Emails from the department's project manager to Melbourne City Council planners show the hospital had no idea a tower was even planned for the site before sales boards went up on Flemington Road in September. "Has an application been submitted for this site?", the project manager wrote to a Melbourne City Council last September. "If this intrudes into the helicopter flight path (including any crane) it would likely have significant operational impacts on the heliport," he wrote. But an application hadn't just gone in for the apartment tower. It had already been approved - seemingly without the hospital or the health department ever being told. The proposed apartment tower is 160 metres from the hospital.

Melbourne City Council has approved a 15-level apartment tower where the building with the red roof now sits. Royal Melbourne Hospital is in the background. Credit:Arsineh Houspian Two-thirds of the apartments in The Principal have now been sold off the plan - creating a legal mess for buyers, the developer and health authorities. The health department and Royal Melbourne Hospital, Melbourne City Council and the developer have all hired QCs to represent them at the state planning tribunal. "Our primary concern is for the safety of critically ill patients who require urgent treatment at one of the state's dedicated trauma centres," the department's spokesman, Bram Alexander, said on Monday. There were 269 emergency landings last year at the hospital, one of the state's two major trauma centres.

"If constructed the approved development will interfere with the flight path of emergency medical services helicopters accessing the Royal Melbourne Hospital helipad," documents lodged by the department in VCAT said. The development, it said, "presents a serious risk to the ongoing safe operation of the heliport". The health department argues that, if The Principal's 165 one and two-bedroom apartments are built, many pilots will be unwilling to fly into the hospital. And if any pilots are prepared to fly into the hospital helipad post-construction, many of the development's most expensive penthouse apartments and the rooftop terrace would be rendered uninhabitable by helicopters taking off.

If the apartment tower was built, "there would be an increase in instances of pilots refusing to fly into the Royal Melbourne Hospital helipad", says an affidavit from Andrew Baker, the head of flying at Australian Helicopters. "It may be necessary to investigate permanent restrictions on night-time departures from the Royal Melbourne Hospital helipad," Mr Baker wrote. Another expert, Robert Bullen from noise consultants Wilkinson Murray, said that if the apartments were built and choppers were willing to perform risky landings, "due to helicopter operations … the development site would be considered unacceptable for new residential development". Choppers would idle for at least five minutes before taking off, he said, and would be travelling as fast as 74km/h by the time they passed the proposed apartment tower.

"Noise levels would be such that conversation and listening activities would be disturbed in outside areas and also inside if windows were open," Mr Bullen wrote in his evidence. The developer, Obiter Investments, has hired one of the country's most expensive planning barrister's, former Victorian Civil and Administrative Tribunal boss Stuart Morris, to defend it before the tribunal he once led. An artist's impression of the proposed apartment tower. Adding to the mystery around how the apartment tower was approved is Lord Mayor Robert Doyle's chairmanship of Melbourne Health. Despite heading the board that runs the hospital, documents lodged in VCAT show the lord mayor was made aware of the project by a council planning officer.

"The lord mayor, deputy lord mayor and councillors were notified of the above recommendation," a council report states, adding that: "The signature and date below confirms that the lord mayor, deputy lord mayor and councillors affirmed this recommendation as the Council's decision." A council spokesman confirmed it had approved the apartments last August, and said that the Department of Human Services and Melbourne Health had applied to VCAT to reduce the height of the proposed apartments. Royal Melbourne Hospital referred queries over risks to the helipad to the health department. It declined to respond as the matter was before the state planning tribunal. The tribunal is expected to make a decision on the matter soon.