Completion Report Primrose Sands.pdf

FOI 24-91
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Short Term Noise Monitoring – Primrose Sands, December 2024

Short Term Noise Monitoring
Program, Primrose Sands

11 June 2024 – 12 December 2024

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FOI 24-91
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Short Term Noise Monitoring – Primrose Sands, December 2024
Version Control
Version
Date
Comments
Sections
1.0
12 December 2024
Initial Version
All
Summary
D e p l o y m e n t   P u r p o s e
This  deployment  aims  to  capture  noise  levels  in  support  of  the  Noise  Abatement  Procedure
(NAP) trial, which commenced in June 2024. Specifically, it focuses on capturing noise levels of
arrivals using the RNP-AR approach and the longer RNAV approach to RWY 30.

D e p l o y m e n t   m o n i t o r i n g   P e r i o d
11 June 2024 – 12 December 2024

M o n i t o r i n g   D e t a i l s
Capture zone: 2.5km radius x 8,202ft (2,500m) altitude.
Noise  threshold  settings  by  time  of  day:  00:00-07:59  =  Threshold  51dB(A),  08:00-13:59  =
Threshold 55dB(A), 14:00-20:59 = Threshold 52dB(A), 21:00-23:59 = Threshold 50dB(A)

K e y   F i n d i n g s
•  Noise Correlation
92.6%  of  the  aircraft  from  Hobart  Airport,  as  per  the  focus  group,  generated  noise
events that correlated to the aircraft.
•  Noise Daily Distribution
The  distribution  of  the  maximum  noise  levels  generated  by  aircraft  falls  within  the
following ranges:
-  76.9% within the range of 60dB(A) to 70dB(A)
-  22.2% greater than 70dB(A).
-  0.9% below 60dB(A).
•  Most Common aircraft
The most prevalent aircraft type during the deployment period was the B738 aircraft.
•  Top loudest noise events
The  top  10  noise  events  for  this  deployment  originated  from  community  sources.
Additionally,  the  top  10  correlated  noise  events  were  associated  with  community
sources in addition to aircraft noise.
•  Busiest Day
The  purpose  was  to  analyze  the  day  that  had  the  most  significant  impact  on  the
community. The busiest day during the deployment period occurred on 11 June 2024.

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Short Term Noise Monitoring – Primrose Sands, December 2024
Glossary of Terms

A
Arrivals
Background noise Level
The noise level in dB(A) that is exceeded 90% of the time. It is considered
(L90)
the background noise level of an environment.
Capture Zone
The region relative to the noise monitor that an aircraft can be within and
be able to be correlated to a noise event.
Correlated Noise Event
A  noise  event  matched  to  an  aircraft  movement  that  flew  through  the
(CNE)
capture zone.
D
Departures
The degree of data completeness achieved during the deployment period.
Data Availability
The data availability percentage factors in any monitor outages that occur.
Day
6:00am-10:00pm
dB(A)
A-weighted decibel. It is an expression of the relative loudness of sounds
as perceived by the human ear.
General Aviation
Movements  other  than  scheduled  commercial  airline  operations.  This
includes private, sports, charter and training operations.
H
Helicopter operations
LaMax
Each noise event will have a peak noise level which is referred to as the
maximum sound level in dB(A) or LaMax
Movement
An aircraft operation, such as an arrival or departure
Night
10:00 pm to 6:00 am
NMT
Noise Monitoring Terminal also referred to as the noise monitor.
A  noise  event  is  created  when  the  noise  level  exceeds  the  threshold
Noise Event
settings for a specified period.
O
Overflight i.e. an aircraft movement that flew over the area but did not arrive
or depart from the airport of concern.
The total number of correlated noise events (CNE) is divided by the total
Overall Correlation
number  of  aircraft  movements  through  the  capture  zone  to  calculate  the
Percentage
overall correlation percentage.
RWY
Runway
An  operation by  an  aircraft  that  arrives and  departs  on  a  runway  without
T
stopping or exiting the runway.  It is also known as Touch and Go.
The threshold represents the value that the noise level must surpass for a
Threshold
specified period to create a noise event.
YMHB
Hobart Airport, Tasmania

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FOI 24-91
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Short Term Noise Monitoring – Primrose Sands, December 2024
1 Purpose
The short-term noise monitoring program targeted locations in suburbs chosen by Airservices
Australia  with  consideration  for  community  feedback.  This  deployment aims  to  capture  noise
levels  in  support  of  the  Noise  Abatement  Procedure  (NAP)  trial,  which  commenced  in  June
2024. Specifically, it focuses on capturing noise levels of arrivals using the RNP-AR approach
and the longer RNAV approach to RWY 30. Furthermore, an extensive analysis was conducted
for the busiest day of the deployment period. This day was chosen for its potential to provide
significant statistical data and insight into a day that had the greatest impact on the community
during the deployment. The analysis provided details of the loudest noise events experienced
and the most prevalent aircraft operations observed.
To adequately depict the variation in flight paths, weather conditions, and operational patterns
from Hobart Airport movements during the trial, a monitoring period from  11 June 2024 to 12
December 2024 was deemed sufficient. However, the monitor will remain in place as part of the
ongoing short term monitoring program.
This short-term monitor was deployed in Primrose Sands. The noise monitoring terminal (NMT)
was positioned to capture aircraft within a three-dimensional cylinder capture zone. The zone
spans a radius of 2.5km and extends to 8,202ft (2,500m) above the NMT site level as depicted
in Figure 1. Considering that the focus group of aircraft operate below 5,000ft (1,524m), a ceiling
of 8,202 (2,500m) was adopted to accommodate potential variations.
The Focus Group for this deployment consists of aircraft operating to the east of Hobart Airport
which include:
•  Fixed-wing jet aircraft arriving to runway 30 of YMHB.

Figure 1: NMT Correlation Zone

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Short Term Noise Monitoring – Primrose Sands, December 2024
2 Deployment Details
The Primrose Sands monitor was installed on 10 June 2024. Complete data is available from
11 June 2024 to 12 December 2024.
NMT ID
399
Deployment Period
11/06/2024 – 12/12/2024
Location
Carlton Bluff Road, Primrose Sands, 7173
NMT Altitude
65ft (20m)
Capture Zone
2.5km radius x 8,202ft (2,500m) altitude
Data Availability
98.1%
The noise detection thresholds which have been selected:
     •        00:00-07:59 = Threshold 51dB(A)
Threshold Settings1
     •       08:00-13:59 = Threshold 55dB(A)
     •       14:00-20:59 = Threshold 52dB(A)
     •       21:00-23:59 = Threshold 50dB(A)
Table 1: NMT Details
3 Findings
3.1.
Noise Correlation Summary

The  total  number  of  aircraft  correlated  noise  events  (CNEs)  that  were  captured  by  the  noise
monitor during the 6-month deployment period is shown in Table 2 below.

Hobart Airport
Hobart Airport
All Movements2

Movements
Focus Group
Number of Movements
1772
1571
1518
through capture zone
Number of CNE
1571
1430
1405
Correlation Summary
88.7%
91.0%
92.6%
Table 2: Aircraft correlation rate

88.7% of all operations that passed through the capture zone were Hobart Airport movements.
A one-week sample of these movements is shown in Figure 2, below. Other operations included
traffic from other airports, such as Hobart Cambridge and Edinburgh Airports.  A correlation of
92.6% was achieved for the focus group of Hobart Airport movements.

1 Threshold setting procedures are explained in section 6.1.1.
2 All-movement tab accounts for operations to and from other airports (E.g. Hobart Cambridge and Edinburgh Airports)
as well as YMHB operations.
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Short Term Noise Monitoring – Primrose Sands, December 2024

Figure 2: One week of Hobart Airport flight tracks passing through the correlation zone

The findings obtained during the short-term deployment at Primrose Sands are as follows:
•  Arrival runway 30 accounts for 98.3% of the operations from Hobart Airport over the
noise monitor.
•  Departure runway 12 accounts for 0.8% of the operations from Hobart Airport over the
noise monitor.
•  The average LaMax and highest LaMax for arrival and departure runways are detailed
in Table 3, below.
Average LaMax
Highest LaMax
Operation Type
Runway
noise dB(A)
dB(A)
Hobart Airport Arrival
30
69.3
84.7
Hobart Airport Departure
12
62.4
66.6
Table 3: Average LaMax and highest LaMax noise levels corresponding to each runway.

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Short Term Noise Monitoring – Primrose Sands, December 2024
3.2.
Daily Distribution of Correlated Noise Events

A summary of the total number of correlated noise events by time of day, and the minimum to
maximum number of CNE on any day, are summarized below in Table 4.
Min
Max
Day Time Count
Night-time Count
Correlated Noise
number of
number of
(6:00am-
(10:00pm-
Event (CNE)
CNE per
CNE per
10:00pm)
6:00am)
day
day
N- Above3 50 dB(A)
1449
4
1
18
(N50+4)
N- Above 60 dB(A)
1435
4
1
17
(N60+4)
N- Above 70 dB(A)
334
0
0
9
(N70+4)
Table 4: Total correlated noise events during deployment period by time

Examination of the N-above distribution values in Figure 3 and Figure 4 (below) show that the
highest daytime noise levels (N70+) were recorded on 11 June 2024. 76.9% of the maximum
noise  level  generated  by  aircraft  falls  within  a  range  of  60dB(A)  to  70dB(A),  0.9%  of  the
maximum  noise  level  generated  by  aircraft  is  less  than  60dB(A)  and  22.2%  of  the  maximum
noise level generated by aircraft is greater than 70dB(A).

3 N-above (or Number-above) is defined as the number of noise event with a LaMax above the specified (eg.N50+)
value.
4 N50+, N60+, N70+ are expressed as number of noise events with a LaMax above 50dB(A), 60 dB(A) and 70 dB(A),
respectively.
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Figure 3: Daytime Daily N-Above Distribution Graph
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Figure 4: Nighttime Daily N-Above Distribution Graph
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Short Term Noise Monitoring – Primrose Sands, December 2024
3.3.
Most Common Aircraft
The most common aircraft type that flew through the  zone during the deployment period is a
B738 aircraft as shown in Table 5, below.

Hobart Airport
Operations
Correlated %
Operation Type
Arrival
832
93%
Departure
2
50%
Touch and Go
0
0%
Overflight
0
0%
Table 5: B738 correlation percentage across the deployment period

3.4.
Top 10 Correlated  Aircraft
The following table shows the top 10 average  and  maximum noise  levels of correlated noise
events (CNEs) for the deployment period from 11 June 2024 to 12 December 2024. The highest
average LaMax of 70 dB(A) is attributed to BCS3 jet arriving to runway 30, shown in Table 6.
Aircraft
Aircraft
Airport  Operation
Total
Average
Max5
Type
Category
Code
Type
Runway
CNE
LaMax dB(A)
dB(A)
B738
J
YMHB
A
30
826
69.8
84.7
A320
J
YMHB
A
30
375
68.8
77.8
BCS3
J
YMHB
A
30
58
70
83.5
SF34
T
YMHB
A
30
47
67.2
73.5
B712
J
YMHB
A
30
44
67.6
72.8
E190
J
YMHB
A
30
34
68.8
72.2
BE20
T
YMHB
A
30
22
63.9
66.8
A21N
J
YMHB
A
30
20
67.8
72
A321
J
YMHB
A
30
18
68.7
74.8
BE20
T
YMHB
D
12
10
61.4
64
Table 6: Top 10 aircraft in the deployment period by total CNE
Aircraft Category: J = Jets, T = Turboprop. Operation Type: D = Departure, A = Arrival

5 Correlated noise events contaminated by community noise have not been uncorrelated, so it remains possible that
the maximum dB value should be lower, as the Maximum Lmax value in the table may be caused by community noise
rather than the aircraft. Examples shown in Figure 5.
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Short Term Noise Monitoring – Primrose Sands, December 2024
3.5.
Noise Event Analysis
The audio verification process involved listening to and confirming the accuracy of the top  20
loudest (LaMax) noise events.
Table 7 outlines the top 10 noise events from all sources. The maximum noise levels (LaMax)
of the noise events for this deployment originated from community sources such as people, rain,
birds, sirens and vehicle noise.
Table 8 outlines the top 10 correlated noise events (that is, correlated with aircraft noise). The
maximum noise levels (LaMax) of correlated noise events for this deployment originated from
other nearby local airport movements (Overflights) as well as Hobart Airport movements.
Some correlated noise events were associated with community sources in addition to aircraft.
This can be seen in the ‘noise source’ details in Table 8 and Figure 5. Consequently, there may
be a benefit in conducting  further noise monitoring in  this location to explore and confirm the
spectrum of noise levels attributed to aircraft, with the exclusion of any impact from community
noise contamination.
Future aircraft noise monitoring in the Primrose Sands area can achieve greater precision by:
•  Choosing a location further away from the main road to minimise contamination of the
aircraft noise events from the community.

Correlated
LaMax
Aircraft  Operation
Start Date/Time
to
Noise Source
Runway
dB(A)
Type6
Type
Aircraft?
22/08/2024 14:22
No
116.5
People talking
-
-
-
22/08/2024 14:22
No
110.8
People talking
-
-
-
01/09/2024 12:52
No
102.8
Birds
-
-
-
27/11/2024 10:19
No
99.0
Sirens
-
-
-
17/07/2024 15:54
No
98.5
Birds
-
-
-
21/09/2024 16:04
No
93.4
Motorbike
-
-
-
27/11/2024 10:26
No
93.4
Sirens
-
-
-
21/09/2024 10:16
No
91.5
Motorbike
-
-
-
14/09/2024 13:08
No
90.8
Rain
-
-
-
04/08/2024 9:13
No
90.7
Motorbike
-
-
-
Table 7: Top 10 loudest noise events during the deployment period by LaMax



6 Dash (-) indicates the details are not publicly available.
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Short Term Noise Monitoring – Primrose Sands, December 2024
Movement
LaMax
Aircraft
Operation
Start Date/Time
Airport7
Noise Source
Runway
dB(A)
Type8
Type9
27/08/2024 12:00
Hobart
84.7
Aircraft and birds
B738
A
30
28/09/2024 11:18
Hobart
83.5
Aircraft and
BCS3
A
30
motorbike
09/11/2024 13:44
Overflight
80.6
Aircraft (Heli) and
B06
O
-
motorbike
25/10/2024 08:28
Overflight
80.2
Aircraft (Heli)
B412
O
-
13/09/2024 17:41
Hobart
78.3
Aircraft
PC21
A
30
11/07/2024 08:20
Hobart
77.8
Aircraft and birds
A320
A
30
18/09/2024 09:51
Hobart
77.4
Aircraft
B738
A
30
30/10/2024 16:53
Overflight
77.2
Aircraft (Heli)
B412
O
-
19/09/2024 12:24
Hobart
77.2
Aircraft and wind
B738
A
30
21/08/2024 11:44
Hobart
76.7
Aircraft and birds
B738
A
30
Table 8: Top 10 loudest aircraft correlated noise events during the deployment period by
LaMax

7 Overflights refers to movements from Hobart Cambridge and Edinburgh Airports etc.
8 Dash (-) indicates the details are not publicly available
9 Operation types A = Arrival, D = Departure, O = Overflight, T = Touch and Go
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Short Term Noise Monitoring – Primrose Sands, December 2024










Figure 5: Top 9 correlated noise event from Table 8 graphed and analysed.
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4 Busiest Day Analysis

4.1.
Discussion
The busiest day during the deployment period occurred on  11 June 2024, with a total of 486
noise events. The noise events consisted of jet, turboprop, bird and wind noise. There were 17
aircraft captured passing through the zone from Hobart Airport movements, of which 16 aircraft
were  from  the  focus  group.  The  predominant  movement  over  the  capture  zone  was  from  jet
operations (94%).

Figure 6: Busiest day flight tracks

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Short Term Noise Monitoring – Primrose Sands, December 2024
4.2.
Busiest Day Graph

Figure 7: Distributions of hourly L90, max CNE level and one-second noise data on the busiest day. Hourly L90 refers to background noise levels; see
Section 6.1.1 for more information. Max CNE level refers to the maximum noise level of the noise event, known as LaMax, which occurs when the aircraft
is within the capture zone of the noise monitor; see Section 6.1.2 for more information. One-second noise data refers to the sound levels that are
recorded every second by the noise monitor.
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Short Term Noise Monitoring – Primrose Sands, December 2024
4.3.
Busiest Day Noise Levels
The loudest event on the 11 June 2024, reaching a maximum noise level of 72.9(A) at 08:59:33
in the morning, lasting for 80 seconds. This audio event is not present in order to determine the
type of community noise.
5 Further Information
The following platforms provide further information on Hobart aircraft noise monitoring.
5.1.
Airservices Australia
Information on the noise and flight path monitoring system including approach to noise
monitoring and frequently asked questions:
https://www.airservicesaustralia.com/community/environment/aircraft-noise/monitoring-aircraft-
noise/
5.2.
WebTrak
Aircraft noise data is displayed from live noise monitors across Hobart, along with historical data:
https://webtrak.emsbk.com/hba3

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6 Appendix
6.1.
Noise Event Detection Details:
ISO  20906  provided  technical  guidance  in  this  short-term  noise  monitoring.  The  NMT  (i.e.,
sound level monitor) used for testing passed the Class 1 periodic calibration tests outlined in
clauses of IEC  61672-3:2013 and IEC 61260-3:2016. The placement of NMT considered the
vicinity of reflective surfaces and the height of the NMT relative to the target aircraft operations
to minimise potential unintended anomalies. The NMT height is fixed on a supporting pole and
the  captured  noise  events  were  observed  acceptable  throughout  the  deployment.  The
background noise levels were taken into account in the monitoring area, to appropriately capture
aircraft noise levels.
6 . 1 .1 .   T h r e s h o l d  S e tt i n g s
Noise monitor threshold settings are established by collecting hourly average L90 data over a
period of two to five days following installation of the noise monitor. L90 represents noise level
which  are  exceeded  90%  of  the  time.  It  is  considered  the  background  noise  level  of  an
environment. For instance, if the L90 hourly noise level reads 50dB(A), it means that for 90% of
that  hour,  the  noise  level  is  above  50dB(A).  The  threshold  is  set  close  to  the  average
L90+10dB(A).  The  addition  of  10dB(A)  effectively  filters  out  most  community  noise,  such  as
birds and animal sounds, machinery, and vehicle noises. As a result, the created noise event
will predominantly contain aircraft noise with minimal community noise.
6 . 1 .2 .   A i r c r a f t   a n d   N o i s e  E v e n t   Co r r e l a t i o n
The correlation of a noise event with an aircraft requires meeting the following conditions:
•  The aircraft passes through the defined capture zone set by the monitor as shown in
Figure 1.
•  The rise and fall time of the measured event matches a sound pattern representative of
an aircraft flyover.
•  Noise levels are greater than the specified threshold for a specified period when aircraft
flies over, this creates a noise event.
•  Maximum noise level of the noise event known as LaMax must occur while the aircraft
is within the capture zone of the noise monitor.
Aircraft that flew within the vicinity of the monitor but did not trigger a correlated noise event may
have failed to meet some of the parameters above. In other instances, this could be attributed
to the lack of air traffic control data (ATC). This occurs when aircraft do not have an operating
transponder  or  when  there  are  radar  outages.  Despite  a  noise  event  being  created  by  the
aircraft, without available ATC data, there will be no aircraft to correlate with the noise event.
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6.2.
Calibration Check
The integrity of the noise monitor relies on regularly verifying the accuracy of the microphone
recording  levels  and  time  synchronisation  of  samples  with  radar  data.  The  microphones  are
replaced  with  laboratory  certified  microphones  every  12  months  and  electrostatic  calibration
tests are automatically performed daily to ensure data quality.
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