He told authorities he believed a passenger's bag might have hit an emergency fuel shutoff switch in the moments before the chopper went down.
The Federal Aviation Administration (FAA) said it was investigating whether the company had been complying with regulations.
"We have not yet spoken with him yet".
The NTSB is asking anyone who may have witnessed the crash or captured it on video or photos to contact them.
A helicopter is hoisted by crane from the East River onto a barge, Monday in NY. One person was rescued by a tugboat and five others were "recovered by divers", it said. Investigators say a strap from a passenger's safety harness may have inadvertently wrapped around a fuel shut-off lever, resulting in engine failure which sent the aircraft plunging into the frigid water.
The slain passengers included Fire-Rescue Officer Brian McDaniel; Trevor Cadigan, a video journalist who hailed from Dallas but had recently worked at a business news site in NY; and Carla Vallejos Blanco, who was from Argentina, according to its consulate.
Cadigan shared a video on his Instagram social media account of what appeared to be himself and others smiling and laughing as they took off in the helicopter on Sunday evening. Two of the passengers were pronounced dead at the scene, while three others were died later in hospital.
Trevor Cadigan, a video journalist.
Brian McDaniel was a fire rescue officer for Dallas Fire-Rescue who had been hired in May 2016, the department said in a statement.
He had recently worked as an intern at Business Insider in New York City.
Blanco was a tourist from Corrientes, Argentina, who'd been in New York for a few days, said her country's consul in New York, Mateo Estreme. Liberty Helicopters has been in business for over 30 years, describing themselves on their website as "the largest and most experienced helicopter sightseeing service in New York City".
Follow the Bangor Daily News on Facebook. She saw McDaniel just last week at the grocery store, when McDaniel told her how excited he was for his trip to NY and how much he loved being a firefighter.
"NY on Air is terribly saddened to acknowledge that its customers were passengers on the Liberty Helicopters flight that went down in the East River last night", FlyNYON said.
The company paid $US23,576 in fines in 2010 and 2011 for violating maintenance, record-keeping and flight operations rules, according to the FAA.
In 2009, a Liberty Helicopters sightseeing craft of the same model as the one in Sunday's wreck collided with a small, private plane over the Hudson River, killing nine people, including a group of Italian tourists.