The Australian Federal Police (AFP) has launched an investigation after someone made hoax calls to pilots, causing a passenger flight to abort landing as it approached Melbourne Airport.

The incident occurred shortly after 5pm on October 27, when Virgin Australia flight 740, en route from the Gold Coast to Melbourne, changed its altitude and course under the instruction of the unauthorised person transmitting from an unknown location.

The ABC understands that 15 unauthorised transmissions occurred over a two-week period. Calls were received by both aircraft and Melbourne Air Traffic Services Centre.

It is believed the person found a way to tap into the air traffic control frequency and communicate directly with planes and control towers.

Police are yet to make any arrests in relation to the incidents.

Flight data from FlightRadar24 shows the plane came within 275 feet of the runway at 5:19pm as it approached Tullamarine Airport.

Three minutes later, online records show the plane climbed to 3,800 feet and started circling over north-west Melbourne.

Later that evening, the hoax caller impersonated the pilot of a light aircraft. He issued a mayday call and pretended to be experiencing engine trouble.

It is believed the person has found a way to tap into the air traffic control frequency and communicate directly with planes and control towers. Photo: AAP.

The ABC has obtained audio from the Melbourne tower radio transmission where air traffic control personnel can be heard scrambling to assess the mayday call.

The air traffic controller initially struggles to hear the position reference given before sighting the light aircraft which the unauthorised individual is pretending to pilot.

“I can see you there now. Roger your mayday. Could you please advise what your situation is,” the air traffic control operator asks.

“Engine failure,” the hoax caller replies. “Descending passing through 4500.”

Twenty seconds later, the air traffic control personnel transmit an announcement for pilots to ignore the transmission which they have determined to be malicious.

The ABC understands further malicious radio calls were made after these events on frequencies that the ABC has been unable to access.

Inquiries were first made by the ABC after receiving a tip from an Airservices source who said “the engineers who used to manage technical issues aren’t around to provide advice or assist” air traffic controllers when these disturbing incidents occurred.

Hoax calls very rare but ‘a huge concern’

The Virgin Independent Pilot Association (VIPA) has confirmed that it received concerns from its members about the incident and has passed these concerns onto Airservices Australia and the Civil Aviation Safety Authority.

“It’s a huge concern. Flight safety is a paramount concern to everyone and if there’s an unauthorised person making illegal transmissions around an airport that could create confusion and subsequently a safety incident,” said VIPA’s President John Lyons.

Mr Lyons said while hoax calls to pilots in Australia happen were very rare, this matter needed to be treated very seriously.

“I mean if an aircraft is instructed to ‘go round’, if a pilot hears the instruction, he has no choice but to follow that instruction,” he said.

“The aircraft would be fully configured in its landing configuration from about 1,500 feet, and at 270 odd feet it would have received clearance to land from the legitimate controller.”

“It’s very unusual to be given a ‘go around’ instruction at such a late point.”

An Airservices Australia spokeswoman told the ABC “the matter is being investigated and it would not be appropriate to comment further”.

After the malicious calls began, authorities notified all affected airlines, pilots and air traffic controllers that hoax caller was still at large and instructions were given to ignore his instructions.

Airservices Australia, the Government-owned organisation responsible for aviation traffic at major airports, is currently in the process of laying off 900 workers.

Over 500 positions have been made redundant to date.

Virgin Australia declined to comment.

Police seek public’s help to catch hoax caller

The AFP has issued a call for public help for any information that will result in the identification and arrest of the person responsible.

An AFP spokesperson said there is no current threat to the safety and security of the travelling public as a result of these unlawful radio transmissions in the Melbourne area and that travellers do not need to change their plans.

“The AFP, Airservices, the Australian Communications and Media Authority (ACMA) and the aviation industry are all committed to ensuring the safety of the travelling public and we are treating this matter extremely seriously,” acting Assistant Commissioner Chris Sheehan said.

“These incidents are being thoroughly investigated by the AFP, with technical support from the ACMA.

“The airlines have been briefed to ensure the advice has been passed on to their pilots and to ensure appropriate measures are in place.”

– ABC