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Federal Register / Vol. 86, No. 164 / Friday, August 27, 2021 / Notices minimum, all of the noise signal between the LAmax and the 10 dB down points in the flyover time history. The instrument operator must note the actual dBA levels at the start and stop of the LAE integration interval and document these levels along with the value of LAmax and the integration interval in seconds for inclusion in the noise data submitted as part of the reporting requirements in paragraph 23 of this regulation.
23 Data ReportingGeneral Reference part 36, appendix J, section J36.111a, as modified: Data representing physical measurements, and corrections to that measured data, including corrections to measurements for equipment response deviations, must be recorded in permanent form and appended to the test reports required by this rule. Each correction is subject to FAA approval.
24 Data Submission Reference part 36, appendix J, section J36.111b, as modified: After the completion of all certification tests required by this rule, the following must be submitted to the FAA:
a A test report containing the following:
i Measured and corrected sound levels obtained with equipment conforming to the standards prescribed in paragraphs 17 through 22 of this rule;
ii A description of the equipment and systems used for measurement and analysis of all acoustic, aircraft performance and flight path, and meteorological data;
iii The atmospheric environmental data required to demonstrate compliance with this rule, as measured throughout the test period;
iv Conditions of local topography, nearby ground cover if any, or events that may have interfered with a sound recording;
v The following aircraft information:
A Type, model, and serial numbers, if any, of aircraft, engines and rotors and/or propellers tested;
B Gross dimensions of aircraft, location of engines or motors, rotors or propellers, number of blades for each rotor or propeller, and the range of rotational speeds of the rotors;
C MTOW at which certification under this rule is requested;
D Aircraft configuration, including landing gear positions;
E Aircraft Airspeeds: VNE and Vmax for both empty weight and maximum payload configuration, or for maximum range, whichever is greatest, and applicable as reference and operational airspeeds;

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F Aircraft gross weight for each test run;
G Indicated and true airspeed for each test run; if indicated and true airspeed for each run are not available, then ground speed as measured from a DGPS, or from an alternate method, may be approved by the FAA;
H Ground speed, if measured, for each run;
I Aircraft engine performance as determined from aircraft instruments and manufacturers data; and J Aircraft flight path above ground level, referenced to the microphone position of the noise measurement station, in feet, determined using an FAA-approved method that is independent of normal flight instrumentation, such as DGPS or photo scaling techniques at the microphone location;
vi Aircraft position and performance data necessary to make the adjustments prescribed in paragraph 27 of this rule and to demonstrate compliance with the performance and position restrictions prescribed in paragraphs 11 through 16 of this rule; and vii The aircraft position in three dimensions and orientation for hover relative to the microphone must be monitored and recorded at all times during the test and data collection, with correlation via time synchronization to the acoustic noise data collection.
b All of the recorded audio data from all phases of all flight tests used to demonstrate compliance with this rule.
c All recordings and data collected during the measurement activity required by paragraph 16 of this rule.
These data will not affect the outcome of this certification findings intended to demonstrate compliance with this rule and may be submitted separately from data that affects certification.
25 Noise Evaluation and CalculationsNoise Evaluation Expressed in LAE Reference: Part 36, appendix J, section J36.201, as modified: The noise evaluation measure must be expressed as the LAE
in units of dBA as prescribed in paragraph 18 of this rule. The LAE
value for each flyover may be determined directly using an integrating sound level meter. Specifications for the integrating sound level meter and requirements governing the use of such instrumentation are prescribed in paragraphs 17 through 22 of this rule.
26 Noise Evaluation and CalculationsCalculation of Noise Levels Reference part 36, appendix J, section J36.203, as modified:
a To demonstrate compliance with the noise level limits specified in paragraph 29 of this rule, the LAE noise
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levels from each valid flyover, corrected as necessary to reference conditions in accordance with paragraph 27 of this rule, must be arithmetically averaged to obtain a single LAE dBA mean value for each flyover series. No individual flyover run may be omitted from the averaging process, unless approved by the FAA.
b The minimum sample size acceptable for the aircraft flyover certification measurements is six. The number of samples must be sufficient to establish statistically a 90 percent confidence limit that does not exceed 1.5 dBA.
c All data used and calculations performed under this paragraph, including the calculated 90 percent confidence limits, must be documented and provided in accordance with the data reporting and submission requirements of paragraphs 23 and 24
of this rule.
27 Data Correction Procedures Reference part 36, appendix J, section J36.205, as modified:
a When certification test conditions measured in accordance with paragraphs 7 through 23 of this rule differ from the reference test conditions prescribed in paragraph 6 of this rule, appropriate adjustments must be made to the measured noise data in accordance with the methods set out in paragraphs 27b and c of this rule.
At minimum, appropriate adjustments in accordance with paragraph 27b of this rule must be made for off-reference altitude and for any difference between reference airspeed and adjusted reference airspeed in accordance with paragraph 27c of this rule.
b The adjustment for off-reference altitude may be approximated from:
>delta< J1 = 12.5 log10HT/250 dB
Where >deltac The adjustment for the difference between reference airspeed and adjusted reference airspeed is calculated from:
>delta< J3 = 10 log10VRA/VR dB;
Where >deltaE:FRFM27AUN1.SGM

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