[Title 40 CFR 87]
[Code of Federal Regulations (annual edition) - July 1, 1996 Edition]
[Title 40 - PROTECTION OF ENVIRONMENT]
[Chapter I - ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)]
[Part 87 - CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES]
[From the U.S. Government Publishing Office]




  40
  PROTECTION OF ENVIRONMENT
  9
  1996-07-01
  1996-07-01
  false
  CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES
  87
  PART 87
  
    PROTECTION OF ENVIRONMENT
    ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
  


PART 87--CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES--Table of Contents




                      Subpart A--General Provisions

Sec.
87.1  Definitions.
87.2  Abbreviations.
87.3  General requirements.
87.4  [Reserved]
87.5  Special test procedures.
87.6  Aircraft safety.
87.7  Exemptions.

 Subpart B--Engine Fuel Venting Emissions (New and In-Use Aircraft Gas 
                            Turbine Engines)

87.10  Applicability.
87.11  Standard for fuel venting emissions.

     Subpart C--Exhaust Emissions (New Aircraft Gas Turbine Engines)

87.20  Applicability.
87.21  Standards for exhaust emissions.

   Subpart D--Exhaust Emissions (In-Use Aircraft Gas Turbine Engines)

87.30  Applicability.
87.31  Standards for exhaust emissions.

                        Subparts E-F--[Reserved]

    Subpart G--Test Procedures for Engine Exhaust Gaseous Emissions 
               (Aircraft and Aircraft Gas Turbine Engines)

87.60  Introduction.
87.61  Turbine fuel specifications.
87.62  Test procedure (propulsion engines).
87.63  [Reserved]
87.64  Sampling and analytical procedures for measuring gaseous exhaust 
          emissions.
87.65--87.70  [Reserved]
87.71  Compliance with gaseous emission standards.

  Subpart H--Test Procedures for Engine Smoke Emissions (Aircraft Gas 
                            Turbine Engines)

87.80  Introduction.
87.81  Fuel specifications.
87.82  Sampling and analytical procedures for measuring smoke exhaust 
          emissions.
87.83--87.88  [Reserved]
87.89  Compliance with smoke emission standards.

    Authority: Secs. 231, 301(a), Clean Air Act, as amended (42 U.S.C. 
7571, 7601(a)), unless otherwise noted.

    Source: 47 FR 58470, Dec. 30, 1982, unless otherwise noted.



                      Subpart A--General Provisions



Sec. 87.1  Definitions.

    (a) As used in this part, all terms not defined herein shall have 
the meaning given them in the Act:
    Act means the Clean Air Act, as amended (42 U.S.C. 7401 et seq.).
    Administrator means the Administrator of the Environmental 
Protection Agency and any other officer or employee of the Environmental 
Protection Agency to whom authority involved may be delegated.
    Aircraft means any airplane for which a U.S. standard airworthiness 
certificate or equivalent foreign airworthiness certificate is issued.
    Aircraft engine means a propulsion engine which is installed in or 
which is manufactured for installation in an aircraft.
    Aircraft gas turbine engine means a turboprop, turbofan, or turbojet 
aircraft engine.
    Class TP means all aircraft turboprop engines.
    Class TF means all turbofan or turbojet aircraft engines except 
engines of Class T3, T8, and TSS.
    Class T3 means all aircraft gas turbine engines of the JT3D model 
family.
    Class T8 means all aircraft gas turbine engines of the JT8D model 
family.
    Class TSS means all aircraft gas turbine engines employed for 
propulsion of aircraft designed to operate at supersonic flight speeds.
    Commercial aircraft engine means any aircraft engine used or 
intended for use by an ``air carrier,'' (including those engaged in 
``intrastate air transportation'') or a ``commercial operator'' 
(including those engaged in ``intrastate air transportation'') as these 
terms are defined in the Federal Aviation Act and the Federal Aviation 
Regulations.
    Commercial aircraft gas turbine engine means a turboprop, turbofan, 
or turbojet commercial aircraft engine.
    Emission measurement system means all of the equipment necessary to 
transport and measure the level of emissions. This includes the sample 
system and the instrumentation system.

[[Page 6]]

    Engine Model means all commercial aircraft turbine engines which are 
of the same general series, displacement, and design characteristics and 
are usually approved under the same type certificate.
    Exhaust emissions means substances emitted to the atmosphere from 
the exhaust discharge nozzle of an aircraft or aircraft engine.
    Fuel venting emissions means raw fuel, exclusive of hydrocarbons in 
the exhaust emissions, discharged from aircraft gas turbine engines 
during all normal ground and flight operations.
    In-use aircraft gas turbine engine means an aircraft gas turbine 
engine which is in service.
    New aircraft turbine engine means an aircraft gas turbine engine 
which has never been in service.
    Power setting means the power or thrust output of an engine in terms 
of kilonewtons thrust for turbojet and turbofan engines and shaft power 
in terms of kilowatts for turboprop engines.
    Rated output (rO) means the maximum power/thrust available for 
takeoff at standard day conditions as approved for the engine by the 
Federal Aviation Administration, including reheat contribution where 
applicable, but excluding any contribution due to water injection.
    Rated pressure ratio (rPR) means the ratio between the combustor 
inlet pressure and the engine inlet pressure achieved by an engine 
operating at rated output.
    Sample system means the system which provides for the transportation 
of the gaseous emission sample from the sample probe to the inlet of the 
instrumentation system.
    Secretary means the Secretary of Transportation and any other 
officer or employee of the Department of Transportation to whom the 
authority involved may be delegated.
    Shaft power means only the measured shaft power output of a 
turboprop engine.
    Smoke means the matter in exhaust emissions which obscures the 
transmission of light.
    Smoke number (SN) means the dimensionless term quantifying smoke 
emissions.
    Standard day conditions means standard ambient conditions as 
described in the United States Standard Atmosphere, 1976, (i.e., 
Temperature =15 deg.C, specific humidity =0.00 kg/ H2O/kg dry air, 
and pressure =101325 Pa.)
    Taxi/idle (in) means those aircraft operations involving taxi and 
idle between the time of landing roll-out and final shutdown of all 
propulsion engines.
    Taxi/idle (out) means those aircraft operations involving taxi and 
idle between the time of initial starting of the propulsion engine(s) 
used for the taxi and turn on to duty runway.

[47 FR 58470, Dec. 30, 1982, as amended at 49 FR 31875, Aug. 9, 1984]



Sec. 87.2  Abbreviations.

    The abbreviations used in this part have the following meanings in 
both upper and lower case:
    FAA  Federal Aviation Administration, Department of Transportation.
    HC  Hydrocarbon(s).
    hr.  Hour(s).
    LTO  Landing takeoff
    min.  Minute(s).
    rO  Rated output.
    rPR  Rated pressure ratio.
    sec.  Seconds.
    SP  Shaft power.
    SN  Smoke number.
    T  Temperature, degrees Kelvin.
    TIM  Time in mode.
    W  Watt(s).
     deg.  Degree.
    %  Percent.

[47 FR 58470, Dec. 30, 1982, as amended at 49 FR 31875, Aug. 9, 1984]



Sec. 87.3  General requirements.

    (a) This part provides for the approval or acceptance by the 
Administrator or the Secretary of testing and sampling methods, 
analytical, techniques, and related equipment not identical to those 
specified in this part. Before either approves or accepts any such 
alternate, equivalent, or otherwise nonidentical procedures or 
equipment, the Administrator or the Secretary shall consult with the 
other in determining whether or not the action requires rulemaking under 
sections 231 and 232 of the Clean Air Act, as amended, consistent with 
the Administrator's

[[Page 7]]

and the Secretary's responsibilities under sections 231 and 232 of the 
Act. (42 U.S.C. 7571, 7572).
    (b) Under section 232 of the Act, the Secretary issues regulations 
to insure compliance with this part.
    (c) With respect to aircraft of foreign registry, these regulations 
shall apply in a manner consistent with any obligation assumed by the 
United States in any treaty, convention or agreement between the United 
States and any foreign country or foreign countries.
Sec. 87.4  [Reserved]



Sec. 87.5  Special test procedures.

    The Administrator or the Secretary may, upon written application by 
a manufacturer or operator of aircraft or aircraft engines, approve test 
procedures for any aircraft or aircraft engine that is not susceptible 
to satisfactory testing by the procedures set forth herein. Prior to 
taking action on any such application, the Administrator or the 
Secretary shall consult with the other.



Sec. 87.6  Aircraft safety.

    The provisions of this part will be revised if at any time the 
Secretary determines that an emission standard cannot be met within the 
specified time without creating a safety hazard.



Sec. 87.7  Exemptions.

    (a) Exemptions based on flights for short durations at infrequent 
intervals. The emission standards of this part do not apply to engines 
which power aircraft operated in the United States for short durations 
at infrequent intervals. Such operations are limited to:
    (1) Flights of an aircraft for the purpose of export to a foreign 
country, including any flights essential to demonstrate the integrity of 
an aircraft prior to its flight to a point outside the United States.
    (2) Flights to a base where repairs, alterations or maintenance are 
to be performed, or to a point of storage, and flights for the purpose 
of returning an aircraft to service.
    (3) Official visits by representatives of foreign governments.
    (4) Other flights the Secretary determines, after consultation with 
the Administrator, to be for short durations at infrequent intervals. A 
request for such a determination shall be made before the flight takes 
place.
    (b) Exemptions for very low production models. The emissions 
standards of this part do not apply to engines of very low total 
production after the date of applicability. For the purpose of this 
part, ``very low production'' is limited to a maximum total production 
for United States civil aviation applications of no more than 200 units 
covered by the same type certificate after January 1, 1984.
    (1) A maximum annual production rate after January 1, 1984 of 20 
units covered by the same type certificate; and
    (2) A maximum total production after January 1, 1984 of 200 units 
covered by the same type certificate.
    (c) Exemptions for New Engines in Other Categories. The emissions 
standards of this part do not apply to engines for which the Secretary 
determines, with the concurrence of the Administrator, that application 
of any standard under Sec. 87.21 is not justified, based upon 
consideration of:
    (1) Adverse economic impact on the manufacturer.
    (2) Adverse economic impact on the aircraft and airline industries 
at large.
    (3) Equity in administering the standards among all economically 
competing parties.
    (4) Public health and welfare effects.
    (5) Other factors which the Secretary, after consultation with the 
Administrator, may deem relevant to the case in question.
    (d) Time Limited Exemptions for In Use Engines. The emissions 
standards of this part do not apply to aircraft or aircraft engines for 
time periods which the Secretary determines, with the concurrence of the 
Administrator, that any applicable standard under Sec. 87.11(a), 
Sec. 87.31(a), or Sec. 87.31(c), should not be applied based upon 
consideration of the following:
    (1) Documentation demonstrating that all good faith efforts to 
achieve compliance with such standard have been made.
    (2) Documentation demonstrating that the inability to comply with 
such

[[Page 8]]

standard is due to circumstances beyond the control of the owner or 
operator of the aircraft.
    (3) A plan in which the owner or operator of the aircraft shows that 
he will achieve compliance in the shortest time which is feasible.
    (4) Applications for a determination that any requirements of 
Sec. 87.11(a), Sec. 87.31(a) or Sec. 87.31(c) do not apply shall be 
submitted in duplicate to the Secretary in accordance with procedures 
established by the Secretary.
    (e) The Secretary shall publish in the Federal Register the name of 
the organization to whom exemptions are granted and the period of such 
exemptions.
    (f) No state or political subdivision thereof may attempt to enforce 
a standard respecting emissions from an aircraft or engine if such 
aircraft or engine has been exempted from such standard under this part.

[47 FR 58470, Dec. 30, 1982, as amended at 49 FR 31875, Aug. 9, 1984; 49 
FR 41002, Oct. 18, 1984]



 Subpart B--Engine Fuel Venting Emissions (New and In-Use Aircraft Gas 
                            Turbine Engines)



Sec. 87.10  Applicability.

    (a) The provisions of this subpart are applicable to all new 
aircraft gas turbines of classes T3, T8, TSS and TF equal to or greater 
than 36 kilonewton rated output, manufactured on or after January 1, 
1974, and to all in-use aircraft gas turbine engines of classes T3, T8, 
TSS and TF equal to or greater than 36 kilonewton rated output 
manufactured after February 1, 1974.
    (b) The provisions of this subpart are also applicable to all new 
aircraft gas turbines of class TF less than 36 kilonewton rated output 
and class TP manufactured on or after January 1, 1975 and to all in-use 
aircraft gas turbines of class TF less than 36 kilonewton rated output 
and class TP manufactured after January 1, 1975.

[49 FR 41002, Oct. 18, 1984]



Sec. 87.11  Standard for fuel venting emissions.

    (a) No fuel venting emissions shall be discharged into the 
atmosphere from any new or in-use aircraft gas turbine engine subject to 
the subpart. This paragraph is directed at the elimination of 
intentional discharge to the atmosphere of fuel drained from fuel nozzle 
manifolds after engines are shut down and does not apply to normal fuel 
seepage from shaft seals, joints, and fittings.
    (b) Conformity with the standard set forth in paragraph (a) of this 
section shall be determined by inspection of the method designed to 
eliminate these emissions.



     Subpart C--Exhaust Emissions (New Aircraft Gas Turbine Engines)



Sec. 87.20  Applicability.

    The provisions of this subpart are applicable to all aircraft gas 
turbine engines of the classes specified beginning on the dates 
specified.



Sec. 87.21  Standards for exhaust emissions.

    (a) Exhaust emissions of smoke from each new aircraft gas turbine 
engine of class T8 manufactured on or after February 1, 1974, shall not 
exceed: Smoke number of 30.
    (b) Exhaust emissions of smoke from each new aircraft gas turbine 
engine of class TF and of rated output of 129 kilonewtons thrust or 
greater, manufactured on or after January 1, 1976, shall not exceed:

SN=83.6(r0)-0.274 (r0 is in kilonewtons).

    (c) Exhaust emission of smoke from each new aircraft gas turbine 
engine of class T3 manufactured on or after January 1, 1978, shall not 
exceed: Smoke number of 25.
    (d) Gaseous exhaust emissions from each new commercial aircraft gas 
turbine engine that is manufactured on or after January 1, 1984, shall 
not exceed:
    (1) Classes TF, T3, T8 engines equal to or greater than 26.7 
kilonewtons rated output:

Hydrocarbons: 19.6 grams/kilonewton r0.

    (2) Class TSS:

Hydrocarbons=140(0.92)rPR grams/kilonewton r0.


[[Page 9]]


    (e) Smoke exhaust emissions from each gas turbine engine of the 
classes specified below shall not exceed:
    (1) Class TF of rated output less than 26.7 kilonewtons manufactured 
on or after (one year from date of publication):

SN=83.6(ro)-0.274 (ro is in kilonewtons) not to exceed a maximum of 
          SN=50.

    (2) Classes T3, T8, TSS and TF of rated output equal to or greater 
than 26.7 kilonewtons manufactured on or after January 1, 1984:

SN=83.6(ro)-0.274 (ro is in kilonewtons) not to exceed a maximum of 
          SN=50.

    (3) Class TP of rated output equal to or greater than 1,000 
kilowatts manufactured on or after January 1, 1984:

SN=187(ro)-168 (ro is in kilowatts)

    (f) The standards set forth in paragraphs (a), (b), (c), (d), and 
(e) of this section refer to a composite gaseous emission sample 
representing the operating cycles set forth in the applicable sections 
of subpart G of this part, and exhaust smoke emissions emitted during 
operations of the engine as specified in the applicable sections of 
subpart H of this part, measured and calculated in accordance with the 
procedures set forth in those subparts.

[47 FR 58470, Dec. 30, 1982, as amended at 49 FR 31875, Aug. 9, 1984]



   Subpart D--Exhaust Emissions (In-use Aircraft Gas Turbine Engines)



Sec. 87.30  Applicability.

    The provisions of this subpart are applicable to all in-use aircraft 
gas turbine engines certified for operation within the United States of 
the classes specified beginning on the dates specified.



Sec. 87.31  Standards for exhaust emissions.

    (a) Exhaust emissions of smoke from each in-use aircraft gas turbine 
engine of Class T8, beginning February 1, 1974, shall not exceed: Smoke 
number of 30.
    (b) Exhaust emissions of smoke from each in-use aircraft gas turbine 
engine of class TF and of rated output of 129 kilonewtons thrust or 
greater, beginning January 1, 1976, shall not exceed:

SN=83.6(r0)-0.274 (r0 is in kilonewtons).

    (c) The standards set forth in paragraphs (a) and (b) of this 
section refer to exhaust smoke emissions emitted during operations of 
the engine as specified in the applicable section of subpart H of this 
part, and measured and calculated in accordance with the procedures set 
forth in this subpart.


[47 FR 58470, Dec. 30, 1982, as amended at 48 FR 2718, Jan. 20, 1983]



                        Subparts E-F--[Reserved]



    Subpart G--Test Procedures for Engine Exhaust Gaseous Emissions 
               (Aircraft and Aircraft Gas Turbine Engines)



Sec. 87.60  Introduction.

    (a) Except as provided under Sec. 87.5, the procedures described in 
this subpart shall be the test program to determine the conformity of 
new aircraft gas turbine engines with the applicable standards set forth 
in this part.
    (b) The test consists of operating the engine at prescribed power 
settings on an engine dynamometer (for engines producing primarily shaft 
power) or thrust measuring test stand (for engines producing primarily 
thrust). The exhaust gases generated during engine operation are sampled 
continuously for specific component analysis through the analytical 
train.
    (c) The exhaust emission test is designed to measure hydrocarbons, 
carbon monoxide and carbon dioxide concentrations, and to determine mass 
emissions through calculations during a simulated aircraft landing-
takeoff cycle (LTO). The LTO cycle is based on time in mode data during 
high activity periods at major airports. The test for propulsion engines 
consists of a least the following four modes of engine operation: Taxi/
idle, takeoff, climbout, and approach. The mass emission for the modes 
are combined to yield the reported values.
    (d) When an engine is tested for exhaust emissions on an engine 
dynamometer or test stand, the complete

[[Page 10]]

engine shall be used with all accessories which might reasonably be 
expected to influence emissions to the atmosphere installed and 
functioning, if not otherwise prohibited by Sec. 87.62(a)(2). Use of 
service air bleed and shaft power extraction to power auxiliary gearbox-
mounted components required to drive aircraft systems is not permitted.
    (e) Other gaseous emissions measurement systems may be used if shown 
to yield equivalent results and if approved in advance by the 
Administrator or the Secretary.

[47 FR 58470, Dec. 30, 1982, as amended at 49 FR 31875, Aug. 9, 1984]



Sec. 87.61  Turbine fuel specifications.

    For exhaust emission testing, fuel meeting the specifications listed 
below shall be used. Additives used for the purpose of smoke suppression 
(such as organometallic compounds) shall not be present.

                 Property and Allowable Range of Values

Specific gravity at 15  deg.C: 0.78-0.82.
Distillation temperature,  deg.C: 10% boiling point, 160-201; final 
boiling point, 240-285.
Net heat of combustion, kJ/kg: 42,860-43,500.
Aromatics, volume %: 15-20.
Naphthalenes, volume %: 1.0-3.0.
Smoke point, mm: 20-28.
Hydrogen, mass %: 13.4-14.0.
Sulfur, mass %: less than 0.3%.
Kinematic viscosity at -20  deg.C, mm/s: 4.0-6.5.

[49 FR 41002, Oct. 18, 1984]



Sec. 87.62  Test procedure (propulsion engines).

    (a)(1) The engine shall be tested in each of the following engine 
operating modes which simulate aircraft operation to determine its mass 
emission rates. The actual power setting, when corrected to standard day 
conditions, should correspond to the following percentages of rated 
output. Analytical correction for variations from reference day 
conditions and minor variations in actual power setting should be 
specified and/or approved by the Secretary:

                                                                        
------------------------------------------------------------------------
                                                         Class          
                                              --------------------------
                     Mode                               TF, T3,         
                                                  TP       T8      TSS  
------------------------------------------------------------------------
Taxi/idle....................................    (\1\)    (\1\)    (\1\)
Takeoff......................................      100      100      100
Climbout.....................................       90       85       65
Descent......................................       NA       NA       15
Approach.....................................       30       30       34
------------------------------------------------------------------------
\1\ See paragraph (a)(2) of this section.                               

    (2) The taxi/idle operating modes shall be carried out at a power 
setting of 7% rated thrust unless the Secretary determines that the 
unique characteristics of an engine model undergoing certification 
testing at 7% would result in substantially different HC emissions than 
if the engine model were tested at the manufacturers recommended idle 
power setting. In such cases the Secretary shall specify an alternative 
test condition.
    (3) The times in mode (TIM) shall be as specified below:

                                                                        
------------------------------------------------------------------------
                                                         Class          
                                              --------------------------
                     Mode                                TF, T3         
                                                  TP     or T8     TSS  
------------------------------------------------------------------------
Taxi/idle (minutes)..........................     26.0     26.0     26.0
Takeoff......................................      0.5      0.7      1.2
Climbout.....................................      2.5      2.2      2.0
Descent......................................      N/A      N/A      1.2
Approach.....................................      4.5      4.0      2.3
------------------------------------------------------------------------

    (b) Emissions testing shall be conducted on warmed-up engines which 
have achieved a steady operating temperature.
Sec. 87.63  [Reserved]



Sec. 87.64  Sampling and analytical procedures for measuring gaseous exhaust emissions.

    The system and procedures for sampling and measurement of gaseous 
emissions shall be as specified by appendices 3 and 5 to ICAO Annex 16, 
Volume II, Aircraft Engine Emissions, First Edition, June 1981, which 
are incorporated herein by reference. This document can be obtained from 
the International Civil Aviation Organization, P.O. Box 400, Succursale: 
Place de L'Aviation Internationale, 1000 Sherbrooke Street West, 
Montreal, Quebec, Canada H3A 2R2 at $3.00 per copy. It is also available 
for inspection

[[Page 11]]

at the Office of the Federal Register Information Center, 800 North 
Capitol Street, NW., suite 700, Washington, DC. This incorporation by 
reference was approved by the Director of the Federal Register on 
September 3, 1982. These materials are incorporated as they exist on the 
date of the approval and a notice of any change in these materials will 
be published in the Federal Register. Frequent changes are not 
anticipated.
Secs. 87.65--87.70  [Reserved]



Sec. 87.71  Compliance with gaseous emission standards.

    Compliance with each gaseous emission standard by an aircraft engine 
shall be determined by comparing the pollutant level in grams/
kilonewton/thrust/cycle or grams/kilowatt/cycle as calculated in 
Sec. 87.64 with the applicable emission standard under this part.



  Subpart H--Test Procedures for Engine Smoke Emissions (Aircraft Gas 
                            Turbine Engines)



Sec. 87.80  Introduction.

    Except as provided under Sec. 87.5, the procedures described in this 
subpart shall be the test program to determine the conformity of new and 
in-use gas turbine engines with the applicable standards set forth in 
this part. The test is essentially the same as that described in 
Secs. 87.60 through 87.62, except that the test is designed to determine 
the smoke emission level at various operating points representative of 
engine usage in aircraft. Other smoke measurement systems may be used if 
shown to yield equivalent results and if approved in advance by the 
Administrator or the Secretary.



Sec. 87.81  Fuel specifications.

    Fuel having specifications as provided in Sec. 87.61 shall be used 
in smoke emission testing.



Sec. 87.82  Sampling and analytical procedures for measuring smoke exhaust emissions.

    The system and procedures for sampling and measurement of smoke 
emissions shall be as specified by Appendix 2, Volume II, Aircraft 
Engine Emissions to ICAO Annex 16, Aircraft Engine Emissions, First 
Edition, June, 1981. This document can be obtained from the 
International Civil Aviation Organization, P.O. Box 400, Succursale: 
Place de L'Aviation Internationale, 1000 Sherbrooke Street West, 
Montreal, Quebec, Canada H3A 2R2 at $3.00 per copy. It is also available 
for inspection at the Office of the Federal Register Information Center, 
800 North Capitol Street, NW., suite 700, Washington, DC. This 
incorporation by reference was approved by the Director of the Federal 
Register on September 3, 1982. These materials are incorporated as they 
exist on the date of the approval and a notice of any change in these 
materials will be published in the Federal Register. Frequent changes 
are not anticipated.
Secs. 87.83--87.88  [Reserved]



Sec. 87.89  Compliance with smoke emission standards.

    Compliance with each smoke emission standard shall be determined by 
comparing the plot of SN as a function of power setting with the 
applicable emission standard under this part. The SN at every power 
setting must be such that there is a high degree of confidence that the 
standard will not be exceeded by any engine of the model being tested. 
The level of confidence required, a practical interpretation of the 
requirement for total compliance, and a testing program to assure 
compliance will be established by the Secretary prior to January 1, 
1984, and shall be approved by the Administrator.