Amendment of the Type Certification Procedures for Changes in Helicopter Type Design to Attach or Remove External Equipment

SUMMARY: This final rule amends the existing helicopter noise

certification procedures with respect to certain changes in type

designs. The applicability of the noise certification procedures is

amended to exclude those changes in type design that involve the

attachment or removal of external equipment, floats and skis, and

certain airframe and operational changes made to accommodate such

changes in type design (acoustical change requirements). Also excluded

from the applicability of the acoustical change requirements are

helicopter flight operations with doors and/or windows removed or in an

open position. This amendment also makes U.S. helicopter noise

certification regulations more consistent with the International Civil

Aviation Organization (ICAO) standards.

EFFECTIVE DATE: May 7, 1996.

FOR FURTHER INFORMATION CONTACT:

Mr. Kenneth E. Jones, Research and Engineering Branch (AEE-110),

Technology Division, Office of Environment and Energy, FAA, 800

Independence Avenue, SW., Washington, D.C. 20591; telephone (202) 267-

8933, facsimile (202) 267-5594.

SUPPLEMENTARY INFORMATION: The purpose of this rulemaking is to amend

the applicability of the helicopter noise certification procedures to

exclude those changes in helicopter type design that involve the

attachment or removal of external equipment, floats and skis, and

certain airframe and operational changes made to accommodate such

changes in type design (acoustical change requirements). Also excluded

from the acoustical change requirements are helicopter flight

operations with doors and/or windows removed or in an open position.

This amendment is based on Notice of Proposed Rulemaking (NPRM) Notice

No. 95-15 (60 FR 48790, September 20, 1995; Docket No. 28334) in which

comments were invited. No comments were received in the docket in

response to the NPRM. Accordingly, the final rule is adopted as

proposed in the NPRM.

Background

Statement of the Problem

The certification procedures for aeronautical products and parts

are contained in 14 CFR part 21. Under part 21, an applicant for

approval of a change to a helicopter type certificate must show

compliance with the noise regulations in 14 CFR part 36 (part 36) if

the change in type design may increase the noise level of the

helicopter (an acoustical change). Section 21.93 defines an

``acoustical change'' and classifies the aircraft which must

demonstrate compliance with part 36 following an acoustical change.

Section 21.93(b)(4) describes helicopters required to demonstrate

compliance with part 36 for an acoustical change, and specifically

excludes helicopters designated exclusively for ``agricultural aircraft

operations,'' ``dispensing firefighting materials,'' or ``carrying

external loads.'' The intent of the existing Sec. 21.93(b)(4) is to

exclude helicopters designated exclusively to carry external loads from

the requirement to demonstrate compliance with part 36.

This amendment addresses type certification (including noise

requirements) procedures for changes to helicopter type designs to

configure helicopters for carriage of external equipment. External

equipment is defined herein as any instrument, mechanism, part,

apparatus, or accessory that is attached to or extends from the

helicopter exterior but is not used nor is intended to be used in

operating or controlling a helicopter in flight and its not part of an

airframe or engine. Examples of external equipment are spotlights,

cameras, airborne signs, and cargo tanks and baskets.

External equipment may be attached to a helicopter as a Class A

Rotorcraft External Load Combination under 14 CFR part 133 (part 133)

``Rotorcraft External Load Operations'', or alternatively, the external

equipment may be attached to the helicopter as a change in type design

under Subpart D of part 21. The noise certification requirements do not

apply to any helicopter, regardless of airworthiness certification

category, that is designated exclusively for carrying external loads

pursuant to part 133. Section 133.51 states that ``[a] Rotocraft

External-Load Operator Certificate is a current and valid airworthiness

certificate for each rotocraft . . . listed by registration number on a

list attached to the certificate, when the rotocraft is being used in

operations conducted under [part 133].'' However, when the original

helicopter noise certification rules were adopted in part 21, external

equipment was not excluded from the acoustical change provisions of

Sec. 21.93. Thus, except for helicopters operated under part 133, the

addition of external equipment was, prior to this amendment, subject to

the acoustical change provisions of Sec. 21.93. This amendment of

Sec. 21.93 reconciles the procedural treatment of external equipment

added to helicopters with the intent of Sec. 21.93(b)(4) by expanding

the acoustical change exception to include carriage of external

equipment.

History of Aircraft Noise Certification Regulations Relevant to This

Amendment

On November 3, 1969, the Administrator of the FAA adopted part 36

entitled ``Noise Standards: Aircraft Type Certification.'' That action

implemented the FAA's regulatory noise abatement program by prescribing

type certification noise standards for subsonic turbojet powered

airplanes. Procedural changes were concurrently made to part 21,

``Certification Procedures for Products and Parts,'' to provide

criteria and requirements for demonstrating compliance with the

specifications in part 36 (34 FR 18355, November 18, 1969). The noise

certification requirements of parts 21 and 36 are designed to promote

the incorporation of noise abatement technology into aircraft design.

Parts 21 and 36 have been amended as appropriate to add new aircraft

types to the certification requirements or change the technical

specifications as necessary. Subsequently, helicopter noise

certification requirements were adopted with amendment 36-14 to part 36

and amendment 21-61 to part 21 (53 FR 3534, February 5, 1988).

The first amendment to part 21 relevant to the original aircraft

noise certification regulation was amendment 21-27 (34 FR 18355,

November 10, 1969). That amendment established the general requirement

that an applicant must demonstrate compliance with the applicable

provisions of the part 36 procedures prior to issuance of an original,

amended, or supplemental type certificate. The same amendment to part

21 included the addition under Sec. 21.93(b) that specified an

``acoustical change'' as any voluntary change in type design of a

transport category or turbojet-powered airplane that may increase the

noise levels of that airplane. Section 21.93 was subsequently amended

in response to

[[Page 20697]]

the promulgation of part 36 noise standards for propeller-driven

airplanes (Amdt. 21-42; 40 FR 1029, January 6, 1975), supersonic

airplanes (Amdt. 21-47; 43 FR 28406, June 29, 1978), commuter category

airplanes (Amdt. 21-59; 52 FR 1806, January 15, 1987), and helicopters

(Admt. 21-61; 53 FR 3534, February 5, 1988).

Section 21.93 has also been amended to exclude certain changes in

aircraft type design from the acoustical change requirements. The

necessity for excluding these changes in type design became apparent

only after experience was gained from implementation of the original

noise certification regulations for the aircraft type in question. For

turbojet-powered airplanes, amendment 21-56 (47 FR 756, January 7,

1982) excludes time-limited engine and/or nacelle changes, where the

change in type design specifies that the airplane may not be operated

for a period of more than 90 days, and amendment 21-62 (53 FR 16360,

May 6, 1988) excludes both gear down flight with one or more

retractable landing gear down during the entire flight and spare engine

and nacelle carriage external to the skin of the aircraft. For

propeller-driven commuter category and propeller-driven small

airplanes, amendment 21-63 (53 FR 47394, November 22, 1988) excludes

``antique'' airplanes (i.e., those airplanes that have flight time

before January 1, 1955) and land configurated aircraft reconfigured

with floats and skis.

Synopsis of the Amendment

This amendment changes the acoustical change provisions of

Sec. 21.93 to exclude helicopters that have been modified by the

addition or removal of external equipment mounted on the helicopter

airframe or floats (rigid or bag) and skis. This amendment also

excludes certain changes in helicopter type design from the acoustical

change requirements otherwise applicable to certain airframe changes

made to accommodate the external equipment and to helicopter flight

operations with doors and/or windows removed or in an open position.

This amendment also applies to any operating limitations placed on, or

removed from the helicopter as a consequence of the addition or removal

of external equipment, floats, and skis.

The FAA recognizes the utility aspect of the helicopter as an

aerial platform of external equipment. It is a common practice in the

helicopter industry to add or remove external equipment as mission

requirements vary. Although external equipment may be offered by the

original manufacturer of the helicopter, it is usually added as an

after-market addition by individual operators to meet specific mission

needs. Given the potential variety of external equipment, the nature of

the external equipment is not considered part of the basic design of a

given helicopter and does not influence the basic aerodynamic design or

the incorporation of noise abatement technology into the helicopter

design. As stated in the preamble of the final rule (cited previously)

for the original helicopter noise certification rulemaking, ``. . . the

[helicopter] noise standards apply [only] to internal load

configurations.''

This amendment is consistent with a similar provision in the

applicability section of the helicopter noise certification standard

approve by the ICAO under its International Standards and Recommended

Practices: Environmental Protection; Annex 16, Volume 1, Chapters 8 and

11 (Third Edition-July 1993). This amendment brings the acoustical

change provision in the U.S. noise certification regulations into

closer harmony with that used by foreign noise certification

authorities.

The FAA has determined that this amendment will provide benefits in

the form of regulatory relief to the helicopter industry and to

individual helicopter operators. This amendment will result in little

or no increase of public exposure to helicopter noise emissions. Prior

to this amendment, type certification procedures and the helicopter

regulations changed by this amendment imposed an undue financial burden

on the helicopter industry and operators without providing any

measurable benefit to the public.

Details of the amendment and limitations of the amendment are

provided in the following analysis.

Sec. 21.93 Classification of changes in type design.

Part 21 prescribes that certain types of aircraft, including

helicopters, must demonstrate compliance with the applicable

requirements of part 36 if a change in type design results in an

acoustical change. Section 21.93 specifies an ``acoustical change'' as

any voluntary change in type design (including operational limitations)

that may increase the noise levels of an aircraft. This amendment,

applicable only to helicopters, excludes the installation or removal of

external equipment from being considered an acoustical change. The

amendment specifically excludes from the acoustical change provision

the addition or removal of all external equipment where ``external

equipment'' means any instrument, mechanism, part, apparatus,

appurtenance, or accessory (e.g., spotlights, cameras and other optical

devices, public address systems, hoists, airborne signs, tow banners,

cargo tanks and baskets, emergency flotation gear, personnel platforms,

wire strike kits, crop spraying equipment, scientific apparatus and

their accessories) that is not used or intended to be used in operating

or controlling an aircraft in flight, that is attached to the

helicopter, and is not part of an airframe or engine. This amendment

applies to changes in the airframe made to:

(1) Accommodate the addition or removal of external equipment:

(2) Facilitate the use of external equipment; or

(3) Facilitate the safe operation of the helicopter with external

equipment mounted on the helicopter.

Examples of airframe changes that are excepted include fairings,

attachment hardware, cavities constructed in the airframe to

accommodate conformally attached equipment, and bubble windows. This

amendment also excludes from the acoustical change provision external

load attaching means, the airworthiness certification of which is

specified in Secs. 27.865 and 29.865.

This amendment excludes the addition or removal of floats and skis

on helicopters from the acoustical change provision. This amendment

makes it clear that any changes in the operating limitations placed on

the helicopter as a consequence of the addition or removal of external

equipment, floats, and skis is not an acoustical change. Similarly, it

also excludes flight operations conducted with one or more doors and/or

windows removed or in an open position.

The FAA has included addition or removal of floats and skis on

helicopters under this amendment in order to provide the same provision

for helicopters as is currently provided small propeller driven

airplanes and propeller driven commuter category airplanes under

Sec. 21.93(b)(3). The acoustical change requirements of Sec. 21.93 do

not require a noise certification compliance demonstration for such

airplanes because the FAA did not have a rational basis to consider

such design configurations in the original rulemaking that established

noise certification requirements for theses aircraft. While the

addition of floats and skis adversely affects the aerodynamic

performance, and consequently the noise levels, of both small airplanes

and helicopters, the FAA lacks the acoustical and performance data

necessary to develop

[[Page 20698]]

noise certification regulations relevant to small airplanes and

helicopters that are reconfigured by the addition of floats or skis.

If a noise compliance demonstration is otherwise required for

compliance with part 36, the noise flight test must be conducted

without any external equipment, floats, or skis mounted to the

helicopter and with doors and windows mounted and closed (i.e.,

aerodynamically clean configuration) unless otherwise approved or

required by the FAA. In granting such approvals or establishing such

requirements, the rationale for the FAA's decision will be based on

whether or not the measured helicopter noise levels from a proposed

noise compliance demonstration would be representative of a ``clean

configured'' helicopter. For example, assume a cavity was created in

the fuselage (as a related airframe change) to accommodate a

conformally (flush) fitted camera. Under this amendment, both the

camera and the cavity are excluded from the acoustical change

requirements of part 21. However, in the event of any future noise

testing of that helicopter for a change in type design unrelated to the

camera and cavity, such a noise test without the camera mounted and the

cavity exposed would likely lead to unrepresentative noise levels due

to alternation of the aerodynamic performance of the helicopter. In

this example, during the actual noise test for the unrelated change in

type design, the FAA would probably require that the flush-mounted

camera be inserted in its associated fuselage cavity or that the

fuselage cavity be covered in a manner that would return the fuselage

to its original aerodynamic shape. Similarly, any analysis for the

purpose of demonstrating a ``non-acoustical change'' under Sec. 21.93

must assume performance levels consistent with an aerodynamically clean

helicopter (relative to the changes in type design excluded under this

amendment). That is, a decrease in a noise certification level effected

by the addition of equipment excluded under this amendment may not be

used to ``mathematically'' offset an increase in noise from a change in

type design not affected by this amendment. For example, assuming the

certification basis for a given helicopter is part 36 Appendix J, an

increase in the flyover noise certification level caused by the upgrade

of a transmission may not be offset by the decrease in noise from the

assumed addition of external equipment, floats or skis as part of the

change in type design for the transmission.

The FAA also deletes by this amendment the previous text in

Sec. 21.93(b)(4)(i) and (ii). Those paragraphs indicated examples of

design changes which would be considered acoustical changes. Since

Sec. 21.93(b) already makes it clear that ``any voluntary change in the

type design of an aircraft that may increase the noise levels of the

aircraft is an `acoustical change' . . . .'' paragraphs

Sec. 21.93(b)(4)(i) and (ii) could have been erroneously interepreted

to indicate that (any) change to a muffler (including a change to a

quieter muffler) is by regulation an acoustical change. Paragraphs (i)

and (ii) did not represent a regulatory requirement and added nothing

toward the interpretation of the acoustical change requirements for

helicopters. The amended text addresses the definition of external

equipment and the exclusions discussed earlier in this synopsis.

The FAA has examined such factors as the utility aspect of the

helicopter mission, the necessity for the addition or removal of

external equipment to meet mission needs, the relevance of such

equipment with regard to the incorporation of noise abatement

technology in the design of the helicopter, and the desire for

commonality of U.S. noise certification regulations with relevant

international standards and foreign national regulations. After

consideration of these factors, the Administrator determined that the

amendment is consistent with the criteria set forth for proposing and

amending aircraft noise abatement regulations under the authority of

Sec. 611(d) of the Federal Aviation Act of 1958.

International Compatibility

The FAA has reviewed corresponding ICAO standards and JAA

regulations, were they exist. This amendment makes U.S. helicopter

noise certification regulations more consistent with the ICAO

standards.

Paper Reduction Act

In accordance with the Paperwork Reduction Act of 1980 (Pub. L. 96-

511), there are no requirements for information collection associated

with this amendment.

Regulatory Evaluation Summary

Three principal requirements pertain to the economic impacts of

changes to the Federal Regulations. First, Executive Order 12866

directs Federal agencies to promulgate new regulations or modify

existing regulations only if the expected benefits to society outweigh

the expected costs. Second, the regulatory Flexibility Act of 1980

requires agencies to analyze the economic impact of regulatory changes

on small entities. Finally, the Office of Management and Budget directs

agencies to assess the effect of regulatory changes on international

trade. In conducting these analyses, the FAA has determined that this

rule: (1) Will generate benefits exceeding costs; (2) is not

``significant'' as defined in the Executive Order and DOT's policies

and procedures; (3) will not have a significant impact on a substantial

number of small entities; (4) will lessen restraints on international

trade. These analyses, available in the docket, are summarized below.

Benefits

The final rule will provide regulatory relief and a cost savings of

$31,690,468 (non-discounted) or $23,409,159 discounted, over a ten year

period, to helicopter manufacturers, modifers, and operators. Of this

amount, the projected cost savings for part 36 noise certification

testing are as follows: Appendix H testing for helicopter manufacturers

is $4,800,000 (non-discounted) or $4,264,244 discounted; Appendix J

testing for helicopter manufacturers is $3,000,000 (non-discounted) or

$2,330,305 discounted; and Appendix J Testing for modifers, $22,500,000

(non-discounted) or $15,803,025 discounted. The FAA will also realize

administrative cost savings under these appendices as follows: Appendix

H, $222,460 (non-discounted) or $178,312 discounted; Appendix J,

$231,740 (non-discounted) or $173,525 discounted; and Appendix J (for

modifiers), $936,268 (non-discounted) or $659,748 discounted.

Costs

From a number of noise certification studies, the FAA has learned

that allowing applicants to attach external equipment to their

helicopters will result in no net increase in helicopter noise or, at

worst, insignificant increases in noise levels.

Regulatory Flexibility Determination

The Regulatory Flexibility Act of 1980 (RFA) was enacted by

Congress to ensure that small entities are not unnecessarily and

disproportionately burdened by government regulations. The RFA requires

a Regulatory Flexibility Analysis if a rule will have a significant

economic impact, either detrimental or beneficial, on a substantial

number of small entities. FAA Order 2100.14A, Regulatory Flexibility

Criteria and Guidance prescribes standards for complying with RFA

review requirements in FAA

[[Page 20699]]

rulemaking actions. The order defines ``small entities'' in terms of

size thresholds, ``significant economic impact'' in terms of annualized

cost threshold, and ``substantial number'' as a number that is not less

than eleven and that is more than one-third of the small entities

subject to the final rule.

The FAA has determined that, in accordance with the above order,

the final rule to part 21 will not have a significant economic impact

on a substantial number of small entities. The final rule will directly

affect two types of entities: (1) Light helicopter manufacturers, and

(2) small helicopter modifiers.

For small aircraft and aircraft parts manufacturers, Order 2100.14A

specifies a size threshold for classification as a small entity as 75

or fewer employees. Based upon this size threshold, all of the affected

U.S. manufacturers are large. For the purpose of the regulatory

flexibility determination, an aircraft modifier is considered a small

entity if it has 200 on fewer employees.

The FAA concludes that a substantial number of small entities (less

than one third) will not be significantly affected by the final rule.

Therefore, the final rule will not impose a significant economic impact

on a substantial number of small entities, and a regulatory flexibility

analysis is not required.

Trade Impact Assessment

The FAA has determined that the final rule will neither affect the

sale of foreign aviation products and services in the United States nor

the sale of U.S. products and services in foreign countries. This

determination is based on the FAA's contention that the final rule will

align the U.S. standards more closely with foreign standards for noise

certification of external equipment.

Federalism Implications

The regulations herein will not have a 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, in accordance with

Executive Order 12612, it is determined that this proposed rule would

not have sufficient federalism implications to warrant the preparation

of a Federalism Assessment.

Environmental Analysis

Pursuant to the Department of Transportation ``Policies and

Procedures for Considering Environmental Impacts'' (FAA Order 1050.1D),

the FAA has determined that this rule does not significantly affect the

human environment. A Finding of No Significant Impact has been prepared

and placed in the docket.

Justification for Immediate Adoption

The FAA has determined that further delay in the adoption of this

rule would cause undue burden to U.S. manufacturers, modifiers, and

operators of helicopters. This final rule does not impose new

regulatory requirements; rather, it corrects an oversight in the

original helicopter noise certification rulemaking, which unnecessarily

applied acoustical change noise certification requirements to some

external load configurations. Although the preamble of that original

rulemaking stated that the noise certification regulations applied only

to internal load configurations, the necessary amendatory language that

would effect that applicability was not made in all of the relevant

portions of the noise certification regulations. At present, there are

several applications pending for changes in helicopter type design

which call for the addition of external equipment. Without this rule,

those applicants are unintentionally subject to costly noise

certification testing. Accordingly, the FAA has determined that good

cause exist to make this rule effective in less than 30 days.

Conclusion

The FAA has determined that this final rule: (1) is not a

significant regulatory action under Executive Order 12866; (2) is not a

significant regulatory action under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. In addition, this final rule will have little or no

affect on trade opportunities for U.S. firms doing business overseas,

or on foreign firms doing business in the United States.

List of Subjects in 14 CFR Part 21

Aircraft, Helicopters, Noise control.

The Amendment

Accordingly, the Federal Aviation Administration amends 14 CFR part

21 as follows:

PART 21--CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS

1. The authority citation for part 21 continues to read as follows:

Authority: 42 U.S.C. 7572; 49 U.S.C. 106(g), 40105, 40113,

44701-44702, 44707, 44709, 44711, 44713, 44715, 45303.

2. Section 21.93 is amended by revising paragraph (b)(4) to read as

follows:

Sec. 21.93 Classification of changes in type design.

* * * * *

(b) * * *

(4) Helicopters except:

(i) Those helicopters that are designated exclusively:

(A) for ``agricultural aircraft operations'', as defined in

Sec. 137.3 of this chapter, as effective on January 1, 1966;

(B) for dispensing fire fighting materials; or

(C) for carrying external loads, as defined in Sec. 133.1(b) of

this chapter, as effective on December 20, 1976.

(ii) Those helicopters modified by installation or removal of

external equipment. For purposes of this paragraph, ``external

equipment'' means any instrument, mechanism, part, apparatus,

appurtenance, or accessory that it attached to, or extends from, the

helicopter exterior but is not used nor is intended to be used in

operating or controlling a helicopter in flight and is not part of an

airframe or engine An ``acoustical change'' does not include:

(A) addition or removal of external equipment;

(B) changes in the airframe made to accommodate the addition or

removal of external equipment, to provide for an external load

attaching means, to facilitate the use of external equipment or

external loads, or to facilitate the safe operation of the helicopter

with external equipment mounted to, or external loads carried by, the

helicopter;

(C) reconfiguration of the helicopter by the addition or removal of

floats and skis;

(D) flight with one or more doors and/or windows removed or in an

open position; or

(E) any changes in the operational limitations placed on the

helicopter as a consequence of the addition or removal of external

equipment, floats, and skis, or flight operations with doors and/or

windows removed or in an open position.

* * * * *

Issued in Washington DC on May 1, 1996.

David R. Hinson,

Administrator.

[FR Doc. 96-11374 Filed 5-6-96; 8:45 am]

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