Findings released into Victorian water bomber crash during bushfire mission

The Australian Transport Safety Bureau has released its findings into the crash of a $30 million Skycrane helicopter during firefighting efforts in January last year.

The investigation has found the steep and high speed descent of the aircraft and an unnecessary crew member on board were significant factors contributing to the crash.

Two pilots and an engineer were on board the Sikorsky S-64E Skycrane helicopter, dubbed Christine, when it plunged into Wood Creek Dam, near Jericho, on January 28 last year.

The crew "all waited until the last moment to draw a breath, and did not unbuckle and exit the helicopter until motion had ceased", the ATSB report said.

The collision occurred following an approach to the dam to fill an external tank with water for firebombing operations.

"All three crew escaped, and inflated their life jackets. Two crew were uninjured, and one crew member sustained a knee injury," the report said.

One of the main points in the findings was that the licensed aircraft maintenance engineer on board "increased the risk of injury".

"While the Crew Chief had significant system and task knowledge, he was not required to be on board the helicopter," the ATSB report found.

"On this occasion, his presence exposed him to the significant hazards associated with underwater egress."

The ATSB found that the approach path to the dam was incrementally shortened over the course of the day's operations.

The crew calculated how much water the aircraft could carry, but reduced the calculated figure by 91kg to "optimise performance for departure from the dip site".

But the report found that the crew changed their flight path, shortening their approach to the dam.

"A witness to the event reported that the aircraft had an apparent high rate of descent and a nose-high attitude," the report said.

"It is likely that the final tight approach path was at the upper margins of allowable speed and angle of bank, requiring a steep flare that contributed to the aircraft entering vortex ring state on approach."

The findings added "the shape of the dam and surrounds of the site reduced the opportunity for recovery, and the aircraft impacted the water".

The company operating the aircraft, Erickson Inc., has made safety changes in response to the crash, including "a policy preventing non-essential personnel from being aboard during firefighting operations".

The ATSB said the crash demonstrated that Helicopter Underwater Escape Training (HUET) was fundamental to survival.

It said its findings should not be read as apportioning blame or liability to any organisation or individual.