Australia's transport safety investigator won't examine a helicopter crash at Sydney's Bankstown Airport because doing so would only achieve a "very limited" safety benefit.
The chopper's pilot instructor and his student escaped with only minor injuries when the two-seat Robinson R22 came down from low altitude after midday on Sunday.
The two men, aged 56 and 43, were treated by paramedics at the scene.
The Australian Transport Safety Bureau on Monday said it wouldn't look into the crash.
"The ATSB receives approximately 17,000 notifications per year and must prioritise allocation of resources to those occurrences that have the potential to deliver the greatest safety benefits to the travelling public," a spokesman said in a statement to AAP.
"Based on the information provided immediately after the incident by the instructor and the student pilot, the ATSB determined there would be very limited safety benefit in conducting an investigation."