New York ( CNN ) -- Moments after pilot Paul Dudley maneuvered his Bell 206 Jet Ranger into the air near midtown Manhattan , he radioed that the helicopter was experiencing problems , officials said Wednesday . Dudley , an experienced commercial pilot with 2,200 hours of flight time , careened above New York 's East River as his craft lost altitude and eventually plunged into the water , according to National Transportation Safety Board member Mark Rosekind . A 15-member NTSB team is now trying to find out why the helicopter crashed , killing one woman and injuring four other people , he said . The woman , Sonia Marra of Sydney , Australia , died on her 40th birthday . Marra , a British citizen , was traveling with a friend , her mother and her stepfather when the chopper went down Tuesday afternoon . Trapped in the craft 's back seat as it submerged , she was the sole passenger unable to escape as the copter inverted and sank , New York Mayor Michael Bloomberg said Tuesday . A source close to the investigation identified the survivors as Paul Nicholson , 71 ; Harriet Nicholson , 60 ; and Helen Tamaki , 43 . The Nicholsons are Marra 's stepfather and mother , and Tamaki is a family friend , the source said . The chopper crashed as it approached for a riverside helipad landing . Images broadcast on CNN affiliate WCBS soon after the crash showed at least three people being towed to shore in a rescue effort . Rosekind said on CNN 's `` American Morning '' that the helicopter was not on an air tour flight , but a private flight , and that a complete investigation would begin Wednesday . `` The NTSB is going to focus not just on what happened , but why , '' he said . U.S. Rep. Carolyn Maloney , who represents Manhattan 's East Side in Congress , said she was `` saddened and deeply concerned '' about the crash . `` There have been at least 28 helicopter crashes in our city over the last three decades , '' she said in a statement . `` Federal transportation officials should investigate not only the causes of this crash , but also whether it is safe to have such a high volume of helicopter traffic over our densely populated city . '' Had the crash occurred over land , the death toll could have been much higher , Maloney said . Dudley , the pilot , previously made an emergency landing in a small Cessna plane in a Brooklyn , New York , park in 2006 . CNN 's Jason Kessler , Eden Pontz and Rob Frehse contributed to this report .
NEW : The experienced commercial pilot had 2,200 hours of flight time . NEW : He was a licensed private pilot with more than 10,000 flying hours. The victim -- a British citizen from Sydney -- was traveling with family members and friend . Three others escaped after the helicopter sank in the East River .