Helen Tamaki, the second woman who dies from East River helicopter crash.

Helen Tamaki is the second person who died from injuries suffered in the crash of a helicopter that plunged into the East River off of Midtown Manhattan with five people onboard last Tuesday.

On October 4, Sonia Marra had organized the doomed flight over Manhattan’s skyline to celebrate her 40th birthday with her parents, who now live in Portugal, and her partner, Helen Tamaki.

Helen Tamaki, 43, who lived in Australia, had been hospitalized in critical condition since being pulled from the water unconscious minutes after the helicopter crashed just after liftoff.

Sonia Marra, the British tourist who was celebrating her 40th birthday, was trapped in the helicopter when it sank and she died at the scene.

Helen Tamaki died one week later, on Tuesday evening, according to officials at New York’s Bellevue Hospital.

Harriet Nicholson, Sonia Marra’s mother, remains hospitalized, according to local media reports; Sonia Marra’s stepfather, Paul Nicholson and Paul Dudley, the helicopter pilot, who is a family friend, escaped with minor injuries.

The pilot was treated at the scene.

Eyewitnesses said the helicopter was not equipped with floats and was upside down in the water as rescuers arrived.

The cause of the helicopter crash remains under investigation.

According to eye-witnesses, the chopper spun wildly and barely got off the ground before landing upside-down in the river off a helipad on the river’s edge, on East 34th Street in Manhattan.

The veteran pilot, Paul Dudley, has told the National Transportation Safety Board that the helicopter’s nose swung to the left as he lifted off and that he was unable to regain control as he tried to steer the aircraft back to the heliport.

According to the investigators’ preliminary report, the Bell 206 helicopter had just undergone an annual inspection, during which mechanics disassemble much of the aircraft to check for rust and corrosion. A final report is expected within months.