A small passenger plane in Australia had to make an emergency landing after one of its propellers apparently fell off while approaching Sydney Airport, an official said on Friday.
"The propeller and the assembly completely fell off up in the sky. It's very unusual," Peter Gibson, the spokesman for the Australian Civil Aviation Safety Authority, said.
"We don't know where the propeller landed. We haven't heard from anyone on the ground about finding it yet," Gibson added.
The Regional Express flight from Albury to Sydney was carrying 16 passengers and three crew members. The pilots made a pan-pan call - used to ask urgent assistance in non-life-threatening situations - around noon on Friday as they were descending towards the airport.
After making the emergency landing, officials saw that the right propeller of the two-engined Saab 340 plane was missing.
Local media said it happened some 20 kilometres ahead of touchdown at Sydney's Kingsford Smith airport at approximately 6,000 feet.
No one in the plane was injured, Gibson told DPA.
"Even with one propeller they can still balance and fly and so was able to land ... It happens, but it's very rare. I don't recall hearing about such an incident in Australia," he said. 
The airline said it was investigating, with more details expected later. The government investigation body, the Australian Transport Safety Bureau, also said they will conduct an independent probe surrounding the incident.
Rex is one of Australia's largest regional airlines and operates services between smaller cities and towns.