Appendix A prescribes methodologies for conducting airplane noise certification tests and for measurement and evaluation of noise data for comparison with maximum noise levels specified in Appendix B (see Note 1). Specific requirements include:
a) specifications of various physical and environmental conditions under which airplane noise certification measurements are permitted; these conditions are related to the noise test site, wind velocity/direction and atmospheric sound attenuation;
b) procedures for measuremen t of atmospheric parameters;
c) methods for synchronization of airplane position and performance measurements with noise measurements;
d) specifications for noise certification measurement and analysis systems (see Note 2);
e) methods to calculate atmospheric sound attenuation coefficients and effective perceived noise level (in units of EPNdB);
f) methods for adjustment of measured flight test data to reference conditions;
g) nomenclature for symbols and units; and
h) specification of data to be reported to FAA.
Note 1.— Part 36 Appendix A requirements are nearly identical to those of Appendix 2 of Annex 16 Volume 1, Amendment 7. Subsequent changes to Annex 16 Volume 1 after Amendment 7 have not created any significant differences between the requirements of part 36 Appendix A and Annex 16 Volume 1 Appendix 2 at the time of publication of this AC.
Note 2.— Some provisions of Appendix A may also apply to the noise certification of helicopters as prescribed in Appendix H of part 36.
(2) Equivalent procedures Equivalent Procedures are described in 1(c) of the introductory purpose section of this AC. Section 402 of this AC identifies several potential applications of equivalent procedures for jet and heavy prop airplanes. The ICAO ETM (Reference G5) also provides general and technical guidance on equivalent procedures that have been accepted as a technical means for demonstrating complian ce with the noise certificatio n requirements of ICAO Annex 16, Volume 1. Equivalent procedures provided in the ICAO ETM are incorporated into this AC to the extent applicable to the U.S. regulations.. FAA has not approved these procedures for any current or future aircraft noise certification actions. (See Suppl emental Information Items in Subpart O, §1501, regarding the FAA’s approval process for equivalent procedures).
(3) Applicant’s responsibility Applicants must prepare noise compliance demonstration plans for FAA approval that include proposed methods for compliance with the requirements of B36.1 of part 36. Equivalent procedure proposals in these plans must include substantiation of their technical validity and feasibility of application to the airplane type for which noise certification is requested. (See Subpart O §1501, Supplem ental Information, of part 36 for noise compliance demonstration plan documentation requirements.)
201(b)(2) Noise measurement constraints §36.103(a) Page 41
(1) Noise measurement points The locations of test noise measurement points frequently do not coincide with the reference noise measurement point locations specified in B36.3 of part 36. For example, locations of flyover noise measurement points may be subject to test site anomalies that would make it impractical to set up microphones at the reference locations. An applicant that has an approved equivalent procedure to measure airplane noise data for generation of NPD plots using the Flight Path Intercept procedure may select test noise measurement points (particularly the flyover point) so as to optimize the noise recording system signal-to-noise ratios.
(2) Equivalent procedures The FAA does not consider equivalencies that modifies reference flight conditions (see 201(a)(10) paragraph 2 of this AC) without following public process.
(3) General approved flight test procedures, principles, methods and flight crew operational practices are included in AC 25-7A, Flight Test Guide (Reference G3).
201(b)(3) Flight manual statement of Chapter 4 or Chapter 5 equivalency §36.105, §36.106 The FAA is not authorized to approve aircraft co mpliance with Annex 16, Volume 1 Noise Standards.
(Reference G7). This is the responsibility of the foreign airworthiness authority involved. FAA participation is limited to witnessing tests and reviewing data. For the cases where Stage 3 compliance has been demonstrated it is permissible, but not a requirement, to insert the statement in 201(d) s ection 36.1581(a)(8) of this AC. In those cases where Stage 4 compliance has been demonstrated, the following statement must be included in the AFM or operations manual:
“Certification Noise Levels The following noise levels comply with part 36, Appendix B, Stage 4 maximum noise level requirements and were obtained by analysis of approved data from noise tests conducted under the provisions of part 36, Amendment 36-XX (insert part 36 amendment to which the airplane was certificated). The noise measurement and evaluation procedures used to obtain these noise levels are considered by the FAA to be equivalent to the Chapter 4 noise level required by the International Civil Aviation Organization (ICAO) in Annex 16, Volume I, Appendix 2, Amendment 7, effective March 21, 2002.”
Similarly, if the compliance demonstration has been demonstarted for Stage 5, the following statement must be included in the AFM or operations manual:
“Certification Noise Levels:
The following noise levels comply with part 36, Appendix B, Stage 5 maximum noise level requirements and were obtained by analysis of approved data from noise tests conducted under the provisions of part 36, Amendment [insert part 36 amendment number to which the airplane was certificated]. The noise measurem ent and evaluation procedures used to obtain these noise levels are considered by the FAA to be equivalent to the Chapter 14 noise levels required by the International Civil Aviation Organization (ICAO) in Annex 16, Volume 1, Appendix 2, Amendment 11-B, applicable January 1, 2015.” [Incorporated by reference, see § 36.6].
201(c) Subpart H – Helicopters 201(c)(1) Noise limits §36.805(c) Page 42
(1) Stage 1 helicopter If §36.805(c) applies, then noise testing will lead to one of the following:
a) The helicopter is demonstrated to be a Stage 2 helicopt er: the tradeoff provisions in H36.305(b) of part 36 may be used to demonstrate compliance with the Stage 2 noise level requir ement. The certificated helicopter is not designated as a first civil version, instead the certificated helicopter is designated as a Stage 2 helicopter;
b) The helicopter is demonstrated to be a Stage 1 helicopter via the “Stage 2 + 2 EPNdB” noise limits specified in H36.305(a)(1)(ii) of part 36 and is consequently designated as the first civil version. The trade provisions in H36.305(b) of part 36 may not be used for a first civil version; or
c) The helicopter fails to demonstrate compliance with the (Stage 2 + 2) noise limits specified in H36.305(a)(1)(ii) of part 36: The helicopter will be denied a type certificate until such time that the helicopter, modified as necessary, successfully demonstrates compliance with at least the requirements for a first civil version outlined above in outcome (b). The helicopter fails to demonstrate compliance if one or more of the demonstrated Appendix H noise levels exceeds the corresponding noise level limit or that flight procedure and the helicopter does not ot herwise meet the Stage 2 limits (note: a helicopter may exceed the Stage 1 limit for a given flight procedure and yet achieve St age 2 compliance through the use of tradeoffs).
(2) Change in type design If an applicant has substantiated that a proposed change in type design (as designated in §21.93) would be less noisy or no noisier than the (parent) first civil version helicopter, no additional demonstration of compliance with part 36 is required. The derivative helicopter remains a first civil version. The applicant may elect to:
a) carry forward the parent’s noise numbers to the rotorcraft flight manual of the derived version; or
b) voluntarily noise test the derivative helicopter in or der to substantiate lower noise certification levels.
However, if the derivative helicopter is found to be a Stage 2 helicopter as a result of the voluntary noise test, and if the applicant chooses to certify the derivative helicopter as a Stage 2 helicopter, that derivative helicopter is no longer classified as a first civil version.
(3) Subsequent civil version The §36.805(c) requirement for a subsequent civil version applies only to a helicopter previously designated as a first civil version. A subsequent civil version (unless otherwise excepted under §21.93(b)(4) from the acoustical change requirements) is:
a) any change in type design of the first civil version that would result in one or more of the noise certification levels of the subsequent civil version that are greater than the corresponding noise certification levels of the first civil version; or
b) any change in the first civil version that is suffic ient to require a new type certificate (as provided in §21.19).
As specified in §36.805(c), a subsequent civil version must comply with the Stage 2 noise limits.
201(d) Subpart 0 – Operating Li mitations; and Information Page 43
201(d)(1) Procedures, noise levels, and other information §36.1501 The following types of documentation may be required in implementation of an aircraft (airplane or rotorcraft) noise certification process.
(1) Noise certification plans Applicant noise certification plans should be provided to FAA in the early stages of an aircraft program and contain specific types of information including proposals for the methodology an applicant intends to use to certify a given type of aircraft. These plans, when approved, establish an aircraft’s noise certification basis under part
36. When an aircraft program involves agreements between FAA and foreign certificating authorities, these plans may specify an aircraft’s noise certification basis under both part 36 and the noise regulation used by the foreign authority (e.g., ICAO Annex 16, Volume 1).
Noise certification plans must include the following types of information:
a) an overview of the contents of a forthcoming noise compliance demonstration plan and noise certification report;
b) description of applicable noise certification regulati ons and the tests, reports, data submittals and flight manual pages planned to complete an aircraft noise certification process;
c) description of conformity requirements;
d) DERs and other cognizant personnel to be involved in the aircraft noise certification process;
e) milestone schedule of key events; and
f) miscellaneous information (e.g., acronyms, organizational codes, etc.).
2) Noise compliance demonstration plans (aircraft flight test) Noise compliance demonstration plans contain the specific methodology (including equivalent procedures) by which an applicant proposes to establis h compliance of a specific aircraft conf iguration with applicable part 36 requirements. These plans must define the information, data, and procedures that an applicant proposes in order to comply with the requirements of part 36. After approval by FAA, flight tests specified in this plan are included as a part of the Type Inspection Authorization (TIA) used to fulfill requirements for TC, STC, and amended TC certification.
Noise compliance demonstration plans must include the following types of information:
a) introduction: identify applicable part 36 requirements and aircraft noise certification basis, including part 36 amendment level;
b) aircraft description: type, model, engines, propellers/rotors, test aircraft serial numbers, engine ratings, engine nacelle acoustic treatments, aircraft gross dimensions (including propeller and/or rotor diameter), airplane engine and ILS antenna locations, aircraft/engine conformity);
c) noise certification methodology: test concepts and equivalent procedures, plans for determining airplane engine spooldown characteristics and airframe noise, aircraft/engine performance substantiation, estimated reference conditions including airspeeds, th rust (power) reduction distances, altitudes, thrust (power) settings, methods for determination of EPNL r values and 90% confidence limits, and flight manual format;
d) test description: test site location and characteristics (e.g., topography, ground cover and obstructions), location of noise measurement points, weather constraints, aircraft configuration including flap settings, airbrake and landing gear positions, APU Operation, conditions of pneumatic bleeds and power/takeoffs, test matrix, including weights, target altitudes, airspeeds, engine thrust (power), and test tolerances;
e) measurement system components and procedures including calibration procedures : acoustical, meteorological, time/space position, aircraft/engine performance;
f) data evaluation procedures including calibration and data processing : approval status of data processing software and version level, adjustment and normalization procedures (acoustical, meteorological, time/space position, and airplane engine performance);
g) aircraft certification schedule, including noise certification and TC dates: flight test plans should be submitted to FAA 60 days prior to start of testing. If new and novel equivalent procedures are proposed, or exemptions are required, then submittal of test plans earlier than 60 days prior to the start of testing may be necessary;
h) references;
i) a listing of all equivalent procedures utilized: for example, flight path intercept procedure;
(3) Noise compliance demonstration plans (airplane families) Noise certification of airplane families (derived versions) often require FAA approval of equivalent procedures involving measurement and evaluation of static engine noise test data as described in Chapter 4 of this AC (402(a)(2) for jets and 402(b)(2) for heavy props), in addition to the information listed in Item (2), above. These procedures include projection of static engine noise test data for development of flyover, lateral, and approach NPD plots that define differences between the airplanes used for the original noise certification flight test and a derived version (see Note 1). When use of static engine noise data is proposed, test plans must also be submitted to FAA and either integrated into the basic noise compliance demonstration plan, or submitted to FAA as separate plans and referenced in the basic plan.
Static engine noise test plans must include the following information:
a) engine description: type, model, test engine serial numbers, nacelle acoustic treatments, engine conformity requirements;
b) test description : test facility, engine installation, turbul ence control screen configuration, weather constraints, acoustical and meteorol ogical measurement points, bleed schedules, test run matrix and sequence including thrust (power) settings and test tolerances;
c) measurement system components and procedures including calibration procedures : acoustical, meteorological, engine performance;
d) data evaluation procedures including calibration, data processing, adjustment and normalization procedures: acoustical, meteorological, engine performance;
e) schedules: static noise test, noise certification and TC dates;
f) references; and
g) a listing of all equivalent procedures utilized.
Note.— Applicants may also generate separate static test plans in cases where development of airplane families is anticipated but not yet formalized and there is opportunity to obtain static engine noise data (because of engine availability) for future noise certification applications.
(4) Noise compliance demonstration plans (analytical methods) For certain aircraft type design changes (e.g., weight/thrust, airframe design changes and thrust (power) reduction distances or minor changes in engine components or acoustical treatments), applicants may propose using analytical equivalent procedures to derive noise increments to an aircraft’s certificated noise levels (see 402(a)(2) of this AC for jets and 402(b)(2) of this AC for heavy props) as applicable to the type of aircraft being certificated) or to demonstrate a no acoustical change (NAC) between the original certificated aircraft and the derived version.
Noise compliance demonstration plans must include the following information:
a) aircraft description: type, model, , engines, propellers/rotors;
b) description of type design changes;
c) noise certification methodology : overall concepts, description/substantiation of analytical equivalent procedures or methods of assessment of NAC aircraft reference conditions, methods for determination of EPNLr and 90% confidence limit values;
d) aircraft certification schedules; and
e) references.
(5) DER “raw data” reports FAA Order 8110.37E (Reference G6) specifies that Acoustical Designated Engineering Representatives (DERs) may, within the limits of their authority (defined in their letter of appointment) and with prior FAA approval, witness noise certification tests condu cted in accordance with FAA approv ed noise compliance demonstration plans.
In cases where tests are witnessed by DERs, the FAA may require the following information to validate that tests are being conducted in accordance with approved plans.
a) test event log: includes event times and conditions, nominal engine thrusts (powers) and thrust (power) stability, atmospheric conditions, airspeeds and deviations relative to target speeds, valid and invalid test points (including reasons for invalid points);
b) test measurement system components (type/model) and measurement/calibration procedures;
c) measurement system calibration events and results;
d) measurement system failures, malfunctions, non-standard operations, spurious signals and corrective actions taken;
e) report of test condition compliance with part 36 test site requirements;
f) field data: samples of measured and corrected noise spectra, acoustical, meteorological, time/space position, aircraft performance field data and data adjustments, EPNdB estimates, and DER notes; and
g) summary of meetings.
(6) Noise certification reports Noise certification reports must provide information, data, and procedures demonstrating compliance with the requirements of part 36 and FAA approved noise certification demonstration plans.
(7) Noise certification reports (aircraft flight test) These reports must include the following:
a) introduction: identify applicable part 36 requirements and aircraft noise certification basis, including part 36 amendment level;
b) aircraft description : type, model, engines, propellers/rotors, test aircraft and part serial numbers, aircraft/engine conformity status, reference c onditions (MTOW/MLW, thrust (power), altitudes, airspeeds, takeoff profiles;
c) noise certification methodology : noise certification methodology elements of a noise certification demonstration compliance plan approved by FAA for the aircraft configuration that is being certified and the specific report sections in which implementation of each element is addressed;
d) test description: test site location and characteristics (e.g., topography, ground cover, and obstructions), location of noise measurement poin ts, test conditions fo r each noise measurement point (including weather), aircraft configuration (e.g., flap, airbrake, landing gear and CG positions, APU operation, conditions of pneumatic bleeds and power takeoffs, airc raft weights, altitudes, airspeeds, engine thrust (power)), engine spooldown measurement points and test conditions, airframe noise measurement points and test conditions, and valid and invalid measurements;
e) measurement system components and procedures including calibration procedures : acoustical, meteorological, time/space position, aircraft/engine performance equipment;
f) data evaluation procedures including calibration, data processing and adjustment procedures :
acoustical, meteorological, time/space position, aircraft/engine performance;
g) data analysis and normalization results : analysis results for height of maximum lateral noise, thrust (power) reduction distance, airframe noise adjustment s, engine spooldown characteristics, normalized aircraft data (e.g., noise, power, distance (NPD plots)), values of EPNLr and 90% confidence limits, and aircraft flight manual pages;
h) if test witnessing is delegated, then the witness l og or notes specified in section 5 above must be included;
and
i) references.
(8) Noise certification reports (airplane families) Noise certification reports involving airplane family plan concepts must include additional information on noise certification methodology and, if applicable, results of static engine noise tests as follows:
a) noise certification methodology: identify approved equivalent procedures for projection of static engine noise data to flight conditions in NPD plot format and methods for defining:
NPD plot differences between flight datum (originally certified airplanes) and derived versions, and Page 47
“Residual” NPD plot differences between flight test data and projected flight data for the originally certified airplane;
b) static engine noise test results
c) engine description: type, model, serial numbers, nacelle acoustic treatments, engine conformity status]
d) test description : test facility, engine installation, turbulence control screen, acoustical and meteorological measurement points, bleed schedules, valid and invalid test points, test conditions for each test point (weather, engine thrust (power);
e) measurement systems and procedures including calibration procedur es: acoustical, meteorological and engine performance;
f) data evaluation procedures: including calibration and data processing, and adjustment and normalization of acoustical, meteorological, and engine performance;
(9) Equivalent procedure applications, documentation and approval process An applicant proposes to use equivalent procedures must be included in aircraft noise compliance demonstration plans (see Note 1). Such proposals may involve new procedures or procedures that have been used previously.
However, applicants must be capable of implementing proposed procedures and such procedures must be applicable to the specific aircraft model for which a TC is requested (see Note 2). Equivalent procedures must be substantiated to yield the same noise levels as the procedures prescribed in part 36.
FAA Order 8110.4C (Reference G4), paragraph 7-5 specifies AEE as the FAA approving authority for Equivalent Procedures (see Note 3). However, as experience is gained with the application of a particular procedure, AEE may delegate approval of the procedure to ACO or NCS specialists (see Reference G8). For example, FAA policy currently permits NCS approval (or ACO approval when authority is delegated) of NPD equivalencies representing extensions of data used to demonstrate comp liance with part 36 for original certified aircraft. NCS (or ACO) approval authority is limited to cases where either the NPD curve fit is linear and the proposed extension is not greater than 5 percent, or the NPD curve fit is 2 nd order and the proposed extension is not greater than 2.5 percent. The NCS also has approval authority for use of existing NPD plots for amended type designs (excluding extrapolation and increments to NPD plots – see Note 4).
Although equivalent procedures may be submitted as proprietary property of an applicant, when several applicants propose closely related or similar procedures (e.g., Flight Path Intercepts), they may be considered to be common industry knowledge and may be described in this AC. Information on equivalent procedures is provided in this AC in Chapter 4, section 402 for subsonic jets, heavy props and helicopters, Chapter 5, section 502 for light props, and Chapter 6, section 602 or light helicopters.
Note 1.— Equivalent procedure proposals should be submitted to FAA early in an aircraft noise certification program because approval may require more than one year.
Note 2.— Prior to approving an e quivalent procedure, the FAA must assess an applicant’s capability to effectively implement the procedure as well as the appropriateness of the procedure for the specific type of aircraft for which certification is requested.
Note 3.— The FAA does not consider equivalencies that modifies reference flight conditions (see 201(a)(10) paragraph 2 of this AC) without following public process.
Note 4.— Data obtained during noise certification tests may support extrapolation of noise databases (e.g., for engine thrust (power) range extensions above and below what was tested). Guidance on extrapolation of NPD databases is provided in 402(a)(2)(B)) of this AC.
(10) No acoustical change (NAC) documentation Aircraft type design changes that are categorized as NAC require FAA approval under the provisions of part 21 rather than part 36. Applicants’ proposals for approval of NAC must be submitted to the FAA in writing. The written submittal must define the planned changes in aircraft type design, and must include information, data and analyses that will substantiate that the specified type design change will not result in an “acoustical change” (see Subpart A, §36.1(c)(2) of part 36).
NAC substantiation documentation must include:
a) introduction (concepts and requirements);
b) description of aircraft baseline and proposed type design changes;
c) methodology for substantiating an NAC;
d) description of tests and/or analyses performed; and
e) test and/or analyses results relating to complia nce with FAA NAC criteria (s ee Subpart A, §36.1(c)(3) of part 36).
Note 1.— Section 21.93(b) of part 21 states that, “…any voluntary change in the type design of an aircraft that may increase the noise levels of that aircraft is an ‘acoustical change’.” Therefore NAC is determined on an aircraft by aircraft basis rather than just on the basis of the type certificate data sheet (TCDS) information for the aircraft model.
Note 2.— Section 183.29(i) of part 183 specifies that Acoustical DERs may not determine that a type design change is an NAC. As such, Acoustical DERs may not make recommendations for approval of NACs under Form 8110-3.
(11) Other noise-related documentation FAA develops noise-related documentation other than that required of applicants under Subpart O, §1501 of part 36 as follows:
a) Findings required by public law 103-272 (Reference G2):
Compliance with Public Law 103-272 requires that FAA, before issuing an original TC for any aircraft of any category, regardless of whether part 36 applies to the aircraft, must make a finding to determine whether:
Substantial noise abatement cannot be achieved for that aircraft by prescr ibing standards and regulations consistent with the limitations of section 44715(b), or Substantial noise abatement may be so achieved in which case the regulatory process must be used to determine the extent of noise reduction to be required before an original TC may be issued.
Note.— The specific process required for FAA to complete Noise Finding documentation is presented in paragraph 7-3 of FAA Order 8110.4C (Reference G4).
b) Environmental Assessments:
Compliance with the National Environmental Policy Act of 1969 may require that the FAA conduct an Page 49
Environmental Assessment (EA) as specified in Ch apter 4 of FAA Order 1050.1F (Reference G1 xx).
An EA is conducted when type certificate actions (New, Amended, or Supplemental) are initiated for aircraft types for which part 36 requirements do not exist (see Note 1). An Environmental Impact Statement (EIS) or Finding of No Significant Impact (FONSI) must be prepared by the FAA (see Note
2). The FAA may grant an interim aircraft noise certification upon completion of an EA while appropriate rulemaking is being completed.
Note 1.— Applicants may be requested to provide appropriate noise data to FAA to support the EA and/or rulemaking processes Note 2.— Procedures for generation of an EA, EIS or FONSI are also found in FAA Order 1050.1E (Reference G1).
(12) Procedures
a) Applicant’s responsibility : Applicants must generate and submit to FAA the following noise certification documentation:
Noise certification plans;
Noise compliance demonstration plans (including proposed equivalent procedures);
Noise certification reports;
NAC substantiation.
b) DER’s responsibility : Acoustical DERs responsibilities are as defined in FAA Order 8110.37E (Reference G6).
201(d)(2) Non-flight test data §36.1501(b)
(1) Airplane families Chapter 4 of this AC, 402(a)(3) for jets, and 402(b)(3) for heavy props, present guidance on static engine noise tests and projection of static engine noise data to flight conditions. Comparisons of projections of static engine noise data from the engines of an originally certified airplane with those of modified configuration engines could enable certification of modified configurations without further expensive and time consuming flight tests (see §36.1501(b) of part 36). An originally certified airplane and its derived versions are known as an “Airplane Family”.
(2) Tests for supplemental data:
An applicant should attempt to obtain static engine or flig ht test noise data at engine thrust (power) settings and ranges, and airplane flight configurations and conditions that may be needed in the foreseeable future. This may necessitate over-boosting of the engine thrust (power) (with the permission of the engine manufacturer), resetting of the engine idle thrust (power) to lower limits, testing to higher or lower range of airspeed and angles of attack, testing at higher or lower altitudes, etc.
201(d)(3) Manuals, markings and placards §36.1581(a)
(1) Aircraft flight manual Page 50
An approved Airplane Flight Manual (AFM) or Rotorcra ft Flight Manual (RFM) is required for certification of each aircraft type in compliance with §36.1581 of the Airworthiness Standards for parts 21.24 (Primary Category), 23, 25, 27, or 29. Section 36.1581 of part 36 requires that certificated noise level compliance information be included in an AFM or RFM. These levels must be cont ained in an FAA approved section of an AFM or RFM other than the limitations section. Fo r example, the performance section is an appropriate place to include the certificated noise level compliance inform ation. The certificated noise levels ar e to be reported to 0.1 dB in the AFM or RFM. Further, an AFM or RFM must specify the ty pe certificate limitations if any, that are established as a result of part 36 compliance, combined with the airworthiness limitations.
(2) Rotorcraft flight manual In addition to the requirements of §36.1581, §H36.3(e) and §J36.3(c)(1) of part 36 require that the values of V H and VNE defined for noise certification must be listed in the RFM. The value of V NE is located in the limitations section of the RFM. The value of VH should be listed in the section of the RFM containing the certificated noise level compliance information.
(3) Airplane flight manual limitation section
a) An AFM may be issued for a single airplane or a group of similar airplanes (including more than one series of a specific model). The AFM must clearly identify (by airplane serial number) the operating limitations, including the maximum weight limits that apply to an airplane.
b) The AFM may address a single configuration (har dware build) or multiple configurations. If an AFM includes information for more than one configuration (hardware build), the appropriate airplane operating limitations must be clearly identified for each config uration. Furthermore, if not all configurations are approved for the airplanes listed in the AFM, the AFM must clearly identify by se rial number, the proper operating limitations for each airplane.
c) The operating limitations contained in the Limitations Section (including any noise-limited weights) must be expressed in mandatory language, not permissive language. The terminology used in the AFM must be consistent with the relevant regulatory language.
(4) Multiple airplane noise certifications
a) Multiple noise-limited gross weight pairs (takeoff and landing) for one airplane configuration are not permitted by Subpart A, §36.1(g) for compliance with part 36. Only one set of gross weight limits that pertain to a particular configuration (hardware build) may be established under part 36 for a particular airplane.
b) An airplane configuration (hardware build) may be certificated only to a single Stage as it qualifies under part 36 (Stage 1, Stage 2, Stage 3, Stage 4, or Stage 5). The limitations section of the AFM for an airplane configuration may not contain operating limitations that would result in noise levels exceeding part 36 noise limits. However, a Stage, 2 airplane may be recertif icated as Stage 3, provid ed that it meets the noise limits for Stage 3 and the AFMs are revised and approved for configurations appropriate for compliance with Stage 3, and the Stage 2 approval is deleted.
(5) Landing flap restriction
a) An operating limitation preventing the use of an approved landing flap setting cannot be imposed under part 36 and must be established under the airworthiness requirements or through a voluntary type design change.
If such a restriction is requested by an applicant in order to comply with part 36 certification requirements that flap setting limit must be incorporated into the design and operation of the airplane.
b) For some Stage 3 airplanes, a “softguard” (such as a crushable cover plate) or frangible device must be Page 51
installed on the flap selection control to safeguard its use in instances other than emergency. This device makes obvious the flap settings that are not to be used for normal operation. Fracture or deformation of the softguard would indicate use of landing flap settings that have not been approved in demonstrating compliance with part 36. For airworthiness purposes, the design of these devices allows the flight crew use of airworthiness approved restricted flaps in emergencies (declared and undeclared). The device may not be resettable by the flight crew; a damaged softguard or frangible device must be repaired as a maintenance action accomplished in accordance with part 43 prior to the next flight.
(6) Procedures
a) Applicant responsibility:
An applicant must identify limiting configurations that may be required to satisfy airworthiness and/or noise regulatory requirements. The limiting configurations, including approved aircraft gross weights, are identified in the “Limitation Sections” of the approved aircraft AFM or RFM.
(7) Implementation of landing flap restrictions FAA policy allows a choice of two options for an applicant to implement landing flap restrictions, where their approval is consistent with applicable airworthiness requirements:
a) where permitted and possible, remove the cockpit flap selection control and performance information from the Performance Section of the original AFM that is relevant to flap settings not considered in demonstrating compliance with part 36; and
b) if flap settings not considered in demonstrating comp liance with part 36 are to remain selectable then, to prevent their use in normal operations:
— Restrictions against their use, except under emer gency (declared and undeclared) operations, must be incorporated into the AFM Limitations Section.
— Operational information must be relocated to the Emergency Procedures Section.
— For Stage 3 airplanes, must install a “softguard” or frangible device over the flap selection control.
— Placards may be installed to provide appropriate information to the flight crew.
(8) ICAO certifications The FAA is not authorized to approve aircraft compliance with Annex 16, Volume 1 Noise Standards. (Reference G7). This is the responsibility of the foreign airworthin ess authority involved. FAA participation is limited to witnessing tests and reviewing data. If the Stage 4 or Stage 5 compliance has been demonstrated refer to §36.105 or §36.106 of part 36. In those cases where Stage 3 compliance has been demonstrated, it is permissible to insert the following statement in the AFM:
“Certification Noise Levels The following noise levels comply with part 36, Appendix B, Stage 3 noise level requirements and were obtained by analysis of approved data from noise tests conducted under the provisions of part 36, Amendment 36-XX (Insert part 36 amendment to which airplane was certificated). The noise measurement and evaluation procedures used to obtain these noise levels are essentially equivalent to those required by the International Civil Aviation Organization (ICAO) in Annex 16, Volume I, Amendment 7, Chapter 3. ICAO Annex 16, Volume I, Chapter 3 approval is applicable only after endorsement by the Civil Aviation Authority of the country of airplane registration.”