SYDNEY, Feb. 7 (Xinhua) -- There were two people killed when their gyrocopter crashed into shallow water off the coast of Western Australia on Wednesday afternoon.

Police divers have scoured the area for parts of the aircraft which witnesses told local media appeared fine before it plunged around 200m into the ocean.

Gyrocopters are lightweight sports aviation aircraft and have the highest fatal accident rate of any aircraft or operation type in Australia.

"They obviously have a higher level of risk than a normal sized aircraft," Peter Gibson from the Civil Aviation authority told Xinhua.

"While there have been accidents in the past, they're not considered unsafe," he said.

The cause of the crash is unclear and police are investigating with the help of the Australian Sport Rotorcraft Association who regulate the pastime.

"People who are doing sports aviation understand and accept the risks of doing that, whether it's flying a gyrocopter or parachuting or hang gliding," Gibson said.

"If you take part in that sport you understand the risks of doing so and you accept those risks," Gibson added.