can be used to directly calculate tfirst and tlast as a function of x, i.e.:
ݐൌ െܸ √ ܸଶ െ4 ሺ 12ܽሻሺܺ െݔ ሻ 2ሺ 12ܽሻ
c) tr,j is then given by the difference between these two time values.
803(a)(7) Other non-constant airs peed and flight path conditions [ETM GM No. 16 ATT H 2.3] (Reserved) Page 265
Chapter 9 GUIDELINES FOR AIRCRAFT RECERTIFICATION TO STAGE 4 and 5
CHAPTER TABLE OF CONTENTS
901 INTRODUCTION266
902 ASSESSMENT CRITERIA267
902(a) General267
902(b) Recertification from Stage 3 to Stage 4 or Stage 5267
902(c) Recertification from Stage 2 to Stage 4 or Stage 5270
902(d) Recertification from Part 36, Stage 3 to Stage 4 or Stage 5270
903 RECERTIFICATION GUIDELINES FOR “MODIFIED”AIRPLANES271
903(a) Operational Limitations271
903(a)(1) Flap deflection271
903(a)(2) Propeller speed272
903(a)(3) Maximum authorized takeoff and landing weight272
903(a)(4) Takeoff thrust de-rate272
903(b) Demonstration Methods272
903(b)(1) Demonstration of lateral noise measured at 650 m272
903(b)(2) Center of gravity position during takeoff272
901 INTRODUCTION [ETM 9.1] Although the procedures described in this Chapter were developed for recertification to Stage 4 from its original certification, they are equally acceptable for recertification to Stage 5 from its original certification.
In other words recertification to Stage 4 also mean s recertification to Stage 5 if its noise limits and supplementary requirements are met. Recertification using the pro cedures in this Chapter is acceptable because there were no substantial procedural modifica tions to Part 36 between Stage 4 (Amendment 24) to Stage 5 (Amendement 31) that will influence the certification noise level.
Recertification is defined as the “Certification of an aircraft , with or without revision to noise levels, to a Standard different to that which it had been originally certificated”. The recertification of helicopters and light propeller-driven airplanes to a different Standard from that to which they were originally certificated is not considered.
In the case of an airplane being recer tificated to part 36, amendment 36-24 an d later, noise recertification should be granted on the basis that the evidence used to determine co mpliance is as satisfactory as the evidence expected of a new type design. In this respect the date used by the FAA to determine the recertification basis should be the date of acceptance of the first application for recertification.
Section 902 of this chapter addresses the assessment of existing approved noise levels associated with applications for the recertification of an airplane to Stage 4 or Stage 5. Section 903 includes guidelines for the recertification to Stage 4 of airplanes specially “modified” in order to achieve compliance with Stage 4 or Stage 5. The appropriate process for determining the compliance of a recertificated aircraft with a new standard should be determined by the aircraft’s certification noise levels and the associated substantiation documents. A flow chart describing the process for the recertification of subsonic jet airplanes from Stage 3 to Stage 4 or Stage 5 is presented in Figure 54. In the application of these recertification guidelines, existing arrangements be tween certificating authorities should be respected. It is expected that bilateral arrangements will facilitate the mutual recognition between authorities of approvals granted in accordance with the guidelines recommended in this AC.
902 ASSESSMENT CRITERIA [ETM 9.2] 902(a) General Sections 902(b) and (d) are concerned with the assessment of existing approved noise levels associated with applications for the recertification of an airplane from Stage 3 to Stage 4 or 5 under part 36. Section 902(c) is concerned with the recertification of an airplane from Stage 2 to Stage 4 or 5 under part 36.
In applying the assessment criteria of each section, if the ap plicant is able to answer in the affirmative, to the satisfaction of FAA, all the questions that may be relevant then reassessment is not required. The existing approved Stage 3 noise levels of the airplane should be used to determine compliance with the new standard. Otherwise, in order to satisfy the requirements of FAA, the applicant may propose additional analysis or data. Such analysis may lead to an adjustment being applied to the existing approved Stage 3 noise levels. Applicants, at their discretion, may elect to provide new test data in place of, or in addition to, the analysis.
Note.— The FAA’s assessment of the suitability of the existing approved noise levels for compliance with the requirements of Stage 4 or Stage 5 will include a review of any equivalencies proposed by the applicant to meet the assessment criteria.
902(b) Recertification from Stage 3 to Stage 4 or Stage 5 [ETM 9.2.2] Noise levels already approved for compliance with Stage 3 and submitted in support of applications for recertification of existing aircraft should be assessed against the criteria presented in this section. These criteria have been developed to ensure satisfactory compliance with the new standard. The criteria consist of a list of simple questions concerning the manner in which the original Stage 3 data were obtained and subsequently processed. The questions are the result of a comparison of the various amendments and revisions to part 36, and to this AC to which an aircraft’s existing Stage 3 noise levels may have been approved.
For airplanes that were approved with Amendment 36-24 or later, a reassessment is not required. The airplane’s existing approved Stage 3 noise levels should be used to determine compliance with Stage 4 or Stage 5.
For airplanes that were approved in accordance with Amendment 36-23 or earlier, the applicant is required to show that the existing approved Stage 3 noise levels are equivalent to those approved to Amendment 36-24 by answering the following questions. Unless otherwise noted, section references refer to Amendment 36-24 to part 36.
For all airplanes:
a) Was full takeoff power used throughout the reference f light path in the determination of the lateral noise level? (See B36.3(a) of part 36, Amendment 36-24.)
b) Was the “average engine” rather than the “minimum engine” thrust or power used in the calculation of the takeoff reference flight path? (See B36.7(b)(1) of part 36, Amendment 36-24.)
Note.— The applicant may demonstrate compliance with Stage 4 or Stage 5 requirements by determining the lateral and flyover noise levels by adding a delta dB corresponding to the difference between the average and the minimum engine, as derived from approved NPD data based on the airplane performance changes due to this difference.
c) Was the “simplified” method of adjustment defined in A36.9.3 of part 36, used, and if so, was –7.5 used as the factor in the calculation of the noise propagation path duration correction term? (See A36.9.3.3.2 of part 36, Amendment 36-24.)
d) Was the takeoff reference speed between V 2 + 10 kt and V2 + 20 kt? (See B36.7(b)(4) of part 36, Amendment
36-24.)
Note.— The takeoff reference speed used to demonstrate compliance with Stage 4 requirements must meet the requirements of B36.7(b)(4) of part 36, Amendment 36-24.
e) Was the four half-second linear average approximati on to exponential averaging used and, if so, were the 100 percent weighting factors used? (See A36.3.7.5 of part 36, Amendment 36-24.)
Note.— The applicant is required to demonstrate compli ance with the requirements of A36.3.7.5 of part 36, through Amendment 36-24, which equates to an exponential averaging process for the determination of SLOW weighted sound pressure levels. Simulated SLOW weighted sound pressure levels may be obtained by using one of the two equations described in A36.3.7.5 of part 36 through Amendment 36-24, as appropriate, or by other methods as approved by the FAA.
This space was intentinally left blank Page 268
YES Existing noise levels meet NO Change in aircraft part 36 Stage 4 or 5, configuration/type desigr margin and trade-off requirements?
NO Develop certification plan Part 36, Amendment 36-24 or later?
YES YES Meets Advisory Circular 36-4, Chapter 9 reassessment criteria? Approval by the FAA NO Certification demonstration and documentation Reassessment required Obtain FAA approval of the method to resolve the criteria that were not met Approval by the FAA YES et part 3f NO ements?
Meets part 38 Stage 5.
margins and supplemental YES Stage 5 Stage 3 ertificatior Stage 4 margin and trade-off requirements:
minimum of 10 EPNdB cumulative margin;
minimum 2 EPNdB at any two certification points:
no trade-off.
Stage 5 margin and supplemental requirements minimum of 17 EPNoB cumulative margin to Stage 3 limits minimum 1 EPNdB at each certification points no-trade-off Figure 54. "Road map" for recertification of subsonic jet airplanes Page 269
For jet airplanes only:
f) Were the noise measurements conducted at a test site below 1200 ft (366 m), and if not, was a jet source noise correction applied? (See 403(b)(3) of this AC.)
g) Do the engines have bypass ratios of more than 2, and if not, was the peak lateral noise established by undertaking a number of flights over a range of heights? (See 402(a)(1)(C) of this AC.)
h) In the event that “family” certification methods were used, were the 90 percent confidence intervals for the pooling together of flight and static engine test data established according to the guidance in this AC? (See 305(c) of this AC.)
i) Do the engines have bypass ratios of 2 or less, and if not, in the event that “family” certification methods were used, did all associated static engine tests involve the use of a turbulence control screen (TCS) or ICD?
(See 402(a)(3)(C)(ii) of this AC.)
For propeller-driven airplanes only:
j) Were symmetrical microphones used at every position along the lateral array for the determination of the peak lateral noise level? (See B36.3(a)(1) of part 36, Amendment 36-24.)
k) Was the approach noise level demonstrated at the noisiest configuration? (See B36.7(c)(5) of part 36, Amendment 36-24.)
l) Was the target airspeed flown during the flight tests appropriate to the actual test weight of the airplane? (See 402(a)(1)(B)(i) of this AC.)
902(c) Recertification from St age 2 to Stage 4 or Stage 5 [ETM 9.2.3] Many aircraft originally certificated to the standards of Stage 2 of part 36, may have already been recertificated to the standards of Stage 3. In such a case the approved Stage 3 noise levels may be assessed for compliance with Stage 4 or Stage 5 according to the criteria of 902 of this Chapter. For a Stage 2 aircraft not already recertificated to Stage 3, noise data originally developed to demonstrate compliance with the requirements of Stage 2 should first be corrected in an approved manner to the requirements of Stage 3 part 36, through Amendment 36-24, before the aircraft is assessed against the requirements of Stage 4 or Stage 5.
In the assessment of data submitted in support of an application for the recertification of an airplane from Stage 2 to Stage 3, the recommendations of 903(b)(1) should be followed.
902(d) Recertification from Part 36 , Stage 3 to Stage 4 or Stage 5 [ETM 9.2.4] Noise levels already approved to part 36, Stage 3, and submitted in support of applica tions for recertification of existing aircraft to Stage 4 should be assessed against the criteria presented as follows.
For Stage 3 airplanes that were approved in accordance with part 36, Amendment 24 (effective date 7 August 2002) or later, the only assessment criterion of 902(b) of this AC that may not have been satisfied is criterion g). Aside from consideration of criterion g), the existing approved part 36, Stage 3, noise levels of the airplane should be used to determine compliance with Stage 4 or Stage 5.
For Stage 3 airplanes that were approved in accordance with Amendments 36-7 through 36-23 of part 36, in addition to the reassessment criteria of 902(b) of this Chapter, the following criteria should also be considered:
a) Was the speed component of the EPNL duration adjustment determined by using 10 log V/V r? (See A36.9.3.3.1 of part 36, Amendment 36-24.)
b) For derivative engine certifications using static engine test procedures, is the summation of the magnitudes, neglecting signs, of the noise changes for the three reference certification conditions between the “flight datum” airplane and derived version not greater than 5 EPNdB, with a maximum 3 EPNdB at any one of the reference conditions? (See 402(a)(3)(C) of this AC.)
Note.— These limitations may be exceeded under the circumstances described in 402(a)(3)(B) of this AC.
RECERTIFICATION GUIDELINES FOR “MODIFIED”AIRPLANES [ETM 9.3] An existing airplane may have been approved with Stage 3 certification noise levels that are higher than the maximum levels required by Stage 4. For such an airplane to be cons idered for recertification to Stage 4 or Stage 5, it will be necessary to “modify” the airplane in order to lower its noise levels below the limits required by Stage 4 or Stage 5.
In order for the FAA to evaluate appli cations for recertification of “modified” airplanes in a consistent manner, the guidelines described in this section should be followed. These guidelines will be developed to cover other “modification” possibilities.
903(a) Operational Limitations [ETM 9.3.1] Operational limitations may be imposed on a recertificated aircraft as a condition of compliance with the new noise certification requirements. In this context, an “operationa l limitation” is defined as a restriction on either the configuration or manner in which an aircraft may be flown .
903(a)(1) Flap deflection [ETM 9.3.1.1] For the noise certification demonstration on approach:
a) Only the most critical flap deflecti on (i.e., that which gives the highest noise level) must be certificated. Noise levels for other flap deflections may be approved only as supplementary information and should be determined in conformity with B36.7(c) of part 36, through Amendment 36-24 by using the same demonstrations as for the most critical flap deflection.
b) Typically for a jet airplane, the most critical flap configuration is associated with the maximum flap deflection. If the aircraft in its original state ca nnot comply with the requirements at the maximum flap deflection or, if an applicant wishes to have an aircraft certificated at less than maximum deflection, the flap deflection must be limited by means of a physical limit which, for the sake of prudence, may be frangible. A simple flight manual limitation is not acceptable. It is permitted to exceed the frangible limit only in the case of an emergency situation, defined here as an unforeseen situation which endangers the safety of the airplane or persons, necessitating the violation of the operational limitation. In such cases the frangible device must be replaced according to established maintenance practices and the replacement recorded in the aircraft log before the next flight. Reference to emergency exceedance of the frangible limit must be incorporated into only the emergency procedures section of the AFM.
c) It is necessary to actually fly the approach profile defined in B36.3(c) of part 36.
d) It should be noted that in the case of a recertificated propeller-driv en airplane, the most critical flap configuration may not be associated with the maximum flap deflection, and all normally permitted flap deflections must be flown in order to determine the noisiest configuration.
903(a)(2) Propeller speed [ETM 9.3.1.2] The demonstration of the certification noise level on approach must be made with the aircraft in its most critical configuration (i.e., that which produces the highest noise level). For propeller-driven airplanes, the configuration includes the propeller rotational speed. For a recertificated propeller-driven airplane, only the noisiest propeller speed defined for normal operation on approach may be approved. It should not be acceptable to define an alternative normal procedure using a different “quieter”, typically slower, propeller speed. A noise level for such a procedure may be approved as supplementary information only.
903(a)(3) Maximum authorized takeoff and landing weight [ETM 9.3.1.3] It may be possible to lower the certification noise levels of an airplane by lowering its maximum authorized takeoff and/or landing weight. An individual aircraft must be certificated at only one pair of maximum takeoff/landing weight at any one time. Noise levels for other takeoff/landing weight may be approved only as supplementary information.
903(a)(4) Takeoff thrust de-rate [ETM 9.3.1.4] If a de-rating in takeoff thrust is used, a method for control of this thrust is required. The methods that may be available, at the discretion of the FAA, could include a physical or electronic control, engine re-designation, and a flight manual limitation. De-rated takeoff thrust defined for noise purposes must be equal to the takeoff operating thrust limit for normal operation and may be exceeded in an emergency situation. In all cases the flight manual limitations and performance sections must be consistent.
903(b) Demonstration Methods [ETM 9.3.2] 903(b)(1) Demonstration of lateral noise measured at 650 m [ETM 9.3.2.1] The location of the noise measurement points for measuring lateral noise is defined in B36.3(a)(2) of part 36 as being along a line parallel to, and 2133 ft (650 m) from, the ex tended runway centerline. In the case of an airplane recertificated to Stage 4 or Stag e 5, but initially certificated as Stage 2, lateral noise data taken at a lateral offset of 2133 ft (650 m) are acceptable only if they are corrected to an offset of 1476 ft (450 m) by means of the “integrated” method of adjustment. In such cases, at any particular time, the “measured” and “reference” acoustic emission angles must be the same.
903(b)(2) Center of gravity position during takeoff [ETM 9.3.2.2] The demonstration of approach noise level must be made with the aircraft in its most critical configuration (i.e., noisiest). Configuration includes the location of the center of gravity position which, for approach, is most critically fully forward. No such restriction exis ts for the demonstration of takeoff noise levels, and the applicant is therefore free to select any configuration provided it is within the no rmal limits defined in the flight manual. In the case of a recertificated airplane, the cent er of gravity position used in the definition of the reference takeoff profile must be within the normal certificated range.
Appendix 1. GENERAL REFERENCES G1. FAA Order 1050.1E, Policies and Procedures For Considering Environmental Impacts , (Change 1, March 20, 2006), or current version G2. Public Law 103-272, Codification of Certain U.S. Transportation Laws as Title 49, United States Code, Section 44715, July 5, 1994 G3. Advisory Circular (AC) 25-7A, Flight Test Guide, (Change 1, June 3, 1999), or current version G4. FAA Order 8110.4C, Type Certification Process, (Change 3, March 24, 2011), or current version G5. ICAO Committee on Aviation Environmental Protection (CAEP), Environmental Technical Manual, (Doc 9501), Volume l, Procedures for Noise Certification of Aircraft, First Edition, 2010 G6. FAA Order 8110.37E, March 30, 2011, Designated Engineering Representative (DER) Guidance Handbook, or current version G7. International Civil Aviation Organization (ICAO), Environmental Protection, Annex 16, Volume 1, Aircraft Noise, Sixth Edition -2011. (Amendment 10, Applicable November 17, 2011) G8. Required Aproval level for Part 36 Subpart B and C Equivalent Procedures , FAA AEE Memorandum, August 19, 1998 Page 273
Appendix 2. TECHNICAL REFERENCES T1. Bureau Central de la Electrotechnique Internationale, Electroacoustics — Instruments for Measurement of Aircraft Noise — Performance Requirements for System s to Measure One-third-octave-band Sound Pressure Levels in Noise Certification of Transport-Category Aeroplanes, IEC 61265, April 1995.
T2. Bureau Central de la Electrotechnique Internationale, Electroacoustics — Octave-band and Fractional-octaveband Filters, IEC 61260, July 1995.
T3. Bureau Central de la Electrotechnique Internationale, Electroacoustics — Sound Level Meters , IEC 61672-1, 2002.
T4. ESDU International plc., The Correction of Measured Noise Spectra for the Effects of Ground Reflection, Data Item No. 94035 (Amendment A), December 1995.
T5. Fink, M.R., Airframe Noise Prediction Method, USA DOT Report FAA-RD-77-29, Washington, D.C., 29 March 1977.
T6. Laufer, J., R.E. Kaplan and W.T. Chu, “Noise Produced by Subsonic Jets,” Proceedings of the Second Inter- Agency Symposium on University Research in Transportation Noise, 1974, Volume 1, pp. 50-58.
T7. National Marine Electronics Association, Standards for Interfacing Marine Electronics Devices, NMEA 0183, Version 1.5, December 1987.
T8. National Marine Electronics Association, Standards for Interfacing Marine Electronics Devices, NMEA 0183, Version 2.0, 1 January 1992.
T9. Radio Technical Commission for Aeronautics, Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment, DO-229C, 28 November 2001.
T10. Radio Technical Commission for Maritime Services, Recommended Standards for Differential Navstar GPS Service, Paper 194-93/SC104-STD, Version 2.1, January 1994.
T11. SAE International, Gas Turbine Coaxial Exhaust Flow Noise Prediction, Aerospace Information Report AIR 1905, December 1985.
T12. SAE International, Gas Turbine Jet Exhaust Noise Prediction, Aerospace Recommended Practice ARP 876E, February 2006.
T13. SAE International, Measurement of Far Field Noise from Gas Turbine Engines During Static Operation, Aerospace Recommended Practice ARP 1846A, March 2008.
T14. SAE International, Method for Predicting Lateral Attenuation of Airplane Noise, Aerospace Information Report AIR 5662, April 2006.
T15. SAE International, Practical Methods to Obtain Free-Field Sound Pressure Levels from Acoustical Measurements Over Ground Surfaces, Aerospace Information Report AIR 1672B, June 1983.
T16. SAE International, Standard Values of Atmospheric Absorption as a Function of Temperature and Humidity, Aerospace Recommended Practice ARP 866A, March 1975.
T17. Tester, B.J. and V.M. Szewczyk, Mixing Noise: Comparison of Measurement and Theory. American Institute of Aeronautics and Astronautics Paper 79-0570, March 1979.
T18. Ueno, Mami, Kazuaki Hoshinoo et al., Assessment of Atmospheric Delay Correction Models for the Japanese MSAS, Proceedings of ION GPS, http://gauss.gge.unb.ca/papers.pdf/iongps2001.ueno.pdf, 2001.
T19. United States Coast Guard, Broadcast Standard for the USCG DGPS Navigation Service, COMDTINST M16577, 1 April 1993.
Appendix 3. BIBLIOGRAPHY
1. Cochran, W.G. “Approximate Significance Levels of the Behrens-Fisher Test.” Biometrics, 10 (1964): 191-195.
2. Kendall, M.G. and A. Stuart. The Advanced Theory of Statistics. Volumes 1, 2 and 3. New York: Hafner, 1971.
3. Kendall, M.G. and G.U. Yule. An Introduction to the Theory of Statistics. 14th ed. New York: Griffin, 1950.
4. Rose, D.M. and F.W. Scholz. Statistical Analysis of Cumulative Shipper-Receiver Data. U.S. Nuclear Regulatory Commission, Division of Facility Operations, Office of Nuclear Regulatory Research, Washington, D.C., 1983.
NUREG/CR-2819. NRC FIN B1076.
5. Snedecor, G.W. and W.G. Cochran. Statistical Methods. 6th ed. Arnes, Iowa: The Iowa State University Press, 1968.
6. Walpole, R.E. and R.H. Myers. Probability and Statistics for Engineers and Scientists. New York: MacMillan, 1972.
7. Wonnacott, T.H. and R.J. Wonnacott. Introductory Statistics, 5th ed. N.p.: John Wiley & Sons, 1990.