New York Fire Department said the helicopter appeared to have crash-landed on top of a tower.
Police said the suspect was carrying an improvised explosive device, believed to be a crude pipe bomb, which he intentionally detonated.
An NYPD chief has defended officers who opened fire on a crowded Manhattan street after a man slashed an off-duty cop's face in a chase.
A climber who scaled Donald Trump's 58-storey political headquarters in a bid to meet the billionaire has been arrested by police.
The two-day solar phenomenon occurs only twice a year at opposite ends of the summer solstice.