The pilot of a light aircraft which ditched near a popular Perth beach failed to regularly check fuel levels, investigators say.
The Australian Transport Safety Bureau found that there was enough fuel on the flight when it left Carnarvon in April but the engine was likely connected to the wrong tank.
"The engine power issues probably occurred due to a lack of fuel in the selected right tank," the ATSB's Stuart Macleod said.
"The pilot responded to power anomalies by carrying out some of the emergency procedures, but did not select the other – left – tank, which contained usable fuel."
While en route to Jandakot via Geraldton, Michelle Yeates' engine lost power a number of times before she turned into the the wind for a forced emergency landing on a nearby beach just north of Fremantle.
"Unable to maintain height, the pilot decided to turn into wind for a forced landing on the adjacent Leighton Beach, but then opted to ditch into the ocean after observing a number of people on the beach," Mr Macleod said.
The plane landed about 30 to 50 metres offshore before the pilot's teenage son quickly opened the door and the pair swam to the shore uninjured.
Ms Yeates, a commercial pilot, took the private flight with her son to observe a solar eclipse in WA's northwest.
When things went awry, she said she tried to land in a way that wouldn't flip the plane over.
"I was only at 1500 feet, I didn't have much time to react so I just sent out a mayday to the tower and then just turned around and landed on the water — I tried to get as close to the beach as I could without hitting anybody," she said at the time.
"You train to do that sort of thing so I've trained for that many, many times."
Police said Ms Yeates did an "exceptional job" bringing the plane down and the pair were lucky not to be injured.
Mr Macleod said the accident was a good example of the importance of proper fuel management and emergency preparedness.
"Pilots must carry out in-flight fuel quantity checks at regular intervals, including a cross check and recording of key data," he said.
