the stabilized airspeed be

maintained throughout the measured

portion of the flyover. Stabilized

airspeed will insure the highest quality

noise data by avoiding variability of

advancing tip Mach number that

effectively impacts noise.

Proposed section J36.3(c)(1) would

add the requirement airspeed VNE that

must be included in the approved Flight

Manual. These changes standardize the

languages used in appendices H and J

without substantive change.

Section J36.101 Noise Certification

and Measurement Conditions

Proposed section J36.101(c)(4) revises

the location where meteorological data

is measured. This change would

harmonize this proposal with the JAR

and adds flexibility without substantive

change. It also makes the language of

this section compatible with

J36.101(c)(6).

Proposed section J36.101(c)(6):

1. Specifies that the physical location

of meteorological instruments be

representative of the atmospheric

conditions existing near the surface over

the geographical area where the

helicopter noise measurements are

made.

2. Provides that a fixed meteorological

station, such as those found at airports,

may be used to meet the location

requirement.

3. Adds the requirement that a fixed

meteorological station must be within

2,000 meters of the noise measurement

area. The 2,000-meter distance

limitation is a reasonable allowance

when using a ‘‘fixed meteorological

station.’’

These proposed changes harmonize

this proposal with the JAR and add

flexibility without substantive change

since part 36 requirements specify that

59640 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

the meteorological measurements be

made ‘‘at the noise monitoring station,’’

while JAR requirements specify that if

the measurement site is within 2,000

meters of an aerodrome thermometer,

the aerodrome reported temperature be

used.

Section J36.109 Measurement of

Helicopter Noise Received on the

Ground

Under this proposal, three references

to section H36.109 are being changed to

section B36.3. Section H36.109 was

removed because the data appears in

section B36.3. Note: The jet noise

harmonization proposed rule (65 FR

42796, July 11, 2000) includes a

proposal for amending the values in

section B36.3. The proposed change

would also apply to helicopter noise

and tests but the proposal is not

repeated in this NPRM to avoid

confusion.

Proposed section J36.305(a) would

have the same correction as made in

section H36.305(a) above.

Proposed section J36.305(a) increases

the upper weight limit from 6,000

pounds to 7,000 pounds maximum gross

weight. This is a conforming change for

reasons already described.

Paperwork Reduction Act

The Paperwork Reduction Act of 1995

(44 U.S.C. 3507(d)) requires that the

FAA consider the impact of paperwork

and other information collection

burdens imposed on the public. We

have determined that there are no new

information collection requirements

associated with this proposed rule.

International Compatibility

In keeping with the U.S. obligations

under the Convention on International

Civil Aviation, it is FAA policy to

comply with International Civil

Aviation Organization (ICAO) Standards

and Recommended Practices to the

maximum extent practicable. The FAA

has reviewed the corresponding ICAO

Standards and Recommended Practices

and has identified the following two

differences with these proposed

regulations. These two differences are

applicability provisions that already

exist and do not represent substantive

changes. If this proposal is adopted, the

FAA will file these differences with

ICAO.

(1) Sections 36.11 and H36.305 of part

36 allow for higher than Stage 2 noise

limits for helicopter changes in the type

design of certain (Stage 1) helicopters

certified before the ‘‘grandfather’’ clause

date of March 6, 1986; and

(2) Section 36.805(c) allows for higher

than Stage 2 noise limits for helicopter

changes in the type design of certain

(Stage 1) helicopters that the FAA

recognizes as the first civil version that

was designed, constructed for and

accepted for operational use by an

Armed Force of the United States.

Economic Evaluation

Proposed changes to Federal

regulations must undergo several

economic analyses. First, Executive

Order 12866 directs that each Federal

agency propose or adopt a regulation

only upon a determination that the

benefits of the intended regulation

justify its costs. Second, the Regulatory

Flexibility Act of 1980 requires agencies

to analyze the economic impact of

regulatory changes on small entities.

Third, the Trade Agreements Act (19

U.S.C. section 2531–2533) prohibits

agencies from setting standards that

create unnecessary obstacles to the

foreign commerce of the United States.

In developing U.S. standards, this Trade

Act also requires agencies to consider

international standards and, where

appropriate, use them as the basis of

U.S. standards. And fourth, the

Unfunded Mandates Reform Act of 1995

requires agencies to prepare a written

assessment of the costs, benefits and

other effects of proposed or final rules

that include a Federal mandate likely to

result in the expenditure by State, local

or tribal governments, in the aggregate,

or by the private sector, of $100 million

or more annually (adjusted for

inflation.)

In conducting these analyses, FAA

has determined this rule (1) has benefits

which do justify its costs, is not a

‘‘significant regulatory action’’ as

defined in the Executive Order and is

not ‘‘significant’’ as defined in DOT’s

Regulatory Policies and Procedures; (2)

will not have a significant impact on a

substantial number of small entities; (3)

reduces barriers to international trade;

and (4) does not impose an unfunded

mandate on state, local, or tribal

governments, or on the private sector.

These analyses, available in the docket,

are summarized below.

This notice of proposed rulemaking

would provide nearly uniform noise

certification standards for helicopters

certificated in the United States, the

JAA countries, and any other countries

that have adopted as their national

regulation either the United States

regulation, the JAA regulation, or the

ICAO standard.

The proposals would more closely

harmonize the flight test conditions,

procedures, and reporting requirements

mandated by the provisions of Subpart

A and appendices H, and J of 14 CFR

part 36 with the corresponding

applicable provisions of the Joint

Aviation Regulations (JAR) 36 and the

International Civil Aviation

Organization (ICAO) Annex 16.

Specifically, the proposal would amend

some of the technical specifications of

appendices H and J and add a new

definition to Subpart A of part 36.

The FAA concludes that the proposed

rule would be cost beneficial. The

proposed rule would require fewer

flyover passes, takeoffs, and microphone

systems, would eliminate humidity and

wind speed measurements and the

requirements to process test data twice

and issue separate reports for FAA and

ICAO methods, and would extend the

gross weight upper limit for the

appendix J certification test procedure.

The cost savings of the proposed rule

are estimated to be $17.31 million

($12.16 million, discounted) over a 10

year period. The one-time cost of this

proposed rule would be $40,800

($33,305 discounted) and would accrue

to those manufacturers that need to

obtain ICAO/JAA certification.

Initial Regulatory Flexibility

Determination

The Regulatory Flexibility Act of 1980

(RFA) establishes ‘‘as a principle of

regulatory issuance that agencies shall

endeavor, consistent with the objective

of the rule and of applicable statutes, to

fit regulatory and informational

requirements to the scale of the

business, organizations, and

governmental jurisdictions subject to

regulation.’’ To achieve that principle,

the Act requires agencies to solicit and

consider flexible regulatory proposals

and to explain the rationale for their

actions. The Act covers a wide-range of

small entities, including small

businesses, not-for-profit organizations

and small governmental jurisdictions.

Agencies must perform a review to

determine whether a proposed or final

rule will have a significant economic

impact on a substantial number of small

entities. If the determination is that it

will, the agency must prepare a

regulatory flexibility analysis as

described in the Act.

However, if an agency determines that

a proposed or final rule is not expected

to have a significant economic impact

on a substantial number of small

entities, section 605(b) of the 1980 act

provides that the head of the agency

may so certify and a regulatory

flexibility analysis is not required. The

certification must include a statement

providing the factual basis for this

determination, and the reasoning should

be clear.

Small entities are firms employing

1,500 employees or less based on Small

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59641

Business Administration guidelines.

Enactment of this proposal would

impose a one-time cost of $10,200 per

small entity, which would be incurred

by two small helicopter manufacturers

that met the criterion of small entity.

The yearly cost-savings per small entity

would be $265,000. In view of the

substantial net cost-savings per small

entity, the FAA has determined that this

proposed rule would not have a

significant adverse economic impact on

a substantial number of small entities;

therefore, a regulatory flexibility

analysis is not required under the terms

of the RFA. The FAA solicits comments

with respect to this finding and

determination and requests that all

comments be accompanied by clear

documentation.

International Trade Impact Assessment

The Trade Agreement Act of 1979

prohibits Federal agencies from

engaging in any standards or related

activities that create unnecessary

obstacles to the foreign commerce of the

United States. Legitimate domestic

objectives, such as safety, are not

considered unnecessary obstacles. The

statute also requires consideration of

international standards and where

appropriate, that they be used as the

basis for U.S. standards. In addition,

consistent with this Administration’s

belief in the general superiority and

desirability of free trade, it is the policy

of this Administration to remove or

diminish to the extent feasible, barriers

to international trade, including both

barriers affecting the export of American

goods and services to foreign countries

and barriers affecting the import of

foreign goods and services into the

United States.

This proposed rule is a direct action

to respond to this policy by increasing

the harmonization of the U.S. Federal

regulations with the European Joint

Aviation Requirements. The results

would facilitate international trade.

Unfunded Mandated Assessment

The Unfunded Mandates Reform Act

of 1995 (the Act), enacted as Public Law

104–4 on March 22, 1995, is intended,

among other things, to curb the practice

of imposing unfunded Federal mandates

on State, local, and tribal governments.

Title II of the Act requires each Federal

agency to prepare a written statement

assessing the effects of any Federal

mandate in a proposed or final agency

rule that may result in a $100 million or

more expenditure (adjusted annually for

inflation) in any one year by State, local,

and tribal governments, in the aggregate,

or by the private sector; such a mandate

is deemed to be a ‘‘significant regulatory

action.’’

This proposed rule does not contain

such a mandate. Therefore, the

requirements of Title II of the Unfunded

Mandates Reform Act of 1995 do not

apply.

Executive Order 13132, Federalism

The FAA has analyzed this proposed

rule under the principles and criteria of

Executive Order 13132, Federalism. The

FAA has determined that this action

would not have substantial direct effects

on the States, on the relationship

between the national Government and

the States, or on the distribution of

power and responsibilities among the

various levels of government. Therefore,

the FAA has determined that this notice

of proposed rulemaking would not have

federalism implications.

Environmental Assessment

FAA Order 1050.1D defines FAA

actions that may be categorically

excluded from preparation of a National

Environmental Policy Act (NEPA)

environmental assessment (EA) or

environmental impact statement (EIS).

In accordance with FAA Order 1050.1D,

appendix 4, paragraph 4(j), regulations,

standards, and exemptions (excluding

those, which if implemented may cause

a significant impact on the human

environment) qualify for a categorical

exclusion. The FAA has determined that

this rule qualifies for a categorical

exclusion because no significant

impacts to the environment are

expected to result from its finalization

or implementation.

Energy Impact

The energy impact of the notice has

been assessed in accordance with the

Energy Policy and Conservation Act

(EPCA) Public Law 94–163, as amended

(42 U.S.C. 6362) and FAA Order 1053.1.

It has been determined that the notice

is not a major regulatory action under

the provisions of the EPCA.

List of Subjects in 14 CFR Part 36

Aircraft, Noise control.

The Proposed Amendment

In consideration of the foregoing the

Federal Aviation Administration

proposes to amend 14 CFR part 36, as

follows:

PART 36—NOISE STANDARDS:

AIRCRAFT TYPE AND

AIRWORTHINESS CERTIFICATION

1. The authority citation for part 36

continues to read as follows:

Authority: 42 U.S.C. 4321 et seq.; 49 U.S.C.

106(g), 40113, 44701–44702, 44704, 44715;

sec. 305, Pub. L. 96–193, 94 Stat. 50, 57; E.O.

11514, 35 FR 4247, 3 CFR, 1966–1970 Comp.,

p. 902.

2. Section 36.1 is amended by adding

a new paragraph (h)(5) to read as

follows:

§ 36.1 Applicability and definitions.

* * * * *

(h) * * *

(5) Maximum normal operating RPM

means the highest rotor speed for each

reference procedure corresponding to

the airworthiness limit imposed by the

manufacturer and approved by the FAA.

Where a tolerance on the highest rotor

speed is specified, the maximum normal

operating rotor speed is the highest rotor

speed for which that tolerance is given.

If the rotor speed is automatically linked

with flight condition, the maximum

normal operating rotor speed

corresponding with that flight condition

must be used during the noise

certification procedure. If rotor speed

can be changed by pilot action, the

highest normal operating rotor speed

specified in the flight manual limitation

section for power-on conditions must be

used during the noise certification

procedure.

3.–4. Section 36.11 is amended by

revising the introductory text and by

removing ‘‘6,000’’ and adding ‘‘7,000’’

in its place in paragraph (a)(1) to read

as follows:

§ 36.11 Acoustical change: Helicopters.

This section applies to all helicopters

in the primary, normal, transport, and

restricted categories for which an

acoustical change approval is applied

for under § 21.93(b) of this chapter on or

after March 6, 1986. Compliance with

the requirements of this section must be

demonstrated under appendix H of this

part, or, for helicopters having a

maximum certificated takeoff weight of

not more than 7,000 pounds,

compliance with this section may be

demonstrated under appendix J of this

part.

§ 36.801 [Amended]

5. Section 36.801 is revised by

removing the term ‘‘6,000’’ in the

second sentence and adding the term

‘‘7,000’’ in its place.

Subpart O—Documentation, Operating

Limitations and Information

6. Revise the heading of Subpart O to

read as set forth above:

7. In § 36.1581 paragraph (a)(2) is

revised and paragraph (a)(3) is added to

read as follows:

59642 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

§ 36.1581 Manuals, markings, and

placards.

* * * * *

(2) For propeller driven small

airplanes the noise level information

must be one value for takeoff as defined

and required by appendix G of this part,

along with the maximum takeoff weight

and configuration.

(3) For rotorcraft the noise level

information must be one value for each

takeoff, flyover, and approach as

defined and required by appendix H of

this part or one value for flyover as

defined and required by appendix J of

this part along with the maximum

takeoff weight, maximum landing

weight (for appendix H), and

configuration.

* * * * *

Appendix H [Amended]

8. In appendix H, section H36.3 is

amended by revising paragraphs (a)(1),

(c)(2), (d), (e), (f)(1)(i), and (f)(1)(ii) to

read as follows:

Section H36.3 Reference test conditions.

(a) * * *

(1) Sea level pressure of 2,116 psf (76 cm

mercury, 1,013.25 hPa).

(c) * * *

(2) The reference flight path is defined as

a straight line segment inclined from the

starting point (1,640 feet prior to the center

microphone location at 65 feet above ground

level) at an constant climb angle β defined by

the certificated best rate of climb and Vy for

minimum engine performance. The constant

climb angle β is derived from the

manufacturer’s data (approved by the FAA)

to define the flight profile for the reference

conditions. The constant climb angle β is

drawn through Cr and continues, crossing

over station A, to the position corresponding

to the end of the type certification takeoff

path represented by position Ir.

(d) Level flyover reference profile. The

beginning of the level flyover reference

profile is represented by helicopter position

Dr (Figure H2). The helicopter approaches

position Dr in level flight 492 feet above

ground level as measured at Station A.

Reference airspeed must be either 0.9VH;

0.9VNE; 0.45VH+65 kts (0.45VH+120km/h); or

0.45VNE+65kts (0.45VNE+120 km/h),

whichever of the four speeds is least. The

helicopter crosses directly overhead station A

in level flight and proceeds to position Jr.

(e) For noise certification purposes, VH is

defined as the airspeed in level flight

obtained using the minimum specification

engine torque corresponding to maximum

continuous power available for sea level,

25°C ambient conditions at the relevant

maximum certificated weight. VNE is the

never-exceed airspeed. The value of VH and

VNE used for noise certification must be

included in the approved Flight Manual.

(f) * * *

(1) * * *

(i) The beginning of the approach profile is

represented by helicopter position E. The

position of the helicopter is recorded for a

sufficient distance (EK) to ensure recording

of the entire interval during which the

measured helicopter noise level is within 10

dB of Maximum Tone Corrected Perceived

Noise Level (PNLTM), as required. ErKr

represents a stable flight condition in terms

of torque, rpm, indicated airspeed, and rate

of descent resulting in a 6° approach angle.

(ii) The test approach profile is defined by

the approach angle η passing directly over

the station A at a height of AH, to position

K, which terminates the approach noise

certification profile. The test approach angle

η must be between 5.5° and 6.5°.

* * * * *

9. In appendix H, section H36.5, the

Flight Profile Identification-Positions

table is amended by removing the

symbols S, Sr, T and Tr and their

descriptions; the Flight Profile Distances

table is amended by removing the

symbols ASr, AT, and ATr and their

meanings. The Flight Profile

Identification-Positions table is revised

by adding three new symbols and their

descriptions in alphabetical order to

read as follows:

Section H36.5 Symbols and units.

Fr—Position on reference takeoff path

directly above noise measuring Station A.

Gr—Position on reference flyover path

directly above noise measuring Station A.

Hr—Position on reference approach path

directly above noise measuring Station A.

10. In appendix H, Section H36.101 is

revised by removing paragraphs

(b)(6)(iii) and (b)(8)(iii); by redesignating

paragraph (b)(9) as (d)(4); and by

revising paragraphs (b)(8)(ii), (c)(2),

(c)(3), (c)(5), (d)(2), (d)(3) and newly

redesignated paragraph (d)(4) to read as

follows:

Section H36.101 Noise certification test

and measurement conditions.

(b) * * *

(8) * * *

(ii) Each test weight must be within +5

percent and ¥10 percent of the maximum

certification weight.

(c) * * *

(2) Ambient air temperature between 14°F

and 95°F (¥10°C and 35°C), inclusively, at

a point 10 meters above the ground at the

noise measuring station. The temperature

and relative humidity measured at a point 10

meters above the ground at the noise

measuring station must be used to adjust for

propagation path absorption.

(3) Relative humidity and ambient

temperature at a point 10 meters above the

ground at the noise measuring station is such

that the sound attenuation in the one-third

octave band centered at 8 kHz is not greater

than 12 dB/100 meters and the relative

humidity is between 20 percent and 95

percent, inclusively.

* * * * *

(5) No anomalous meteorological

conditions (including turbulence) that will

significantly affect the noise level of the

aircraft when the noise is recorded at each

noise measuring station.

* * * * *

(d) * * *

(2) The helicopter height and lateral

position relative to the reference flight track

(which passes through the flight track noise

measuring station) must be determined using

an FAA-approved method. The equipment

used to make the determination must be

independent of normal flight

instrumentation, such as radar tracking,

theodolite triangulation, laser trajectography,

photo scaling, or differential global

positioning system.

(3) The helicopter position along the flight

path must be related to the noise recorded at

the noise measuring stations by means of

synchronizing signals at an approved

sampling rate. The position of the helicopter

must be recorded relative to the reference

flight track during the entire time interval in

which the recorded signal is within 10 dB of

PNLTM. Measuring and sampling equipment

must be approved by the FAA.

(4) Aircraft performance data sufficient to

make the corrections required under section

H36.205 of this appendix must be recorded

at an FAA-approved sampling rate using

FAA approved equipment.

11. In appendix H, Section H36.103 is

amended by revising paragraphs (b)(1),

(b)(3), (b)(4), (b)(5), and (b)(6), and by

adding new paragraph (b)(7) to read as

follows:

Section H36.103 Takeoff test conditions.

* * * * *

(b) * * *

(1) An airspeed of either Vy ±5 knots or the

lowest approved speed ±5 knots for the climb

after takeoff, whichever speed is greater,

must be established and maintained

throughout the 10 dB-down time interval.

(2) * * *

(3) Upon reaching a point 1,640 feet (500

meters) from the noise measuring station, the

helicopter must be stabilized at the

maximum take-off power that corresponds to

minimum installed engine(s) specification

power available for the reference ambient

conditions or gearbox torque limit,

whichever is lower.

(4) The helicopter must be maintained

throughout the 10 dB-down time interval at

the best rate of climb speed Vy ±5 knots, or

the lowest approved speed for climb after

takeoff, whichever is greater, for an ambient

temperature at sea level of 25°C.

(5) The average rotor speed must not vary

from the maximum normal operating rotor

RPM by more than ±1.0 percent during the

10 dB-down time interval.

(6) The helicopter must stay within ±10° or

±20 m, whichever is greater, from the vertical

above the reference track throughout the

10dB-down time interval.

(7) A constant takeoff configuration

selected by the applicant must be maintained

throughout the takeoff reference procedure

with the landing gear position consistent

with the airworthiness certification tests for

establishing Best Rate-of-Climb and Speed for

Best Rate-of-Climb.

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59643

12. In appendix H, Section H36.105 is

amended by revising paragraphs (b),

introductory text, (b)(1), (b)(3), (c)(1),

and (c)(2) to read as follows:

Section H36.105 Flyover test conditions.

* * * * *

(b) A test series must consist of at least six

flights with an equal number of runs in each

direction, over the flight-track noise

measuring station (with simultaneous

measurements at all three noise measuring

stations)—

(1) In level flight cruise configuration;

(2) * * *

(3) The helicopter must stay within ±10° or

±20 m, whichever is greater, from the vertical

above the reference track throughout the 10

dB-down time interval.

(c) * * *

(1) At a speed of 0.9VH; 0.9VNE; 0.45VH +

65 kts (0.45VH + 120 km/h); or 0.45VNE + 65

kts (0.45VNE + 120 km/h), whichever speed

is less, maintained throughout the measured

portion of the flyover;

(2) At average rotor speed which must not

vary from the maximum normal operating

rotor RPM by more than ±1.0 percent during

the 10 dB-down time interval.

* * * * *

13. In appendix H, Section H36.107 is

amended by revising paragraphs (b)(3)

and (b)(5) and adding new paragraph

(b)(6) to read as follows:

Section H36.107 Approach test

conditions.

* * * * *

(b) * * *

(3) The helicopter must stay within ±10° or

±20 m, whichever is greater, from the vertical

above the reference track throughout the 10

dB-down time interval;

* * * * *

(4) * * *

(5) At average rotor speed which must not

vary from the maximum normal operating

rotor RPM by more than ±1.0 percent during

the 10 dB-down time interval; and

(6) A constant approach configuration used

in airworthiness certification tests, with the

landing gear extended, must be maintained

throughout the approach reference

procedure.

* * * * *

14. In appendix H, Section H36.109 is

revised to read as follows:

Section H36.109 Measurement of

helicopter noise received on the ground.

The measurement system and the

measurement, calibration and general

analysis procedures to be used are provided

in Appendix A, section A36.3 of this part.

15. In appendix H, Section H36.111 is

amended by revising paragraph (c)(2),

by removing paragraph (c)(2)(iv) and the

undesignated text following (c)(2)(iv),

by revising paragraphs (c)(2)(i), (c)(2)(ii)

and (c)(2)(iii), and by revising paragraph

(c)(3) to read as follows:

Section H36.111 Reporting and correcting

measured data.

* * * * *

(c) * * *

(2) The measured flight path must be

corrected by an amount equal to the

difference between the applicant’s predicted

flight path for the certification reference

conditions and the measured flight path at

the test conditions. Necessary corrections

relating to aircraft flight path or performance

may be derived from FAA-approved data for

the difference between measured and

reference engine conditions, together with

appropriate allowances for sound attenuation

with distance. The Effective Perceived Noise

Level (EPNL) correction must be less than 2.0

EPNdB except for take-off flight condition,

where the correction must not exceed 4.0

EPNdB, of which the arithmetic sum of ∆1

(described in section H36.205(f)(1)) and the

term ¥7.5 log (AL/ALr) from ∆2 term

(described in section H36.205(g)(1)(i)) must

not exceed 2.0 EPNdB, for any combination

of the following:

(i) The aircraft is not passing vertically

above the measuring station.

(ii) Any difference between the reference

flight track and the actual test flight track.

(iii) Detailed correction requirements

prescribed in section H36.205 of this

appendix.

(3) Aircraft sound pressure levels within

the 10 dB-down time interval must exceed

the mean background sound pressure levels

determined under section B36.3.9.11 by at

least 3 dB in each one-third octave band or

be corrected under an FAA approved method

to be included in the computation of the

overall noise level of the aircraft. An EPNL

may not be computed or reported from data

from which more than four one-third octave

bands in any spectrum within the 10 dBdown time interval have been excluded

under this paragraph.

* * * * *

16. Section H36.113 is amended by

revising paragraphs (b) and (c)(1)(iii) to

read as follows:

Section H36.113 Atmospheric

attenuation of sound.

* * * * *

(b) Attenuation rates. The procedure for

determining the atmospheric attenuation

rates of sound with distance for each onethird octave bands must be in accordance

with Society of Automotive Engineering

(SAE) ARP 866A included in section A36.7.

(c) * * *

(1) * * *

(iii) The temperature and relative humidity

measured at 10 meters above the ground

must be used to adjust for propagation path

absorption.

* * * * *

17. In appendix H, Section H36.205 is

amended by removing paragraphs

(a)(1)(iii), (a)(2), and (a)(3)(v); removing

the last two sentences in paragraph

(b)(3) and (d)(3); by revising paragraphs

(a)(1)(i), (a)(1)(ii), (a)(3)(iii), (a)(3)(iv),

(b)(2), (c)(1), (d)(2), (e), (f)(1)(i), (f)(2)(i),

(f)(3), (f)(4), and (g)(1)–(i)–(iv), and by

revising Figures H1, H2, and H3 to read

as follows:

Section H36.205 Detailed data correction

procedures.

* * * * *

(a) * * *

(1) If a positive or negative value results

from any difference between reference and

test conditions, an appropriate correction

must be made to the EPNL calculated from

the measured noise data. Conditions that can

result in a different value include:

(i) Atmospheric absorption of sound under

test conditions that are different than the

reference; or

(ii) Test flight path at an altitude that is

different than the reference

(3) * * *

(iii) The distances for which PNLTM is

observed from both the test and reference

profiles to the noise measuring station must

be calculated and used to determine a noise

duration correction due to any change in the

altitude of aircraft flyover. The duration

correction must be added algebraically to the

EPNL calculated from the measured noise

data.

(iv) For aircraft flyover, from FAAapproved data in the form of curves or tables

giving the variation of EPNL with Mach

Number, source noise corrections are

determined and must be added to the EPNL,

to account for noise level changes due to

differences between test conditions and

reference conditions.

(b) * * *

(2) For the actual takeoff, the helicopter

approaches position C in level flight at 65

feet (20 meters) above ground level at the

flight track noise measuring station and at

either Vy ±5 knots or the lowest approved

speed for the climb after takeoff, whichever

speed is greater.

* * * * *

(c) Level flyover profiles. (1) The noise type

certification level flyover profile is shown in

Figure H2. Airspeed must be stabilized

within ±5 knots of the reference airspeed

given in section H36.3(d). If the test

requirements are otherwise met, flight

direction may be reversed for each

subsequent flyover, to obtain three test runs

in each direction.

* * * * *

(d) * * *

(2) The helicopter approaches position H

along a 6° (±0.5°) average approach slope

throughout the 10dB-down time interval. The

approach procedure must be acceptable to

the FAA.

* * * * *

(e) Correction of noise at source during

level flyover. (1) For level overflight, if any

combination of the following factors,

airspeed deviations from reference, rotor

speed deviations from reference, and

temperature deviations from reference,

results in a noise

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59646 Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules

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correlating parameter whose value deviates

from the reference value of this parameter,

then source noise adjustments must be

determined from the manufacturer’s data

approved by the FAA.

(f) * * *

(1) * * *

(i) Step 1. A set of corrected values are then

computed as follows:

SPLic = SPLi + (α i—α io) (AL¥ALr) + 20

log (AL/ALr)

where SPLi and SPLic are the measured and

corrected sound pressure levels, respectively,

in the -ith one-third octave band. The first

correction term accounts for the effects of

change in atmospheric sound absorption

where αi and αio are the sound absorption

coefficients for the test and reference

atmospheric conditions, respectively, for the

-ith one-third octave band, and AL is the

measured takeoff sound propagation path.

The second correction term accounts for the

effects of atmospheric sound absorption on

the change in the sound propagation path

length where ALr is the corrected takeoff

sound propagation path. The third correction

term accounts for the effects of the inverse

square law on the change in the sound

propagation path length.

* * * * *

(2) Approach flight path. (i) The procedure

described in paragraph (f)(1) of this section

for takeoff flight paths is also used for the

approach flight path, except that the value for

SPLic relate to the approach sound

propagation paths shown in Figure H3 as

follows:

SPLic = SPLi ∂ (α i—α io) AN ∂ α io

(AN¥ANr) ∂ 20 log (AN/ANr)

Federal Register / Vol. 65, No. 194 / Thursday, October 5, 2000 / Proposed Rules 59647

where the lines AN and ANr are the

measured and reference approach sound

propagation paths, respectively.

* * * * *

(3) Sideline microphones. The procedure

prescribed in paragraph (f)(1) of this section

for takeoff flight paths is also used for the

propagation to the sideline microphones,

except that the values of SPLic relate only in

the measured sideline sound propagation

path as follows:

SPLic = SPLi + (α i¥α io)KX + α io

(KX¥KXr) + 20 log (KX/KXr)

K is the sideline measuring station where:

X = L and Xr = Lr for takeoff

X = M and Xr = Mr for flyover

X = N and Xr = Nr for approach

(4) Level flyover flight path. The procedure

described in paragraph (f)(1) of this section

for takeoff flight paths is also used for the

level flyover flight path, except that the

values of SPLic relate only to the flyover

sound propagation paths as follows:

SPLic = SPLi + (α i¥α io)AM + α io

(AM¥AMr) + 20 log (AM/AMr)

(g) * * *

(1) * * *

(i) Takeoff flight path. For the takeoff flight

path shown in Figure H1, the correction term

is calculated using the formula—

∆2 = ¥7.5 log (AL/ALr) + 10 log (V/Vr)

which represents the correction that must be

added algebraically to the EPNL calculated

from the measured data. The lengths AL and

ALr are the measured and corrected takeoff

distances from the noise measuring station A

to the measured and the corrected flight

paths, respectively. A negative sign indicates

that, for the particular case of a duration

correction, the EPNL calculated from the

measured data must be reduced if the

measured flight path is at greater altitude

than the corrected flight path.

(ii) Approach flight path. For the approach

flight path shown in Figure H3, the

correction term is calculated using the

formula—

∆2 = ¥7.5 log (AN/ANr) + 10 log (V/Vr)

where AN is the measured approach distance

from the noise measuring station A to the

measured flight path and 394 feet is the

overhead distance from station A to the

reference flight path.

(iii) Sideline microphones. For the sideline

flight path, the correction term is calculated

using the formula—

∆2 = ¥7.5 log (KX/KXr) + 10 log (V/Vr)

K is the sideline measuring station

where X = L and Xr = Lr for takeoff

where X = M and Xr = Mr for flyover

where X = N and Xr = Nr for approach

(iv) Level flyover flight paths. For the level

flyover flight path, the correction term is

calculated using the formula—

∆2 = ¥7.5 log (AM/AMr) + 10 log (V/Vr)

where AM is the measured flyover distance

from the noise measuring station A to the

measured flight path and 492 feet is the

overhead distance from station A to the

reference flight path.

* * * * *

18. I appendix H, Section

H36.305(a)(2) is revised to read as

follows:

Section H36.305 Noise levels. 

(a) * * *

(2) Stage 2 noise limits are as follows:

(i) For takeoff calculated noise levels—109

EPNdB for maximum takeoff weights of

176,370 pounds or more, reduced by 3.0

EPNdB per halving of the weight down to 89

EPNdB, after which the limit is constant.

(ii) For flyover calculated noise levels—108

EPNdB for maximum weights of 176,370

pounds or more, reduced by 3.0 EPNdB per

halving of the weight down to 88 EPNdB,

after which the limit is constant.

(iii) For approach calculated noise levels—

110 EPNdB for maximum weights of 176,370

pounds or more, reduced by 3.0 EPNdB per

halving of the weight down to 90 EPNdB,

after which the limit is constant.

* * * * *

Appendix J [Amended]

19. Amend the title of Appendix J and

section J36.1 introductory text by

removing the reference ‘‘6,000’’ and

adding ‘‘7,000’’ in its place

20. In appendix J, Section J36.3 is

amended by revising paragraph (c)

introductory text and paragraph (c)(1) to

read as follows:

Section J36.3 Reference test conditions.

* * * * *

(c) Level flyover reference profile. The

reference flyover profile is a level flight 492

feet (150 meters) above ground level as

measured at the noise measuring station. The

reference flyover profile has a linear flight

track and passes directly over the noise

monitoring station. Airspeed is stabilized at

0.9VH; 0.9VNE; 0.45VH + 65 kts (0.45VH + 120

km/h); or 0.45VNE + 65 kts (0.45VNE + 120

km/h), whichever of the four airspeeds is

least, and maintained throughout the

measured portion of the flyover. Rotor speed

is stabilized at the power on maximum

normal operating RPM throughout the 10 dBdown time interval.

(1) For noise certification purposes, VH is

defined as the airspeed in level flight

obtained using the minimum specification

engine power corresponding to maximum

continuous power available for sea level,

77°F (25°C) ambient conditions at the

relevant maximum certificated weight. The

value of VH and VNE used for noise

certification must be included in the Flight

Manual.

* * * * *

21. In appendix J, Section J36.101 is

amended by revising paragraph (c)(4)

and (c)(6) to read as follows:

Section J36.101 Noise certification test

and measurement conditions.

* * * * *

(c) * * *

(4) Measurements of ambient temperature,

relative humidity, wind speed, and wind

direction must be made between 4 feet (1.2

meters) and 33 feet (10 meters). Unless

otherwise approved by the FAA, ambient

temperature and relative humidity must be

measured at the same height above the

ground.

* * * * *

(6) If the measurement site is within 2,000

meters of an airport’s weather measurement

equipment, the airport reported temperature,

relative humidity and wind velocity may be

used. A fixed meteorological station (such as

those found at airports or other facilities),

within 2,000 meters of the noise measuring

station, may meet this requirement.

* * * * *

22. In appendix J, Section J36.109 is

amended by revising paragraphs

(d)(1)(ii) and (e)(1) by removing the

reference to ‘‘section H36.109(c)(3) of

appendix H’’ and adding the reference

‘‘section A36.3.6 of appendix B’’ in its

place and revising paragraph (c)(4) to

read as follows:

Section J36.109 Measurement of

helicopter noise received on the ground

* * * * *

(c)(4) Procedures for calibration and

checking of system used must follow those

described in Section A36.3.9.

* * * * *

23. Section J36.305 is amended by

revising paragraph (a) to read as follows:

Section J36.305 Noise Limits.

(a) For primary, normal, transport, and

restricted category helicopters having a

maximum certificated takeoff weight of not

more than 7,000 pounds and noise tested

under this appendix, the Stage 2 noise limit

is 82 decibels SEL for helicopters up to 1,737

pounds maximum certificated takeoff weight

at which the noise certification is requested,

and increasing at a rate of 3.0 decibels per

doubling of weight thereafter. The limit may

be calculated by the equation: LAE (limit) =

82 + 3.0 [log10 (MTOW/1737)/log10(2)] dB,

where MTOW is the maximum takeoff

weight, in pounds, for which certification

under this appendix is requested.

Issued in Washington, DC, on September

19, 2000.

James D. Erickson,

Director of Environment and Energy.

[FR Doc. 00–24634 Filed 10–4–00; 8:45 am]

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