The floats are supposed allow a helicopter to stay upright, rather than overturning and submerging.
"For about a minute and a half no one came out of the water", Brianna Jesme said.
"Someone climbed out of the helicopter and then was on top of the yellow raft".
Others reported seeing someone in the water clinging to a flotation device.
"We need to know before we get in the chopper how to get ourselves out quickly", Adams said.
The five passengers killed when a helicopter plunged into New York City's East River were identified on Monday, as the pilot said the engine had failed.
Police and fire officials said they did not immediately have information about the number of passengers or injuries.
"[He was] a fantastic person", she said. "Just figuring out what to expect".
News footage showed one victim being loaded into an ambulance while emergency workers gave him chest compressions.
She expects that the NTSB would be on site for five to seven days, investigating air traffic control, operations, airworthiness, survival factors, power plants and weather with Todd Gunther, a senior aviation investigator with 30 years of experience, at the helm.
"The local helicopter tourist industry has not cleaned up its act", said John Dellaportas, the president of Stop the Chop, a nonprofit that has been sounding the alarm about safety issues and wants the helicopter tour industry shut down.
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But much of the peace agreement has already been implemented, including the rebels disarming and demobilizing. Both left and right-wing coalitions chose their candidates in primaries over the weekend.
The helicopter went down near Gracie Mansion, the mayoral residence. "The other five did not", said Robert A. Nigro, commissioner of the Fire Department of NY. "He really believed in me, and I will never forget or stop appreciating that fact".
Questions were raised Monday about whether the pilot could have saved, or tried to save, his passengers.
The passengers were reportedly trapped inside the submerged helicopter due to the safety harnesses they were wearing.
How can you be sure the helicopter you're riding on is safe?
He added: "There's no way those people could've gotten out of the helicopter". The New Jersey-based company said on its website it has the largest fleet in the Northeast and had an "unparalleled" safety record.
A helicopter is seen crashed in New York City's East River on March 11, in this picture obtained from social media. McDaniel flashed a thumbs up. The video captures a view of a river and a bridge, the sun setting in the distance. Three others taken to the hospital in critical condition later died.
Shortly after 2 a.m., Howard received a call back from the NYPD. "Engine failure. We've got an engine failure over the East River".
Liberty, a tour and charter helicopter company, has been involved in at least five accidents or other incidents in the last 10 years, according to FAA data. In June 2005, two helicopters crashed into the East River in the same week.
And in 2009, Capt. The pilot was able to escape the Sunday night crash after the aircraft flipped upside down in the water killing several passengers, officials said.