The Australian Transport Safety Bureau is investigating an incident in which a Tiger Airways Australia Airbus A320 flew too low while landing at Melbourne airport on 7 June.
The aircraft, registration VH-VNG, was conducting an instrument approach when it "descended to a level below the lowest safety altitude", said the bureau.
No one was injured in the incident. The aircraft was operating on the Brisbane-Melbourne route. The bureau expects to complete its investigation in June 2012, it said