An open letter has been submitted to the NSW Minister for Planning, The Hon Rob Stokes, highlighting the aviation industry’s genuine concerns with the proposed Open Cycle Gas Turbine within the vicinity of Shellharbour Airport – calling for an independent assessment to protect aviation safety.
AOPA, RAAus, ASAC, and SAAA have signed a 22 page letter and submission to demonstrate both the seriousness and importance of this matter, encouraging the NSW Government to action the recommendations provided by the Civil Aviation Safety Authority to the NSW Department of Planning, Industry, and Environment.
“I would like to thank the SAAA, RAAus and ASAC for joining with AOPA Australia to work collectively in responding to this important issue, ” Benjamin Morgan, CEO AOPA Australia.
“The jointly signed letter demonstrates our industry’s genuine concerns for aviation safety and I am hopeful that Minister Stokes and the NSW Government will take appropriate action in supporting an open and transparent independent assessment, ” he said.
AOPA Australia and the co-signed representative bodies believe an independent assessment should be undertaken in an open and transparent manner to ensure the highest levels of aviation safety are maintained and stakeholder confidence is reinvigorated.
11th June 2021
The Hon Rob Stokes
Minister for Planning
52 Martin Place
Sydney NSW 2000
Dear Minister Stokes
Our organisations collectively write to you to express our deep concern about the risk that the conditionally approved Tallawarra B project poses to the safety of aviation at Shellharbour Airport.
Energy Australia have been working towards building an Open Cycle Gas Turbine (OCGT) power plant at Tallawarra since 2010. One of the main complexities associated with this proposal is that it poses a risk to aviation safety at the Shellharbour airport.
The Civil Aviation Safety Authority (CASA) recommended modelling has shown that every OCGT unit studied in the period since 2010 would pose a significant risk to the safety of aviation. Energy Australia are now seek- ing full approval for an OCGT unit with the addition of a mechanical diffuser on the stack in order to reduce the impact to airport users.
The following is relevant in understanding the level of concern we collectively have regarding the risk this proposal might pose to the safety of aviation at Shellharbour Airport:
- The assessment consultant that the proponent used for all assessments since 2010 confirmed to En- ergy Australia in writing that a mechanical diffuser on the stack will not sufficiently reduce the plume velocity because the primary driver of vertical velocity is thermal, which the mechanical diffuser does not address. Energy Australia subsequently changed plume modelling consultants.
- Every plume rise assessment completed for Tallawarra till recently has been fully transparently docu- mented and shared with NSW Department Infrastructure, Energy and Environment, CASA and Shellhar- bour City Council. The parties were able to consult sufficiently to demonstrate that each unit assessed posed a significant risk to the safety of aviation. No data at all on the proposed mechanical solution has been shared with anybody in the aviation community, with the airport owners or the local community that will be affected by this despite requests from Shellharbour City Council and the Aircraft Owners and Pilots Association of Australia (AOPA). We call upon yourself to intervene to ensure the transpar- ency demonstrated previously is honoured in relation to the assessment of the proposed mechanical solution.
Under Civil Aviation Safety Regulation 139.180 (1)(b) CASA may determine in writing that a proposed object, such as an OCGT, may pose a hazard to aircraft operations.
Based on earlier CASA advice, Energy Australia needed to ensure that the Critical Plume Velocity (CPV) was no greater than 6.1m/s at 700ft. CASA has now advised your department on 29 March 2021 that they are unable to determine:
- Whether the condition of CPV 6.1m/s at 700ft is met as CASA intended, and;
- Based on the modelling, whether the proposal will cause a risk to the safety of aviation.
The unique nature of this new proposal is defined by proposing to build an OCGT in the vicinity of, and within the circuit of an aerodrome. As such, this calls for the use of engineering solutions to effectively control the vertical velocity of the plume to enable the CASA determined criteria of a CPV of 6.1m/s at 700ft to be met.
CASA’s existing guidance material on plume rise assessments does not consider the modelling required for this proposal as previous developments of this nature have not needed engineering controls to manage the vertical plume velocity as they were generally located sufficiently outside of the circuit area of an aerodrome.
CASA has recommended to the Department that an independent modelling assessment be undertaken. Our organisation’s support and encourage this independent assessment. We further encourage the sharing of all data associated with independent assessment.
Furthermore, should the project proceed, due to the possible significant risk to aviation, and the fact that this novel approach requires use of alternate modelling, we recommend that the plume characteristics be actual- ly measured as part of the commissioning process. We are aware of an independent international company competent to conduct such activity and are able to supply these details should you require them.
Our organisations are concerned that there is a very strong chance of a fatal accident occurring in the circuit of Shellharbour Airport should this project proceed without an appropriate independent assessment to en- sure to the best of our collective ability that the project does not pose a risk to the safety of aviation.
We commend the above actions to you.
Signed by AOPA Australia, RAAus, SAAA & ASAC