SYDNEY, March 22 (Xinhua) -- Australian aviation authorities have launched a full investigation after a helicopter went down Wednesday in the Great Barrier Reef, killing a 65-year-old woman and a 79-year-old man from the United States.

The single-engine airbus H120 (formerly known as a Eurocopter 120b) was reported to have crashed into the water 250 meters away from a remote pontoon used mostly by snorkelers and scuba divers, at Hardy Reef 65 km north of the Whitsundays.

File Photo

Three others, including two passengers and a pilot of the plane, were injured in the crash. Witnesses who saw the crash "heroically" recovered the three from the water and performed cardiopulmonary resuscitation (CPR) on them while waiting for emergency paramedics to arrive on the scene, the Queensland State Police said Thursday.

Whitsunday Air Services, the company which owns the crashed helicopter, said in a statement they are extremely saddened by this incident.

"Whitsunday Air Services is continuing to work with the Queensland Police, the Australian Transport Safety Bureau and the Civil Aviation Safety Authority to assist with their investigations."

The tourism operator has also said they have suspended all flights while a full review process is undertaken.

At this stage, one of the three survivors remained in serious condition, while the other two have only minor injuries.

The latest incident came just four months after another Whitsunday Air Services helicopter sank near Hamilton Island after the engine lost power and was forced to make an emergency landing.

Although the pilot and passengers were rescued, the Robinson R44 helicopter was not recovered.