Appendix 3.8 Calculation of Lmax at the NSRs |
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(Flight
Path - Approach from East and Take Off to West) |
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Scenario 1a: |
S76C+ operated at
Existing Helipad |
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Table
1.1: Measured Lmax Level, dB(A) from Existing Helipad |
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Distance to |
S76C+ (w/o background) |
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Existing |
Approach |
Hovering |
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Hovering |
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Helipad |
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to landing |
Idling |
to take off |
Take Off |
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Wayson |
312 |
79.5 |
83.4 |
80.0 |
81.4 |
83.3 |
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Ka On |
264 |
75.3 |
77.2 |
77.2 |
77.1 |
82.3 |
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Harbour Commercial Building |
213 |
81.0 |
84.5 |
76.3 |
81.9 |
82.5 |
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Table
1.2: Corrected Lmax Level on existing NSRs, dB(A) due to Existing Helipad
with corrected distance |
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Distance to |
S76C+ |
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Existing |
Approach |
Hovering |
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Hovering
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Helipad |
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to landing |
Idling |
to take off |
Take Off |
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Talon Tower |
358 |
78.3 |
82.2 |
78.8 |
80.2 |
82.1 |
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Ka On |
264 |
75.3 |
77.2 |
77.2 |
77.1 |
82.3 |
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The Bauhinia |
222 |
80.6 |
84.1 |
75.9 |
81.5 |
82.1 |
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Table
1.3: Noise Certification Levels - S92 vs S76C+* |
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S76C+ |
S92 |
Delta |
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Take off |
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Left Mic |
83.3 |
80.8 |
-2.5 |
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Center Mic |
83.2 |
83.3 |
0.1 |
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Right Mic |
80.8 |
80.7 |
-0.1 |
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Approach |
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Left Mic |
79.3 |
82.2 |
2.9 |
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Center Mic |
87.6 |
87.8 |
0.2 |
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Right Mic |
87.7 |
86.8 |
-0.9 |
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*ref: See
Appendix 3.3 |
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Scenario 1c / 2c / 2f |
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S76C+ / S92 Passing by
along the flight path |
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Closest Distance to Flight Path |
S76C+ |
S92 |
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Pass By |
Pass By |
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(away)* |
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Talon Tower |
250 |
82.9 |
83.0 |
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Ka On |
230 |
82.8 |
82.9 |
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The Bauhinia |
190 |
79.5 |
79.6 |
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Distance from noise source |
S76C+ |
S92 |
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Pass By |
Pass By |
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(away)* |
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Sea View Mansion |
350 |
80 |
80 |
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Harmony Court |
330 |
80 |
81 |
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Hongway Garden |
285 |
82 |
82 |
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*worst case
scenario |
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Closest
distance between Talon Tower between the flight path was adopted as the
reference distance |
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Scenario
2a & 2d: Corrected Lmax Level at
existing NSRs, dB(A) due to proposed helipad with corrected distance |
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Distance to |
S76C+ |
S92 |
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New |
Approach |
Hovering |
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Hovering |
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Approach |
Hovering |
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Hovering |
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Helipad |
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to landing |
Idling |
to take off |
Take Off |
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to landing |
Idling |
to take off |
Take Off |
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Talon Tower |
432 |
76.7 |
80.6 |
77.2 |
78.6 |
80.5 |
79.6 |
83.5 |
80.1 |
78.7 |
80.6 |
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Ka On |
328 |
73.4 |
70.3 |
70.3 |
70.2 |
80.4 |
76.3 |
73.2 |
73.2 |
70.3 |
80.5 |
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The Bauhinia |
191 |
81.9 |
75.4 |
67.2 |
72.8 |
83.4 |
84.8 |
78.3 |
70.1 |
72.9 |
83.5 |
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Note: |
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1. The
above noise levels predicted in Scenario 1a assuming that the flight path is
approaching from the east and take off to the west. |
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2. No
screening effect is expected to Talon Tower for all modes of helicopter
operation. |
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3.
Screening effect is expected on Ka On when the helicopter is in idling &
hovering mode at the proposed helipad. Attenuation of 10 dB(A) for idling
& hovering are applied to the noise levels |
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4. As the measurment data at Ka On during
approach mode are similar to the case for the proposed helipad, no screening
correction are applied in the noise levels for approach mode. |
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5. No
screening effects is expected to the Bauhinia during approach mode of
helicopter operation at the proposed helipad according to the flight path. |
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6.
Screening effect is expected on the Bauhinia when the helicopter is in idling
and hovering mode at the proposed helipad.
Attenuation of 10 dB(A) for idling & hovering are applied to the
noise levels. |
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7. +2.9
dB(A) was added to the Lmax of S76C+ during approach, hovering to landing and
idling for the correction to S92 |
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8. +0.1
dB(A) was added to the Lmax of S76C+ during hovering to take off and take off
for the correction to S92 |
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Scenario 3a / 3c: |
One S76C+ idling at
Existing Helipad and and One S76C+ / S92 operated at New Helipad |
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Scenario
3a: Cumulative impact (Lmax)
when one S76C+ Idling on existing
helipad and one S76C+ Approach / Hovering / Takeoff on proposed helipad |
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Distance to |
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New |
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Lmax, dB(A) |
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Helipad |
Approach |
Hovering* |
Takeoff |
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Talon Tower |
432 |
80.9 |
82.8 |
82.7 |
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Ka On |
328 |
78.7 |
78.0 |
82.1 |
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The Bauhinia |
191 |
82.9 |
78.7 |
84.2 |
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*Worst case
scenario |
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Scenario
3c: Cumulative impact (Lmax)
when one S76C+ Idling on existing
helipad and one S92 Approach / Hovering / Takeoff on proposed helipad |
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Distance to |
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New |
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Lmax, dB(A) |
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Helipad |
Approach |
Hovering* |
Takeoff |
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Talon Tower |
432 |
82.2 |
84.7 |
82.8 |
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Ka On |
328 |
79.8 |
78.7 |
82.2 |
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The Bauhinia |
191 |
85.4 |
80.3 |
84.2 |
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*Worst case
scenario |
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Scenario 4a / 4c: |
One S76C+ operated at
Existing Helipad and One S76C+ / S92 idling at New Helipad |
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Scenario
4a: Cumulative impact (Lmax)
when one S76C+ Approach / Hovering /
Takeoff on existing helipad and one S76C+ Idling on proposed helipad |
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Distance to |
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New |
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Lmax, dB(A) |
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Helipad |
Approach |
Hovering* |
Takeoff |
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Talon Tower |
432 |
80.8 |
83.4 |
83.3 |
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Ka On |
328 |
76.5 |
78.0 |
82.6 |
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The Bauhinia |
191 |
80.8 |
84.2 |
82.3 |
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*Worst case
scenario |
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Scenario
4c: Cumulative impact (Lmax)
when one S76C+ Approach / Hovering /
Takeoff on existing helipad and one S92 Idling on proposed helipad |
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Distance to |
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New |
Lmax, dB(A) |
Lmax, dB(A) |
Lmax, dB(A) |
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Helipad |
Approach |
Hovering* |
Takeoff |
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Talon Tower |
432 |
82.3 |
84.3 |
84.2 |
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Ka On |
328 |
77.4 |
78.7 |
82.8 |
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The Bauhinia |
191 |
81.0 |
84.3 |
82.4 |
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*Worst case
scenario |
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