The Civil Aviation Safety Authority has found “human error” was the likely cause of the September 13 incident, in which a pilot ascended into controlled airspace despite being unable to establish communications with the Adelaide control tower, InDaily can reveal.

Air traffic controllers instructed a small plane, carrying an undisclosed number of passengers, to divert from a landing at Adelaide Airport when they discovered the helicopter had become airborne without clearance.

According to CASA the SAAB 340 airplane – which typically seats about 30 passengers – came within one kilometre laterally and 550 metres vertically of the helicopter before the Adelaide control tower instructed it to perform a “go around” to avoid it.

Asked why the helicopter took off despite being unable to communicate with air traffic control, a spokesperson for CASA told InDaily: “Our investigation indicated that this was likely human error.”

The spokesperson said air traffic control’s actions meant that neither the helicopter nor the plane were in danger as a result of the unauthorised take-off.

“Air traffic control followed the appropriate procedures and instructed the aircraft to (perform) a ‘go around’ when they became aware that the helicopter was airborne,” the spokesperson said, adding that no one was facing criminal prosecution or disciplinary action as a result of the incident.

CASA declined to provide its investigation report to InDaily.

The Adelaide City Council last night agreed to abandon the Bonython Park helipad proposal, which had been spearheaded by outspoken Adelaide entrepreneur Shane Yeend.

A council spokesperson confirmed to InDaily that the permit for the ill-fated September 13 flight was given to Yeend’s company, Helistar Aviation.

Council CEO Mark Goldstone has commissioned an independent investigation into the council’s procedures concerning the helipad proposal, warning that “I will take any action necessary” as a result of that investigation.

North ward councillor Phil Martin questioned whether any conflicts of interest had marred the process, whether any councillor or staff member had asked “other local government identities” not to criticise it and how much it had cost since it started in 2015.

Martin argued that the council’s consultation process regarding the helipad on the YourSay website had been “compromised” last year by a Glam Adelaide competition, which had offered the chance at a $1500 joy flight as a prize for voting ‘yes’.

Council director for community Clare Mockler told InDaily all helicopter operators had to provide a risk assessment and a site management plan to the council, to ensure public safety, before gaining a permit.

Mockler said the council does not engage CASA in individual permit assessments.

Instead: “CASA await the daily flight plan and then give clearance from that point in real time rather than days in advance,” she said.

“Helicopter operators are however required to meet all the necessary requirements of CASA when landing or taking off.”

Yeend described the series of events as “a total clusterfuck”.

“They should fire the whole council and start again,” he told InDaily.

“I can’t believe it’s going to go around again.

“It’s a total clusterfuck.”

Last night’s decision rules out the Bonython Park location but commits to investigating other potential parklands locations for a helipad.

Asked whether he was disappointed that it had been his company that caused the incident that led to last night’s decision, Yeend said he was “only an investor” in Helistar, but that he had been campaigning for a commercial helipad in Adelaide for 12 years.

“To be honest, I’ve spent my life as an entrepreneur making things happen,” said Yeend.

“It’s been 12 years of constant lobbying and work.

“I’ve never come up against something so hard that’s so simple to (fix).”

He said he was not involved in the September 13 flight and “I’m not sure what directions were given” to the helicopter pilot.

However, he said he had piloted a helicopter flight in the area previous week – carrying a journalist from The Advertiser – and “we didn’t have any issue” with radio signals.

He questioned the rationale for ruling out the Bonython Park location, noting: “What do I need – a $4000 radio (antenna)?”

“If there’s a will, there’s a way.”

According to a review of the Bonython Park helipad proposal by Heliport Design Group, presented in council agenda papers last night, the September 13 incident was caused by a “communications black spot” which was “not location dependent” and that the problem could be solved by “radio relays or alternative means”.

The report found that the area beside the River Torrens could be used for helicopter operations only after “extensive works” to remove trees, limit building plans, restrict public access and rectify communications issues.

InDaily contacted Helistar Aviation chief executive Barrie Hosking for comment.