[Federal Register Volume 63, Number 222 (Wednesday, November 18, 1998)]
[Proposed Rules]
[Pages 64146-64151]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-30578]
[[Page 64145]]
_______________________________________________________________________
Part II
Department of Transportation
_______________________________________________________________________
Federal Aviation Administration
_______________________________________________________________________
14 CFR Part 36
Noise Certification Standards for Propeller-Driven Small Airplanes;
Proposed Rule
Federal Register / Vol. 63, No. 222 / Wednesday, November 18, 1998 /
Proposed Rules
[[Page 64146]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 36
[Docket No. FAA-1998-4731; Notice No. 98-16]
RIN 2120-AG65
Noise Certification Standards for Propeller-Driven Small
Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of Proposed Rulemaking (NPRM).
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SUMMARY: The FAA is proposing changes to the noise certification
standards for propeller-driven small airplanes. These proposals are
based on the joint effort of the Federal Aviation Administration (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
propeller-driven small airplanes. These proposed changes would provide
uniform noise certification standards for airplanes certificated in the
United States and in the JAA countries. 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 19, 1999.
ADDRESSES: Comments on this proposed rulemaking should be mailed or
delivered, in duplicate, to: U.S. Department of Transportation Dockets,
Docket No. FAA-1998-4731, 400 Seventh Street, SW., Room Plaza 401,
Washington, DC 20590. Comments may also be sent electronically to the
following Internet address: [email protected] Comments may be
filed and/or examined in Room Plaza 401 between 10 a.m. and 5 p.m.
weekdays except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Mehmet Marsan, Office of Environment
and Energy (AEE), Federal Aviation Administration, 800 Independence
Avenue, SW., Washington, DC 20591; telephone (202) 267-7703.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed rule by submitting such written data, views, or arguments as
they may desire. Comments relating to the environmental, energy,
federalism, or economic impact that might result from adopting the
proposals in this notice are also invited. Substantive comments should
be accompanied by cost estimates. Comments must identify the regulatory
docket or notice number and be submitted in triplicate to the Rules
Docket address specified above.
All comments received, as well as a report summarizing each
substantive public contact with FAA personnel on this rulemaking, will
be filed in the docket. The docket is available for public inspection
before and after the comment closing date.
All comments received on or before the closing date will be
considered by the Administrator before taking action on this proposed
rulemaking. Late-filed comments will be considered to the extent
practicable. The proposals contained in this notice may be changed in
light of the comments received. Commenters wishing the FAA to
acknowledge receipt of their comments submitted in response to this
notice must include a pre-addressed, stamped postcard with those
comments on which the following statement is made: ``Comments to Docket
No. FAA-1998-4731.'' The postcard will be date stamped and mailed to
the commenter.
Availability of the NPRM
An electronic copy of this document can be downloaded using a modem
and suitable communications software from the FAA regulations section
of the Fedworld electronic bulletin board service (telephone: 703-321-
3339), the Government Printing Office's electronic bulletin board
service (telephone: 202-512-1661).
Internet users may reach the FAA's web page at http://www.faa.gov
or the Government Printing Office's webpage at http://
www.access.gpo.gov/nara for access to recently published rulemaking
documents.
Any person may obtain a copy of this NPRM by mail by submitting a
request to the Federal Aviation Administration, Office of Rulemaking,
800 Independence Avenue, SW., Washington, DC 20591, or by calling (202)
267-9677. Communications must identify the notice number of this NPRM.
Persons interested in being placed on the mailing list for future
NPRM's should request from the FAA's Office of Rulemaking a copy of
Advisory Circular No. 11-2A, Notice of Proposed Rulemaking Distribution
System, that describes the application procedure.
Background
Current 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 contains the FAA's noise standards and regulations
that apply to the issuance of type certificates for all types of
aircraft. The standards and requirements that apply to propeller-driven
small airplanes and propeller-driven commuter category airplanes are
found in Sec. 36.501 and Appendix G of Part 36. Appendix G addresses
Takeoff Noise Requirements for propeller-driven small airplane and
propeller-driven commuter category airplane Certification Tests on or
after December 22, 1988. This appendix was added to part 36 in 1988 to
require actual takeoff noise tests instead of the level flyover test
that was formerly required under Appendix F, for airplanes for which
certification tests were completed before December 22, 1988.
Appendix G specifies the test conditions, procedures, and noise
levels necessary to demonstrate compliance with certification
requirements for propeller driven small airplanes and propeller-driven,
commuter category airplanes.
Government and Industry Cooperation
In June 1990 there was a meeting of the Joint Aviation Authorities
(JAA) Council, which consists of JAA members from European countries,
and the FAA. The FAA Administrator committed FAA to support the
harmonization of the FAA regulations with the Joint Aviation
Regulations (JAR). The Joint Aviation Regulations are being developed
for use by the European authorities that are member countries of the
JAA.
In January 1991, the FAA established the Aviation Rulemaking
Advisory Committee to serve as a forum for the FAA to obtain input from
outside the Government on major regulatory issues facing the agency.
The FAA announced the renewal of ARAC on February 19, 1993 (58 FR 9230)
and on March 1, 1995 (60 FR 11165). One area that ARAC deals with is
noise certification issues. These issues involve the harmonization of
14 CFR part 36 (part 36) with JAR part 36, the associated guidance
material including equivalent procedures, and the interpretation of the
regulations. On May 3, 1994, the ARAC established the FAR/JAR
Harmonization Working Group for Propeller-Driven Small Airplanes (59 FR
22885). The Working Group was tasked with reviewing the applicable
provisions of subparts A and F, and appendices F and
[[Page 64147]]
G of part 36, and harmonizing them with the corresponding applicable
provisions of JAR 36. The Working Group was asked to consider the
current international standards and recommended practices, as issued
under International Civil Aviation Organization (ICAO), Annex 16,
Volume 1, and its associated Technical Manual, as the basis for
development of these harmonization proposals. The Working Group was
also asked to recommend a process whereby subsequent ICAO Annex 16
changes could be properly incorporated into JAR 36 and part 36.
The Working Group reviewed 16 items related to noise limits and
measurement procedures in the regulations. For six of these items, the
Working Group recommended that part 36 be amended to harmonize the
regulations with JAR 36. For four of these items, the Working Group
recommended that JAR 36 be amended to harmonize those regulations with
part 36. For the six remaining items, the Working Group found that no
harmonization is necessary. The Working Group also recommended changes
to harmonize FAA and JAA interpretive and advisory material relating to
noise limits for propeller-driven small airplanes. This NPRM reflects
the six recommendations that address changes to part 36.
Discussion of Proposals
The proposed changes to appendix G would affect the provisions that
establish noise measurement procedures (sec. G36.107), corrections to
test results (sec. G36.201) and specific aircraft noise limits that are
tied to aircraft weight (sec. G36.301).
Section G36.107 Noise Measurement Procedures
Currently, section G36.107 prescribes specific procedures for the
placement of microphones, system calibration and consideration of
ambient noise. The proposed changes would affect the microphone
requirements of paragraph (a). Currently, microphones are required to
be oriented in a known direction so that the maximum sound received
arrives as nearly as possible in the direction for which the
microphones are calibrated, and the microphone sensing elements must be
placed four feet (1.2 m) above ground level.
The proposed change to section G36.107(a) would require the
microphone to be a pressure-type microphone with a protective grid that
is 12.7 mm in diameter. The microphone would have to be mounted in an
inverted position so that the diaphragm is 0.7 mm above and parallel to
a white-painted metal circular plate. The plate would have to be 40 cm
in diameter and at least 2.5 mm thick. The plate would have to be
placed horizontally and flush with the surrounding ground surface with
no cavities below the plate. The microphone would have to be located
three-quarters of the distance from the center to the edge of the plate
along a radius normal to the line of flight of the test airplane.
The proposed changes, which would make the U.S. regulations
consistent with the JAR, are supported by numerous studies, technical
papers, and discussions with interested groups. The technical data
indicate that an inverted microphone that measures reflected noise from
a metal plate at ground level produces more consistent and reliable
data. A microphone that is four feet above the ground is much more
likely to be affected by variable ground reflections that can interact
with the noise produced by the aircraft being measured. The microphone
height reduction and the metal plate substantially eliminate these
variations.
However, studies also show that measurements using the inverted
microphone and metal plate technique produce consistently higher noise
levels than those produced under the current procedure, with the
difference being about 3 dB(A). Therefore, to maintain the present
level of noise stringency, a corresponding change to section G36.301(b)
is necessary as discussed below.
Section G36.201 Corrections to Test Results
Current section G36.201 prescribes corrections to be made to test
results to account for the effects of differences between the
conditions referenced in the prescribed procedures and existing
conditions during an actual test.
Current section G36.201(b) requires atmospheric absorption
correction for noise data obtained when the test conditions are outside
those specified in appendix G, figure G1. Noise data collected outside
the prescribed range of figure G1 are required to be corrected to 77
degrees F and 70 percent relative humidity by an FAA approved method.
The FAA is proposing to change the 77 degrees F reference temperature
to 59 degrees F, to be consistent with the ambient temperature
requirement in current section G36.111(b)(2) that is used for
performance calculations. By making the reference temperatures
consistent for absorption and performance, delays and confusion that
have been caused by the inconsistency in the current rule would be
eliminated. The change would bring part 36 in line with Annex 16.
Current section G36.201(c) requires that helical tip Mach number
and power corrections must be made if the propeller is a variable pitch
type or if the propeller is a fixed pitch type and the test power is
not within five percent of the reference power. The proposed change
would provide an additional exception by stating that a correction is
not necessary if the helical tip Mach number meets one of the
following:
1. The number is at or below 0.70 and the test helical tip Mach
number is within 0.014 of the reference helical tip Mach number.
2. The number is above 0.70 and at or below 0.80 and the test
helical tip Mach number is within 0.007 of the reference helical tip
Mach number.
3. The number is above 0.80 and the test helical tip Mach number is
within 0.005 of the reference helical tip Mach number. For mechanical
tachometers, if the helical tip Mach number is above 0.8 and the test
helical tip Mach number is within 0.008 of the reference helical tip
Mach number.
These additional proposed exceptions are based on an analysis of
noise data from nine U.S.-manufactured aircraft. This analysis
indicated that the proposed values are well within the Type 1 sound
level meter as defined in International Electrotechnical Commission
(IEC) Publication No. 651, which has been incorporated by reference in
part 36. Adding this exemption would simplify some tests without
degrading the results.
Current section G36.201(d)(1) requires that the measured sound
levels must be corrected from the test day meteorological conditions by
adding an increment equal to the result gained from the following
equation:
Delta (M)=(-0.7) HT/1000.
In this equation, HT is the height in feet of the test
aircraft when directly over the noise measurement point, and
is the rate of absorption for the test day conditions at 500 Hz as
referenced in Society of Automotive Engineers (SAE) Publication
Aerospace Recommended Practice (ARP) 866A which has been incorporated
by reference in part 36.
The equation in section G36.201(d)(1) is an approximation. The
accuracy of the calculations can be improved by adopting the exact form
of the equation. Therefore, the FAA proposes to change the equation to
the exact form which reads as follows:
Delta (M)=(HT-0.7 HR)/1000.
In this equation HT is the height in feet under test
conditions, HR is the height in feet under reference
[[Page 64148]]
conditions when the aircraft is directly over the noise measurement
point, and is the same as in the current rule, that is, the
rate of absorption for the test day conditions at 500 Hz as specified
in SAE ARP 866A.
The proposed equation would bring appendix G absorption
calculations in line with the rest of part 36 absorption calculations
and Annex 16.
Current section G36.201(d)(4) requires that the measured sound
levels in decibels must be corrected for engine power by algebraically
adding an increment equal to:
Delta (3)=17 log (PR/PT)
where PT and PR are the test and reference engine
powers respectively.
The FAA proposes that the algebraic correction for engine power be
changed to:
Delta (3)=K3 log (PR/PT)
where PR and PT are the test and reference engine
powers respectively obtained from the manifold pressure/torque gauges
and engine rpm. Under this proposal, the value of K3 would
be determined from approved data from the test airplane. In the absence
of flight test data and at the discretion of the Administrator a value
of K3 = 17 could still be used as under the current rule.
The only difference between the current formula and the proposed
formula is the power correction constant. The current regulation
requires the use of 17 for this constant. The K3=17 value is
an average value that was derived from FAA tests on seven aircraft
where the variation was from 1.5 to 39.3. Although the use of an
average value simplifies the test plan, it could penalize an applicant
who can prove lower values of K3 by test data. Therefore,
the FAA proposes a formula that allows the applicant to use a lower
value for K3 when it has test data to support that value, or
to continue to use a value of 17 with the Administrator's approval when
test data is not available. The proposed formula is also consistent
with the JAR.
Section G36.301 Aircraft Noise Limits
Current section G36.301(b) states that the noise level must not
exceed 73 dB(A) up to and including aircraft weights of 1,320 pounds
(600 kg.), and that for weights greater than 1,320 pounds the noise
limit increases at the rate of 1 dB/165 pounds up to 85 dB(A) at 3,300
pounds, after which it is constant at 85 dB(A) up to and including
19,000 pounds.
As previously discussed, considerations of microphone location,
configuration, and resulting noise limits are interrelated. Since the
proposed changes to the noise measurement procedures of section
G36.107(a) would result in increases in the measured noise levels of
about 3 dB(A), the FAA proposes to increase the limits in section
36.301(b) from 73 dB(A) to 76 dB(A) and from 85 dB(A) to 88 dB(A). This
change would account for the revised microphone height and
configuration requirements. The increased limit is not expected to
result in any increase or decrease in the noise stringency requirements
of the current rule.
In addition to the dB(A) changes discussed, the FAA is proposing a
change to the interpolation requirement of section G36.301(b). For
weights greater than 1,320 pounds, the allowable dB(A) would increase
``with the logarithm of airplane weight at the rate of 9.83 dB(A) per
doubling of weight until the limit of 88 dB(A) is reached * * *,''
rather than at the rate of 1 dB/165 pounds up to 85 dB(A) at 3,300
pounds, as under the current rule. This change would harmonize
interpolation under the FAA regulation with the comparable JAA
regulation without change in noise stringency of the present Appendix
G.
Paperwork Reduction Act
There are no requirements for information collection associated
with this proposed rule that would require approval under the Paperwork
Reduction Act of 1995 (44 U.S.C. 3501 et seq.)
International Compatibility
In keeping with U.S. obligations under the Convention on
International Civil Aviation, it is FAA's policy to comply with ICAO
Standards and Recommended Practices to the maximum extent practicable.
For this NPRM, the FAA has reviewed part 36 Appendix G and ICAO Annex
16 Volume I, Chapter 10. The review showed that the following two items
were left unharmonized: (1) For fixed pitch type propellers, part 36
section G36.201 specifies a simplified data correction procedure if the
engine test power is within 5% of the reference power. The Annex 16
does not have a corresponding simplification and, (2) The part 36
section G36.111 allows the use of maximum continuous installed power
during the second segment of the flight path. The power definition in
Annex 16 for the second segment is defined as maximum power in Chapter
10 section 10.5.2. The maximum installed power is typically lower than
the maximum power and applicable only to older engines. The above two
unharmonized items only effect a small percentage of the airplanes in
the fleet and therefore are not significant enough to be considered as
harmonization issues.
Regulatory Evaluation Summary
Four 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 after consideration of the expected benefits to
society and the expected costs. Second, the Regulatory Flexibility Act
of 1980 requires agencies to analyze the economic impact of regulatory
changes on small entities. Third, the Office of Management and Budget
directs agencies to assess the effect of regulatory changes on
international trade. Finally, Public Law 104-4 requires federal
agencies to assess the impact of any federal mandates on state, local,
tribal government, and the private sector. In conducting these
analyses, the FAA has determined that this rule: (1) would generate
cost savings that would exceed any costs; (2) is not ``significant'' as
defined under section 3(f) of Executive Order 12866 and Department of
Transportation's (DOT) policies and procedures (44 FR 11034, February
26, 1979); (3) would not have a significant impact on a substantial
number of small entities; and (4) would not impose restraints on
international trade. Finally, the FAA has determined that the proposal
would not impose a federal mandate on state, local, or tribal
governments, or the private sector of $100 million per year. These
analyses, available in the docket, are summarized below.
The benefit of the proposed rule is that it would harmonize the
U.S. noise certification regulations with the European Joint Aviation
Requirements for propeller-driven small airplanes. The proposed changes
would provide nearly uniform noise certification standards for
airplanes certificated in the United States and by the European Joint
Aviation Authorities (JAA). This is expected to reduce the number of
noise tests that need to be conducted. The costs to implement the
proposal are negligible, if any. There are no additional costs imposed
by this proposal.
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 would have a significant
economic impact on a
[[Page 64149]]
substantial number of small entities. Because the costs imposed by this
rule would be negligible, the Agency concludes that the proposed rule
would not have a significant economic impact on a substantial number of
small entities.
International Trade Impact Statement
The FAA has determined that the proposed rule would promote the
sale of foreign products and services in the United States and the sale
of U.S. products and services in foreign countries. This determination
is based on the FAA's determination that the rule would align U.S.
standards and JAA member standards for noise certification for
propeller-driven small airplanes.
Environmental Analysis
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 proposes that this rule
qualifies for a categorical exclusion because no significant impacts to
the environment are expected to result from its finalization or
implementation. In accordance with FAA Order 1050.1D, paragraph 32, the
FAA proposes that there are no extraordinary circumstances warranting
preparation of an environmental assessment for this proposed rule.
Federalism Implications
The proposed regulations would not have substantial direct effects
on the states, on the relationship between national government and the
states, or on the distribution of power and responsibilities among
various levels of government. Thus, in accordance with Executive Order
12612, it is determined that such a regulation would not have
federalism implications warranting the preparation of a Federalism
Assessment.
Unfunded Mandates
Title II of the Unfunded Mandates Reform Act of 1995 (the Act),
enacted as Pub. L. 104-4 on March 22, 1995, requires each Federal
agency, to the extent permitted by law, to prepare a written assessment
of the effects of any Federal mandate in a proposed or final agency
rule that may result in the expenditure by State, local, and tribal
governments, in the aggregate, or by the private sector, of $100
million or more (adjusted annually for inflation) in any one year.
Section 204(a) of the Act, 2 U.S.C. 1534(a), requires the Federal
agency to develop an effective process to permit timely input by
elected officers (or their designees) of State, local, and tribal
governments on a proposed ``significant intergovernmental mandate.'' A
``significant intergovernmental mandate'' under the Act is any
provision in a Federal agency regulation that would impose an
enforceable duty upon State, local, and tribal governments, in the
aggregate, of $100 million (adjusted annually for inflation) in any one
year. Section 203 of the Act, 2 U.S.C. 1533, which supplements section
204(a), provides that before establishing any regulatory requirements
that might significantly or uniquely affect small governments, the
agency shall have developed a plan that, among other things, provides
for notice to potentially affected small governments, if any, and for a
meaningful and timely opportunity to provide input in the development
of regulatory proposals.
This rule does not contain a Federal intergovernmental or private
sector mandate that exceeds $100 million a year, therefore the
requirements of the Act do not apply.
List of Subjects in 14 CFR Part 36
Agriculture, Aircraft, Noise control.
The Proposed Amendments
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. Appendix G of part 36 is amended by revising sections
G36.107(a), G36.201(b), including Figure G1, G36.201(c), G36.201(d)(1),
G36.201(d)(4), and G36.301(b), including Figure G2, to read as follows:
Appendix G to Part 36--Takeoff Noise Requirements for Propeller-
Driven Small Airplane and Propeller-Driven Commuter Category
Airplane Certification Tests on or After December 22, 1988
* * * * *
Sec. G36.107 Noise Measurement Procedures.
(a) The microphone must be a pressure type, 12.7 mm in diameter,
with a protective grid, mounted in an inverted position such that
the microphone diaphragm is 0.7 mm above and parallel to a white-
painted metal circular plate. This white-painted metal plate shall
be 40 cm in diameter and at least 2.5 mm thick. The plate shall be
placed horizontally and flush with the surrounding ground surface
with no cavities below the plate. The microphone must be located
three-quarters of the distance from the center to the back edge of
the plate along a radius normal to the line of flight of the test
airplane.
* * * * *
Sec. G36.201 Corrections to Test Results.
* * * * *
(b) Atmospheric absorption correction is required for noise data
obtained when the test conditions are outside those specified in
Figure G1. Noise data outside the applicable range must be corrected
to 59 F and 70 percent relative humidity by an FAA approved method.
[[Page 64150]]
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BILLING CODE 4910-13-C
(c) Helical tip Mach number and power corrections must be made
as follows:
(1) Corrections for helical tip Mach number and power
corrections must be made if--
(i) The propeller is a variable pitch type; or
(ii) The propeller is a fixed pitch type and the test power is
not within 5 percent of the reference power.
(2) No corrections for helical tip Mach number variation need to
be made if the propeller helical tip Mach number is:
(i) At or below 0.70 and the test helical tip Mach number is
within 0.014 of the reference helical tip Mach number.
(ii) Above 0.70 and at or below 0.80 and the test helical tip
Mach number is within 0.007 of the reference helical tip Mach
number.
(iii) Above 0.80 and the test helical tip Mach number is within
0.005 of the reference helical tip Mach number. For mechanical
tachometers, if the helical tip Mach number is above 0.8 and the
test helical tip Mach number is within 0.008 of the reference
helical tip Mach number.
(d) * * *
(1) Measured sound levels must be corrected from test day
meteorological conditions to reference conditions by adding an
increment equal to--
Delta (M) = (H - 0.7 HR)/1000
where H is the height in feet under test conditions,
HR is the height in feet under reference conditions when
the aircraft is directly over the noise measurement point and
is the rate of absorption for the test day conditions at
500 Hz as specified in SAE ARP 866A, entitled ``Standard Values of
Atmospheric Absorption as a function of Temperature and Humidity for
use in Evaluating Aircraft Flyover Noise'' as incorporated by
reference under Sec. 36.6.
* * * * *
(4) Measured sound levels in decibels must be corrected for
engine power by algebraically adding an increment equal to--
Delta(3) = K3 log (PR/P)
where PR and P are the test and reference engine
powers respectively obtained from the manifold pressure/torque
gauges and engine rpm. The value of K3 shall be
determined from approved data from the test airplane. In the absence
of flight test data and at the discretion of the Administrator, a
value of K3 = 17 may be used.
* * * * *
Sec. G36.301 Aircraft Noise Limits.
* * * * *
(b) The noise level must not exceed 76 dB (A) up to and
including aircraft weights of 1,320 pounds (600 kg). For aircraft
weights greater than 1,320 pounds, the limit increases from that
point with the logarithm of airplane weight at the rate of 9.83 dB
(A) per doubling of weight, until the limit of 88 dB (A) is reached,
after which the limit is constant up to and including 19,000 pounds
(8,618 kg). Figure G2 shows noise level limits vs airplane weight.
BILLING CODE 4910-13-P
[[Page 64151]]
[GRAPHIC] [TIFF OMITTED] TP18NO98.001
BILLING CODE 4910-13-C
Issued in Washington, DC, on November 9, 1998.
James D. Erickson,
Director of Office of Environment and Energy.
[FR Doc. 98-30578 Filed 11-17-98; 8:45 am]
BILLING CODE 4910-13-P
