(Bloomberg) — A recreational operator, who didn't know thatfederal authorities had temporarily banned all drone flights in NewYork, was to blame for a September collision between hisrecreational device aircraft and an Army helicopter.

Out of sight

The NationalTransportation Safety Board on Thursday also cited the droneoperator's failure to see the helicopter because the device wasflying so far away it was out of his sight. The drone operator, whowasn't identified in the short report, was in Brooklyn and 2.5miles away from the device, the NTSB concluded. The crash happenedjust offshore of Staten Island.

Related: Safety incidents rise along with popularity ofcivilian drones

At the time of the accident, the United Nations General Assembly was meeting andflights in the area by civilian aircraft were prohibited, accordingto the NTSB. The Federal AviationAdministration also forbids drone operators from flying beyondtheir line of sight.

The collision was the first confirmed mid-air impact between amanned aircraft and one of the millions of drones bought in theU.S. in recent years. Reports of safety incidents involving droneshave climbed continually and averaged more than 200 a month lastsummer, according to federal data.

The drone was an SZ DJI Technology Co. Phantom 4, a small devicethat is made by the world's largest civilian unmanned aircraftmanufacturer.

Multiple drone-safety issues

The NTSB report comes as the FAA is wrestling with multipledrone-safety issues. They include whether to allow routine flightsover people, which drones should be required to send radio beaconswith their identity and location, and how to build a low-levelair-traffic system for the small consumer flying devices.

Small drones like the one involved in the New York collisionweigh only a few pounds, but they contain metal motors and camerasthat can cause significant damage to a jetliner at high speeds, astudy commissioned by the FAA found last month. While the studyfound it was unlikely a drone impact alone could take down anairliner, it could cause enough damage to shut down a jetengine.

The Transportation SafetyBoard of Canada is also looking into an incident in Quebec onOct. 12 when a small drone struck a charter flight carrying sixpassengers. The plane suffered minor damage to its left wing andlanded safely.

Related: 9 essential facts about drones

While civilian drones are increasingly equipped with GPS devicesthat limit flights to within 400 feet (122 meters) from the groundand within sight of the operator — which is supposed to bethe legal restrictions — incident reports to the FAAsuggest the devices aren't working as designed and the rules arewidely ignored.

On Sept. 28, for example, pilots on a Boeing Co. 737-800 thathad just taken off from Chicago O'Hare International Airportreported spotting a drone at 9,000 feet altitude. The aircraft is awidely used airliner, but the name of the carrier wasn'tidentified.