Aviation Noise Monitoring Plan and datasets 2021-2022

Full description

The Australian Antarctic Division’s (AAD’s) Aviation Noise and Wildlife Monitoring Program (the Program) was established in 2021 to assess the efficacy of mitigation measures outlined in Environmental Impact Assessment – Australian Antarctic Program Aviation Operations 2020-2025 to minimise impacts to wildlife from aircraft noise disturbance and visual stimuli. Noise and wildlife monitoring are requirements of the AAD’s Aviation Operations Environmental Monitoring Plan. Monitoring of noise is relevant to all aircraft activities undertaken by the Australian Antarctic Program (AAP), including rotary and fixed-wing aircraft, remotely piloted aircraft, intra- and inter- continental flights, and airdrops.

The monitoring conducted under the Aviation Noise and Wildlife Monitoring Program incorporates both visual and acoustic impacts to wildlife while AAP aircraft are in operation. The Program has been designed primarily to ascertain the noise from aircraft at a range of distances, and to detect any acute responses to aircraft. These generally manifest as immediate behavioural changes that are readily observable via footage or direct observation. A ‘Before-During-After’ (BDA) approach is used to provide a Control/Impact design to the monitoring program, with the Before temporal phase being the control phase of the monitoring event (i.e., before an aircraft event such as a pass-by, take-off or landing) and the During-After phases being the impact phases.

In the 2021-22 season, sound meters and video cameras were set up close to (but not within 20 m of) wildlife near to Davis station, East Antarctica, to monitor aircraft sound received at the wildlife’s location, and any behavioural changes.
There were 3 monitoring locations in the 2021-22 season:
• Davis Beach: -68.577483°, 77.965983° (precise location of equipment varied depending on the location of wildlife along the beach)
• Marchants Landing: -68.581090°, 77.956380°
• Black Bluff: -68.572633°, 77.967950°
All aircraft noise recordings were of single-engine AS350 B3 “Squirrel” helicopters.

The following data streams were captured for each monitoring event:
• Flight data (aircraft type, coarse airframe tracking data)
• Behavioural data (video recordings of wildlife response)
• Sound data (audio recordings of ambient and aircraft sounds), and
• Field data (monitoring event data and meteorological data to provide context to the results).

Datasets and documents:
This dataset contains the raw sound level data collected for the AAD’s Aviation Noise and Wildlife Monitoring Program 2021-22. During each monitoring event, sounds were recorded continuously by a calibrated Rion NL-52 EX sound meter. Calibrations were validated before and after the field measurements using a calibrated source with a 1 kHz tone at a level of 94 dB re 20 μPa.

The acoustic recordings were separated into four time periods: Before, During, and After periods, which were based on the timing of each aviation event, and Ambient periods, which captured sound levels during monitoring events when no aviation activities occurred (this occurred on 2 occasions when aviation activities were cancelled following equipment set-up). Ambient sound was defined as the all-encompassing sounds at a point, comprising sound from all sources near and far. This included anthropogenic sounds from station activities that were not related to aviation operations.

Time periods were defined as follows:
• Before periods commenced once voice notes and set-up sounds were no longer able to be heard on the recording and ended 1 minute before the start of the During phase.
• During periods captured periods when aircraft sounds could be heard on the recording, with the start and end times delineated when the LAeq was approximately 5 dB above ambient sound levels.
• After periods commenced 1 minute after the end of a During phase and ended either 1 minute prior to the next During phase, after a maximum of 1 hour, or immediately prior to the first detection of sounds related to equipment pick-up (i.e. the end of the monitoring event).
• Ambient periods commenced once equipment set-up sounds were no longer able to be heard on the recording and ended immediately prior to the first detection of equipment pick-up sounds.
Sound playbacks and time traces of the audio recordings were reviewed to assist with confirming the start and end times of each time period.

Lineage

Progress Code: completed

Notes

Purpose
The overarching objective of the Program is to evaluate the effectiveness of longstanding separation distances employed by the AAD as means of avoiding disturbance to concentrations of wildlife from AAP aircraft. These distances are agreed and enforced as a condition of authorisation for the operation of AAD aircraft.