The NTSB released video of investigators poring over the chopper Tuesday at the Brooklyn Marine Terminal.
Meanwhile the FAA says it is giving urgent attention to harnesses for photographic flights.
It was a photo shoot flight, one without doors for the best views.
And for safety, passengers were wearing special harnesses that allowed them to move around the chopper without falling out.
But by design they are hard to take off, and in the dark, upside down with water rushing in, none of the five passengers could get free.
Investigators are looking into the harnesses, not just for the survival factors after the crash but also because the pilot claims one passenger's harness may have accidentally tripped a fuel cutoff valve, causing the engine to fail.
But they're also looking at the inflatable pontoons that are designed to deploy during a water landing to keep the chopper upright.
They did inflate Sunday night but for some reason didn't work as designed, and it tipped over anyway, dragging the victims to their deaths tied up as they were in the harnesses.
As for the harnesses, the Federal Aviation Administration released a statement:
"We are giving urgent attention to the use of harnesses specifically for aerial photography flights. We are supporting the NTSB and we will take appropriation action based on what we learn from the investigation. As a matter of overall safety awareness, we are preparing further communications and educational outreach to aerial photography operators and consumers on the use of these harnesses."
All aviation crashes are caused by a cascade of smaller contributing factors. Three of them in this case were the potential fuel cutoff, the problem with the pontoons and the inability of the passengers to get free.
It'll be up to the NTSB to determine what else contributed to the tragedy and make recommendations that can prevent something like it from happening again.
Meanwhile family and friends continued to mourn the victims of the crash.
At Madison Square Garden Tuesday night, the Knicks paid tribute to Tristan Hill, who had previously been a basketball operations assistant with the Westchester Knicks, the team's Development League affiliate.
And at an airport in Texas, firefighter Brian McDaniel had a hero's welcome home. He had been in New York visiting his high school friend Trevor Cadigan, a young journalist and former summer intern at the ABC affiliate in Dallas.
Now Cadigan's family has filed the first lawsuit against Liberty Helicopter, which owned and operated the doomed chopper.
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