Whilst I fully support aviation in every way, I know why they are complaining. Helicopter traffic in the Mel CBD particularly on a weekend can be moderately intense. I was on the river last weekend, perhaps 8-10 movements in the hour that I noticed. It doesn't sound like many but it's not an airport, it's the helipads right in town on the river outside the Casino and popular pedestrian areas. Like it or not, they are noisy and often sit running for extended periods. They are running joy flights from right outside Crown, takeoff down the river and climb out towards the Westgate.