Hate to speculate but a friend had a rotor brake fire in a 76 the symptoms of which were white smoke followed by black.
No indication in the cockpit. He was on the ground at the time and fortunately an alert ground staff spotted it and the a/c was not too badly damaged.
Seems NY not having the best of luck these days.
You have to love the US Media - in the rush to report facts are sometimes of secondary importance - makes all their reporting suspect.
Being as there are so many media helicopters one would think they would check with their pilots for some input before reporting.
Remember the JFK jr. media frenzy?