A Queensland police jet with the state's top emergency services officials aboard has been forced to return to Brisbane after dramatically plunging earthwards over Bundaberg.
On the plane were Police Minister Mark Ryan, Police Commissioner Ian Stewart, Corrective Services Commissioner Peter Martin, Fire and Emergency Services Commissioner Katarina Carroll, Maritime Safety Queensland head Captain Patrick Quirk and a government staffer.
The group was on its way to meet Premier Annastacia Palaszczuk at an Australia Day event in Townsville on Friday when the 1999 Cessna Citation 560 suddenly lost altitude, sources have told AAP.
Aviation authorities have launched an investigation into what caused the mid-air drama.
It is understood those on board heard a series of loud bangs and could smell smoke inside the cabin.
The pilots were forced to return the aircraft to the Government Air Wing in Brisbane at a low altitude and speed for an emergency landing, a government spokesman said.
"Commissioner Stewart immediately took charge, reassuring other passengers and directing them to follow emergency procedures as the pilots turned the plane around," he told AAP.
"The plane took off at 5.50am and was met under emergency landing at the Government Air Wing by several fire appliances and representatives of Brisbane Airport Corporation just after 7am.
A Queensland Police spokesman said the Public Safety Business Agency, the government department responsible for its aircraft, had submitted a report of the incident to the Civil Aviation Safety Authority and Australian Transport Safety Bureau.
Mr Ryan said the frightening experience was caused by "technical issues".
"But I knew the fantastic and highly experienced pilots of the Government Air Wing were in control," he said.
"I'm grateful to them for their professionalism, skill, reassurance and calmness."
The premier said she was relieved everyone was safe.
"That's what is most important," Ms Palaszczuk said.
"Queensland is a big state and air travel is part of doing our job."