The collision damaged the helo's fuselage and two blades. A piece of the drone was found in the oil cooler, a source told Fox 5. No injuries were reported.
Information on the drone -- who it belonged to and where it came from -- is still unknown.
Although New York City bans drones from flying in most locations, drones registered with the Federal Aviation Administration are permitted to fly above a handful of city parks.
The incident comes a month after the Defense Department formally gave guidance to all U.S. military installations on how best to address drones they deem a threat — including shooting them down.