"It means that inappropriate buildings can be built not just at Essendon, but at other airports. "There’s more risk, and we need to know how that was justified.” The family of trucking billionaire Lindsay Fox and businessman Max Beck acquired a 99-year lease on Essendon Airport in 2001 for $22 million, and set about developing retail and commercial buildings around the airport. That included the DFO complex built south of the main runway in 2005.

The wider airport precinct is now reportedly worth more than $1 billion, and is home to a hotel, car yards, offices, a whisky distillery and other commercial property, with other developments in the pipeline. It had been expected at the time of the purchase that aviation activities would cease at what used to be Melbourne's international airport. The 2017 plane crash into the DFO has promoted regulators to investigate how the shopping centre was approved. Credit:Seven News But it is today Australia's largest corporate jet base, and home to Victoria's police and emergency air services and other aviation operations. Documents released to the AFAP under freedom of information laws show the DFO building was approved by then-federal transport minister John Anderson on the condition that it did not adversely impact on “navigation aids or operational activities” at the airport.

But the AFAP has challenged whether that is what occurred, after discovering in planning documents also released under FOI that the DFO sits just 128 metres from the centre of the runway. That is within the 150 metre flyover area - essentially a buffer zone - either side of the runway's centre line that would form a 300 metre "runway strip width" recommended by the United Nation's aviation safety body, the International Civil Aviation Organization. Five people were killed in the 2017 plane crash. Credit:Justin McManus Two large water tanks, light poles and fencing also sit within the 300 metre zone, which is intended to safeguard aircraft if they run off the tarmac during take-off or landing. As a member nation, Australia's Civil Aviation Safety Authority (CASA) is expected to try to keep its own safety standards in line with ICAO's.

The AFAP said that when the DFO was approved in 2004, CASA's standards allowed the runway to have a strip width of less than 300 metres, but only if a detailed safety case was put forward and all relevant stakeholders were consulted. The pilots body has been unable to access that safety case, with an FOI request met with the response that there was no such document. CASA and the airport could not say if one was ever produced. More buildings? CASA later implemented the 300 metre standard in its own rules, and in 2015 granted an “instrument” that had the effect of retrospectively approving the DFO building, while ordering Essendon to still tell pilots it had a 300 metre strip width. That width is given to pilots in official operational material and informs operators what aircraft they can use, as well as how they are insured.

So concerned about the objects within the buffer zone, the AFAP has issued a safety bulletin to pilots warning that the strip width was closer to 230 metres. Essendon Airport now wants to narrow the strip width back to 180 metres, and started consulting late last year with operators at the airport about how that could affect their operations. Essendon Airport is home to Victoria's emergency services air wings. Credit:Paul Jeffers Some operators have raised concerns that narrowing the width could lead to more buildings being built close to the runway, or otherwise interfering with operations or safety, according to one operator who declined to be named. The AFAP's Captain Diamond said that the airport was "trying to narrow the runway strip width even more without proper safety analysis and will allow even more inappropriate buildings to infringe the international standards".

A spokesman for Essendon Fields Airport said it had "always operated within all applicable aviation safety regulations", but declined to comment in more detail on matters that were subject to the ATSB's investigation. It said that its main runway had operated with the strip width of 180 metres from 1972 to 2015, and that the DFO and other objects were not within the restricted area when they were approved and built. CASA 'too busy' to check plans Other documents released to AFAP under FOI show the federal government approved the DFO development on the condition that the airport would consult with CASA about its plans and comply with any of its safety requirements. But letters from CASA to the airport released under FOI say it did not have time to check the DFO plans.

“Gathering the information required for the authority’s assessment of whether every item in a Draft Master Plan will be compliant with civil aviation safety requirements would be time-consuming and expensive,” one letter says. Essendon is Australia's biggest private jet base. Credit:Joe Armao A CASA spokesman said the DFO building was marked on charts and equipped with hazard lights. "The current runway width is not compromising safety," he said. CASA declined to answer why it ordered the airport to publish a 300 metre strip width or if that needed to be updated.

Safety probe In February 2017, a Beechcraft King Air light aircraft turned sharply to the left shortly after takeoff and crashed into the southern end of the DFO, killing all five people on board. The aircraft hit the southern end of the building - well outside the disputed runway buffer zone. The Australian Transport Safety Bureau found that pilot error was to blame, but while looking into the crash, decided to launch a separate investigation into how the DFO complex was approved "from an aviation safety perspective".

That probe is nearing completion, with its final report currently out for review by the parties involved ahead of its public release. The AFAP's probing of Essendon Airport has prompted AusALPA - a body it is part of which represents more than 7000 professional Australian pilots on safety matters - to look carefully at what it considers inappropriate developments at a number of other airports. Captain Diamond said the Essendon Airport example showed the approval processes for buildings around airports needed tightening, at a time when many airports were building around their airstrips. “There needs to be a review and we need to have robust assessment processes that at the moment are being abridged or avoided in the planning stages," he said. "We need to tidy that up and have the regulations much more firm in protecting both the airspace around airports and the physical characteristics of airports."

Airports including Brisbane, Canberra and Cairns have and continue to build new hotels, office blocks and other buildings around their airports. “These sorts of developments are pretty standard around airports around the world,” said Canberra Airport's managing director Steven Byron. “There is a very rigorous process,” including consultation with airlines, regulators and the public, he said. Brisbane Airport said the planning processes in place ensured that aviation operation safety and efficiency were not compromised by developments. The federal department of infrastructure, which also had to approve the DFO building, directed questions to CASA.