FAA Federal Aviation Regulations (FARS, 14 CFR)

PART D -- NOISE LIMITS UNDER §36.805

 

Section H36.301      Noise measurement, evaluation, and calculation

Compliance with this part of this appendix must be shown with noise levels measured, evaluated, and calculated as prescribed under Parts B and C of this appendix.

 

Section H36.303 [RESERVED]

 

Section H36.305      Noise levels

(a) Limits. For compliance with this appendix, it must be shown by flight test that the calculated noise levels of the helicopter, at the measuring points described in section H36.305(a) of this appendix, do not exceed the following, with appropriate interpolation between weights:

(1) Stage 1 noise limits for acoustical changes for helicopters are as follows:

(i) For takeoff, flyover, and approach calculated noise levels, the noise levels of each Stage 1 helicopter that exceed the Stage 2 noise limits plus 2 EPNdB may not, after a change in type design, exceed the noise levels created prior to the change in type design.

(ii) For takeoff, flyover, and approach calculated noise levels, the noise levels of each Stage 1 helicopter that do not exceed the Stage 2 noise limits plus 2 EPNdB may not, after the change in type design, exceed the Stage 2 noise limits plus 2 EPNdB.

(2) Stage 2 noise limits are as follows:

(i) For takeoff calculated noise levels -- 109 EPNdB for maximum takeoff weights of 176,370 pounds or more, reduced by 3.01 EPNdB per halving of the weight down to 89 EPNdB for maximum weights of 1,764 pounds or less.

(ii) For flyover calculated noise levels -- 108 EPNdB for maximum weights of 176,370 pounds or more, reduced by 3.01 EPNdB per halving of the weight down to 88 EPNdB for maximum weights of 1,764 pounds or less.

(iii) For approach calculated noise levels -- 110 EPNdB for maximum weights of 176,370 pounds or more, reduced by 3.01 EPNdB per halving of the weight down 90 EPNdB for maximum weight of 1,764 pounds or less.

(b) Tradeoffs. Except to the extent limited under §36.11(b) of this part, the noise limits prescribed in paragraph (a) of this section may be exceeded by one or two of the takeoff, flyover, or approach calculated noise levels determined under section H36.203 of this appendix if

(1) The sum of the exceedances is not greater than 4 EPNdB;

(2) No exceedance is greater than 3 EPNdB; and

(3) The exceedances are completely offset by reduction in the other required calculated noise levels.

[Amdt. 36-14, 53 FR 3541, Feb. 5, 1988; 53 FR 4099, Feb. 11, 1988; 53 FR 7728, Mar. 10, 1988, as amended by Amdt. 36-54, 67 FR 45237, July 8, 2002]