Max Quartermain crashed shortly after takeoff as he flew four passengers on a golfing holiday from Essendon Airport on February 21 last year.

An aviation watchdog investigation report released on Monday found the pilot failed to complete checklists before takeoff that would have detected the plane's rudder trim was in nose-left position.

This hampered the Beechcraft King Air aircraft's ability to ascend and after about 10 seconds of being airborne it hit a DFO shopping centre building.

Two people on the ground received minor injuries and everyone aboard was killed.

The probe found the pilot had five missed opportunities to recognise that the trim tab, which helps control the aircraft movement, was not in a neutral position.

"It appears as if the checklist was not followed correctly," ATSB Chief Commissioner Greg Hood said on Monday.

"There were multiple opportunities in the checklist for the pilot to ensure the rudder trim was in the neutral position prior to take off.

"For reasons which we were unable to determine, these opportunities were missed.

"This accident and the loss of life of the pilot and four passengers in the view of the ATSB, could have been prevented had a checklist been followed thoroughly prior to takeoff."

The aircraft's plunge into the DFO building did not increase the severity of the crash, the report found . Had the building not been there, the plane probably would have led to to an uncontrolled crash into a busy freeway, causing potentially more casualties, investigators said.

The cockpit voice recorder failed to record the accident due to a switch that had not been reset before the flight, depriving investigators of potentially valuable information.

The plane was also above its maximum takeoff weight, although this was not thought to have influenced the accident.

In a statement, the pilot's wife said her thoughts were with the grieving families.

"I know in those terrifying final moments he would have been doing everything in his power to bring the plane safely back to the airport to save his passengers," Cilla Quartermain said.

Australian Associated Press