Five men were killed when a light plane plunged into a Melbourne shopping centre and a year later investigators are still piecing together what led to the fateful flight.
With a final report into the crash still to be released, a separate probe will consider whether Essendon Airport's proximity to shops, businesses and a freeway is safe.
Pliot Max Quartermain was flying American tourists Greg Reynolds De Haven, Glenn Garland, Russell Munsch and John Washburn to King Island to play golf when the dual-engine aircraft crashed into DFO Essendon and exploded into a fireball on February 21, 2017.
The flight lasted just nine seconds and Mr Quartermain made seven mayday calls before the crash.
It is Victoria's worst air disaster in 30 years.
The Australian Transport Saftey Bureau's preliminary report, released in March, ruled out an early theory of catastrophic engine failure during take off.
The report also revealed the black box did not record audio on its final flight.
Initially expected by March 2018, the final report has been delayed until June due to the complex nature of the crash, an ATSB spokesman told AAP.
Investigators are also working to determine whether the buffer zone around Essendon Airport is adequate.
The DFO shopping centre, part of the Bulla Road Precinct Retail Outlet Centre development, is on land owned by Essendon Airport.
Its construction was approved by the federal government in 2004, despite concern from locals.
"The investigation will examine the building approval process from an aviation safety perspective, including any airspace issues associated with the development," a bureau spokesman said.
DFO Essendon staff and store retailers will host a private morning tea on Wednesday to reflect on the anniversary of the crash.
