Image from NTSB final report of a Sept. 21, 2017, collision between a U.S. Army Black Hawk and a hobby drone. Courtesy of the NTSB.
A privately owned/operated unmanned aircraft system (UAS) collided with a U.S. Army Sikorsky UH-60M Sept. 21 on Hoffman Island, New York, outside New York City. The NTSB’s final report, released Thursday, said probable cause was that the operator flew the drone beyond line of sight, unable to see the helicopter.
According to the final report, the UH-60 was flying in Class G airspace some 300 feet above mean sea level (operating over the ocean) when it collided with a hobby drone — a DJI Phantom 4. The aircraft sustained minor damage; a 1.5-inch dent on the leading edge of one of the main rotor blades with various scratches and material transfer, and some cracks in the composite fairing and window frame material. The helicopter did land “uneventfully,” the report said. The drone was destroyed; some parts were “lodged in the helicopter.” According to the NTSB, the helicopter’s pilot saw the drone before impact and tried to avoid the drone; there was not enough time to do so successfully. On board the UH-60 was two pilots and two crew chiefs. The pilot in command had 1,570 hours on the UH-60. This was the crew’s first experience with UAS.
The NTSB said the drone pilot did not hold an FAA remote pilot certificate and didn’t need to. Hobby/recreational pilots are expected to comply with Part 101 (Part 107 applies to commercial operations). Part 101 includes maintaining visual contact with the drone at all times and not interfering with manned aircraft. At the time of the collision, two temporary flight restrictions (TFR) were in effect for the area, authorizing the Army aircraft and prohibiting the drone. However, the drone operator was unaware. According to the report, the pilot solely relied on the DJI GO4 app for airspace awareness. The app does have a TFR function, but the function was not active at the time of the incident. (The NTSB report added that the only way to fully comply with FAA airspace restrictions is to check FAA TFR information at the time of flight.)
The collision occurred two minutes before the end of civil twilight. At the time of the collision, the drone pilot did not have visual contact with his aircraft or the helicopter. He had hit the “return-to-home” button on his control tablet, and the drone was making its way back to the operator when it collided with the helicopter. The NTSB said that even though recreational drones can fly at night under certain conditions, the drone pilot answered authority questions in a way that the NTSB assumed he was likely unaware of best practices and guidelines for night operations. According to the report, all the drone pilot knew about regulations and guidelines was to “stay away from airports,” and that he should fly below 400 feet. However, he relied on the app to tell him if he was allowed to fly and had no knowledge of TFRs.
The drone pilot was unaware of the collision until he was contacted by the NTSB. According to the report, he had just assumed the drone malfunctioned and fell into the ocean.
According to the final report:
“The National Transportation Safety Board determines the probable cause(s) of this incident to be:
The failure of the [small drone] pilot to see and avoid the helicopter due to his intentional flight beyond visual line of sight. Contributing to the incident was the [small drone] pilot's incomplete knowledge of the regulations and safe operating practices.”