Pt. 36, App. A

(1) XY represents the portion of the measured flight path that includes the noise time
history relevant to the calculation of flyover
and approach EPNL; XrYr represents the corresponding portion of the reference flight
path.

(2) Q represents the airplane-s position on
the measured flight path at which the noise
was emitted and observed as PNLTM at the
noise measuring station K. Qr is the corresponding position on the reference flight
path, and Kr the reference measuring station.
QK and QrKr are, respectively, the measured

and reference noise propagation paths, Qr
being determined from the assumption that
QK and QrKr form the same angle q with their
respective flight paths.
(b) The portions of the test flight path and
the reference flight path described in paragraph (b)(1) and (2), and illustrated in Figure
A36-7(a) and (b), include the noise time history that is relevant to the calculation of
lateral EPNL.
(1) In figure A36-7(a), XY represents the
portion of the measured flight path that includes the noise time history that is relevant
to the calculation of lateral EPNL; in figure
A36-7(b), XrYr represents the corresponding
portion of the reference flight path.
(2) Q represents the airplane position on
the measured flight path at which the noise
was emitted and observed as PNLTM at the

noise measuring station K. Qr is the corresponding position on the reference flight
path, and Kr the reference measuring station.
QK and QrKr are, respectively, the measured
and reference noise propagation paths. In
this case Kr is only specified as being on a
particular Lateral line; Kr and Qr are therefore determined from the assumptions that
QK and QrKr:
(i) Form the same angle q with their respective flight paths; and
(ii) Form the same angle y with the
ground.
NOTE: For the lateral noise measurement,
sound propagation is affected not only by inverse square and atmospheric attenuation,
but also by ground absorption and reflection
effects which depend mainly on the angle y.

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