“This includes a greater spread of turboprops outside the ‘swathe’ of operations than we expected,” a spokeswoman said.
“Turboprops use a mix of jet and non-jet flight paths, including visual approaches.
“A visual approach is when a pilot is operating the aircraft by visual references. This approach can therefore vary by several kilometres.”
The changes, which come into force on Friday, include a new noise abatement procedure for Brisbane Airport.
“This temporary procedure will be in place until operations increase to both runways, which will then result in a similar traffic management outcome,” the spokeswoman said.
Federal Brisbane MP Trevor Evans, one of the politicians who wrote to Airservices Australia – along with state MP Tim Nicholls and councillor David McLachlan – said the change meant new instructions would be issued to air traffic controllers to stop pilots deviating from approved flight paths.
“This new procedure could significantly reduce the number of planes that are currently short-cutting and deviating from approved flight paths as they approach the runway,” Mr Evans said.
He said the major problem was from aircraft arriving from mining towns and from northern and regional Queensland.
“They have been allowed to approach on a visual, meaning they haven’t been required to so strictly stick to the approved flight paths.”
Mr Evans has also asked the Civil Aviation Safety Authority to review tail-wind restrictions, which can prevent aircraft from flying over Moreton Bay rather than populated areas.
In July, soon after the new parallel runway opened, residents began to complain that aircraft noise was intolerable in Balmoral, Morningside, New Farm, Hawthorne, Cannon Hill, Hamilton and Hendra.
In the first fortnight of operation, there was a seven-fold increase in complaints, many from suburbs that did not expect aircraft to fly overhead.
By August, residents were complaining of “horrendous” noise, with up to seven overhead flights in 10 minutes, telling Brisbane Times planes appeared to be flying lower than they were led to believe they would.
By October, residents were taking their own decibel readings of overhead aircraft, as the number of complaints increased tenfold to 311 in one month.
Most turboprop aircraft from Brisbane Airport are operated by Qantas’s regional subsidiary, QantasLink.
A Qantas spokesman said: “All QantasLink pilots follow the approved flight paths provided by Airservices Australia.”
A Brisbane Airport Corporation spokeswoman confirmed pilots were making visual approaches to the airport.
She said there had been greater flexibility for pilots to choose flight paths because COVID-19 had reduced the expected number of flights at the airport.
“As a result, in percentage terms, there has been a greater use of visual approaches north of the river from turboprop aircraft,” she said, adding that this did not mean the airport was operating outside its 2007 approvals.
Mr Evans said allowing a significant number of aircraft to deviate from the approved flight paths was contrary to the terms and spirit of the environmental impact study.
Long-term Hamilton residents Deidre Stringer and Peter Moorhouse are used to aircraft noise but said the noise overhead had become far worse since the new runway opened in July.
Both want Airservices Australia and the Civil Aviation Safety Authority to review the 2007 approvals for the new runway and how it is operating.
“I think that is a good idea because by my understanding, they are not at the moment, and some of the airlines are doing their own thing to save money on [aviation] petrol,” Ms Stringer said.
During a 50-minute interview with Mr Moorhouse, there were nine loud overhead flights.
“I really think residents would just like a fair go and have a good quality of life, because that is why we all live here in Queensland,” he said.
Tony Moore is a senior reporter at the Brisbane Times