examples small helicopters noise footprint above 62.5 db three different altitudes 1000’ agl...
TRANSCRIPT
EXAMPLESSMALL HELICOPTERS
NOISE FOOTPRINTABOVE 62.5 dB
THREE DIFFERENT ALTITUDES
1000’ AGL1400’ AGL2000’ AGL
Altitude(Distance) 1000’
Distance on the Ground = 1732’ or 1/3 Mile
Distance – 2000’
Average Noise Levels on the Ground69 dB* 62.5 dB
HELICOPTER ASSOCIATION INTERNATIONAL (HAI)DISTANCE/NOISE RELATIONSHIP
*HAI GENERAL RULE:IF THE DISTANCE IS HALVED,THE NOISE IS INCREASED 6-7 dB
From Noise Tests
AVERAGE HALF-FOOTPRINT OF NOISE ABOVE 62.5 dB
Estimated
2
HELICOPTER AT 1000’ AGL – AVG FOOTPRINT NOISE ABOVE 62.5 dB– 2/3 MILE WIDE (At 60 dB noise begins to interfere with speech communication)
CutCorner
CutCorner
Agreed Path
3
NOISE
Altitude(Distance) 1400 ‘
66.4 dB
Distance – 2000’
AVG HALF-FOOTPRINT 1428’ or 1/4 Mile
62.5 dBAverage Noise Levels on the Ground From Noise Tests
ROBINSON HELICOPTER CO. FLIGHTS AVERAGED 1400’ AGL. INCREASING THE ALTITUDE FROM 1000’ TO 1400’ REDUCES NOISE DIRECTLY BELOW AND REDUCES THE 62.5 dB FOOTPRINT FROM 1/3 MILE TO 1/4 MILE.
RESULTS OF INCREASED ALTITUDE
4Estimated
HELICOPTER AT 1400’ AGL – AVG FOOTPRINT NOISE ABOVE 62.5 dB – 1/2 MILE WIDE (At 60 dB noise begins to interfere with speech communication)
CutCorner
CutCorner
Agreed Path
5
NOISE
Altitude(Distance) 2000’
62.5 dB
AT AN ALTITUDE (DISTANCE) OF 2000’ THE AVERAGE FOOTPRINT IS 6.52 dB DIRECTLY BELOW THE HELICOPTER.
RESULTS OF INCREASING ALTITUDE
6From Noise Tests
HELICOPTER AT 2000’ AGL – AVERAGE NOISE FOOTPRINT 62.5 dB
7
NOISENOISE